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Sample records for arecibo sdss survey

  1. The GALEX Arecibo SDSS survey: III. Evidence for the Inside-Out Formation of Galactic Disks

    CERN Document Server

    Wang, Jing; Overzier, Roderik; Catinella, Barbara; Schminovich, David; Heckman, Timothy M; Moran, Sean M; Haynes, Martha P; Giovanelli, Riccardo; Kong, Xu

    2010-01-01

    We analyze a sample of galaxies with stellar masses greater than $10^{10} M_{\\odot}$ and with redshifts in the range $0.025Arecibo SDSS Survey (GASS) or from the Arecibo Legacy Fast ALFA survey (ALFALFA). At a given value of $M_*$, our sample consists primarily of galaxies that are more HI-rich than average. We constructed a series of three control samples for comparison with these HI-rich galaxies. As expected, HI-rich galaxies differ strongly from galaxies of same stellar mass that are selected without regard to HI content. The majority of these differences are attributable to the fact that galaxies with more gas are bluer and more actively star-forming. In order to identify those galaxy properties that are causally connected with HI content, we compare results derived for the HI sample with those derived for galaxies matched in stellar mass, size and NUV-$r$ colour. The only photometric property that is clearly attributable to incre...

  2. THE GALEX ARECIBO SDSS SURVEY. VII. THE BIVARIATE NEUTRAL HYDROGEN-STELLAR MASS FUNCTION FOR MASSIVE GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Lemonias, Jenna J.; Schiminovich, David [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Catinella, Barbara [Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, D-85741 Garching (Germany); Heckman, Timothy M. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Moran, Sean M., E-mail: jenna@astro.columbia.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-10-20

    We present the bivariate neutral atomic hydrogen (H I)-stellar mass function (HISMF) φ(M{sub H{sub I}}, M{sub *}) for massive (log M{sub *}/M{sub ☉} \\gt 10) galaxies derived from a sample of 480 local (0.025 < z < 0.050) galaxies observed in H I at Arecibo as part of the GALEX Arecibo SDSS Survey. We fit six different models to the HISMF and find that a Schechter function that extends down to a 1% H I gas fraction, with an additional fractional contribution below that limit, is the best parameterization of the HISMF. We calculate Ω{sub H{sub I,{sub M{sub *>10{sup 1}{sup 0}}}}} and find that massive galaxies contribute 41% of the H I density in the local universe. In addition to the binned HISMF, we derive a continuous bivariate fit, which reveals that the Schechter parameters only vary weakly with stellar mass: M{sub H{sub I}{sup *}}, the characteristic H I mass, scales as M{sub *}{sup 0.39}; α, the slope of the HISMF at moderate H I masses, scales as M{sub *}{sup 0.07}; and f, the fraction of galaxies with H I gas fraction greater than 1%, scales as M{sub *}{sup -0.24}. The variation of f with stellar mass should be a strong constraint for numerical simulations. To understand the physical mechanisms that produce the shape of the HISMF, we redefine the parameters of the Schechter function as explicit functions of stellar mass and star formation rate (SFR) to produce a trivariate fit. This analysis reveals strong trends with SFR. While M{sub H{sub I}{sup *}} varies weakly with stellar mass and SFR (M{sub H{sub I}{sup *}} ∝ M{sub *}{sup 0.22}, M{sub H{sub I}{sup *}} ∝ SFR{sup –0.03}), α is a stronger function of both stellar mass and especially SFR (α ∝ M{sub *}{sup 0.47}, α ∝ SFR{sup 0.95}). The HISMF is a crucial tool that can be used to constrain cosmological galaxy simulations, test observational predictions of the H I content of populations of galaxies, and identify galaxies whose properties deviate from average trends.

  3. Target Selection for the Arecibo Pisces-Perseus Supercluster Survey (APPSS)

    Science.gov (United States)

    Craig, David W.; O'Donoghue, Aileen A.; Haynes, Martha P.; Rosenberg, Jessica L.; Venkatesan, Aparna; Hallenbeck, Gregory L.; Jones, Michael; Koopmann, Rebecca A.; Undergraduate ALFALFA Team

    2016-01-01

    The Arecibo Pisces-Perseus Supercluster Survey (APPSS) is a new large targeted HI survey now underway using Arecibo's L-band Wide receiver system. A major goal is to constrain models of the Pisces Perseus infall, producing 5-σ detections of infall motions ˜500 km s-1. We are targeting sources that are likely to be at the PPS distance, but that are just below the the HI mass detection threshold of the ALFALFA survey. We expect to identify ˜800 objects of mass ˜108—9 M⊙ which will alllow us to constrain the lower mass end of the HI mass function in this infall environment.We have pursued a multi-pronged approach to target selection for this survey. Sources from ALFALFA, SDSS, and the GALEX GCAT single source catalogs were matched and intercompared via multi-band color photometry, surface brightnesses, and appearance in SDSS images. Final target selection based on visual inspection of SDSS images was found to correlate well with a color-selection technique based on GALEX/NUV - SDSS/r. Along with the details of the source selection we will discuss the facilitation and implementation of this process via a multi-institution collaborative website, and early results from the APSS survey.This work has been supported by NSF grant AST-1211005.

  4. The Arecibo Galaxy Environment Survey V : The Virgo Cluster (I)

    CERN Document Server

    Taylor, R; Auld, R; Minchin, R F

    2012-01-01

    We present 21 cm observations of a 10 $\\times$ 2 degree region in the Virgo cluster, obtained as part of the Arecibo Galaxy Environment Survey. 289 sources are detected over the full redshift range (-2,000 $<$ $v$$_{hel}$ $<$ + 20,000 km/s) with 95 belonging to the cluster ($v$$_{hel}$ $<$ 3,000 km/s). We combine our observations with data from the optically selected Virgo Cluster Catalogue (VCC) and the Sloan Digital Sky Survey (SDSS). Most of our detections can be clearly associated with a unique optical counterpart, and 30% of the cluster detections are new objects fainter than the VCC optical completeness limit. 7 detections may have no optical counterpart and we discuss the possible origins of these objects. 7 detections appear associated with early-type galaxies. We perform HI stacking on the HI-undetected galaxies listed in the VCC in this region and show that they must have significantly less gas than those actually detected in HI. Galaxies undetected in HI in the cluster appear to be really ...

  5. The Arecibo Pisces-Perseus Survey: An Undergraduate ALFALFA Team Project

    Science.gov (United States)

    O'Donoghue, Aileen A.; Koopmann, Rebecca A.; Haynes, Martha P.; Jones, Michael; Craig, David; Hallenbeck, Gregory L.; Rosenberg, Jessica L.; Venkatesan, Aparna; Undergraduate ALFALFA Team

    2016-01-01

    The Milky Way's position in an outer filament of Lanieakea affords us a striking view of the Pisces-Perseus Supercluster (PPS) arcing roughly from 22h to 4h and 0° to +50° concentrated between cz = 4,000 km/s and cz = 8,000 km/s as a "wall" parallel to the plane of the sky. It is bounded by voids both between Laniakea and PPS and beyond PPS. Within this box, the 70% ALFALFA survey has detected 4,800 galaxies within cz = 8,000 km/s. Of these, 80% have masses greater than 108 M⊙. At the distance of the PPS, galaxies with MHI ≤ 108 M⊙ are below the ALFALFA detection limit. Thus to further explore this rich diversity of galaxy environments and the adjoining voids, the Undergraduate ALFALFA Team is in the process of using the L-band Wide receiver at Arecibo Observatory for the Arecibo Pisces-Perseus Supercluster Survey (APPSS). We will observe galaxies with 108 M⊙ ≤ MHI ≤ 109 M⊙ chosen from the SDSS DR12 and GALEX catalogs. We are limiting our observations to the PPS ridge in 21h 30m to 3h 15m and 23° to 35°. Since this region lacks SDSS spectroscopy, targets have been selected using photometric criteria derived from SDSS and GALEX observations for galaxies detected by ALFALFA. The results of these observations will allow us to constrain the HI mass function along the PPS ridge. Application of the Tully-Fisher relation will allow a robust measure of the infall velocities of galaxies into the filament. This work has been supported by NSF grant AST-1211005.

  6. HI Absorbers from Arecibo Legacy Fast ALFA Survey

    Science.gov (United States)

    Wu, Z. Z.; Haynes, M. P.; Giovanelli, R.; Zhu, M.; Chen, R. R.

    2015-03-01

    We present some preliminary results of an on-going study of the HI 21-cm absorption line based on the 40% data release of the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey. Ten HI absorption candidates have been detected. Five of them are previously published in the literature, and the rest of them are new detections that need further confirmation. For those sources with no detected absorptions, we calculated the upper limits of their foreground HI column density N_{HI}. The statistical result of the N_{HI} distribution indicates that the ratio of average spin temperature to covering factor T_{s}/f for DLAs (the damped Lyα systems) might be larger than 500 K. Radio frequency interference (RFI) and standing waves are the main issues affecting the detection of HI absorption profiles. Our study can serve as the pathfinder for a large scale search of HI 21-cm absorption lines using the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) which is an Arecibo-type radio telescope currently under construction in China. We discuss two types of observational studies of HI absorptions toward extragalactic sources using the FAST telescope.

  7. The Arecibo Galaxy Environment Survey IX: the isolated galaxy sample

    Science.gov (United States)

    Minchin, R. F.; Auld, R.; Davies, J. I.; Karachentsev, I. D.; Keenan, O. C.; Momjian, E.; Rodriguez, R.; Taber, T.; Taylor, R.

    2016-02-01

    We have used the Arecibo L-band Feed Array (ALFA) to map three regions, each of 5 deg2, around the isolated galaxies NGC 1156, UGC 2082, and NGC 5523. In the vicinity of these galaxies we have detected two dwarf companions: one near UGC 2082, previously discovered by the Arecibo Legacy Fast ALFA (ALFALFA) survey, and one near NGC 1156, discovered by this project and reported in an earlier paper. This is significantly fewer than the 15.4^{+1.7}_{-1.5} that would be expected from the field H I mass function from ALFALFA or the 8.9 ± 1.2 expected if the H I mass function from the Local Group applied in these regions. The number of dwarf companions detected is, however, consistent with a flat or declining H I mass function as seen by a previous, shallower, H I search for companions to isolated galaxies. We attribute this difference in H I mass functions to the different environments in which they are measured. This agrees with the general observation that lower ratios of dwarf to giant galaxies are found in lower density environments.

  8. Fast radio burst discovered in the Arecibo pulsar ALFA survey

    International Nuclear Information System (INIS)

    Recent work has exploited pulsar survey data to identify temporally isolated, millisecond-duration radio bursts with large dispersion measures (DMs). These bursts have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; they may also be linked to new source classes. Until now, however, all so-called fast radio bursts (FRBs) have been detected with the Parkes radio telescope and its 13-beam receiver, casting some concern about the astrophysical nature of these signals. Here we present FRB 121102, the first FRB discovery from a geographic location other than Parkes. FRB 121102 was found in the Galactic anti-center region in the 1.4 GHz Pulsar Arecibo L-band Feed Array (ALFA) survey with the Arecibo Observatory with a DM = 557.4 ± 2.0 pc cm–3, pulse width of 3.0 ± 0.5 ms, and no evidence of interstellar scattering. The observed delay of the signal arrival time with frequency agrees precisely with the expectation of dispersion through an ionized medium. Despite its low Galactic latitude (b = –0.°2), the burst has three times the maximum Galactic DM expected along this particular line of sight, suggesting an extragalactic origin. A peculiar aspect of the signal is an inverted spectrum; we interpret this as a consequence of being detected in a sidelobe of the ALFA receiver. FRB 121102's brightness, duration, and the inferred event rate are all consistent with the properties of the previously detected Parkes bursts.

  9. The Arecibo Galaxy Environment Survey VI : The Virgo Cluster (II)

    CERN Document Server

    Taylor, R; Auld, R; Minchin, R F; Smith, R

    2012-01-01

    We present 21 cm observations of a 5 x degree region in the Virgo cluster, obtained as part of the Arecibo Galaxy Environment Survey. 13 cluster members are detected, together with 36 objects in the background. We compare and contrast the results from this area with a larger 10 x degree region. We combine the two data sets to produce an HI mass function, which shows a higher detection rate at low masses (but finds fewer massive galaxies) than less sensitive wider-area surveys, such as ALFALFA. We find that the HI-detected galaxies are distributed differently to the non-detections, both spatially and in velocity, providing further evidence that the cluster is still assembling. We use the Tully-Fisher relation to examine the possibility of morphological evolution. We find that highly deficient galaxies, as well as some early-type galaxies, have much lower velocity widths than the Tully-Fisher relation predicts, indicating gas loss via ram pressure stripping. We also find that HI detections without optical count...

  10. Fast Radio Burst Discovered in the Arecibo Pulsar ALFA Survey

    CERN Document Server

    Spitler, L G; Hessels, J W T; Lorimer, D R; McLaughlin, M A; Chatterjee, S; Crawford, F; Deneva, J S; Kaspi, V M; Wharton, R S; Allen, B; Bogdanov, S; Brazier, A; Camilo, F; Freire, P C C; Jenet, F A; Karako-Argaman, C; Knispel, B; Lazarus, P; Lee, K J; van Leeuwen, J; Lynch, R; Lyne, A G; Ransom, S M; Scholz, P; Siemens, X; Stairs, I H; Stovall, K; Swiggum, J K; Venkataraman, A; Zhu, W W; Aulbert, C; Fehrmann, H

    2014-01-01

    Recent work has exploited pulsar survey data to identify temporally isolated, millisecond-duration radio bursts with large dispersion measures (DMs). These bursts have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; they may also be linked to new source classes. Until now, however, all so-called fast radio bursts (FRBs) have been detected with the Parkes radio telescope and its 13-beam receiver, casting some concern about the astrophysical nature of these signals. Here we present FRB 121102, the first FRB discovery from a geographic location other than Parkes. FRB 121102 was found in the Galactic anti-center region in the 1.4-GHz Pulsar ALFA survey with the Arecibo Observatory with a DM = 557.4 $\\pm$ 3 pc cm$^{-3}$, pulse width of $3\\; \\pm 0.5$ ms, and no evidence of interstellar scattering. The observed delay of the signal arrival time with frequency agrees precisely with the expectation...

  11. Arecibo pulsar survey using ALFA. III. Precursor survey and population synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Swiggum, J. K.; Lorimer, D. R.; McLaughlin, M. A.; Bates, S. D.; Senty, T. R. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Champion, D. J.; Lazarus, P. [Max-Planck-Institut für Radioastronomie, D-53121 Bonn (Germany); Ransom, S. M. [NRAO, Charlottesville, VA 22903 (United States); Brazier, A.; Chatterjee, S.; Cordes, J. M. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Hessels, J. W. T. [ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); Nice, D. J. [Department of Physics, Lafayette College, Easton, PA 18042 (United States); Ellis, J.; Allen, B. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee WI 53211 (United States); Bhat, N. D. R. [Center for Astrophysics and Supercomputing, Swinburne University, Hawthorn, Victoria 3122 (Australia); Bogdanov, S.; Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Crawford, F. [Department of Physics and Astronomy, Franklin and Marshall College, Lancaster, PA 17604-3003 (United States); Deneva, J. S. [Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612 (United States); and others

    2014-06-01

    The Pulsar Arecibo L-band Feed Array (PALFA) Survey uses the ALFA 7-beam receiver to search both inner and outer Galactic sectors visible from Arecibo (32° ≲ ℓ ≲ 77° and 168° ≲ ℓ ≲ 214°) close to the Galactic plane (|b| ≲ 5°) for pulsars. The PALFA survey is sensitive to sources fainter and more distant than have previously been seen because of Arecibo's unrivaled sensitivity. In this paper we detail a precursor survey of this region with PALFA, which observed a subset of the full region (slightly more restrictive in ℓ and |b| ≲ 1°) and detected 45 pulsars. Detections included 1 known millisecond pulsar and 11 previously unknown, long-period pulsars. In the surveyed part of the sky that overlaps with the Parkes Multibeam Pulsar Survey (36° ≲ ℓ ≲ 50°), PALFA is probing deeper than the Parkes survey, with four discoveries in this region. For both Galactic millisecond and normal pulsar populations, we compare the survey's detections with simulations to model these populations and, in particular, to estimate the number of observable pulsars in the Galaxy. We place 95% confidence intervals of 82,000 to 143,000 on the number of detectable normal pulsars and 9000 to 100,000 on the number of detectable millisecond pulsars in the Galactic disk. These are consistent with previous estimates. Given the most likely population size in each case (107,000 and 15,000 for normal and millisecond pulsars, respectively), we extend survey detection simulations to predict that, when complete, the full PALFA survey should have detected 1000{sub −230}{sup +330} normal pulsars and 30{sub −20}{sup +200} millisecond pulsars. Identical estimation techniques predict that 490{sub −115}{sup +160} normal pulsars and 12{sub −5}{sup +70} millisecond pulsars would be detected by the beginning of 2014; at the time, the PALFA survey had detected 283 normal pulsars and 31 millisecond pulsars, respectively. We attribute the deficiency in normal pulsar

  12. Arecibo Pulsar Survey Using ALFA. III. Precursor Survey and Population Synthesis

    CERN Document Server

    Swiggum, J K; McLaughlin, M A; Bates, S D; Champion, D J; Ransom, S M; Lazarus, P; Brazier, A; Hessels, J W T; Nice, D J; Ellis, J; Senty, T R; Allen, B; Bhat, N D R; Bogdanov, S; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J S; Freire, P C C; Jenet, F A; Karako-Argaman, C; Kaspi, V M; Knispel, B; Lee, K J; Van Leeuwen, J; Lynch, R; Lyne, A G; Scholz, P; Siemens, X; Stairs, I H; Stappers, B W; Stovall, K; Venkataraman, A; Zhu, W W

    2014-01-01

    The Pulsar Arecibo L-band Feed Array (PALFA) Survey uses the ALFA 7-beam receiver to search both inner and outer Galactic sectors visible from Arecibo ($32^{\\circ}\\lesssim \\ell \\lesssim 77^{\\circ}$ and $168^{\\circ}\\lesssim \\ell \\lesssim 214^{\\circ}$) close to the Galactic plane ($|b|\\lesssim5^{\\circ}$) for pulsars. In this paper we detail a precursor survey of this region with PALFA, which observed a subset of the full region (slightly more restrictive in $\\ell$ and $|b|\\lesssim1^{\\circ}$) and detected 45 pulsars. For both Galactic millisecond and normal pulsar populations, we compare the survey's detections with simulations to model these populations and, in particular, to estimate the number of observable pulsars in the Galaxy. We place 95\\% confidence intervals of 82,000 to 143,000 on the number of detectable normal pulsars and 9,000 to 100,000 on the number of detectable millisecond pulsars in the Galactic disk. These are consistent with previous estimates. Given the most likely population size in each ca...

  13. The Arecibo Galaxy Environment Survey IX: The Isolated Galaxy Sample

    CERN Document Server

    Minchin, R F; Davies, J I; Karachentsev, I D; Keenan, O C; Momjian, E; Rodriguez, R; Taber, T; Taylor, R

    2015-01-01

    We have used the Arecibo L-band Feed Array to map three regions, each of 5 square degrees, around the isolated galaxies NGC 1156, UGC 2082, and NGC 5523. In the vicinity of these galaxies we have detected two dwarf companions: one near UGC 2082, previously discovered by ALFALFA, and one near NGC 1156, discovered by this project and reported in an earlier paper. This is significantly fewer than the 15.4 $^{+1.7}_{-1.5}$ that would be expected from the field HI mass function from ALFALFA or the 8.9 $\\pm$ 1.2 expected if the HI mass function from the Local Group applied in these regions. The number of dwarf companions detected is, however, consistent with a flat or declining HI mass function as seen by a previous, shallower, HI search for companions to isolated galaxies.We attribute this difference in Hi mass functions to the different environments in which they are measured. This agrees with the general observation that lower ratios of dwarf to giant galaxies are found in lower density environments.

  14. The Arecibo Galaxy Environment Survey: Precursor Observations of the NGC 628 group

    CERN Document Server

    Auld, R; Davies, J I; Catinella, B; Henning, P A; Linder, S; Momjian, E; Müller, E; O'Neil, K; Sabatini, S; Schneider, S; Bothun, G; Cortese, L; Disney, M; Hoffman, G L; Putman, M; Rosenberg, J L; Baes, M; De Blok, W J G; Boselli, A; Brinks, E; Brosch, N; Irwin, J; Karachentsev, I D; Kilborn, V A; Koribalski, B; Spekkens, K

    2006-01-01

    The Arecibo Galaxy Environment Survey (AGES) is one of several HI surveys utilising the new Arecibo L-band Feed Array (ALFA) fitted to the 305m radio telescope at Arecibo. The survey is specifically designed to investigate various galactic environments to higher sensitivity, higher velocity resolution and higher spatial resolution than previous fully sampled, 21 cm multibeam surveys. The emphasis is on making detailed observations of nearby objects although the large system bandwidth (100 MHz) will allow us to quantify the HI properties over a large instantaneous velocity range. In this paper we describe the survey and its goals and present the results from the precursor observations of a 5 degree x 1 degree region containing the nearby (~10 Mpc) NGC 628 group. We have detected all the group galaxies in the region including the low mass (M{HI}~10^7Mo) dwarf, dw0137+1541 (Briggs, 1986). The fluxes and velocities for these galaxies compare well with previously published data. There is no intra-group neutral gas...

  15. The Arecibo Legacy Fast ALFA Survey : X. The HI Mass Function and Omega_HI From the 40% ALFALFA Survey

    NARCIS (Netherlands)

    Martin, Ann M.; Papastergis, Emmanouil; Giovanelli, Riccardo; Haynes, Martha P.; Springob, Christopher M.; Stierwalt, Sabrina

    2010-01-01

    The Arecibo Legacy Fast ALFA (ALFALFA) survey has completed source extraction for 40% of its total sky area, resulting in the largest sample of HI-selected galaxies to date. We measure the HI mass function from a sample of 10,119 galaxies with 6.2

  16. The Arecibo Galaxy Environment Survey: Observations towards the NGC 7817/7798 Galaxy Pair

    Science.gov (United States)

    Harrison, Amanda; Robert Minchin

    2016-01-01

    The Arecibo Galaxy Environment Survey (AGES) examines the environment of neutral hydrogen gas in the interstellar medium. AGES uses the 305m Arecibo Radio Telescope and the Arecibo L-Band Feed Array to create a deep field neutral hydrogen survey which we used to detect galaxies in an area five square degrees around the galaxy pair NGC 7817/7798. By finding and investigating hydrogen rich galaxies we hope to gain a better understanding of how the environment affects galaxy evolution. H1 line profiles were made for the detected H1 emission and ten galaxies which had the characteristic double-horned feature were found. NGC 7798 was not detected, but NGC 7817 and the other galaxies were cross-identified in NASA/IPAC Extragalactic Database as well as in Sloan Digital Sky Survey to obtain optical data. Out of the ten, two of the sources were uncatalogued. We analyzed the hydrogen spectra and aperture photometry to learn about the characteristics of these galaxies such as their heliocentric velocity, flux, and mass of the neutral hydrogen. Furthermore, we graphed the Tully-Fisher and the Baryonic Tully-Fisher of the ten sources and found that most followed the relation. One that is the biggest outlier is suspected be a galaxy cluster while other outliers may be caused by ram pressure stripping deforming the galaxy.

  17. HI Absorption Lines Detected from the Arecibo Legacy Fast ALFA Survey Data

    Science.gov (United States)

    Zhong-zu, Wu; Martha P, Haynes; Riccardo, Giovanelli; Ming, Zhu; Ru-rong, Chen

    2015-10-01

    We present some preliminary results of an on-going study of HI 21-cm absorption lines based on the 40% survey data released by the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). (1) Ten HI candidate absorbers have been detected. Five of them are previously published in the literature, and the rest of them are new detections that need further confirmation. (2) For those sources with no detected absorptions, we have calculated the upper limit of their foreground HI column density NHI. The statistical result of the NHI distribution indicates that the ratio Ts/f between the averaged spin temperature and coverage factor for DLAs (the damped Lyα systems) might be larger than 500 K. The radio frequency interference (RFI) and standing wave are the main factors affecting the detection of HI absorption lines, which have been analyzed and discussed as well in order to find a method of solution. Our study can serve as a pathfinder for the future large-scale search of HI 21-cm absorption lines using the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST), which is an Arecibo-type radio telescope currently under construction in China with greatly increased sensitivity, bandwidth, and observational sky area. As prospects, we have discussed two types of observational studies of HI absorption lines toward extragalactic sources using the FAST telescope.

  18. LCDM Satellites and HI Companions - The Arecibo ALFA Survey of NGC 2903

    OpenAIRE

    Irwin, J. A.; Hoffman, G.L.; Spekkens, K.; Haynes, M. P.; Giovanelli, R.; Linder, S. M.; Catinella, B.; Momjian, E.; Koribalski, B. S.; Davies, J; Brinks, E.; de Blok, W. J. G.; Putman, M. E.; Van Driel, W.

    2008-01-01

    We have conducted a deep, complete HI survey, using Arecibo/ALFA, of a field centered on the nearby, isolated galaxy, NGC 2903, which is similar to the Milky Way in its properties. The field size was 150 kpc x 260 kpc and the final velocity range spanned from 100 to 1133 km/s. The ALFA beams have been mapped as a function of azimuth and cleaned from each azimuth-specific cube prior to forming final cubes. The final HI data are sensitive down to an HI mass of 2 x 10^5 Mo and column density of ...

  19. A blind HI Mass Function from the Arecibo Ultra-Deep Survey (AUDS)

    CERN Document Server

    Hoppmann, L; Freudling, W; Zwaan, M A; Minchin, R F; Calabretta, M R

    2015-01-01

    The Arecibo Ultra Deep Survey (AUDS) combines the unique sensitivity of the telescope with the wide field of the Arecibo L-band Feed Array (ALFA) to directly detect 21cm HI emission from galaxies at distances beyond the local Universe bounded by the lower frequency limit of ALFA (z=0.16). AUDS has collected 1110 hours of integration time in two fields with a combined area of 1.35 square degrees. In this paper we present data from 50% of the total survey, corresponding to a sensitivity level of 80 micro-Jy. We discuss the data reduction, the search for galaxies, parametrisation, optical identification and completeness. We detect 102 galaxies in the mass range of log M_HI/M_sun-2log h=5.6-10.3. We compute the HI mass function (HIMF) at the highest redshifts so far measured. A fit of a Schechter function results in alpha=-1.37+-0.03, Phi=(7.72+-1.4)*10^3 h^3/Mpc^3 and log M_HI/M_sun=9.75+-0.041+2log h. Using the measured HIMF, we find a cosmic HI density of Omega_HI=(2.33+-0.07)*10^-4/h for the sample z=0.065. W...

  20. ARECIBO PALFA SURVEY AND EINSTEIN-HOME: BINARY PULSAR DISCOVERY BY VOLUNTEER COMPUTING

    International Nuclear Information System (INIS)

    We report the discovery of the 20.7 ms binary pulsar J1952+2630, made using the distributed computing project Einstein-Home in Pulsar ALFA survey observations with the Arecibo telescope. Follow-up observations with the Arecibo telescope confirm the binary nature of the system. We obtain a circular orbital solution with an orbital period of 9.4 hr, a projected orbital radius of 2.8 lt-s, and a mass function of f = 0.15 Msun by analysis of spin period measurements. No evidence of orbital eccentricity is apparent; we set a 2σ upper limit e ∼-3. The orbital parameters suggest a massive white dwarf companion with a minimum mass of 0.95 Msun, assuming a pulsar mass of 1.4 Msun. Most likely, this pulsar belongs to the rare class of intermediate-mass binary pulsars. Future timing observations will aim to determine the parameters of this system further, measure relativistic effects, and elucidate the nature of the companion star.

  1. The Arecibo Legacy Fast ALFA Survey: The Galaxy Population Detected by ALFALFA

    CERN Document Server

    Huang, Shan; Giovanelli, Riccardo; Brinchmann, Jarle

    2012-01-01

    Making use of HI 21 cm line measurements from the ALFALFA survey (alpha.40) and photometry from the Sloan Digital Sky Survey (SDSS) and GALEX, we investigate the global scaling relations and fundamental planes linking stars and gas for a sample of 9417 common galaxies: the alpha.40-SDSS-GALEX sample. In addition to their HI properties derived from the ALFALFA dataset, stellar masses (M_*) and star formation rates (SFRs) are derived from fitting the UV-optical spectral energy distributions. 96% of the alpha.40-SDSS-GALEX galaxies belong to the blue cloud, with the average gas fraction f_HI = M_HI/M_* ~ 1.5. A transition in SF properties is found whereby below M_* ~ 10^9.5 M_sun, the slope of the star forming sequence changes, the dispersion in the specific star formation rate (SSFR) distribution increases and the star formation efficiency (SFE) mildly increases with M_*. The evolutionary track in the SSFR-M_* diagram, as well as that in the color magnitude diagram are linked to the HI content; below this trans...

  2. Target Selection for the SDSS-III MARVELS Survey

    OpenAIRE

    Paegert, Martin; Stassun, Keivan G.; De Lee, Nathan; Pepper, Joshua; Fleming, Scott W.; Sivarani, Thirupathi; Mahadevan, Suvrath; Mack III, Claude E.; Dhital, Saurav; Hebb, Leslie; Ge, Jian

    2015-01-01

    We present the target selection process for the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III. MARVELS is a medium-resolution ($R \\sim 11000$) multi-fiber spectrograph capable of obtaining radial velocities for 60 objects at a time in order to find brown dwarfs and giant planets. The survey was configured to target dwarf stars with effective temperatures approximately between $4500$ and $6250 \\, \\mbox{K}$. For...

  3. Comets in Large Sky Surveys: From SDSS to LSST

    Science.gov (United States)

    Solontoi, Michael

    A well-controlled selection criteria is developed to reduce the number of plausible comet candidates in the Sloan Digital Sky Survey (SDSS) through the use of a training sample of serendipitously detected comets. This criteria reduces the 215 million object SDSS Fifth Public Data Release by a factor of more than 103, and additional constraints reduce the number of candidates to only 4510, while still preserving over 70% of the comet observations. The good understanding of selection effects allows a study of their population statistics. Measurements of the colors, sizes, surface brightness profiles and rates of dust production are made for thirty-one comets based on their SDSS photometry. The distribution of colors are extremely narrow, and found to be statistically indistinguishable to that of the Jupiter Trojans. No evidence for a correlations between color and any physical, dynamical, or observational parameters are found. A sample of Jupiter Family Comets observed by the SDSS is used to determine their cumulative luminosity function. Simulations of characteristic comet orbits demonstrate that the Large Synoptic Survey Telescope (LSST) will observe individual Jupiter Family Comets hundreds of times over their entire orbit. Simulations of Long Period Comets predict that LSST will make dozens of observations of each LPC, either on their way into and out of the Solar System, or while passing through perihelion. LSST will make an unprecedented number of comet observations to r ˜ 24.5, tracing their time evolution from presumed inactivity at large heliocentric distances, through the onset of out-gassing, and then back to inactivity, allowing for robust determination of cometary population statistics.

  4. The Arecibo Galaxy Environments survey IV: the NGC7448 region and the HI mass function

    CERN Document Server

    Davies, J I; Burns, L; Minchin, R; Momjian, E; Schneider, S; Smith, M; Taylor, R; van Driel, W

    2011-01-01

    In this paper we describe results from the Arecibo Galaxy Environments Survey (AGES). The survey reaches column densities of ~3x10^18 cm^-2 and masses of ~10^7 M_O, over individual regions of order 10 sq deg in size, out to a maximum velocity of 18,000 km s^-1. Each surveyed region is centred on a nearby galaxy, group or cluster, in this instance the NGC7448 group. Galaxy interactions in the NGC7448 group reveal themselves through the identification of tidal tails and bridges. We find ~2.5 times more atomic gas in the inter-galactic medium than in the group galaxies. We identify five new dwarf galaxies, two of which appear to be members of the NGC7448 group. This is too few, by roughly an order of magnitude, dwarf galaxies to reconcile observation with theoretical predictions of galaxy formation models. If they had observed this region of sky previous wide area blind HI surveys, HIPASS and ALFALFA, would have detected only 5% and 43% respectively of the galaxies we detect, missing a large fraction of the atom...

  5. Four Highly Dispersed Millisecond Pulsars Discovered in the Arecibo PALFA Galactic Plane Survey

    CERN Document Server

    Crawford, F; Lyne, A G; Stappers, B W; Nice, D J; Stairs, I H; Lazarus, P; Hessels, J W T; Freire, P C C; Allen, B; Bhat, N D R; Bogdanov, S; Brazier, A; Camilo, F; Champion, D J; Chatterjee, S; Cognard, I; Cordes, J M; Deneva, J S; Desvignes, G; Jenet, F A; Kaspi, V M; Knispel, B; Kramer, M; van Leeuwen, J; Lorimer, D R; Lynch, R; McLaughlin, M A; Ransom, S M; Scholz, P; Siemens, X; Venkataraman, A

    2012-01-01

    We present the discovery and phase-coherent timing of four highly dispersed millisecond pulsars (MSPs) from the Arecibo PALFA Galactic plane survey: PSRs J1844+0115, J1850+0124, J1900+0308, and J1944+2236. Three of the four pulsars are in binary systems with low-mass companions, which are most likely white dwarfs, and which have orbital periods on the order of days. The fourth pulsar is isolated. All four pulsars have large dispersion measures (DM > 100 pc cm-3), are distant (> 3.4 kpc), faint at 1.4 GHz (< 0.2 mJy), and are fully recycled (with spin periods P between 3.5 and 4.9 ms). The three binaries also have very small orbital eccentricities, as expected for tidally circularized, fully recycled systems with low-mass companions. These four pulsars have DM/P ratios that are among the highest values for field MSPs in the Galaxy. These discoveries bring the total number of confirmed MSPs from the PALFA survey to fifteen. The discovery of these MSPs illustrates the power of PALFA for finding weak, distant ...

  6. ARECIBO PULSAR SURVEY USING ALFA: PROBING RADIO PULSAR INTERMITTENCY AND TRANSIENTS

    International Nuclear Information System (INIS)

    We present radio transient search algorithms, results, and statistics from the ongoing Arecibo Pulsar ALFA (PALFA) survey of the Galactic plane. We have discovered seven objects through a search for isolated dispersed pulses. All of these objects are Galactic and have measured periods between 0.4 and 4.7 s. One of the new discoveries has a duty cycle of 0.01%, smaller than that of any other radio pulsar. We discuss the impact of selection effects on the detectability and classification of intermittent sources, and compare the efficiencies of periodicity and single-pulse (SP) searches for various pulsar classes. For some cases we find that the apparent intermittency is likely to be caused by off-axis detection or a short time window that selects only a few bright pulses and favors detection with our SP algorithm. In other cases, the intermittency appears to be intrinsic to the source. No transients were found with DMs large enough to require that they originate from sources outside our Galaxy. Accounting for the on-axis gain of the ALFA system, as well as the low gain but large solid-angle coverage of far-out sidelobes, we use the results of the survey so far to place limits on the amplitudes and event rates of transients of arbitrary origin.

  7. DISCOVERY AND FOLLOW-UP OF A NEARBY GALAXY FROM THE ARECIBO ZONE OF AVOIDANCE SURVEY

    International Nuclear Information System (INIS)

    The Arecibo L-Band Feed Array Zone of Avoidance (ALFA ZOA) Survey has discovered a nearby galaxy, ALFA ZOA J1952+1428, at a heliocentric velocity of +279 km s-1. The galaxy was discovered at low Galactic latitude by 21 cm emission from neutral hydrogen (H I). We have obtained follow-up observations with the Expanded Very Large Array and the 0.9 m Southeastern Association for Research in Astronomy optical telescope. The H I distribution overlaps an uncataloged, potential optical counterpart. The H I linear size is 1.4 kpc at our adopted distance of D = 7 Mpc, but the distance estimate is uncertain as Hubble's law is unreliable at low recessional velocities. The optical counterpart has mB = 16.9 mag and B - R = 0.1 mag. These characteristics, including MHi = 107.0 Msun and LB = 107.5 Lsun, if at 7 Mpc, indicate that this galaxy is a blue compact dwarf, but this remains uncertain until further follow-up observations are complete. Optical follow-up observations are ongoing and near-infrared follow-up observations have been scheduled.

  8. LCDM Satellites and HI Companions - The Arecibo ALFA Survey of NGC 2903

    CERN Document Server

    Irwin, J A; Spekkens, K; Haynes, M P; Giovanelli, R; Linder, S M; Catinella, B; Momjian, E; Koribalski, B S; Davies, J; Brinks, E; De Blok, W J G; Putman, M E; Van Driel, W

    2008-01-01

    We have conducted a deep, complete HI survey, using Arecibo/ALFA, of a field centered on the nearby, isolated galaxy, NGC 2903, which is similar to the Milky Way in its properties. The field size was 150 kpc x 260 kpc and the final velocity range spanned from 100 to 1133 km/s. The ALFA beams have been mapped as a function of azimuth and cleaned from each azimuth-specific cube prior to forming final cubes. The final HI data are sensitive down to an HI mass of 2 x 10^5 Mo and column density of 2 x 10^{17} cm^{-2} at the 3sigma x 2deltaV level, where sigma is the rms noise level and deltaV is the velocity resolution. NGC 2903 is found to have an HI envelope that is larger than previously known, extending to at least 3 times the optical diameter of the galaxy. Our search for companions yields one new discovery with an HI mass of 2.6 x 10^6 Mo. The companion is 64 kpc from NGC 2903 in projection, is likely associated with a small optical galaxy of similar total stellar mass, and is dark matter dominated, with a to...

  9. The Arecibo Galaxy Environment Survey X: The Structure of Halo Gas Around M33

    CERN Document Server

    Keenan, Olivia; Taylor, Rhys; Minchin, Robert

    2015-01-01

    As part of the HI Arecibo Galaxy Environments Survey (AGES) we have observed 5$\\times$4 degrees of sky centred on M33, reaching a limiting column density of $\\sim 1.5 \\times 10^{17}$ cm$^{-2}$ (line width of 10 km s$^{-1}$ and resolution 3.5\\arcmin). We particularly investigate the absence of optically detected dwarf galaxies around M33, something that is contrary to galaxy formation models. We identify 22 discrete HI clouds, 11 of which are new detections. The number of objects detected and their internal velocity dispersion distribution is consistent with expectations from standard galaxy formation models. However, the issue remains open as to whether the observed velocity dispersions can be used as a measure of the HI clouds total mass i.e. are the velocities indicative of virialised structures or have they been influenced by tidal interactions with other structures in the Local Group? We identify one particularly interesting HI cloud, AGESM33-31, that has many of the characteristics of HI distributed in t...

  10. New Discoveries from the Arecibo 327 MHz Drift Pulsar Survey Radio Transient Search

    CERN Document Server

    Deneva, J S; McLaughlin, M A; Bagchi, M; Bates, S D; Freire, P C C; Martinez, J G; Jenet, F; Garver-Daniels, N

    2016-01-01

    We present Clusterrank, a new algorithm for identifying dispersed astrophysical pulses. Such pulses are commonly detected from Galactic pulsars and rotating radio transients (RRATs), which are neutron stars with sporadic radio emission. More recently, isolated, highly dispersed pulses dubbed fast radio bursts (FRBs) have been identified as the potential signature of an extragalactic cataclysmic radio source distinct from pulsars and RRATs. Clusterrank helped us discover 14 pulsars and 8 RRATs in data from the Arecibo 327 MHz Drift Pulsar Survey (AO327). The new RRATs have DMs in the range $23.5 - 86.6$ pc cm$^{-3}$ and periods in the range $0.172 - 3.901$ s. The new pulsars have DMs in the range $23.6 - 133.3$ pc cm$^{-3}$ and periods in the range $1.249 - 5.012$ s, and include two nullers and a mode-switching object. We estimate an upper limit on the all-sky FRB rate of $10^5$ day$^{-1}$ for bursts with a width of 10 ms and flux density $\\gtrsim 83$ mJy. The DMs of all new discoveries are consistent with a G...

  11. New Discoveries from the Arecibo 327 MHz Drift Pulsar Survey Radio Transient Search

    Science.gov (United States)

    Deneva, J. S.; Stovall, K.; McLaughlin, M. A.; Bagchi, M.; Bates, S. D.; Freire, P. C. C.; Martinez, J. G.; Jenet, F.; Garver-Daniels, N.

    2016-04-01

    We present Clusterrank, a new algorithm for identifying dispersed astrophysical pulses. Such pulses are commonly detected from Galactic pulsars and rotating radio transients (RRATs), which are neutron stars with sporadic radio emission. More recently, isolated, highly dispersed pulses dubbed fast radio bursts (FRBs) have been identified as the potential signature of an extragalactic cataclysmic radio source distinct from pulsars and RRATs. Clusterrank helped us discover 14 pulsars and 8 RRATs in data from the Arecibo 327 MHz Drift Pulsar Survey (AO327). The new RRATs have DMs in the range 23.5–86.6 pc cm‑3 and periods in the range 0.172–3.901 s. The new pulsars have DMs in the range 23.6–133.3 pc cm‑3 and periods in the range 1.249–5.012 s, and include two nullers and a mode-switching object. We estimate an upper limit on the all-sky FRB rate of 105 day‑1 for bursts with a width of 10 ms and flux density ≳83 mJy. The DMs of all new discoveries are consistent with a Galactic origin. In comparing statistics of the new RRATs with sources from the RRATalog, we find that both sets are drawn from the same period distribution. In contrast, we find that the period distribution of the new pulsars is different from the period distributions of canonical pulsars in the ATNF catalog or pulsars found in AO327 data by a periodicity search. This indicates that Clusterrank is a powerful complement to periodicity searches and uncovers a subset of the pulsar population that has so far been underrepresented in survey results and therefore in Galactic pulsar population models.

  12. Target Selection for the SDSS-III MARVELS Survey

    CERN Document Server

    Paegert, Martin; De Lee, Nathan; Pepper, Joshua; Fleming, Scott W; Sivarani, Thirupathi; Mahadevan, Suvrath; Mack, Claude E; Dhital, Saurav; Hebb, Leslie; Ge, Jian

    2015-01-01

    We present the target selection process for the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III. MARVELS is a medium-resolution ($R \\sim 11000$) multi-fiber spectrograph capable of obtaining radial velocities for 60 objects at a time in order to find brown dwarfs and giant planets. The survey was configured to target dwarf stars with effective temperatures approximately between $4500$ and $6250 \\, \\mbox{K}$. For the first 2 years MARVELS relied on low-resolution spectroscopic pre-observations to estimate the effective temperature and $\\log(g)$ for candidate stars and then selected suitable dwarf stars from this pool. Ultimately, the pre-observation spectra proved ineffective at filtering out giant stars; many giants were incorrectly classified as dwarfs, resulting in a giant contamination rate of $\\sim$30\\% for the first phase of the MARVELS survey. Thereafter, the survey instead applied a reduced proper motion cut to eliminate ...

  13. Machine learning classification of SDSS transient survey images

    Science.gov (United States)

    du Buisson, L.; Sivanandam, N.; Bassett, Bruce A.; Smith, M.

    2015-12-01

    We show that multiple machine learning algorithms can match human performance in classifying transient imaging data from the Sloan Digital Sky Survey (SDSS) supernova survey into real objects and artefacts. This is a first step in any transient science pipeline and is currently still done by humans, but future surveys such as the Large Synoptic Survey Telescope (LSST) will necessitate fully machine-enabled solutions. Using features trained from eigenimage analysis (principal component analysis, PCA) of single-epoch g, r and i difference images, we can reach a completeness (recall) of 96 per cent, while only incorrectly classifying at most 18 per cent of artefacts as real objects, corresponding to a precision (purity) of 84 per cent. In general, random forests performed best, followed by the k-nearest neighbour and the SkyNet artificial neural net algorithms, compared to other methods such as naive Bayes and kernel support vector machine. Our results show that PCA-based machine learning can match human success levels and can naturally be extended by including multiple epochs of data, transient colours and host galaxy information which should allow for significant further improvements, especially at low signal-to-noise.

  14. The Arecibo Legacy Fast ALFA Survey: X. The HI Mass Function and Omega_HI From the 40% ALFALFA Survey

    CERN Document Server

    Martin, Ann M; Giovanelli, Riccardo; Haynes, Martha P; Springob, Christopher M; Stierwalt, Sabrina

    2010-01-01

    The Arecibo Legacy Fast ALFA (ALFALFA) survey has completed source extraction for 40% of its total sky area, resulting in the largest sample of HI-selected galaxies to date. We measure the HI mass function from a sample of 10,119 galaxies with 6.2 < log (M_HI/M_Sun) < 11.0 and with well-described mass errors that accurately reflect our knowledge of low-mass systems. We characterize the survey sensitivity and its dependence on profile velocity width, the effect of large-scale structure, and the impact of radio frequency interference in order to calculate the HIMF with both the 1/Vmax and 2DSWML methods. We also assess a flux-limited sample to test the robustness of the methods applied to the full sample. These measurements are in excellent agreement with one another; the derived Schechter function parameters are phi* = 4.8 (+/- 0.3) * 10^-3, log (M*/M_Sun) + 2 log(h_70) = 9.96 (+/- 0.2), and alpha = -1.33 (+/- 0.02). We find Omega_HI = 4.3 (+/- 0.3) * 10^-4, 16% larger than the 2005 HIPASS result, and ou...

  15. Arecibo Pulsar Survey Using ALFA. IV. Mock Spectrometer Data Analysis, Survey Sensitivity, and the Discovery of 41 Pulsars

    CERN Document Server

    Lazarus, P; Hessels, J W T; Karako-Argaman, C; Kaspi, V M; Lynch, R; Madsen, E; Patel, C; Ransom, S M; Scholz, P; Swiggum, J; Zhu, W W; Allen, B; Bogdanov, S; Camilo, F; Cardoso, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J S; Ferdman, R; Freire, P C C; Jenet, F A; Knispel, B; Lee, K J; van Leeuwen, J; Lorimer, D R; Lyne, A G; McLaughlin, M A; Siemens, X; Spitler, L G; Stairs, I H; Stovall, K; Venkataraman, A

    2015-01-01

    The on-going PALFA survey at the Arecibo Observatory began in 2004 and is searching for radio pulsars in the Galactic plane at 1.4 GHz. Observations since 2009 have been made with new wider-bandwidth spectrometers than were previously employed in this survey. A new data reduction pipeline has been in place since mid-2011 which consists of standard methods using dedispersion, searches for accelerated periodic sources, and search for single pulses, as well as new interference-excision strategies and candidate selection heuristics. This pipeline has been used to discover 41 pulsars, including 8 millisecond pulsars (MSPs; P = 100 ms that gradually becomes up to a factor of ~10 worse for P > 4 s at DM < 150 pc/cc. This degradation of sensitivity at long periods is largely due to red noise. We find that 35 +- 3% of pulsars are missed despite being bright enough to be detected in the absence of red noise. This reduced sensitivity could have implications on estimates of the number of long-period pulsars in the Gal...

  16. Machine Learning Classification of SDSS Transient Survey Images

    CERN Document Server

    Buisson, L du; Bassett, B A; Smith, M

    2014-01-01

    We show that multiple machine learning algorithms can match human performance in classifying transient imaging data from the SDSS supernova survey into real objects and artefacts. This is the first step in any transient science pipeline and is currently still done by humans, but future surveys such as LSST will necessitate fully machine-enabled solutions. Using features trained from eigenimage analysis (PCA) of single-epoch g, r, i-difference images we can reach a completeness (recall) of 95%, while only incorrectly classifying 18% of artefacts as real objects, corresponding to a precision (purity) of 85%. In general the k-nearest neighbour and the SkyNet artificial neural net algorithms performed most robustly compared to other methods such as naive Bayes and kernel SVM. Our results show that PCA-based machine learning can match human success levels and can naturally be extended by including multiple epochs of data, transient colours and host galaxy information which should allow for significant further impr...

  17. Difference Imaging of Lensed Quasar Candidates inthe SDSS Supernova Survey Region

    Energy Technology Data Exchange (ETDEWEB)

    Lacki, Brian C.; Kochanek, Christopher S.; Stanek, Krzysztof Z.; Inada, Naohisa; Oguri, Masamune

    2008-02-04

    Difference imaging provides a new way to discover gravitationally lensed quasars because few non-lensed sources will show spatially extended, time variable flux. We test the method on lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and their surrounding fields. Starting from 20768 sources, including 49 SDSS quasars and 36 candidate lenses/lensed images, we find that 21 sources including 15 SDSS QSOs and 7 candidate lenses/lensed images are non-periodic variable sources. We can measure the spatial structure of the variable flux for 18 of these sources and identify only one as a non-point source. This source does not display the compelling spatial structure of the variable flux of known lensed quasars, so we reject it as a lens candidate. None of the lens candidates from the SQLS survive our cuts. Given our effective survey area of order 0.71 square degrees, this indicates a false positive rate of order one per square degree for the method. The fraction of quasars not found to be variable and the false positive rate should both fall if we analyze the full, later data releases for the SDSS fields. While application of the method to the SDSS is limited by the resolution, depth, and sampling of the survey, several future surveys such as Pan-STARRS, LSST, and SNAP will avoid these limitations.

  18. SDSS-IV MaNGA: Survey Design and Progress

    Science.gov (United States)

    Yan, Renbin; MaNGA Team

    2016-01-01

    The ongoing SDSS-IV/MaNGA Survey will obtain integral field spectroscopy at a resolution of R~2000 with a wavelength coverage from 3,600A to 10,300A for 10,000 nearby galaxies. Within each 3 degree diameter pointing of the 2.5m Sloan Telescope, we deploy 17 hexagonal fiber bundles with sizes ranging from 12 to 32 arcsec in diameter. The bundles are build with 2 arcsec fibers and have a 56% fill factor. During observations, we obtained sets of exposures at 3 different dither positions to achieve near-critical sampling of the effective point spread function, which has a FWHM about 2.5 arcsec, corresponding to 1-2 kpc for the majority of the galaxies targeted. The flux calibration is done using 12 additional mini-fiber-bundles targeting standard stars simultaneously with science targets, achieving a calibration accuracy better than 5% over 90% of the wavelength range. The target galaxies are selected to ensure uniform spatial coverage in units of effective radii for the majority of the galaxies while maximizing spatial resolution. About 2/3 of the sample is covered out to 1.5Re (primary sample) and 1/3 of the sample covered to 2.5Re (secondary sample). The sample is designed to have approximately equal representation from high and low mass galaxies while maintaining volume-limited selection at fixed absolute magnitudes. We obtain an average S/N of 4 per Angstrom in r-band continuum at a surface brightness of 23 AB arcsec-2. With spectral stacking in an elliptical annulus covering 1-1.5Re, our primary sample galaxies have a median S/N of ~60 per Angstrom in r-band.

  19. The alignment of SDSS satellites with the VPOS: effects of the survey footprint shape

    Science.gov (United States)

    Pawlowski, Marcel S.

    2016-02-01

    It is sometimes argued that the uneven sky coverage of the Sloan Digital Sky Survey (SDSS) biases the distribution of satellite galaxies discovered by it to align with the polar plane defined by the 11 brighter, classical Milky Way (MW) satellites. This might prevent the SDSS satellites from adding significance to the MW's vast polar structure (VPOS). We investigate whether this argument is valid by comparing the observed situation with model satellite distributions confined to the exact SDSS footprint area. We find that the SDSS satellites indeed add to the significance of the VPOS and that the survey footprint rather biases away from a close alignment between the plane fitted to the SDSS satellites and the plane fitted to the 11 classical satellites. Finding the observed satellite phase-space alignments of both the classical and SDSS satellites is an ˜5σ event with respect to an isotropic distribution. This constitutes a robust discovery of the VPOS and makes it more significant than the Great Plane of Andromeda (GPoA). Motivated by the GPoA, which consists of only about half of M31's satellites, we also estimate which fraction of the MW satellites is consistent with being part of an isotropic distribution. Depending on the underlying satellite plane width, only 2 to 6 out of the 27 considered MW satellites are expected to be drawn from isotropy, and an isotropic component of ≳50 per cent of the MW satellite population is excluded at 95 per cent confidence.

  20. The alignment of SDSS satellites with the VPOS: effects of the survey footprint shape

    CERN Document Server

    Pawlowski, Marcel S

    2015-01-01

    It is sometimes argued that the uneven sky coverage of the Sloan Digital Sky Survey (SDSS) biases the distribution of satellite galaxies discovered by it to align with the polar plane defined by the 11 brighter, classical Milky Way (MW) satellites. This might prevent the SDSS satellites from adding significance to the MW's Vast Polar Structure (VPOS). We investigate whether this argument is valid by comparing the observed situation with model satellite distributions confined to the exact SDSS footprint area. We find that the SDSS satellites indeed add to the significance of the VPOS and that the survey footprint rather biases away from a close alignment between the plane fitted to the SDSS satellites and the plane fitted to the 11 classical satellites. Finding the observed satellite phase-space alignments of both the classical and SDSS satellites is a ~5{\\sigma} event with respect to an isotropic distribution. This constitutes a robust discovery of the VPOS and makes it more significant than the Great Plane o...

  1. GOALS, STRATEGIES AND FIRST DISCOVERIES OF AO327, THE ARECIBO ALL-SKY 327 MHz DRIFT PULSAR SURVEY

    International Nuclear Information System (INIS)

    We report initial results from AO327, a drift survey for pulsars with the Arecibo telescope at 327 MHz. The first phase of AO327 will cover the sky at declinations of –1° to 28°, excluding the region within 5° of the Galactic plane, where high scattering and dispersion make low-frequency surveys sub-optimal. We record data from a 57 MHz bandwidth with 1024 channels and 125 μs sampling time. The 60 s transit time through the AO327 beam means that the survey is sensitive to very tight relativistic binaries even with no acceleration searches. To date we have detected 44 known pulsars with periods ranging from 3 ms to 2.21 s and discovered 24 new pulsars. The new discoveries include 3 ms pulsars, three objects with periods of a few tens of milliseconds typical of young as well as mildly recycled pulsars, a nuller, and a rotating radio transient. Five of the new discoveries are in binary systems. The second phase of AO327 will cover the sky at declinations of 28°-38°. We compare the sensitivity and search volume of AO327 to the Green Bank North Celestial Cap survey and the GBT350 drift survey, both of which operate at 350 MHz

  2. SDSS J0246-0825: A New Gravitationally Lensed Quasar from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Inada, N; Burles, S; Gregg, M D; Becker, R H; Schechter, P L; Eisenstein, D J; Oguri, M; Castander, F J; Hall, P B; Johnston, D E; Pindor, B; Richards, G T; Schneider, D P; White, R L; Brinkmann, J; Szalay, A; York, D G

    2005-11-10

    We report the discovery of a new two-image gravitationally lensed quasar, SDSS J024634.11-082536.2 (SDSS J0246-0825). This object was selected as a lensed quasar candidate from the Sloan Digital Sky Survey (SDSS) by the same algorithm that was used to discover other SDSS lensed quasars (e.g., SDSS J0924+0219). Multicolor imaging with the Magellan Consortium's Walter Baade 6.5-m telescope and the spectroscopic observations using the W. M. Keck Observatory's Keck II telescope confirm that SDSS J0246-0825 consists of two lensed images ({Delta}{theta} = 1''.04) of a source quasar at z = 1.68. Imaging observations with the Keck telescope and the Hubble Space Telescope reveal an extended object between the two quasar components, which is likely to be a lensing galaxy of this system. From the absorption lines in the spectra of quasar components and the apparent magnitude of the galaxy, combined with the expected absolute magnitude from the Faber-Jackson relation, we estimate the redshift of the lensing galaxy to be z = 0.724. A highly distorted ring is visible in the Hubble Space Telescope images, which is likely to be the lensed host galaxy of the source quasar. Simple mass modeling predicts the possibility that there is a small (faint) lensing object near the primary lensing galaxy.

  3. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Luminous Red Galaxy Target Selection

    Science.gov (United States)

    Prakash, Abhishek; Licquia, Timothy C.; Newman, Jeffrey A.; Ross, Ashley J.; Myers, Adam D.; Dawson, Kyle S.; Kneib, Jean-Paul; Percival, Will J.; Bautista, Julian E.; Comparat, Johan; Tinker, Jeremy L.; Schlegel, David J.; Tojeiro, Rita; Ho, Shirley; Lang, Dustin; Rao, Sandhya M.; McBride, Cameron K.; Ben Zhu, Guangtun; Brownstein, Joel R.; Bailey, Stephen; Bolton, Adam S.; Delubac, Timothée; Mariappan, Vivek; Blanton, Michael R.; Reid, Beth; Schneider, Donald P.; Seo, Hee-Jong; Carnero Rosell, Aurelio; Prada, Francisco

    2016-06-01

    We describe the algorithm used to select the luminous red galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-field Infrared Survey Explorer. LRG targets are required to meet a set of color selection criteria and have z-band and i-band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS ancillary programs to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least ∼89% of the target sample yields secure redshift measurements. We also present tests of the uniformity and homogeneity of the sample, demonstrating that it should be clean enough for studies of the large-scale structure of the universe at higher redshifts than SDSS-III/BOSS LRGs reached.

  4. The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, Hiroaki; /Tokyo U.; Prieto, Carlos Allende; /Laguna U., Tenerife; An, Deokkeun; /Ewha Women' s U., Seoul; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Aubourg, Eric; /APC, Paris /DAPNIA, Saclay; Balbinot, Eduardo; /Rio Grande do Sul U. /Rio de Janeiro Observ.; Beers, Timothy C.; /Michigan State U.; Berlind, Andreas A.; /Vanderbilt U.; Bickerton, Steven J.; /Princeton U.; Bizyaev, Dmitry; /Apache Point Observ.; Blanton, Michael R.; /New York U., CCPP /Penn State U.

    2011-01-01

    The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.

  5. Host galaxy spectra and consequences for supernova typing from the SDSS SN survey

    International Nuclear Information System (INIS)

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey, this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of SN host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future analysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased toward lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  6. The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey

    CERN Document Server

    Smee, Stephen; Uomoto, Alan; Roe, Natalie; Schlegel, David; Rockosi, Constance M; Carr, Michael A; Leger, French; Dawson, Kyle S; Olmstead, Matthew D; Brinkmann, Jon; Owen, Russell; Barkhouser, Robert H; Honscheid, Klaus; Harding, Paul; Long, Dan; Lupton, Robert H; Loomis, Craig; Anderson, Lauren; Annis, James; Bernardi, Mariangela; Bhardwaj, Vaishali; Bizyaev, Dmitry; Bolton, Adam S; Brewington, Howard; Briggs, John W; Burles, Scott; Burns, James G; Castander, Francisco; Connolly, Andrew; Davenport, James R; Ebelke, Garrett; Epps, Harland; Feldman, Paul D; Friedman, Scott; Frieman, Joshua; Heckman, Timothy; Hull, Charles L; Knapp, Gillian R; Lawrence, David M; Loveday, Jon; Mannery, Edward J; Malanushenko, Elena; Malanushenko, Viktor; Merrelli, Aronne; Muna, Demitri; Newman, Peter; Nichol, Robert C; Oravetz, Daniel; Pan, Kaike; Pope, Adrian C; Ricketts, Paul G; Shelden, Alaina; Sandford, Dale; Siegmund, Walter; Simmons, Audrey; Smith, D; Snedden, Stephanie; Schneider, Donald P; Strauss, Michael; SubbaRao, Mark; Tremonti, Christy; Waddell, Patrick; York, Donald G

    2012-01-01

    We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-$\\alpha$ absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber sp...

  7. The SDSS-IV extended Baryonic Oscillation Spectroscopic Survey: Luminous Red Galaxy Target Selection

    CERN Document Server

    Prakash, Abhishek; Newman, Jeffrey A; Ross, Ashley J; Myers, Adam D; Dawson, Kyle S; Kneib, Jean-Paul; Percival, Will J; Bautista, Julian E; Comparat, Johan; Tinker, Jeremy L; Schlegel, David J; Tojeiro, Rita; Ho, Shirley; Lang, Dustin; Rao, Sandhya M; McBride, Cameron K; Zhu, Guangtun Ben; Brownstein, Joel R; Bailey, Stephen; Bolton, Adam S; Delubac, Timothee; Mariappan, Vivek; Blanton, Michael R; Reid, Beth; Schneider, Donald P; Seo, Hee-Jong; Rosell, Aurelio Carnero; Prada, Francisco

    2015-01-01

    We describe the algorithm used to select the Luminous Red Galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-Field Infrared Survey Explorer (WISE). LRG targets are required to meet a set of color selection criteria and have z-band and i-band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least 89% of the target sample yield...

  8. Difference Imaging of Lensed Quasar Candidates in the SDSS Supernova Survey Region

    CERN Document Server

    Lacki, Brian C; Stanek, Krzysztof Z; Inada, Naohisa; Oguri, Masamune

    2008-01-01

    Difference imaging provides a new way to discover gravitationally lensed quasars because few non-lensed sources will show spatially extended, time variable flux. We test the method on lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and their surrounding fields. Starting from 20768 sources, including 49 SDSS quasars and 36 candidate lenses/lensed images, we find that 21 sources including 15 SDSS QSOs and 7 candidate lenses/lensed images are non-periodic variable sources. We can measure the spatial structure of the variable flux for 18 of these sources and identify only one as a non-point source. This source does not display the compelling spatial structure of the variable flux of known lensed quasars, so we reject it as a lens candidate. None of the lens candidates from the SQLS survive our cuts. Given our effective survey area of order 0.71 square degrees, this indicates a false positive rate of order one per square degree for themethod. T...

  9. Intrinsic galaxy alignments from the 2SLAQ and SDSS surveys: luminosity and redshift scalings and implications for weak lensing surveys

    CERN Document Server

    Hirata, C M; Ishak, M; Seljak, U; Nichol, R; Pimbblet, K A; Ross, N P; Wake, D; Hirata, Christopher M.; Mandelbaum, Rachel; Ishak, Mustapha; Seljak, Uros; Nichol, Robert; Pimbblet, Kevin A.; Ross, Nicholas P.; Wake, David

    2007-01-01

    Correlations between intrinsic shear and the density field on large scales, a potentially important contaminant for cosmic shear surveys, have been robustly detected at low redshifts with bright galaxies in SDSS data. Here we present a more detailed characterization of this effect, which can cause anti-correlations between gravitational lensing shear and intrinsic ellipticity (GI correlations). This measurement uses 36278 Luminous Red Galaxies (LRGs) from the SDSS spectroscopic sample with 0.153sigma detections of the effect for all galaxy subsamples within the SDSS LRG sample; for the 2SLAQ sample, we find a 2sigma detection for a bright subsample, and no detection for a fainter subsample. Fitting formulae are provided for the scaling of the GI correlations with luminosity, transverse separation, and redshift. We estimate contamination in the measurement of sigma_8 for future cosmic shear surveys on the basis of the fitted dependence of GI correlations on galaxy properties. We find contamination to the power...

  10. The SDSS-IV eBOSS emission-line galaxy pilot survey

    CERN Document Server

    Comparat, J; Jouvel, S; Raichoor, A; Kneib, J-P; Yeche, C; Abdalla, F B; Cras, C Le; Maraston, C; Wilkinson, D M; Zhu, G; Jullo, E; Prada, F; Schlegel, D; Xu, Z; Zou, H; Bautista, J; Bizyaev, D; Bolton, A; Brownstein, J R; Dawson, K S; Gaulme, S Escoffier P; Kinemuchi, K; Malanushenko, E; Malanushenko, V; Mariappan, V; Newman, J A; Oravetz, D; Pan, K; Percival, W J; Prakash, A; Schneider, D P; Simmons, A; Allam, T M C Abbott S; Banerji, M; Benoit-Lévy, A; Bertin, E; Brooks, D; Capozzi, D; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Castander, F J; Cunha, C E; da Costa, L N; Desai, S; Doel, P; Eifler, T F; Estrada, J; Flaugher, B; Fosalba, P; Frieman, J; Gaztanaga, E; Gerdes, D W; Gruen, D; Gruendl, R A; Gutierrez, G; Honscheid, K; James, D J; Kuehn, K; Kuropatkin, N; Lahav, O; Lima, M; Maia, M A G; March, M; Marshall, J L; Miquel, R; Plazas, A A; Reil, K; Roe, N; Romer, A K; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Scarpine, V; Sevilla-Noarbe, I; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Thomas, D; Walker, A R; Zhang, Y

    2015-01-01

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe approximately 270,000 emission-line galaxies (ELGs) to measure the Baryonic Acoustic Oscillation standard ruler (BAO) at redshift 0.9. To test different ELG selection algorithms, based on data from several imaging surveys, 9,000 spectra were observed with the SDSS spectrograph as a pilot survey. First, we provide a detailed description of each target selection algorithm tested. Then, using visual inspection and redshift quality flags, we find that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a robust BAO measurement. Also, we show the correlations between sky emission, signal-to-noise ratio in the emission lines and redshift error. As a result, we provide robust redshift distributions for the different target selection schemes tested. Finally, we infer two optimal target selection algorithms to be applied on DECam photometry that fulfill the eBOSS ...

  11. The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

    CERN Document Server

    Prieto, Carlos Allende; Anderson, Scott F; Aubourg, Éric; Balbinot, Eduardo; Beers, Timothy C; Berlind, Andreas A; Bickerton, Steven J; Bizyaev, Dmitry; Blanton, Michael R; Bochanski, John J; Bolton, Adam S; Bovy, Jo; Brandt, W N; Brinkmann, J; Brown, Peter J; Brownstein, Joel R; Busca, Nicolas G; Campbell, Heather; Carr, Michael A; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A C; Cuesta, Antonio J; da Costa, Luiz N; Davenport, James R A; Dawson, Kyle; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L; Edmondson, Edward M; Eisenstein, Daniel J; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L; Fan, Xiaohui; Castellá, Bruno Femení a; Font-Ribera, Andreu; Frinchaboy, Peter M; Ge, Jian; Gillespie, Bruce A; Gilmore, G; Hernández, Jonay I González; Gott, J Richard; Gould, Andrew; Grebel, Eva K; Gunn, James E; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W; Hawley, Suzanne L; Hearty, Frederick R; Ho, Shirley; Hogg, David W; Holtzman, Jon A; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I; Jiang, Linhua; Johnson, Jennifer A; Jordan, Cathy; Jordan, Wendell P; Kazin, Eyal A; Kirkby, David; Klaene, Mark A; Knapp, G R; Kneib, Jean-Paul; Kochanek, C S; Koesterke, Lars; Kollmeier, Juna A; Kron, Richard G; Lang, Dustin; Goff, Jean-Marc Le; Lee, Young Sun; Lin, Yen-Ting; Long, Daniel C; Loomis, Craig P; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H; Ma, Zhibo; MacDonald, Nicholas; Mahadevan, Suvrath; Maia, Marcio A G; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Masters, Karen L; McBride, Cameron K; McGehee, Peregrine M; McGreer, Ian D; Ménard, Brice; Miralda-Escudé, Jordi; Morrison, Heather L; Mullally, F; Muna, Demitri; Munn, Jeffrey A; Murayama, Hitoshi; Myers, Adam D; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C; O'Connell, Robert W; Ogando, Ricardo L C; Olmstead, Matthew D; Oravetz, Daniel J; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Pâris, Isabelle; Percival, Will J; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M; Prada, Francisco; Price-Whelan, Adrian M; Raddick, M Jordan; Ramos, Beatriz H F; Reylé, Céline; Rich, James; Richards, Gordon T; Rix, Hans-Walter; Robin, Annie C; Rocha-Pinto, Helio J; Rockosi, Constance M; Roe, Natalie A; Rollinde, Emmanuel; Ross, Ashley J; Ross, Nicholas P; Rossetto, Bruno M; Sánchez, Ariel G; Sayres, Conor; Schlegel, David J; Schlesinger, Katharine J; Schmidt, Sarah J; Schneider, Donald P; Sheldon, Erin; Shu, Yiping; Simmerer, Jennifer; Simmons, Audrey E; Sivarani, Thirupathi; Snedden, Stephanie A; Steinmetz, Matthias; Strauss, Michael A; Tanaka, Masayuki; Thakar, Aniruddha R; Thomas, Daniel; Tinker, Jeremy L; Tofflemire, Benjamin M; Tojeiro, Rita; Tremonti, Christy A; Magaña, M Vargas; Verde, Licia; Vogt, Nicole P; Wake, David A; Wang, Ji; Weaver, Benjamin A; Weinberg, David H; White, Martin; White, Simon D M; Yanny, Brian; Yasuda, Naoki; Yeche, Christophe; Zehavi, Idit

    2011-01-01

    The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly alpha forest, and a radial velocity search for planets around ~8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg^2 in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg^2, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galacti...

  12. Improved Photometric Calibration of the SNLS and the SDSS Supernova Surveys

    CERN Document Server

    Betoule, M; Regnault, N; Cuillandre, J -C; Astier, P; Guy, J; Balland, C; Hage, P El; Hardin, D; Kessler, R; Guillou, L Le; Mosher, J; Pain, R; Rocci, P -F; Sako, M; Schahmaneche, K

    2012-01-01

    We present a combined photometric calibration of the SNLS and the SDSS supernova survey, which results from a joint effort of the SDSS and the SNLS collaborations. We deliver fluxes calibrated to the HST spectrophotometric star network for large sets of tertiary stars that cover the science fields of both surveys in all photometric bands. We also cross-calibrate directly the two surveys and demonstrate their consistency. For each survey the flat-fielding is revised based on the analysis of dithered star observations. The calibration transfer from the HST spectrophotometric standard stars to the multi-epoch tertiary standard star catalogs in the science fields follows three different paths: observations of primary standard stars with the SDSS PT telescope; observations of Landolt secondary standard stars with SNLS MegaCam instrument at CFHT; and direct observation of faint HST standard stars with MegaCam. In addition, the tertiary stars for the two surveys are cross-calibrated using dedicated MegaCam observati...

  13. The Swift AGN and Cluster Survey. II. Cluster Confirmation with SDSS Data

    Science.gov (United States)

    Griffin, Rhiannon D.; Dai, Xinyu; Kochanek, Christopher S.; Bregman, Joel N.

    2016-01-01

    We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray sources located in the SDSS DR8 footprint to search for galaxy over-densities in three-dimensional space using SDSS galaxy photometric redshifts and positions near the Swift cluster candidates. We find 104 Swift clusters with a >3σ galaxy over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmation as galaxy clusters. We present a series of cluster properties including the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in ˜85% of the 104 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≲ 0.3 and is still 80% complete up to z ≃ 0.4, consistent with the SDSS survey depth. These analysis results suggest that our Swift cluster selection algorithm has yielded a statistically well-defined cluster sample for further study of cluster evolution and cosmology. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 23, and 1 matches in optical, X-ray, and Sunyaev-Zel’dovich catalogs, respectively, and so the majority of these clusters are new detections.

  14. The SDSS View of the Palomar-Green Bright Quasar Survey

    CERN Document Server

    Jester, S; Richards, G T; Green, R F; Schmidt, M; Hall, P B; Strauss, M A; Vanden Berk, Daniel E; Stoughton, C; Gunn, J E; Brinkmann, J; Kent, S M; Smith, J A; Tucker, D L; Yanny, B; Jester, Sebastian; Schneider, Donald P.; Richards, Gordon T.; Green, Richard F.; Schmidt, Maarten; Hall, Patrick B.; Strauss, Michael A.; Berk, Daniel E. Vanden; Stoughton, Chris; Gunn, James E.; Brinkmann, Jon; Kent, Stephen M.; Tucker, Douglas L.; Yanny, Brian

    2005-01-01

    We investigate the extent to which the Palomar-Green (PG) Bright Quasar Survey (BQS) is complete and representative of the general quasar population by comparing with imaging and spectroscopy from the Sloan Digital Sky Survey. A comparison of SDSS and PG photometry of both stars and quasars reveals the need to apply a color and magnitude recalibration to the PG data. Using the SDSS photometric catalog, we define the PG's parent sample of objects that are not main-sequence stars and simulate the selection of objects from this parent sample using the PG photometric criteria and errors. This simulation shows that the effective U-B cut in the PG survey is U-B 0.5 are inherently rare in bright surveys in any case). We find no evidence for any other systematic incompleteness when comparing the distributions in color, redshift, and FIRST radio properties of the BQS and a BQS-like subsample of the SDSS quasar sample. However, the application of a bright magnitude limit biases the BQS toward the inclusion of objects w...

  15. A Near-Infrared Spectroscopic Survey at the SDSS 2.5-meter Telescope?

    CERN Document Server

    Skrutskie, Michael F

    2015-01-01

    We are posting this 10-year-old white paper to support an upcoming survey description paper for the SDSS-III Apache Point Galactic Evolution Experiment (APOGEE) led by PI Dr. Steven Majewski. The white paper presented here was a contribution to a 2005 "futures" planning process for the Astrophysical Research Consortium led by Dr. Donald York that examined both prospects for extending the work of SDSS and SDSS-II as well as enhancing the capabilities of the Apache Point 3.5-meter telescope and the overall scientific reach of the Consortium. This particular white paper describes the potential for using the Sloan 2.5-meter telescope and its fiber optic infrastructure to conduct a galactic plane chemical abundance survey in the low-extinction 1.6um H-band. The survey would target >1000 red giant stars per night selected from the Two Micron All Sky Survey using a >200 fiber near-infrared spectrograph operating at spectral resolution of R~24,000 with a magnitude limit of H~12 - very close to the final APOGEE implem...

  16. Multi-Scale Morphological Analysis of SDSS DR5 Survey using the Metric Space Technique

    CERN Document Server

    Wu, Yongfeng; Khalil, Andre

    2008-01-01

    Following novel development and adaptation of the Metric Space Technique (MST), a multi-scale morphological analysis of the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) was performed. The technique was adapted to perform a space-scale morphological analysis by filtering the galaxy point distributions with a smoothing gaussian function, thus giving quantitative structural information on all size scales between 5 and 250 Mpc. The analysis was performed on a dozen slices of a volume of space containing many newly measured galaxies from the SDSS DR5 survey. Using the MST, observational data were compared to galaxy samples taken from N-body simulations with current best estimates of cosmological parameters and from random catalogs. By using the maximal ranking method among MST output functions we also develop a way to quantify the overall similarity of the observed samples with the simulated samples.

  17. The SDSS view of the Palomar-Green bright quasar survey

    Energy Technology Data Exchange (ETDEWEB)

    Jester, Sebastian; Schneider, Donald P.; Richards, Gordon T.; Green, Richard F.; Schmidt, Maarten; Hall, Patrick B.; Strauss, Michael A.; Vanden Berk, Daniel E.; Stoughton, Chris; Gunn, James E.; Brinkmann, Jon; Kent, Stephen M.; Smith, J.Allyn; Tucker, Douglas, L.; Yanny, Brian; /Fermilab /Penn State U., Astron. Astrophys. /Princeton U.

    2005-02-01

    The author investigates the extent to which the Palomar-Green (PG) Bright Quasar Survey (BQS) is complete and representative of the general quasar population by comparing with imaging and spectroscopy from the Sloan Digital Sky Survey. A comparison of SDSS and PG photometry of both stars and quasars reveals the need to apply a color and magnitude recalibration to the PG data. Using the SDSS photometric catalog, they define the PG's parent sample of objects that are not main-sequence stars and simulate the selection of objects from this parent sample using the PG photometric criteria and errors. This simulation shows that the effective U-B cut in the PG survey is U-B < -0.71, implying a color-related incompleteness. As the color distribution of bright quasars peaks near U-B = -0.7 and the 2-{sigma} error in U-B is comparable to the full width of the color distribution of quasars, the color incompleteness of the BQS is approximately 50% and essentially random with respect to U-B color for z < 0.5. There is however, a bias against bright quasars at 0.5 < z < 1, which is induced by the color-redshift relation of quasars (although quasars at z > 0.5 are inherently rare in bright surveys in any case). They find no evidence for any other systematic incompleteness when comparing the distributions in color, redshift, and FIRST radio properties of the BQS and a BQS-like subsample of the SDSS quasar sample. However, the application of a bright magnitude limit biases the BQS toward the inclusion of objects which are blue in g-i, in particular compared to the full range of g-i colors found among the i-band limited SDSS quasars, and even at i-band magnitudes comparable to those of the BQS objects.

  18. THE GALEX ARECIBO SDSS SURVEY. VII. THE BIVARIATE NEUTRAL HYDROGEN-STELLAR MASS FUNCTION FOR MASSIVE GALAXIES

    International Nuclear Information System (INIS)

    We present the bivariate neutral atomic hydrogen (H I)-stellar mass function (HISMF) φ(MHI, M*) for massive (log M*/M☉ \\gt 10) galaxies derived from a sample of 480 local (0.025 HI,M*>1010 and find that massive galaxies contribute 41% of the H I density in the local universe. In addition to the binned HISMF, we derive a continuous bivariate fit, which reveals that the Schechter parameters only vary weakly with stellar mass: MHI*, the characteristic H I mass, scales as M*0.39; α, the slope of the HISMF at moderate H I masses, scales as M*0.07; and f, the fraction of galaxies with H I gas fraction greater than 1%, scales as M*-0.24. The variation of f with stellar mass should be a strong constraint for numerical simulations. To understand the physical mechanisms that produce the shape of the HISMF, we redefine the parameters of the Schechter function as explicit functions of stellar mass and star formation rate (SFR) to produce a trivariate fit. This analysis reveals strong trends with SFR. While MHI* varies weakly with stellar mass and SFR (MHI* ∝ M*0.22, MHI* ∝ SFR–0.03), α is a stronger function of both stellar mass and especially SFR (α ∝ M*0.47, α ∝ SFR0.95). The HISMF is a crucial tool that can be used to constrain cosmological galaxy simulations, test observational predictions of the H I content of populations of galaxies, and identify galaxies whose properties deviate from average trends

  19. The SDSS Quasar Survey: Quasar Luminosity Function from Data Release Three

    CERN Document Server

    Richards, G T; Barentine, J C; Brewington, H J; Brinkmann, J; Brunner, R J; Fukugita, M; Gray, J; Gunn, J E; Hall, P B; Harvanek, M; Ivezic, Z; Jester, S; Kent, S M; Kirkland, M E; Kleinman, S J; Knapp, G R; Krzesínski, J; Long, D C; Loveday, J; Lupton, R H; Meiksin, A; Nash, T; Neilsen, E H; Nitta, A; Pope, A; Schlegel, D J; Schneider, D P; Snedden, S A; Stoughton, C; Strauss, M A; Szalay, A S; Thakar, A R; Vanden Berk, Daniel E; Xiaohui F; Yanny, B; York, Do G; Anderson, Scott F.; Berk, Daniel E. Vanden; Brunner, Robert J.; Fan, Xiaohui; Gray, Jim; Gunn, James E.; Hall, Patrick B.; Ivezic, Zeljko; Jester, Sebastian; Kirkland, Margaret E.; Loveday, Jon; Meiksin, Avery; Pope, Adrian; Richards, Gordon T.; Schneider, Donald P.; Stoughton, Chris; Strauss, Michael A.; Szalay, Alexander S.; Thakar, Anirudda R.; Yanny, Brian; York, Donald G.

    2006-01-01

    We determine the number counts and z=0-5 luminosity function for a well-defined, homogeneous sample of quasars from the Sloan Digital Sky Survey (SDSS). We conservatively define the most uniform statistical sample possible, consisting of 15,343 quasars within an effective area of 1622 deg^2 that was derived from a parent sample of 46,420 spectroscopically confirmed broad-line quasars in the 5282 deg^2 of imaging data from SDSS Data Release Three. The sample extends from i=15 to i=19.1 at z3. The number counts and luminosity function agree well with the results of the 2dF QSO Survey, but the SDSS data probe to much higher redshifts than does the 2dF sample. The number density of luminous quasars peaks between redshifts 2 and 3, although uncertainties in the selection function in this range do not allow us to determine the peak redshift more precisely. Our best fit model has a flatter bright end slope at high redshift than at low redshift. For z5-sigma level, must be accounted for in models of the evolution of ...

  20. An Empirical Calibration of the Completeness of the SDSS Quasar Survey

    CERN Document Server

    Vanden Berk, Daniel E; Richards, G T; Hall, P B; Strauss, M A; Brunner, R J; Fan, X; Baldry, I K; York, D G; Gunn, J E; Nichol, R C; Meiksin, A; Brinkmann, J; Berk, Daniel E. Vanden; Schneider, Donald P.; Richards, Gordon T.; Hall, Patrick B.; Strauss, Michael A.; Brunner, Robert; Fan, Xiaohui; Baldry, Ivan K.; York, Donald G.; Gunn, James E.; Nichol, Robert C.; Meiksin, Avery; Brinkmann, Jon

    2005-01-01

    Spectra of nearly 20000 point-like objects to a Galactic reddening corrected magnitude of i=19.1 have been obtained to test the completeness of the SDSS quasar survey. The spatially-unresolved objects were selected from all regions of color space, sparsely sampled from within a 278 sq. deg. area of sky covered by this study. Only ten quasars were identified that were not targeted as candidates by the SDSS quasar survey (including both color and radio source selection). The inferred density of unresolved quasars on the sky that are missed by the SDSS algorithm is 0.44 per sq. deg, compared to 8.28 per sq. deg. for the selected quasar density, giving a completeness of 94.9(+2.6,-3.8) to the limiting magnitude. Omitting radio selection reduces the color-only selection completeness by about 1%. Of the ten newly identified quasars, three have detected broad absorption line systems, six are significantly redder than other quasars at the same redshift, and four have redshifts between 2.7 and 3.0 (the redshift range ...

  1. Two Lensed z~3 Lyman Break Galaxies Discovered in the SDSS Giant Arcs Survey

    CERN Document Server

    Koester, Benjamin P; Hennawi, Joseph F; Sharon, Keren; Wuyts, Eva; Rigby, J R; Bayliss, Matthew B; Dahle, Hakon

    2010-01-01

    We report the discovery of two strongly-lensed z ~ 3 Lyman Break Galaxies (LBGs) discovered as u-band dropouts as part of the SDSS Giant Arcs Survey (SGAS). The first, SGAS J122651.3+215220 at z = 2.9233 is lensed by one of several sub-clusters, SDSS J1226+2152, in a complex massive cluster at z = 0.43. Its (g, r, i) magnitudes are (21.14, 20.60, 20.51) which translate to surface brightnesses, mu_{g,r,i}, of (23.78, 23.11, 22.81). The second, SGAS J152745.1+065219, is an LBG at z = 2.7593 lensed by the foreground SDSS J1527+0652 at z = 0.39, with (g, r, z)=(20.90, 20.52, 20.58) and mu_{g,r,z}=(25.15, 24.52, 24.12). Moderate resolution spectroscopy confirms the redshifts suggested by photometric breaks, and shows both absorption and emission features typical of LBGs. Lens mass models derived from combined imaging and spectroscopy reveal that SGAS J122651.3+215220 is a highly magnified source (M ~40), while SGAS J152745.1+065219 is magnified by no more than M ~ 15. Compared to LBG survey results (Steidel et al....

  2. The SDSS-IV extended Baryonic Oscillation Spectroscopic Survey: Quasar Target Selection

    CERN Document Server

    Myers, Adam D; Prakash, Abhishek; Pâris, Isabelle; Yeche, Christophe; Dawson, Kyle S; Bovy, Jo; Lang, Dustin; Schlegel, David J; Newman, Jeffrey A; Petitjean, Patrick; Kneib, Jean Paul; Laurent, Pierre; Percival, Will J; Ross, Ashley J; Seo, Hee-Jong; Tinker, Jeremy L; Armengaud, Eric; Brownstein, Joel; Burtin, Etienne; Cai, Zheng; Comparat, Johan; Kasliwal, Mansi; Kulkarni, Shrinivas R; Laher, Russ; Levitan, David; McBride, Cameron K; McGreer, Ian D; Miller, Adam A; Nugent, Peter; Ofek, Eran; Rossi, Graziano; Ruan, John; Schneider, Donald P; Sesar, Branimir; Streblyanska, Alina; Surace, Jason

    2015-01-01

    As part of the SDSS-IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will perform measurements of the cosmological distance scale via application of the Baryon Acoustic Oscillation (BAO) method to samples of quasars and galaxies. Quasar surveys are particularly useful in the BAO context as they can trace extremely large volumes back to moderately high redshift. eBOSS will adopt two approaches to target quasars over a 7500 sq. deg. area. First, z > 2.1 quasars will be targeted to improve BAO measurements in the Lyman-Alpha Forest. Second, a homogeneously selected "CORE" sample of quasars at 0.9 2.1 quasars. A supplemental selection based on variability of quasars in multi-epoch imaging from the Palomar Transient Factory should recover an additional ~3-4 per sq. deg. z > 2.1 quasars to g 500,000 new spectroscopically confirmed quasars and > 500,000 uniformly selected spectroscopically confirmed 0.9 < z < 2.2 quasars. At the conclusion of SDSS-IV, the SDSS will have provided unique spectra...

  3. The eleventh and twelfth data releases of the Sloan Digital Sky Survey:final data from SDSS-III

    OpenAIRE

    Alam, Shadab; Albareti, Franco D.; Prieto, Carlos Allende; Anders, F.; Anderson, Scott F; Andrews, Brett H.; Armengaud, Eric; Aubourg, Eric; Bailey, Stephen; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian

    2015-01-01

    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired ...

  4. Origin of the 12µm Emission Across Galaxy Populations from WISE and SDSS Surveys

    OpenAIRE

    Donoso, E; Yan, Lin; Tsai, C. W.; Eisenhardt, P.; Stern, D; Assef, R. J.; Leisawitz, D.; Jarrett, T. H.; Stanford, S A

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer (WISE) sources brighter than 1 mJy at 12µm with the Sloan Digital Sky Survey (SDSS) galaxy spectroscopic catalog to produce a sample of ~10^5 galaxies at =0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR lµminosities in the range ~10^8-10^(12) L_⊙. We identify which stellar populations are responsible for most of the 12µm emission. We find that most (~80%) of t...

  5. Origin of the 12um Emission Across Galaxy Populations from WISE and SDSS Surveys

    OpenAIRE

    Donoso, E; Yan, Lin; Tsai, C; Eisenhardt, P.; Stern, D; Assef, R. J.; Leisawitz, D.; Jarrett, T. H.; Stanford, S A

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer (WISE) sources brighter than 1 mJy at 12um with the Sloan Digital Sky Survey (SDSS) galaxy spectroscopic catalog to produce a sample of ~10^5 galaxies at =0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range ~10^8-10^12 L_sun. We identify which stellar populations are responsible for most of the 12um emission. We find that most (~80%) of t...

  6. The Core Collapse Supernova Rate from the SDSS-II Supernova Survey

    CERN Document Server

    Taylor, Matt; Dilday, Ben; Galbany, Lluis; Gupta, Ravi R; Kessler, R; Marriner, John; Nichol, Robert C; Richmond, Michael; Schneider, Donald P; Sollerman, Jesper

    2014-01-01

    We use the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SNS) data to measure the volumetric core collapse supernova (CCSN) rate in the redshift range (0.03

  7. The core collapse supernova rate from the SDSS-II supernova survey

    OpenAIRE

    Taylor, Matt; Cinabro, David; Dilday, Ben; Galbany, Lluis; Gupta, Ravi R.; Kessler, R.; Marriner, John; Nichol, Robert C.; Richmond, Michael; Schneider, Donald P.; Sollerman, Jesper

    2014-01-01

    We use the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SNS) data to measure the volumetric core collapse supernova (CCSN) rate in the redshift range (0.03 < z < 0.09). Using a sample of 89 CCSN, we find a volume-averaged rate of 1.06 ± 0.19 × 10–4((h/0.7)3/(yr Mpc3)) at a mean redshift of 0.072 ± 0.009. We measure the CCSN luminosity function from the data and consider the implications on the star formation history.

  8. A Survey of CN and CH Variations in Galactic Globular Clusters from SDSS Spectroscopy

    OpenAIRE

    Smolinski, Jason P.; Martell, Sarah L.; Beers, Timothy C.; Lee, Young Sun

    2011-01-01

    We present a homogeneous survey of the CN and CH bandstrengths in eight Galactic globular clusters observed during the course of the Sloan Extension for Galactic Understanding and Exploration (SEGUE) sub-survey of the SDSS. We confirm the existence of a bimodal CN distribution among RGB stars in all of the clusters with metallicity greater than [Fe/H] = -1.7; the lowest metallicity cluster with an observed CN bimodality is M53, with [Fe/H] ~ -2.1. There is also some evidence for individual CN...

  9. The HI Mass Function and Velocity Width Function of Void Galaxies in the Arecibo Legacy Fast ALFA Survey

    CERN Document Server

    Moorman, Crystal M; Hoyle, Fiona; Pan, Danny C; Haynes, Martha P; Giovanelli, Riccardo

    2014-01-01

    We measure the HI mass function (HIMF) and velocity width function (WF) across environments over a range of masses $7.2<\\log(M_{HI}/M_{\\odot})<10.8$, and profile widths $1.3\\log(km/s)<\\log(W)<2.9\\log(km/s)$, using a catalog of ~7,300 HI-selected galaxies from the ALFALFA Survey, located in the region of sky where ALFALFA and SDSS (Data Release 7) North overlap. We divide our galaxy sample into those that reside in large-scale voids (void galaxies) and those that live in denser regions (wall galaxies). We find the void HIMF to be well fit by a Schechter function with normalization $\\Phi^*=(1.37\\pm0.1)\\times10^{-2} h^3Mpc^{-3}$, characteristic mass $\\log(M^*/M_{\\odot})+2\\log h_{70}=9.86\\pm0.02$, and low-mass-end slope $\\alpha=-1.29\\pm0.02$. Similarly, for wall galaxies, we find best-fitting parameters $\\Phi^*=(1.82\\pm0.03)\\times10^{-2} h^3Mpc^{-3}$, $\\log(M^*/M_{\\odot})+2\\log h_{70}=10.00\\pm0.01$, and $\\alpha=-1.35\\pm0.01$. We conclude that void galaxies typically have slightly lower HI masses than ...

  10. SDSS-IV eBOSS emission-line galaxy pilot survey

    Science.gov (United States)

    Comparat, J.; Delubac, T.; Jouvel, S.; Raichoor, A.; Kneib, J.-P.; Yèche, C.; Abdalla, F. B.; Le Cras, C.; Maraston, C.; Wilkinson, D. M.; Zhu, G.; Jullo, E.; Prada, F.; Schlegel, D.; Xu, Z.; Zou, H.; Bautista, J.; Bizyaev, D.; Bolton, A.; Brownstein, J. R.; Dawson, K. S.; Escoffier, S.; Gaulme, P.; Kinemuchi, K.; Malanushenko, E.; Malanushenko, V.; Mariappan, V.; Newman, J. A.; Oravetz, D.; Pan, K.; Percival, W. J.; Prakash, A.; Schneider, D. P.; Simmons, A.; Abbott, T. M. C.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Doel, P.; Eifler, T. F.; Estrada, J.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Miquel, R.; Plazas, A. A.; Reil, K.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Zhang, Y.

    2016-08-01

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195 000 emission-line galaxies (ELGs) to measure the baryonic acoustic oscillation (BAO) standard ruler at redshift 0.9. To test different ELG selection algorithms, 9000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Finally, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements. The catalog is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A121

  11. THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Kyle S.; Ahn, Christopher P.; Bolton, Adam S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J.; Bailey, Stephen [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, Scott F.; Bhardwaj, Vaishali [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Aubourg, Eric; Bautista, Julian E. [APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite (France); Barkhouser, Robert H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Beifiori, Alessandra [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Berlind, Andreas A. [Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235 (United States); Bizyaev, Dmitry; Brewington, Howard [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Blake, Cullen H. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Blanton, Michael R. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Borde, Arnaud [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette (France); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Brandt, W. N., E-mail: kdawson@astro.utah.edu [Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); and others

    2013-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large-scale structure. BOSS uses 1.5 million luminous galaxies as faint as i = 19.9 over 10,000 deg{sup 2} to measure BAO to redshifts z < 0.7. Observations of neutral hydrogen in the Ly{alpha} forest in more than 150,000 quasar spectra (g < 22) will constrain BAO over the redshift range 2.15 < z < 3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Ly{alpha} forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance d{sub A} to an accuracy of 1.0% at redshifts z = 0.3 and z = 0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Ly{alpha} forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D{sub A} (z) and H {sup -1}(z) parameters to an accuracy of 1.9% at z {approx} 2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.

  12. The Arecibo Legacy Fast ALFA Survey: The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function

    CERN Document Server

    Haynes, Martha P; Martin, Ann M; Hess, Kelley M; Saintonge, Amelie; Adams, Elizabeth A K; Hallenbeck, Gregory; Hoffman, G Lyle; Huang, Shan; Kent, Brian R; Koopmann, Rebecca A; Papastergis, Emmanouil; Stierwalt, Sabrina; Balonek, Thomas J; Craig, David W; Higdon, Sarah J U; Kornreich, David A; Miller, Jeffrey R; O'Donoghue, Aileen A; Olowin, Ronald P; Rosenberg, Jessica L; Spekkens, Kristine; Troischt, Parker; Wilcots, Eric M

    2011-01-01

    We present a current catalog of 21 cm HI line sources extracted from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey over ~2800 square degrees of sky: the alpha.40 catalog. Covering 40% of the final survey area, the alpha.40 catalog contains 15855 sources in the regions 07h30m < R.A. < 16h30m, +04 deg < Dec. < +16 deg and +24 deg < Dec. < +28 deg and 22h < R.A. < 03h, +14 deg < Dec. < +16 deg and +24 deg < Dec. < +32 deg. Of those, 15041 are certainly extragalactic, yielding a source density of 5.3 galaxies per square degree, a factor of 29 improvement over the catalog extracted from the HI Parkes All Sky Survey. In addition to the source centroid positions, HI line flux densities, recessional velocities and line widths, the catalog includes the coordinates of the most probable optical counterpart of each HI line detection, and a separate compilation provides a crossmatch to identifications given in the photometric and spectroscopic catalogs associated wi...

  13. The Swift AGN and Cluster Survey. II. Cluster Confirmation with SDSS Data

    CERN Document Server

    Griffin, Rhiannon D; Kochanek, Christopher S; Bregman, Joel N

    2015-01-01

    We study 203 extended X-ray sources in the Swift GRB fields that are located within the Sloan Digital Sky Survey (SDSS) DR8 footprint. We search for galaxy over-densities in three-dimensional space using SDSS galaxies and their photometric redshifts near the Swift cluster candidates. We find 103 Swift clusters with a >3 sigma over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmations as galaxy clusters. We present a series of cluster properties including the redshift, BCG magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in almost half of the 103 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distri...

  14. Search for carbon stars and DZ white dwarfs in SDSS spectra survey through machine learning

    Science.gov (United States)

    Si, JianMin; Luo, ALi; Li, YinBi; Zhang, JianNan; Wei, Peng; Wu, YiHong; Wu, FuChao; Zhao, YongHeng

    2014-01-01

    Carbon stars and DZ white dwarfs are two types of rare objects in the Galaxy. In this paper, we have applied the label propagation algorithm to search for these two types of stars from Data Release Eight (DR8) of the Sloan Digital Sky Survey (SDSS), which is verified to be efficient by calculating precision and recall. From nearly two million spectra including stars, galaxies and QSOs, we have found 260 new carbon stars in which 96 stars have been identified as dwarfs and 7 identified as giants, and 11 composition spectrum systems (each of them consists of a white dwarf and a carbon star). Similarly, using the label propagation method, we have obtained 29 new DZ white dwarfs from SDSS DR8. Compared with PCA reconstructed spectra, the 29 findings are typical DZ white dwarfs. We have also investigated their proper motions by comparing them with proper motion distribution of 9,374 white dwarfs, and found that they satisfy the current observed white dwarfs by SDSS generally have large proper motions. In addition, we have estimated their effective temperatures by fitting the polynomial relationship between effective temperature and g-r color of known DZ white dwarfs, and found 12 of the 29 new DZ white dwarfs are cool, in which nine are between 6,000 K and 6,600 K, and three are below 6,000 K.

  15. The Baryon Oscillation Spectroscopic Survey of SDSS-III

    CERN Document Server

    Dawson, Kyle S; Ahn, Christopher P; Anderson, Scott F; Aubourg, Eric; Bailey, Stephen; Barkhouser, Robert H; Bautista, Julian E; Beifiori, Alessandra; Berlind, Andreas A; Bhardwaj, Vaishali; Bizyaev, Dmitry; Blake, Cullen H; Blanton, Michael R; Blomqvist, Michael; Bolton, Adam S; Borde, Arnaud; Bovy, Jo; Brandt, W N; Brewington, Howard; Brinkmann, Jon; Brown, Peter J; Brownstein, Joel R; Bundy, Kevin; Busca, N G; Carithers, William; Carnero, Aurelio R; Carr, Michael A; Chen, Yanmei; Comparat, Johan; Connolly, Natalia; Cope, Frances; Croft, Rupert A C; Cuesta, Antonio J; da Costa, Luiz N; Davenport, James R A; Delubac, Timothee; de Putter, Roland; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L; Eisenstein, Daniel J; Escoffier, S; Fan, Xiaohui; Ak, N Filiz; Finley, Hayley; Font-Ribera, Andreu; Genova-Santos, R; Gunn, James E; Guo, Hong; Haggard, Daryl; Hall, Patrick B; Hamilton, Jean-Christophe; Harris, Ben; Harris, David W; Ho, Shirley; Hogg, David W; Holder, Diana; Honscheid, Klaus; Huehnerhoff, Joe; Jordan, Beatrice; Jordan, Wendell P; Kauffmann, Guinevere; Kazin, Eyal A; Kirkby, David; Klaene, Mark A; Kneib, Jean-Paul; Goff, Jean-Marc Le; Lee, Khee-Gan; Long, Daniel C; Loomis, Craig P; Lundgren, Britt; Lupton, Robert H; Maia, Marcio A G; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Manera, Marc; Maraston, Claudia; Margala, Daniel; Masters, Karen L; McBride, Cameron K; McDonald, Patrick; McGreer, Ian D; Mena, Olga; Miralda-Escude, Jordi; Montero-Dorta, Antonio D; Montesano, Francesco; Muna, Demitri; Myers, Adam D; Naugle, Tracy; Nichol, Robert C; Noterdaeme, Pasquier; Olmstead, Matthew D; Oravetz, Audrey; Oravetz, Daniel J; Owen, Russell; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K; Paris, Isabelle; Percival, Will J; Perez-Fournon, Ismael; Perez-Rafols, Ignasi; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Pieri, Matthew M; Prada, Francisco; Price-Whelan, Adrian M; Raddick, M Jordan; Rebolo, Rafael; Rich, James; Richards, Gordon T; Rockosi, Constance M; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Rossi, Graziano; Rubino-Martin, J A; Samushia, Lado; Sanchez, Ariel G; Sayres, Conor; Schmidt, Sarah J; Schneider, Donald P; Scoccola, C G; Seo, Hee-Jong; Shelden, Alaina; Sheldon, Erin; Shen, Yue; Shu, Yiping; Slosar, Anze; Smee, Stephen A; Snedden, Stephanie A; Stauffer, Fritz; Steele, Oliver; Strauss, Michael A; Suzuki, Nao; Swanson, Molly E C; Tal, Tomer; Tanaka, Masayuki; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Tremonti, Christy A; Magana, M Vargas; Verde, Licia; Viel, Matteo; Wake, David A; Watson, Mike; Weaver, Benjamin A; Weinberg, David H; Weiner, Benjamin J; West, Andrew A; White, Martin; Wood-Vasey, W M; Yeche, Christophe; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng

    2012-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses luminous galaxies to measure BAO to redshifts z<0.7 and observations of neutral hydrogen in the Lyman alpha forest in quasar spectra to constrain BAO over the redshift range 2.15

  16. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection

    Science.gov (United States)

    Myers, Adam D.; Palanque-Delabrouille, Nathalie; Prakash, Abhishek; Pâris, Isabelle; Yeche, Christophe; Dawson, Kyle S.; Bovy, Jo; Lang, Dustin; Schlegel, David J.; Newman, Jeffrey A.; Petitjean, Patrick; Kneib, Jean-Paul; Laurent, Pierre; Percival, Will J.; Ross, Ashley J.; Seo, Hee-Jong; Tinker, Jeremy L.; Armengaud, Eric; Brownstein, Joel; Burtin, Etienne; Cai, Zheng; Comparat, Johan; Kasliwal, Mansi; Kulkarni, Shrinivas R.; Laher, Russ; Levitan, David; McBride, Cameron K.; McGreer, Ian D.; Miller, Adam A.; Nugent, Peter; Ofek, Eran; Rossi, Graziano; Ruan, John; Schneider, Donald P.; Sesar, Branimir; Streblyanska, Alina; Surace, Jason

    2015-12-01

    As part of the Sloan Digital Sky Survey (SDSS) IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 deg2. First, a “CORE” quasar sample will combine the optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color cut. eBOSS CORE selection (to g 2.1 quasars. Second, a selection based on variability in multi-epoch imaging from the Palomar Transient Factory should recover an additional ˜3-4 deg-2z > 2.1 quasars to g sample should thus be sufficiently dense and homogeneous over 0.9 2.1 will be used to improve BAO measurements in the Lyα Forest. Beyond its key cosmological goals, eBOSS should be the next-generation quasar survey, comprising >500,000 new quasars and >500,000 uniformly selected spectroscopically confirmed 0.9 < z < 2.2 quasars. At the conclusion of eBOSS, the SDSS will have provided unique spectra for more than 800,000 quasars.

  17. Cross-correlation cosmic shear with the SDSS and VLA FIRST surveys

    Science.gov (United States)

    Demetroullas, C.; Brown, M. L.

    2016-03-01

    We measure the cosmic shear power spectrum on large angular scales by cross-correlating the shapes of ˜9 million galaxies measured in the optical Sloan Digital Sky Survey (SDSS) with the shapes of ˜2.7 × 105 radio galaxies measured by the overlapping Very Large Array FIRST (Faint Images of the Radio Sky at Twenty centimetres) survey. Our measurements span the multipole range 10 measurement of the shear power spectrum from either survey alone. Conversely, we demonstrate that a power spectrum measured by cross-correlating the two surveys is unbiased, reducing the impact of the systematics by at least an order of magnitude. We measure an E-mode power spectrum from the data that is inconsistent with zero signal at the 99 per cent confidence (˜2.7σ) level. The B-mode and EB cross-correlations are both found to be consistent with zero (within 1σ). These constraints are obtained after a careful error analysis that accounts for uncertainties due to cosmic variance, random galaxy shape noise and shape measurement errors, as well as additional errors associated with the observed large-scale systematic effects in the two surveys. Our constraints are consistent with the expected signal in the concordance cosmological model assuming recent estimates of the cosmological parameters from the Planck satellite, and literature values for the median redshifts of the SDSS and FIRST galaxy populations. The cross-correlation approach will be ideal for extracting robust results, with the exquisite control of systematics required, from future cosmic shear surveys with the Square Kilometre Array, Large Synoptic Survey Telescope, Euclid and WFIRST-AFTA.

  18. THE ARECIBO LEGACY FAST ALFA SURVEY: THE α.40 H I SOURCE CATALOG, ITS CHARACTERISTICS AND THEIR IMPACT ON THE DERIVATION OF THE H I MASS FUNCTION

    International Nuclear Information System (INIS)

    We present a current catalog of 21 cm H I line sources extracted from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey over ∼2800 deg2 of sky: the α.40 catalog. Covering 40% of the final survey area, the α.40 catalog contains 15,855 sources in the regions 07h30m h30m, +04° h h, +14° 2, a factor of 29 improvement over the catalog extracted from the H I Parkes All-Sky Survey. In addition to the source centroid positions, H I line flux densities, recessional velocities, and line widths, the catalog includes the coordinates of the most probable optical counterpart of each H I line detection, and a separate compilation provides a cross-match to identifications given in the photometric and spectroscopic catalogs associated with the Sloan Digital Sky Survey Data Release 7. Fewer than 2% of the extragalactic H I line sources cannot be identified with a feasible optical counterpart; some of those may be rare OH megamasers at 0.16 < z < 0.25. A detailed analysis is presented of the completeness, width-dependent sensitivity function and bias inherent of the α.40 catalog. The impact of survey selection, distance errors, current volume coverage, and local large-scale structure on the derivation of the H I mass function is assessed. While α.40 does not yet provide a completely representative sampling of cosmological volume, derivations of the H I mass function using future data releases from ALFALFA will further improve both statistical and systematic uncertainties.

  19. SDSS-III Baryon Oscillation Spectroscopic Survey Data Release 12:galaxy target selection and large scale structure catalogues

    OpenAIRE

    Reid, Beth; Ho, Shirley; Padmanabhan, Nikhil; Percival, Will J.; Tinker, Jeremy; Tojeiro, Rita; White, Martin; Eisenstein, Daniel J.; Maraston, Claudia; Ross, Ashley J.; Sanchez, Ariel G.; Schlegel, David; Sheldon, Erin; Strauss, Michael A.; Thomas, Daniel

    2016-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target cat...

  20. THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: THE QUASAR LUMINOSITY FUNCTION FROM DATA RELEASE NINE

    International Nuclear Information System (INIS)

    We present a new measurement of the optical quasar luminosity function (QLF), using data from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III: BOSS). From the SDSS-III Data Release Nine, a uniform sample of 22,301 i ∼2, with confirmed spectroscopic redshifts between 2.2 i (z = 2.2) ≈ –24.5 and see a clear break in the QLF at all redshifts up to z = 3.5. A log-linear relation (in log Φ* – M*) for a luminosity evolution and density evolution model is found to adequately describe our data within the range 2.2 < z < 3.5; across this interval the break luminosity increases by a factor of ∼2.6 while Φ* declines by a factor of ∼8. At z ∼< 2.2 our data are reasonably well fit by a pure luminosity evolution model, and only a weak signature of ''AGN downsizing'' is seen, in line with recent studies of the hard X-ray luminosity function. We compare our measured QLF to a number of theoretical models and find that models making a variety of assumptions about quasar triggering and halo occupation can fit our data over a wide range of redshifts and luminosities

  1. New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey

    CERN Document Server

    Zamora, O; Prieto, C Allende; Carrera, R; Koesterke, L; Edvardsson, B; Castelli, F; Plez, B; Bizyaev, D; Cunha, K; Perez, A E Garcia; Gustafsson, B; Holtzman, J A; Lawler, J E; Majewski, S R; Manchado, A; Meszaros, Sz; Shane, N; Shetrone, M; Smith, V V; Zasowski, G

    2015-01-01

    The Sloan Digital Sky Survey--III (SDSS--III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) has obtained high resolution (R $\\sim$ 22,500), high signal-to-noise ($>$ 100) spectra in the H$-$band spectral region ($\\sim$1.5$-$1.7 $\\mu$m) for about 146,000 stars in the Milky Way galaxy. We have computed specific spectral libraries with effective temperature ($T\\rm{_{eff}}$) ranging from 3500 to 8000 K for the automated chemical analysis of the survey data. The spectral libraries, used to derive stellar parameters and abundances from the APOGEE spectra in the SDSS--III data release 12 (DR12), are based on ATLAS9 model atmospheres and the ASS$\\epsilon$T spectral synthesis code. We present a second set of stellar spectral libraries based on MARCS model atmospheres and the spectral synthesis code Turbospectrum. The ATLAS9/ASS$\\epsilon$T ($T\\rm{_{eff}}$ = 3500$-$8000 K) and MARCS/Turbospectrum ($T\\rm{_{eff}}$ = 3500$-$5500 K) grids of synthetic spectra cover a wide range of metallicity ($-$2.5 $\\leq...

  2. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measuring structure growth using passive galaxies

    OpenAIRE

    Tojeiro, Rita; Percival, Will J.; Brinkmann, Jon; Brownstein, Joel R.; Eisenstein, Daniel J.; Manera, Marc; Maraston, Claudia; McBride, Cameron K.; Muna, Demitri; Reid, Beth; Ross, Ashley J.; Ross, Nicholas P.; Samushia, Lado; Padmanabhan, Nikhil; Schneider, Donald P.

    2012-01-01

    We explore the benefits of using a passively evolving population of galaxies to measure the evolution of the rate of structure growth between z=0.25 and z=0.65 by combining data from the SDSS-I/II and SDSS-III surveys. The large-scale linear bias of a population of dynamically passive galaxies, which we select from both surveys, is easily modeled. Knowing the bias evolution breaks degeneracies inherent to other methodologies, and decreases the uncertainty in measurements of the rate of struct...

  3. THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: QUASAR TARGET SELECTION FOR DATA RELEASE NINE

    International Nuclear Information System (INIS)

    The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10,000 deg2, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations (BAOs) in the distribution of Lyα absorption from the spectra of a sample of ∼150,000 z > 2.2 quasars. Along with measuring the angular diameter distance at z ≈ 2.5, BOSS will provide the first direct measurement of the expansion rate of the universe at z > 2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars in the redshift range 2.2 –2 in this redshift range, with a goal of 20 out of 40 targets deg–2 allocated to the quasar survey. To achieve these surface densities, the magnitude limit of the quasar targets was set at g ≤ 22.0 or r ≤ 21.85. While detection of the BAO signature in the distribution of Lyα absorption in quasar spectra does not require a uniform target selection algorithm, many other astrophysical studies do. We have therefore defined a uniformly selected subsample of 20 targets deg–2, for which the selection efficiency is just over 50% (∼10 z > 2.20 quasars deg–2). This 'CORE' subsample will be fixed for Years Two through Five of the survey. For the remaining 20 targets deg–2, we will continue to develop improved selection techniques, including the use of additional data sets beyond the Sloan Digital Sky Survey (SDSS) imaging data. In this paper, we describe the evolution and implementation of the BOSS QTS algorithms during the first two years of BOSS operations (through 2011 July), in support of the science investigations based on these data, and we analyze the spectra obtained during the first year. During this year, 11,263 new z > 2.20 quasars were spectroscopically confirmed by BOSS, roughly double the number of previously known quasars with z > 2.20. Our current algorithms select an average of 15 z > 2.20 quasars deg–2 from 40

  4. A Survey of CN and CH Variations in Galactic Globular Clusters from SDSS Spectroscopy

    CERN Document Server

    Smolinski, Jason P; Beers, Timothy C; Lee, Young Sun

    2011-01-01

    We present a homogeneous survey of the CN and CH bandstrengths in eight Galactic globular clusters observed during the course of the Sloan Extension for Galactic Understanding and Exploration (SEGUE) sub-survey of the SDSS. We confirm the existence of a bimodal CN distribution among RGB stars in all of the clusters with metallicity greater than [Fe/H] = -1.7; the lowest metallicity cluster with an observed CN bimodality is M53, with [Fe/H] ~ -2.1. There is also some evidence for individual CN groups on the subgiant branches of M92, M2, and M13, and on the red giant branches of M92 and NGC 5053. Finally, we quantify the correlation between overall cluster metallicity and the slope of the CN bandstrength-luminosity plot as a means of further demonstrating the level of CN-enrichment in cluster giants. Our results agree well with previous studies reported in the literature.

  5. Bayesian analysis of the dynamic cosmic web in the SDSS galaxy survey

    CERN Document Server

    Leclercq, Florent; Wandelt, Benjamin

    2015-01-01

    Recent application of the Bayesian algorithm BORG to the Sloan Digital Sky Survey (SDSS) main sample galaxies resulted in the physical inference of the formation history of the observed large-scale structure from its origin to the present epoch. In this work, we use these inferences as inputs for a detailed probabilistic cosmic web-type analysis. To do so, we generate a large set of data-constrained realizations of the large-scale structure using a fast, fully non-linear gravitational model. We then perform a dynamic classification of the cosmic web into four distinct components (voids, sheets, filaments and clusters) on the basis of the tidal field. Our inference framework automatically and self-consistently propagates typical observational uncertainties to web-type classification. As a result, this study produces highly detailed and accurate cosmographic classification of large-scale structure elements in the SDSS volume. By also providing the history of these structure maps, the approach allows an analysis...

  6. THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: THE QUASAR LUMINOSITY FUNCTION FROM DATA RELEASE NINE

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Nicholas P.; White, Martin; Bailey, Stephen [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); McGreer, Ian D. [Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Palanque-Delabrouille, Nathalie; Yeche, Christophe [CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette (France); Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Shen, Yue; Swanson, Molly E. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Brandt, W. N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Aubourg, Eric [APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite (France); Bizyaev, Dmitry; Brewington, Howard; Brinkmann, J. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); DeGraf, Colin; Di Matteo, Tiziana, E-mail: npross@lbl.gov [McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); and others

    2013-08-10

    We present a new measurement of the optical quasar luminosity function (QLF), using data from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III: BOSS). From the SDSS-III Data Release Nine, a uniform sample of 22,301 i {approx}< 21.8 quasars are selected over an area of 2236 deg{sup 2}, with confirmed spectroscopic redshifts between 2.2 < z < 3.5, filling in a key part of the luminosity-redshift plane for optical quasar studies. The completeness of the survey is derived through simulated quasar photometry, and this completeness estimate is checked using a sample of quasars selected by their photometric variability within the BOSS footprint. We investigate the level of systematics associated with our quasar sample using the simulations, in the process generating color-redshift relations and a new quasar K-correction. We probe the faint end of the QLF to M{sub i} (z = 2.2) Almost-Equal-To -24.5 and see a clear break in the QLF at all redshifts up to z = 3.5. A log-linear relation (in log {Phi}* - M*) for a luminosity evolution and density evolution model is found to adequately describe our data within the range 2.2 < z < 3.5; across this interval the break luminosity increases by a factor of {approx}2.6 while {Phi}* declines by a factor of {approx}8. At z {approx}< 2.2 our data are reasonably well fit by a pure luminosity evolution model, and only a weak signature of ''AGN downsizing'' is seen, in line with recent studies of the hard X-ray luminosity function. We compare our measured QLF to a number of theoretical models and find that models making a variety of assumptions about quasar triggering and halo occupation can fit our data over a wide range of redshifts and luminosities.

  7. 2dF-SDSS LRG and QSO (2SLAQ) Survey: Evolution of the Most Massive Galaxies

    CERN Document Server

    Nichol, R; Roseboom, I; Wake, D; Nichol, Robert; Cannon, Russell; Roseboom, Isaac; Wake, David

    2006-01-01

    The 2dF-SDSS LRG and QSO (2SLAQ) survey is a new survey of distant Luminous Red Galaxies (LRGs) and faint quasars selected from the Sloan Digital Sky Survey (SDSS) multi-color photometric data and spectroscopically observed using the 2dF instrument on the Anglo-Australian Telescope (AAT). In total, the 2SLAQ survey has measured over 11000 LRG redshifts, covering 180deg^2 of SDSS imaging data, from 87 allocated nights of AAT time. Over 90% of these galaxies are within the range 0.45=3L*. When combined with the lower redshift SDSS LRGs, the evolution in the luminosity function of these LRGs is fully consistent with that expected from a simple passive (luminosity) evolution model. This observation suggests that at least half of the LRGs seen at z~0.2 must already have more than half their stellar mass in place by z~0.6, i.e., our observations are inconsistent with a majority of LRGs experiencing a major merger in the last 6 Gyrs. However, some "frosting" (i.e., minor mergers) has taken place with ~5% of LRGs sho...

  8. The SDSS-III APOGEE Radial Velocity Survey of M dwarfs I: Description of Survey and Science Goals

    CERN Document Server

    Deshpande, R; Bender, C F; Mahadevan, S; Terrien, R C; Carlberg, J; Zasowski, G; Crepp, J; Rajpurohit, A S; Reyle, C; Nidever, D L; Schneider, D P; Prieto, C Allende; Bizyaev, D; Ebelke, G; Fleming, S W; Frinchaboy, P M; Ge, J; Hearty, F; Hernandez, J; Malanushenko, E; Malanushenko, V; Majewski, S R; Oravetz, D; Pan, K; Schiavon, R P; Shetrone, M; Simmons, A; Stassun, K G; Wilson, J C; Wisniewski, J

    2013-01-01

    We are carrying out a large ancillary program with the SDSS-III, using the fiber-fed multi-object NIR APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations are used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey and results from the first year of scientific observations based on spectra that is publicly available in the SDSS-III DR10 data release. As part of this paper we present RVs and vsini of over 200 M dwarfs, with a vsini precision of ~2 km/s and a measurement floor at vsini = 4 km/s. This survey significantly increases the number of M dwarfs studied for vsini and RV variability (at ~100-200 m/s), and will advance the target selection for planned RV and photometric searches for low mass exoplanets around M dwarfs, such as HPF, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to iden...

  9. A Catalog of Luminous Infrared Galaxies in the IRAS Survey and Second Data Release of SDSS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    We selected a sample of luminous infrared galaxies by cross-identification of the Faint Source Catalogue (FSC) and Point Source Catalogue (PSC) of the IRAS Survey with the Second Data Release of the SDSS. The size of our sample is 1267 for FSC and 427 for PSC by using the 2σ significance level cross-section. The "likelihood ratio" method is used to estimate the individual's reliability and for defining two more reliable subsamples (908 for FSC and 356 for PSC). A catalog of infrared,optical and radio data is compiled and will be used in further work. Some statistical results show that luminous infrared galaxies are quite different from ultra-luminous infrared galaxies. The AGN fractions of galaxies at different infrared luminosities and the radio-infrared correlations are consistent with the previous studies.

  10. The Time-Domain Spectroscopic Survey: Understanding the Optically Variable Sky with SEQUELS in SDSS-III

    CERN Document Server

    Ruan, John J; Green, Paul J; Morganson, Eric; Eracleous, Michael; Myers, Adam D; Badenes, Carles; Bershady, Matthew A; Brandt, William N; Chambers, Kenneth C; Davenport, James R A; Dawson, Kyle S; Flewelling, Heather; Heckman, Timothy M; Isler, Jedidah C; Kaiser, Nick; Kneib, Jean-Paul; MacLeod, Chelsea L; Paris, Isabelle; Ross, Nicholas P; Runnoe, Jessie C; Schlafly, Edward F; Schmidt, Sarah J; Schneider, Donald P; Schwope, Axel D; Shen, Yue; Stassun, Keivan G; Szkody, Paula; Waters, Christoper Z; York, Donald G

    2016-01-01

    The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of ~220,000 optically-variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a preview of the science enabled by TDSS, based on TDSS spectra taken over ~320 deg^2 of sky as part of the SEQUELS survey in SDSS-III, which is in part a pilot survey for eBOSS in SDSS-IV. Using the 15,746 TDSS-selected single-epoch spectra of photometrically variable objects in SEQUELS, we determine the demographics of our variability-selected sample, and investigate the unique spectral characteristics inherent in samples selected by variability. We show that variability-based selection of quasars complements color-based selection by selecting additional redder quasars, and mitigates redshift biases to produce a smooth quasar redshift distribution over a wide range of redshifts. The resulting quasar sample contains systematically higher fractions of blazars and broad ...

  11. A Spectroscopic Survey of Faint Quasars in the SDSS Deep Stripe: I. Preliminary Results from the Co-added Catalog

    CERN Document Server

    Jiang, L; Cool, R J; Eisenstein, D J; Fan, X; Johnston, D; Richards, G T; Schneider, D P; Scranton, R; Strauss, M A; Zehavi, I

    2006-01-01

    In this paper we present the first results of a deep spectroscopic survey of faint quasars in the Sloan Digital Sky Survey (SDSS) Southern Survey, a deep survey carried out by repeatedly imaging a 270 deg^2 area. Quasar candidates were selected from the deep data with good completeness over 02.0) at the faint end, indicating a break in the QLF slope. Using a luminosity-dependent density evolution model, we find that the quasar density at M_{g}<-22.5 peaks at z~2, which is later in cosmic time than the peak of z~2.5 found from surveys of more luminous objects. The SFQS QLF is consistent with the results of the 2dF QSO Redshift Survey, the SDSS, and the 2dF-SDSS LRG and QSO Survey, but probes fainter quasars. We plan to obtain more quasars from future observations and establish a complete faint quasar sample with more than 1000 objects over 10 deg^2.

  12. THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: QUASAR TARGET SELECTION FOR DATA RELEASE NINE

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Nicholas P.; Kirkpatrick, Jessica A.; Carithers, William C.; Ho, Shirley [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Myers, Adam D. [Department of Astronomy, MC-221, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Sheldon, Erin S. [Brookhaven National Laboratory, Blgd 510, Upton, NY 11375 (United States); Yeche, Christophe; Aubourg, Eric [CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Strauss, Michael A.; Lee, Khee-Gan [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Bovy, Jo; Blanton, Michael R.; Hogg, David W. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Brandt, W. N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Croft, Rupert A. C. [Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Da Silva, Robert [Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA 95064 (United States); Dawson, Kyle [Department of Physics and Astronomy, University of Utah, UT (United States); Eisenstein, Daniel J. [Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Hennawi, Joseph F., E-mail: npross@lbl.gov [Max-Planck-Institut fuer Astronomie, Konigstuhl 17, 69117 Heidelberg (Germany); and others

    2012-03-01

    The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10,000 deg{sup 2}, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations (BAOs) in the distribution of Ly{alpha} absorption from the spectra of a sample of {approx}150,000 z > 2.2 quasars. Along with measuring the angular diameter distance at z Almost-Equal-To 2.5, BOSS will provide the first direct measurement of the expansion rate of the universe at z > 2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars in the redshift range 2.2 < z < 3.5, where their colors tend to overlap those of the far more numerous stars. During the first year of the BOSS survey, quasar target selection (QTS) methods were developed and tested to meet the requirement of delivering at least 15 quasars deg{sup -2} in this redshift range, with a goal of 20 out of 40 targets deg{sup -2} allocated to the quasar survey. To achieve these surface densities, the magnitude limit of the quasar targets was set at g {<=} 22.0 or r {<=} 21.85. While detection of the BAO signature in the distribution of Ly{alpha} absorption in quasar spectra does not require a uniform target selection algorithm, many other astrophysical studies do. We have therefore defined a uniformly selected subsample of 20 targets deg{sup -2}, for which the selection efficiency is just over 50% ({approx}10 z > 2.20 quasars deg{sup -2}). This 'CORE' subsample will be fixed for Years Two through Five of the survey. For the remaining 20 targets deg{sup -2}, we will continue to develop improved selection techniques, including the use of additional data sets beyond the Sloan Digital Sky Survey (SDSS) imaging data. In this paper, we describe the evolution and implementation of the BOSS QTS algorithms during the first two years of BOSS operations (through 2011 July), in support of the science investigations

  13. NIBLES - an HI census of stellar mass selected SDSS galaxies: I. The Nan\\c{c}ay HI survey

    CERN Document Server

    van Driel, W; Schneider, S; Lehnert, M D; Minchin, R; Blyth, S-L; Chemin, L; Hallet, N; Joseph, T; Kotze, P; Kraan-Korteweg, R C; Olofsson, A O H; Ramatsoku, M

    2016-01-01

    To investigate galaxy properties as a function of their total stellar mass, we obtained 21cm HI line observations at the 100-m class Nan\\c{c}ay Radio Telescope of 2839 galaxies from the Sloan Digital Sky Survey (SDSS) in the Local Volume (900Survey (NIBLES) sample. They were selected evenly over their entire range of absolute SDSS z-band magnitudes (-13.5 to -24 mag), which were used as a proxy for their stellar masses. Here, a first, global presentation of the observations and basic results is given, their further analysis will be presented in other papers in this series. The galaxies were selected based on their properties, as listed in SDSS DR5. Comparing this photometry to their total HI masses, we noted that, for a few percent, the SDSS magnitudes appeared severely misunderestimated, as confirmed by our re-measurements for selected objects. Although using the later DR9 results eliminated this problem in most cases, 38...

  14. The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III

    CERN Document Server

    Alam, Shadab; Prieto, Carlos Allende; Anders, F; Anderson, Scott F; Andrews, Brett H; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Bautista, Julian E; Beaton, Rachael L; Bender, Chad F; Berlind, Andreas A; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C; Bizyaev, Dmitry; Blanton, Michael R; Blomqvist, Michael; Bochanski, John J; Bolton, Adam S; Bovy, Jo; Bradley, A Shelden; Brandt, W N; Brauer, D E; Brinkmann, J; Brown, Peter J; Brownstein, Joel R; Burden, Angela; Burtin, Etienne; Busca, Nicolás G; Cai, Zheng; Capozzi, Diego; Rosell, Aurelio Carnero; Carrera, Ricardo; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A C; Cuesta, Antonio J; Cunha, Katia; da Costa, Luiz N; Da Rio, Nicola; Davenport, James R A; Dawson, Kyle S; De Lee, Nathan; Delubac, Timothée; Deshpande, Rohit; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L; Edmondson, Edward M; Eisenstein, Daniel J; Escoffier, Stephanie; Esposito, Massimiliano; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Ak, Nurten Filiz; Finley, Hayley; Flaherty, Kevin; Fleming, Scott W; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M; Galbraith-Frew, J G; García-Hernández, D A; Pérez, Ana E García; Gaulme, Patrick; Ge, Jian; Génova-Santos, R; Ghezzi, Luan; Gillespie, Bruce A; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A; Hernández, Jonay I González; Grebel, Eva K; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L; Hayden, Michael; Hearty, Fred R; Ho, Shirley; Hogg, David W; Holley-Bockelmann, Kelly; Holtzman, Jon A; Honscheid, Klaus; Huehnerhoff, Joseph; Jiang, Linhua; Johnson, Jennifer A; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A; Kneib, Jean-Paul; Koenig, Xavier P; Lam, Charles R; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Goff, Jean-Marc Le; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C; Liu, Jian; Long, Daniel C; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H; Mack, Claude E; Mahadevan, Suvrath; Maia, Marcio A G; Majewski, Steven R; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C; Margala, Daniel; Martell, Sarah L; Martig, Marie; Masters, Karen L; McBride, Cameron K; McGehee, Peregrine M; McGreer, Ian D; McMahon, Richard G; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D; Morice-Atkinson, Xan; Morrison, Heather L; Muna, Demitri; Myers, Adam D; Newman, Jeffrey A; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C; Nidever, David L; Noterdaeme, Pasquier; Nuza, Sebastián E; O'Connell, Julia E; O'Connell, Robert W; O'Connell, Ross; Ogando, Ricardo L C; Olmstead, Matthew D; Oravetz, Audrey E; Oravetz, Daniel J; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K; Park, Changbom; Pâris, Isabelle; Pattarakijwanich, Petchara; Pellejero-Ibanez, M; Pepper, Joshua; Percival, Will J; Pérez-Fournon, Ismael; Pérez-Ràfols, Ignasi; Petitjean, Patrick; Pieri, Matthew M; Pinsonneault, Marc H; de Mello, Gustavo F Porto; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M; Raddick, M Jordan; Rahman, Mubdi; Reid, Beth A; Rich, James; Rix, Hans-Walter; Robin, Annie C; Rockosi, Constance M; Rodrigues, Thaíse S; Rodríguez-Rottes, Sergio; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Rossi, Graziano; Ruan, John J; Rubiño-Martín, J A; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P; Schlegel, David J; Schmidt, Sarah J; Schneider, Donald P; Schultheis, Mathias; Schwope, Axel D; Scóccola, C G; Sellgren, Kris; Seo, Hee-Jong; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Skrutskie, M F; Slosar, Anže; Smith, Verne V; Sobreira, Flávia; Stassun, Keivan G; Steinmetz, Matthias; Strauss, Michael A; Streblyanska, Alina; Swanson, Molly E C; Tan, Jonathan C; Tayar, Jamie; Terrien, Ryan C; Thakar, Aniruddha R; Thomas, Daniel; Thompson, Benjamin A; Tinker, Jeremy L; Tojeiro, Rita; Troup, Nicholas W; Vargas-Magaña, Mariana; Verde, Licia; Viel, Matteo; Vogt, Nicole P; Wake, David A; Wang, Ji; Weaver, Benjamin A; Weinberg, David H; Weiner, Benjamin J; White, Martin; Wilson, John C; Wisniewski, John P; Wood-Vasey, W M; Yèche, Christophe; York, Donald G; Zakamska, Nadia L; Zamora, O; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou, Xu; Zhou, Zhimin; Zhu, Guangtun; Zou, Hu

    2015-01-01

    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 sq. deg of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 s...

  15. Observing Strategy for the SDSS-IV/MaNGA IFU Galaxy Survey

    CERN Document Server

    Law, David R; Bershady, Matthew A; Bundy, Kevin; Cherinka, Brian; Drory, Niv; MacDonald, Nicholas; Sanchez-Gallego, Jose R; Weijmans, Anne-Marie; Blanton, Michael R; Klaene, Mark; Moran, Sean M; Sanchez, Sebastian F; Zhang, Kai

    2015-01-01

    MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is an integral-field spectroscopic survey of 10,000 nearby galaxies that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). MaNGA's 17 pluggable optical fiber-bundle integral field units (IFUs) are deployed across a 3 deg field, they yield spectral coverage 3600-10,300 Ang at a typical resolution R ~ 2000, and sample the sky with 2" diameter fiber apertures with a total bundle fill factor of 56%. Observing over such a large field and range of wavelengths is particularly challenging for obtaining uniform and integral spatial coverage and resolution at all wavelengths and across each entire fiber array. Data quality is affected by the IFU construction technique, chromatic and field differential refraction, the adopted dithering strategy, and many other effects. We use numerical simulations to constrain the hardware design and observing strategy for the survey with the aim of ensuring consistent data quality that ...

  16. The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey

    CERN Document Server

    Law, David R; Yan, Renbin; Andrews, Brett H; Bershady, Matthew A; Bizyaev, Dmitry; Blanc, Guillermo A; Blanton, Michael R; Bolton, Adam S; Brownstein, Joel R; Bundy, Kevin; Chen, Yanmei; Drory, Niv; D'Souza, Richard; Fu, Hai; Jones, Amy; Kauffmann, Guinevere; MacDonald, Nicholas; Masters, Karen L; Newman, Jeffrey A; Parejko, John K; Sánchez-Gallego, José R; Sánchez, Sebastian F; Schlegel, David J; Thomas, Daniel; Wake, David A; Weijmans, Anne-Marie; Westfall, Kyle B; Zhang, Kai

    2016-01-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622 - 10,354 Angstroms and an average footprint of ~ 500 arcsec^2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ~ 100 million raw-frame spectra and ~ 10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline (DRP) algorithms and centralized metadata framework that produces sky-subtracted, spectrophotometrically calibrated spectra and rectified 3-D data cubes that combine individual dithered observa...

  17. PROPERTIES OF SATELLITE GALAXIES IN THE SDSS PHOTOMETRIC SURVEY: LUMINOSITIES, COLORS, AND PROJECTED NUMBER DENSITY PROFILES

    International Nuclear Information System (INIS)

    We analyze photometric data in the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) to infer statistical properties of faint satellites associated with isolated bright galaxies (Mr r = -14.5, in the projected radial distance range 100 p /kpc vir). The maximum projected distance corresponds to the range 470-660 kpc for the different samples. We have also considered a color cut consistent with the observed colors of spectroscopic satellites in nearby galaxies so that distant redshifted galaxies do not dominate the statistics. We have tested the implementation of this background subtraction procedure using a mock catalog derived from the Millennium simulation semianalytic galaxy catalog based on a Λ cold dark matter model. We find that the method is effective in reproducing the true projected radial satellite number density profile and luminosity distributions, providing confidence in the results derived from SDSS data. We find that the spatial extent of satellite systems is larger for bright, red primaries. Also, we find a larger spatial distribution of blue satellites. For the different samples analyzed, we derive the average number of satellites and their luminosity distributions down to Mr = -14.5. The mean number of satellites depends very strongly on host luminosity. Bright primaries (Mr r r < -20.5) which have less than one satellite per host. We provide Schechter function fits to the luminosity distributions of satellite galaxies where the resulting faint-end slopes equal to 1.3 ± 0.2, consistent with the universal value. This shows that satellites of bright primaries lack an excess population of faint objects, in agreement with the results in the Milky Way and nearby galaxies.

  18. Observing Strategy for the SDSS-IV/MaNGA IFU Galaxy Survey

    Science.gov (United States)

    Law, David R.; Yan, Renbin; Bershady, Matthew A.; Bundy, Kevin; Cherinka, Brian; Drory, Niv; MacDonald, Nicholas; Sánchez-Gallego, José R.; Wake, David A.; Weijmans, Anne-Marie; Blanton, Michael R.; Klaene, Mark A.; Moran, Sean M.; Sanchez, Sebastian F.; Zhang, Kai

    2015-07-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an integral-field spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). MaNGA’s 17 pluggable optical fiber-bundle integral field units (IFUs) will observe a sample of 10,000 nearby galaxies distributed throughout the SDSS imaging footprint (focusing particularly on the North Galactic Cap). In each pointing these IFUs are deployed across a 3° field; they yield spectral coverage 3600-10300 Å at a typical resolution R ˜ 2000, and sample the sky with 2″ diameter fiber apertures with a total bundle fill factor of 56%. Observing over such a large field and range of wavelengths is particularly challenging for obtaining uniform and integral spatial coverage and resolution at all wavelengths and across each entire fiber array. Data quality is affected by the IFU construction technique, chromatic and field differential refraction, the adopted dithering strategy, and many other effects. We use numerical simulations to constrain the hardware design and observing strategy for the survey with the aim of ensuring consistent data quality that meets the survey science requirements while permitting maximum observational flexibility. We find that MaNGA science goals are best achieved with IFUs composed of a regular hexagonal grid of optical fibers with rms displacement of 5 μm or less from their nominal packing position; this goal is met by the MaNGA hardware, which achieves 3 μm rms fiber placement. We further show that MaNGA observations are best obtained in sets of three 15 minute exposures dithered along the vertices of a 1.44 arcsec equilateral triangle; these sets form the minimum observational unit, and are repeated as needed to achieve a combined signal-to-noise ratio of 5 Å-1 per fiber in the r-band continuum at a surface brightness of 23 AB arcsec-2. In order to ensure uniform coverage and delivered image quality, we require that the

  19. The Thirteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey MApping Nearby Galaxies at Apache Point Observatory

    CERN Document Server

    Albareti, Franco D; Almeida, Andres; Anders, Friedrich; Anderson, Scott; Andrews, Brett H; Aragon-Salamanca, Alfonso; Argudo-Fernandez, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barbuy, Beatriz; Barger, Kat; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Basu, Sarbani; Bates, Dominic; Battaglia, Giuseppina; Baumgarten, Falk; Baur, Julien; Bautista, Julian; Beers, Timothy C; Belfiore, Francesco; Bershady, Matthew; de Lis, Sara Bertran; Bird, Jonathan C; Bizyaev, Dmitry; Blanc, Guillermo A; Blanton, Michael; Blomqvist, Michael; Bolton, Adam S; Borissova, J; Bovy, Jo; Brandt, William Nielsen; Brinkmann, Jonathan; Brownstein, Joel R; Bundy, Kevin; Burtin, Etienne; Busca, Nicolas G; Chavez, Hugo Orlando Camacho; Diaz, M Cano; Cappellari, Michele; Carrera, Ricardo; Chen, Yanping; Cherinka, Brian; Cheung, Edmond; Chiappini, Cristina; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E; Comerford, Julia M; Comparat, Johan; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D; Croft, Rupert; Cunha, Katia; da Costa, Luiz; Ilha, Gabriele da Silva; Darling, Jeremy; Davidson, James W; Dawson, Kyle; De Lee, Nathan; de la Macorra, Axel; de la Torre, Sylvain; Machado, Alice Deconto; Delubac, Timothee; Diamond-Stanic, Aleksandar M; Donor, John; Downes, Juan Jose; Drory, Niv; Bourboux, Helion du Mas des; Du, Cheng; Dwelly, Tom; Ebelke, Garrett; Eigenbrot, Arthur; Eisenstein, Daniel J; Elsworth, Yvonne P; Emsellem, Eric; Eracleous, Michael; Escoffier, Stephanie; Evans, Michael L; Falcon-Barroso, Jesus; Fan, Xiaohui; Favole, Ginevra; Fernandez-Alvar, Emma; Fernandez-Trincado, J G; Feuillet, Diane; Fleming, Scott W; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gao, Yang; Garcia-Hernandez, D A; Perez, Ana E Garcia; Garcia, Rafael A; Garcia-Dias, R; Gaulme, Patrick; Ge, Junqiang; Geisler, Douglas; Marin, Hector Gil; Gillespie, Bruce; Girardi, Leo; Goddard, Daniel; Chew, Yilen Gomez Maqueo; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul; Grier, Catherine J; Grier, Thomas; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Matt; Harding, Paul; Harley, R E; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R; Hearty, Fred; Hekker, Saskia; Toledo, Hector Hernandez; Ho, Shirley; Hogg, David W; Holley-Bockelmann, Kelly; Holtzman, Jon A; Holzer, Parker H; Hu, Jian; Huber, Daniel; Hutchinson, Timothy Alan; Hwang, Ho Seong; Ibarra-Medel, Hector J; Ivans, Inese I; Ivory, KeShawn; Jaehnig, Kurt; Jensen, Trey W; Johnson, Jennifer A; Jones, Amy; Jullo, Eric; Kallinger, T; Kinemuchi, Karen; Kirkby, David; Klaene, Mark; Kneib, Jean-Paul; Kollmeier, Juna A; Lacerna, Ivan; Lane, Richard R; Lang, Dustin; Laurent, Pierre; Law, David R; Goff, Jean-Marc Le; Leauthaud, Alexie; Li, Cheng; Li, Ran; Li, Chen; Li, Niu; Liang, Fu-Heng; Liang, Yu; Lima, Marcos; Lin, Lihwai; Lin, Lin; Lin, Yen-Ting; Long, Dan; Lucatello, Sara; MacDonald, Nicholas; MacLeod, Chelsea L; Mackereth, J Ted; Mahadevan, Suvrath; Maia, Marcio Antonio-Geimba; Maiolino, Roberto; Majewski, Steven R; Malanushenko, Olena; Mallmann, Nicolas Dullius; Manchado, Arturo; Maraston, Claudia; Marques-Chaves, Rui; Valpuesta, Inma Martinez; Masters, Karen L; Mathur, Savita; McGreer, Ian D; Merloni, Andrea; Merrifield, Michael R; Meszaros, Szabolcs; Meza, Andres; Miglio, Andrea; Minchev, Ivan; Molaverdikhani, Karan; Montero-Dorta, Antonio D; Mosser, Benoit; Muna, Demitri; Myers, Adam; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A; Nichol, Robert C; Nidever, David L; Nitschelm, Christian; O'Connell, Julia; Oravetz, Audrey; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John; Paris, Isabelle; Peacock, John A; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J; Percival, Jeffrey W; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew; Pinsonneault, Marc H; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Price-Jones, Natalie; Raddick, M Jordan; Rahman, Mubdi; Raichoor, Anand; Rembold, Sandro Barboza; Reyna, A M; Rich, James; Richstein, Hannah; Ridl, Jethro; Riffel, Rogerio; Riffel, Rogemar A; Rix, Hans-Walter; Robin, Annie C; Rockosi, Constance M; Rodriguez-Torres, Sergio; Rodrigues, Thaise S; Roe, Natalie; Lopes, A Roman; Roman-Zuniga, Carlos; Ross, Ashley J; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Runnoe, Jessie C; Salazar-Albornoz, Salvador; Salvato, Mara; Sanchez, Ariel G; Sanchez, Sebastian F; Sanchez-Gallego, Jose R; Santiago, Basilio Xavier; Schiavon, Ricardo; Schimoia, Jaderson S

    2016-01-01

    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2, MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. This paper describes the first data release from SDSS-IV, Data Release 13 (DR13), which contains new data, reanalysis of existing data sets and, like all SDSS data releases, is inclusive of previously released data. DR13 makes publicly available 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA, the first data released from this survey. It includes new observations from eBOSS, completing SEQUELS. In addition to targeting galaxies and quasars, SEQUELS also targeted variability-selected objects from TDSS and X-ray selected objects from SPIDERS. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification. DR13 releases new reductions of the APOGEE-1 data from SDSS-III, with abundances o...

  20. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems

    Energy Technology Data Exchange (ETDEWEB)

    Eisenstein, Daniel J.; /Arizona U., Astron. Dept. - Steward Observ. /Harvard U., Phys. Dept.; Weinberg, David H.; /Ohio State U.; Agol, Eric; /Washington U., Seattle, Astron. Dept.; Aihara, Hiroaki; /Tokyo U.; Prieto, Carlos Allende; /Laguna U., Tenerife; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Arns, James A.; /Michigan U.; Aubourg, Eric; /APC, Paris /DAPNIA, Saclay; Bailey, Stephen; /LBL, Berkeley; Balbinot, Eduardo; /Rio Grande do Sul U. /Rio de Janeiro Observ.; Barkhouser, Robert; /Johns Hopkins U. /Michigan State U.

    2011-01-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. The Baryon Oscillation Spectroscopic Survey (BOSS) will measure redshifts of 1.5 million massive galaxies and Ly{alpha} forest spectra of 150,000 quasars, using the baryon acoustic oscillation (BAO) feature of large scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z < 0.7 and at z {approx} 2.5. SEGUE-2, a now-completed continuation of the Sloan Extension for Galactic Understanding and Exploration, measured medium-resolution (R = {lambda}/{Delta}{lambda} 1800) optical spectra of 118,000 stars in a variety of target categories, probing chemical evolution, stellar kinematics and substructure, and the mass profile of the dark matter halo from the solar neighborhood to distances of 100 kpc. APOGEE, the Apache Point Observatory Galactic Evolution Experiment, will obtain high-resolution (R {approx} 30,000), high signal-to-noise ratio (S/N {ge} 100 per resolution element), H-band (1.51 {micro}m < {lambda} < 1.70 {micro}m) spectra of 10{sup 5} evolved, late-type stars, measuring separate abundances for {approx} 15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. The Multi-object APO Radial Velocity Large-area Survey (MARVELS) will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m s{sup -1}, {approx} 24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. As of January 2011, SDSS-III has obtained

  1. Origin of the 12um Emission Across Galaxy Populations from WISE and SDSS Surveys

    CERN Document Server

    Donoso, E; Tsai, C; Eisenhardt, P; Stern, D; Assef, R J; Leisawitz, D; Jarrett, T H; Stanford, S A

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer (WISE) sources brighter than 1 mJy at 12um with the Sloan Digital Sky Survey (SDSS) galaxy spectroscopic catalog to produce a sample of ~10^5 galaxies at =0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range ~10^8-10^12 L_sun. We identify which stellar populations are responsible for most of the 12um emission. We find that most (~80%) of the 12um emission in SF galaxies is produced by stellar populations younger than 0.6 Gyr. In contrast, the 12um emission in weak AGN (L[OIII]10^7 L_sun), act as an extension of massive SF galaxies, connecting the SF and weak AGN sequences. This suggests a picture where galaxies form stars normally until an AGN (possibly after a starburst episode) starts to gradually quench the SF activity. We also find that 4.6-12um color is a useful first-order indicator of SF activity in a galaxy when no other data are available.

  2. Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE Survey

    CERN Document Server

    Holtzman, Jon A; Johnson, Jennifer A; Prieto, Carlos Allende; Anders, Friedrich; Andrews, Brett; Beers, Timothy C; Bizyaev, Dmitry; Blanton, Michael R; Bovy, Jo; Carrera, Ricardo; Cunha, Katia; Eisenstein, Daniel J; Feuillet, Diane; Frinchaboy, Peter M; Galbraith-Frew, Jessica; Perez, Ana E Garcia; Hernandez, D Anibal Garcia; Hasselquist, Sten; Hayden, Michael R; Hearty, Fred R; Ivans, Inese; Majewski, Steven R; Martell, Sarah; Meszaros, Szabolcs; Muna, Demitri; Nidever, David L; Nguyen, Duy Cuong; O'Connell, Robert W; Pan, Kaike; Pinsonneault, Marc; Robin, Annie C; Schiavon, Ricardo P; Shane, Neville; Sobeck, Jennifer; Smith, Verne V; Troup, Nicholas; Weinberg, David H; Wilson, John C; Wood-Vasey, W M; Zamora, Olga; Zasowski, Gail

    2015-01-01

    The SDSS-III/APOGEE survey operated from 2011-2014 using the APOGEE spectrograph, which collects high-resolution (R~22,500), near-IR (1.51-1.70 microns) spectra with a multiplexing (300 fiber-fed objects) capability. We describe the survey data products that are publicly available, which include catalogs with radial velocity, stellar parameters, and 15 elemental abundances for over 150,000 stars, as well as the more than 500,000 spectra from which these quantities are derived. Calibration relations for the stellar parameters (Teff, log g, [M/H], [alpha/M]) and abundances (C, N, O, Na, Mg, Al, Si, S, K, Ca, Ti, V, Mn, Fe, Ni) are presented and discussed. The internal scatter of the abundances within clusters indicates that abundance precision is generally between 0.05 and 0.09 dex across a broad temperature range; within more limited ranges and at high S/N, it is smaller for some elemental abundances. We assess the accuracy of the abundances using comparison of mean cluster metallicities with literature values...

  3. The SDSS-III APOGEE radial velocity survey of M dwarfs. I. Description of the survey and science goals

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, R.; Bender, C. F.; Mahadevan, S.; Terrien, R. C.; Schneider, D. P.; Fleming, S. W. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Blake, C. H. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Carlberg, J. K. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Zasowski, G.; Hearty, F. [University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Crepp, J. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Rajpurohit, A. S.; Reylé, C. [Institut UTINAM, CNRS UMR 6213, Observatoire des Sciences de l' Univers THETA Franche-Comt é-Bourgogne, Université de Franche Comté, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France); Nidever, D. L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Prieto, C. Allende; Hernández, J. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Bizyaev, D. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Ebelke, G. [Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Frinchaboy, P. M. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Ge, J. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); and others

    2013-12-01

    We are carrying out a large ancillary program with the Sloan Digital Sky Survey, SDSS-III, using the fiber-fed multi-object near-infrared APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations will be used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey, as well as results from the first year of scientific observations based on spectra that will be publicly available in the SDSS-III DR10 data release. As part of this paper we present radial velocities and rotational velocities of over 200 M dwarfs, with a vsin i precision of ∼2 km s{sup –1} and a measurement floor at vsin i = 4 km s{sup –1}. This survey significantly increases the number of M dwarfs studied for rotational velocities and radial velocity variability (at ∼100-200 m s{sup –1}), and will inform and advance the target selection for planned radial velocity and photometric searches for low-mass exoplanets around M dwarfs, such as the Habitable Zone Planet Finder, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to identify short period binaries, and adaptive optics imaging of a subset of stars enables the detection of possible stellar companions at larger separations. The high-resolution APOGEE spectra, covering the entire H band, provide the opportunity to measure physical stellar parameters such as effective temperatures and metallicities for many of these stars. At the culmination of this survey, we will have obtained multi-epoch spectra and radial velocities for over 1400 stars spanning the spectral range M0-L0, providing the largest set of near-infrared M dwarf spectra at high resolution, and more than doubling the number of known spectroscopic vsin i values for M dwarfs. Furthermore, by modeling telluric lines to correct for small instrumental radial velocity shifts, we

  4. The SDSS-III APOGEE radial velocity survey of M dwarfs. I. Description of the survey and science goals

    International Nuclear Information System (INIS)

    We are carrying out a large ancillary program with the Sloan Digital Sky Survey, SDSS-III, using the fiber-fed multi-object near-infrared APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations will be used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey, as well as results from the first year of scientific observations based on spectra that will be publicly available in the SDSS-III DR10 data release. As part of this paper we present radial velocities and rotational velocities of over 200 M dwarfs, with a vsin i precision of ∼2 km s–1 and a measurement floor at vsin i = 4 km s–1. This survey significantly increases the number of M dwarfs studied for rotational velocities and radial velocity variability (at ∼100-200 m s–1), and will inform and advance the target selection for planned radial velocity and photometric searches for low-mass exoplanets around M dwarfs, such as the Habitable Zone Planet Finder, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to identify short period binaries, and adaptive optics imaging of a subset of stars enables the detection of possible stellar companions at larger separations. The high-resolution APOGEE spectra, covering the entire H band, provide the opportunity to measure physical stellar parameters such as effective temperatures and metallicities for many of these stars. At the culmination of this survey, we will have obtained multi-epoch spectra and radial velocities for over 1400 stars spanning the spectral range M0-L0, providing the largest set of near-infrared M dwarf spectra at high resolution, and more than doubling the number of known spectroscopic vsin i values for M dwarfs. Furthermore, by modeling telluric lines to correct for small instrumental radial velocity shifts, we hope to achieve a

  5. SDSS-II Supernova Survey: An Analysis of the Largest Sample of Type Ia Supernovae and Correlations with Host-galaxy Spectral Properties

    Science.gov (United States)

    Wolf, Rachel C.; D’Andrea, Chris B.; Gupta, Ravi R.; Sako, Masao; Fischer, John A.; Kessler, Rick; Jha, Saurabh W.; March, Marisa C.; Scolnic, Daniel M.; Fischer, Johanna-Laina; Campbell, Heather; Nichol, Robert C.; Olmstead, Matthew D.; Richmond, Michael; Schneider, Donald P.; Smith, Mathew

    2016-04-01

    Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HRs). Our sample consists of 345 photometrically classified or spectroscopically confirmed SNe Ia discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric host-galaxy properties from the SDSS-SNS data release such as host stellar mass and star formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6σ significance of a nonzero linear slope. We also recover correlations between HR and host-galaxy gas-phase metallicity and specific star formation rate as they are reported in the literature. With our large data set, we examine correlations between HR and multiple host-galaxy properties simultaneously and find no evidence of a significant correlation. We also independently analyze our spectroscopically confirmed and photometrically classified SNe Ia and comment on the significance of similar combined data sets for future surveys.

  6. THE ARECIBO LEGACY FAST ALFA SURVEY. V. THE H I SOURCE CATALOG OF THE ANTI-VIRGO REGION AT δ = +270

    International Nuclear Information System (INIS)

    We present a second catalog of H I sources detected in the Arecibo Legacy Fast ALFA Survey. We report 488 detections over 135 deg2, within the region of the sky having 22 h 0 0. We present here the detections that have either (a) S/N>6.5, where the reliability of the catalog is better than 95% or (b) 5.0 Hi7.5 Msun are satellites of either the NGC672/IC1727 nearby galaxy pair or their neighboring dwarf irregular galaxy NGC784. The data of this catalog release include a slice through the Pisces-Perseus foreground void, a large nearby underdensity of galaxies. We report no detections within the void, where our catalog is complete for systems with H i masses of 108 Msun. Gas-rich, optically-dark galaxies do not seem to constitute an important void population, and therefore do not suffice for producing a viable solution to the void phenomenon.

  7. The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

    CERN Document Server

    Ahn, Christopher P; Prieto, Carlos Allende; Anderson, Scott F; Anderton, Timothy; Andrews, Brett H; Bailey, Éric Aubourg Stephen; Barnes, Rory; Bautista, Julian; Beers, Timothy C; Beifiori, Alessandra; Berlind, Andreas A; Bhardwaj, Vaishali; Bizyaev, Dmitry; Blake, Cullen H; Blanton, Michael R; Blomqvist, Michael; Bochanski, John J; Bolton, Adam S; Borde, Arnaud; Bovy, Jo; Brandt, W N; Brinkmann, J; Brown, Peter J; Brownstein, Joel R; Bundy, Kevin; Busca, N G; Carithers, William; Carnero, Aurelio R; Carr, Michael A; Casetti-Dinescu, Dana I; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Crepp, Justin R; Cristiani, Stefano; Croft, Rupert A C; Cuesta, Antonio J; da Costa, Luiz N; Davenport, James R A; Dawson, Kyle S; de Putter, Roland; De Lee, Nathan; Delubac, Timothée; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L; Edmondson, Edward M; Eisenstein, Daniel J; Escoffier, S; Esposito, Massimiliano; Evans, Michael L; Fan, Xiaohui; Castellá, Bruno Femení a; Alvar, Emma Fernández; Ferreira, Leticia D; Ak, N Filiz; Finley, Hayley; Fleming, Scott W; Font-Ribera, Andreu; Frinchaboy, Peter M; García-Hernández, D A; Pérez, A E García; Ge, Jian; Génova-Santos, R; Gillespie, Bruce A; Girardi, Léo; Hernández, Jonay I González; Grebel, Eva K; Gunn, James E; Haggard, Daryl; Hamilton, Jean-Christophe; Harris, David W; Hawley, Suzanne L; Hearty, Frederick R; Ho, Shirley; Hogg, David W; Holtzman, Jon A; Honscheid, Klaus; Huehnerhoff, J; Ivans, Inese I; Ivezić, Zeljko; Jacobson, Heather R; Jiang, Linhua; Johansson, Jonas; Johnson, Jennifer A; Kauffmann, Guinevere; Kirkby, David; Kirkpatrick, Jessica A; Klaene, Mark A; Knapp, Gillian R; Kneib, Jean-Paul; Goff, Jean-Marc Le; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Long, Daniel C; Loomis, Craig P; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H; Ma, Bo; Ma, Zhibo; MacDonald, Nicholas; Mahadevan, Suvrath; Maia, Marcio A G; Majewski, Steven R; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A; Mandelbaum, Rachel; Manera, Marc; Maraston, Claudia; Margala, Daniel; Martell, Sarah L; McBride, Cameron K; McGreer, Ian D; McMahon, Richard G; Ménard, Brice; Meszaros, Sz; Miralda-Escudé, Jordi; Montero-Dorta, Antonio D; Montesano, Francesco; Morrison, Heather L; Muna, Demitri; Munn, Jeffrey A; Murayama, Hitoshi; Myers, Adam D; Neto, A F; Nguyen, Duy Cuong; Nichol, Robert C; Nidever, David L; Noterdaeme, Pasquier; Ogando, Ricardo L C; Olmstead, Matthew D; Oravetz, Daniel J; Owen, Russell; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K; Parihar, Prachi; Pâris, Isabelle; Pattarakijwanich, Petchara; Pepper, Joshua; Percival, Will J; Pérez-Fournon, Ismael; Pérez-Ráfols, Ignasi; Petitjean, Patrick; Pforr, Janine; Pieri, Matthew M; Pinsonneault, Marc H; de Mello, G F Porto; Prada, Francisco; Price-Whelan, Adrian M; Raddick, M Jordan; Rebolo, Rafael; Rich, James; Richards, Gordon T; Robin, Annie C; Rocha-Pinto, Helio J; Rockosi, Constance M; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Rubiño-Martin, J A; Samushia, Lado; Almeida, J Sanchez; Sánchez, Ariel G; Santiago, Basílio; Sayres, Conor; Schlegel, David J; Schlesinger, Katharine J; Schmidt, Sarah J; Schneider, Donald P; Schwope, Axel D; Scóccola, C G; Seljak, Uros; Sheldon, Erin; Shen, Yue; Shu, Yiping; Simmerer, Jennifer; Simmons, Audrey E; Skibba, Ramin A; Slosar, A; Sobreira, Flavia; Sobeck, Jennifer S; Stassun, Keivan G; Steele, Oliver; Steinmetz, Matthias; Strauss, Michael A; Swanson, Molly E C; Tal, Tomer; Thakar, Aniruddha R; Thomas, Daniel; Thompson, Benjamin A; Tinker, Jeremy L; Tojeiro, Rita; Tremonti, Christy A; Magaña, M Vargas; Verde, Licia; Viel, Matteo; Vikas, Shailendra K; Vogt, Nicole P; Wake, David A; Wang, Ji; Weaver, Benjamin A; Weinberg, David H; Weiner, Benjamin J; West, Andrew A; White, Martin; Wilson, John C; Wisniewski, John P; Wood-Vasey, W M; Yanny, Brian; Yèche, Christophe; York, Donald G; Zamora, O; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhu, Guangtun; Zinn, Joel C

    2012-01-01

    The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T_eff-0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SDSS-III Sloan Extension for Galactic Understanding and Exploration-2 (SEGUE-2). The astrometry error introduced in the DR8 imaging catalogs has...

  8. SDSS-II Supernova Survey: An Analysis of the Largest Sample of Type Ia Supernovae and Correlations with Host-Galaxy Spectral Properties

    CERN Document Server

    Wolf, Rachel C; Gupta, Ravi R; Sako, Masao; Fischer, John A; Kessler, Rick; Jha, Saurabh W; March, Marisa C; Scolnic, Daniel M; Fischer, Johanna-Laina; Campbell, Heather; Nichol, Robert C; Olmstead, Matthew D; Richmond, Michael; Schneider, Donald P; Smith, Mathew

    2016-01-01

    Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HR). Our sample consists of 345 photometrically-classified or spectroscopically-confirmed SNeIa discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric host-galaxy properties from the SDSS-SNS data release (Sako et al. 2014) such as host stellar mass and star-formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6{\\sigma} significance of a non-zero linear slope. We also recover correlations between HR and host-galaxy gas-phase metallicity and s...

  9. The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Lampeitl, Hubert; /Portsmouth U., ICG; Smith, Mathew; /Cape Town U. /Portsmouth U., ICG; Nichol, Robert C.; /Portsmouth U., ICG; Bassett, Bruce; /South African Astron. Observ. /Cape Town U.; Cinabro, David; /Wayne State U.; Dilday, Benjamin; /Rutgers U., Piscataway; Foley, Ryan J.; /Harvard-Smithsonian Ctr. Astrophys.; Frieman, Joshua A.; /Chicago U. /Fermilab; Garnavich, Peter M.; /Notre Dame U.; Goobar, Ariel; /Stockholm U., OKC; Im, Myungshin; /Seoul Natl. U. /Rutgers U., Piscataway

    2010-05-01

    We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  10. SDSS-IV MaNGA IFS Galaxy Survey --- Survey Design, Execution, and Initial Data Quality

    CERN Document Server

    Yan, Renbin; Law, David R; Bershady, Matthew A; Andrews, Brett; Cherinka, Brian; Diamond-Stanic, Aleksandar M; Drory, Niv; MacDonald, Nicholas; Sánchez-Gallego, José R; Thomas, Daniel; Wake, David A; Weijmans, Anne-Marie; Westfall, Kyle B; Zhang, Kai; Aragón-Salamanca, Alfonso; Belfiore, Francesco; Bizyaev, Dmitry; Blanc, Guillermo A; Blanton, Michael R; Brownstein, Joel; Cappellari, Michele; D'Souza, Richard; Emsellem, Eric; Fu, Hai; Gaulme, Patrick; Graham, Mark T; Goddard, Daniel; Gunn, James E; Harding, Paul; Jones, Amy; Kinemuchi, Karen; Li, Cheng; Li, Hongyu; Maiolino, Roberto; Mao, Shude; Maraston, Claudia; Masters, Karen; Merrifield, Michael R; Oravetz, Daniel; Pan, Kaike; Parejko, John K; Sanchez, Sebastian F; Schlegel, David; Simmons, Audrey; Thanjavur, Karun; Tinker, Jeremy; Tremonti, Christy; Bosch, Remco van den; Zheng, Zheng

    2016-01-01

    The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy (IFS) for 10K nearby galaxies at a spectral resolution of R~2000 from 3,622-10,354A. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (Re) while maximizing spatial resolution. About 2/3 of the sample is covered out to 1.5Re (Primary sample), and 1/3 of the sample is covered to 2.5Re (Secondary sample). We describe the survey ex...

  11. The Arecibo Remote Command Center Program

    Science.gov (United States)

    Crawford, Fronefield; Jenet, Fredrick; Siemens, Xavier; Dolch, Timothy; Stovall, Kevin

    2016-07-01

    The Arecibo Remote Command Center (ARCC) is a multi-institution research and education program that introduces undergraduates to the field of pulsar research. Specifically, the program trains students to work in small teams to operate several of the world's largest radio telescopes (both Arecibo and the Green Bank Telescope). Students conduct survey observations for the PALFA Galactic plane pulsar survey and conduct timing observations of millisecond pulsars (MSPs) for the NANOGrav search for gravitational waves using these telescopes. In addition, ARCC students search pulsar candidates generated from processed survey data in order to find both new radio MSPs and non-recycled pulsars. The ARCC program currently operates at four U.S. institutions and involves more than 50 undergraduate students each year. To date, ARCC students have discovered 64 new pulsars in this program.

  12. SDSS-III Baryon Oscillation Spectroscopic Survey Data Release 12: galaxy target selection and large scale structure catalogues

    CERN Document Server

    Reid, Beth; Padmanabhan, Nikhil; Percival, Will J; Tinker, Jeremy; Tojeiro, Rita; White, Martin; Eisenstein, Daniel J; Maraston, Claudia; Ross, Ashley J; Sanchez, Ariel G; Schlegel, David; Sheldon, Erin; Strauss, Michael A; Thomas, Daniel; Wake, David; Beutler, Florian; Bizyaev, Dmitry; Bolton, Adam S; Brownstein, Joel R; Chuang, Chia-Hsun; Dawson, Kyle; Harding, Paul; Kitaura, Francisco-Shu; Leauthaud, Alexie; Masters, Karen; McBride, Cameron K; More, Surhud; Olmstead, Matthew D; Oravetz, Daniel; Nuza, Sebastian E; Pan, Kaike; Parejko, John; Pforr, Janine; Prada, Francisco; Rodriguez-Torres, Sergio; Salazar-Albornoz, Salvador; Samushia, Lado; Schneider, Donald P; Scoccola, Claudia G; Simmons, Audrey; Vargas-Magana, Mariana

    2015-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target catalogue caused by changes either in the targeting algorithm or properties of the data used, the pattern of spectroscopic observations, the spatial distribution of targets for which redshifts were not obtained, and variations in the target sky density due to observational systematics. We document here the target selection algorithms used to create the galaxy samples that comprise BOSS. We also present the algorithms used to create large scale structure catalogues for the final Data Release (DR12) samples and the associated ...

  13. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems

    CERN Document Server

    Eisenstein, Daniel J; Agol, Eric; Aihara, Hiroaki; Prieto, Carlos Allende; Anderson, Scott F; Arns, James A; Aubourg, Eric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert; Beers, Timothy C; Berlind, Andreas A; Bickerton, Steven J; Bizyaev, Dmitry; Blanton, Michael R; Bochanski, John J; Bolton, Adam S; Bosman, Casey T; Bovy, Jo; Brewington, Howard J; Brandt, W N; Breslauer, Ben; Brinkmann, J; Brown, Peter J; Brownstein, Joel R; Burger, Dan; Busca, Nicolas G; Campbell, Heather; Cargile, Phillip A; Carithers, William C; Carlberg, Joleen K; Carr, Michael A; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A C; da Costa, Luiz N; Cunha, Katia; Davenport, James R A; Dawson, Kyle; De Lee, Nathan; de Mello, Gustavo F Porto; de Simoni, Fernando; Dean, Janice; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L; Edmondson, Edward M; Eiting, Jacob M; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L; Fan, Xiaohui; Castella, Bruno Femenia; Ferreira, Leticia Dutra; Fitzgerald, Greg; Fleming, Scott W; Font-Ribera, Andreu; Ford, Eric B; Frinchaboy, Peter M; Perez, Ana Elia Garcia; Gaudi, B Scott; Ge, Jian; Ghezzi, Luan; Gillespie, Bruce A; Gilmore, G; Girardi, Leo; Gott, J Richard; Gould, Andrew; Grebel, Eva K; Gunn, James E; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W; Hawley, Suzanne L; Hearty, Frederick R; Hernandez, Jonay I Gonzalez; Ho, Shirley; Hogg, David W; Holtzman, Jon A; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I; Jiang, Linhua; Jiang, Peng; Johnson, Jennifer A; Jordan, Cathy; Jordan, Wendell P; Kauffmann, Guinevere; Kazin, Eyal; Kirkby, David; Klaene, Mark A; Kneib, Jean-Paul; Knapp, G R; Kochanek, C S; Koesterke, Lars; Kollmeier, Juna A; Kron, Richard G; Lang, Dustin; Lawler, James E; Goff, Jean-Marc Le; Lee, Brian L; Lee, Young Sun; Leisenring, Jarron M; Lin, Yen-Ting; Liu, Jian; Long, Daniel C; Loomis, Craig P; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H; Ma, Bo; Ma, Zhibo; MacDonald, Nicholas; Mack, Claude; Mahadevan, Suvrath; Maia, Marcio A G; Malanushenko, Elena; Malanushenko, Viktor; Majewski, Steven R; Makler, Martin; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Maseman, Paul; Masters, Karen L; McBride, Cameron K; McDonald, Patrick; McGreer, Ian D; McMahon, Richard G; Requejo, Olga Mena; Menard, Brice; Miralda-Escude, Jordi; Morrison, Heather L; Mullally, Fergal; Muna, Demitri; Murayama, Hitoshi; Myers, Adam D; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C; Nidever, David L; O'Connell, Robert W; Ogando, Ricardo L C; Olmstead, Matthew D; Oravetz, Daniel J; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Parejko, John K; Paris, Isabelle; Pellegrini, Paulo; Pepper, Joshua; Percival, Will J; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M; Prada, Francisco; Price-Whelan, Adrian M; Raddick, M Jordan; Ramos, Beatriz H F; Ryle, Celine; Reid, I Neill; Rich, James; Richards, Gordon T; Rieke, George H; Rieke, Marcia J; Rix, Hans-Walter; Robin, Annie C; Rocha-Pinto, Helio J; Rockosi, Constance M; Roe, Natalie A; Rollinde, Emmanuel; Ross, Ashley J; Ross, Nicholas P; Rossetto, Bruno; Sanchez, Ariel G; Santiago, Basilio; Sayres, Conor; Schiavon, Ricardo; Schlegel, David J; Schlesinger, Katharine J; Schmidt, Sarah J; Schneider, Donald P; Sellgren, Kris; Shelden, Alaina; Sheldon, Erin; Shetrone, Matthew; Shu, Yiping; Silverman, John D; Simmerer, Jennifer; Simmons, Audrey E; Sivarani, Thirupathi; Skrutskie, M F; Slosar, Anze; Smee, Stephen; Smith, Verne V; Snedden, Stephanie A; Stassun, Keivan G; Steele, Oliver; Steinmetz, Matthias; Stockett, Mark H; Stollberg, Todd; Strauss, Michael A; Tanaka, Masayuki; Thakar, Aniruddha R; Thomas, Daniel; Tinker, Jeremy L; Tofflemire, Benjamin M; Tojeiro, Rita; Tremonti, Christy A; Magana, Mariana Vargas; Verde, Licia; Vogt, Nicole P; Wake, David A; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A; White, Martin; White, Simon D M; Wilson, John C; Wisniewski, John P; Wood-Vasey, W Michael; Yanny, Brian; Yasuda, Naoki; Yeche, Christophe; York, Donald G; Young, Erick; Zasowski, Gail; Zehavi, Idit; Zhao, Bo

    2011-01-01

    Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. BOSS will measure redshifts of 1.5 million massive galaxies and Lya forest spectra of 150,000 quasars, using the BAO feature of large scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z100 per resolution element), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars, measuring separate abundances for ~15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to detect gi...

  14. The infrared luminosities of ˜332 000 SDSS galaxies predicted from artificial neural networks and the Herschel Stripe 82 survey

    Science.gov (United States)

    Ellison, Sara L.; Teimoorinia, Hossein; Rosario, David J.; Mendel, J. Trevor

    2016-01-01

    The total infrared (IR) luminosity (LIR) can be used as a robust measure of a galaxy's star formation rate (SFR), even in the presence of an active galactic nucleus (AGN), or when optical emission lines are weak. Unfortunately, existing all sky far-IR surveys, such as the Infrared Astronomical Satellite (IRAS) and AKARI, are relatively shallow and are biased towards the highest SFR galaxies and lowest redshifts. More sensitive surveys with the Herschel Space Observatory are limited to much smaller areas. In order to construct a large sample of LIR measurements for galaxies in the nearby Universe, we employ artificial neural networks (ANNs), using 1136 galaxies in the Herschel Stripe 82 sample as the training set. The networks are validated using two independent data sets (IRAS and AKARI) and demonstrated to predict the LIR with a scatter σ ˜ 0.23 dex, and with no systematic offset. Importantly, the ANN performs well for both star-forming galaxies and those with an AGN. A public catalogue is presented with our LIR predictions which can be used to determine SFRs for 331 926 galaxies in the Sloan Digital Sky Survey (SDSS), including ˜129 000 SFRs for AGN-dominated galaxies for which SDSS SFRs have large uncertainties.

  15. The 3XMM/SDSS Stripe 82 Galaxy Cluster Survey: Cluster catalogue and discovery of two merging cluster candidates

    CERN Document Server

    Takey, Ali; Mahmoud, Eman A; Ali, Gamal B

    2016-01-01

    We present a galaxy cluster survey based on XMM-Newton observations that are located in the Stripe 82 of the Sloan Digital Sky Survey (SDSS). The survey covers an area of 11.25 deg$^2$. The X-ray cluster candidates were selected as serendipitously extended detected sources from the third XMM-Newton serendipitous source catalogue (3XMM-DR5). A cross-correlation of the candidate list that comprises 94 objects with recently published X-ray and optically selected cluster catalogues provided optical confirmations and redshift estimates for about half of the candidate sample. We present a catalogue of X-ray cluster candidates previously known in X-ray and/or optical bands from the matched catalogues or NED. The catalogue consists of 54 systems with redshift measurements in the range of 0.05-1.19 with a median of 0.36. Of these, 45 clusters have spectroscopic confirmations as stated in the matched catalogues. We spectroscopically confirmed another 6 clusters from the available spectroscopic redshifts in the SDSS-DR1...

  16. The OLS-lens survey: The discovery of five new galaxy-galaxy strong lenses from the SDSS

    CERN Document Server

    Willis, J P; Hewett, P C; Maddox, N; Warren, S J

    2006-01-01

    Bright galaxy-galaxy strong lenses are much more powerful than lensed quasars for measuring the mass profiles of galaxies, but until this year only a handful have been known. Here we present five new examples, identified via the optimal line-of-sight gravitational lens search strategy applied to luminous red galaxies in the Sloan Digital Sky Survey (SDSS). Our survey largely complements a similar survey by Bolton et al., who recently presented several new lenses. The lensed background galaxies are selected from the SDSS spectra via the presence of narrow emission line signatures, including the [OII] 3726,3729, Hb and [OIII] 4960,5008 lines, superposed on the spectra of the bright, intervening, deflector galaxies. Our five confirmed new systems include deflector galaxies with redshifts z=0.17-0.28 and lensed galaxies with redshifts z=0.47-1.18. Simulations of moderately deep (few orbits) HST-ACS imaging of systems such as these, where the lensed source is brighter than r~23, are presented. These demonstrate th...

  17. The properties of the cool circumgalactic gas probed with the SDSS, WISE, and GALEX surveys

    International Nuclear Information System (INIS)

    We explore the distribution of cool (∼104 K) gas around galaxies and its dependence on galaxy properties. By cross-correlating about 50,000 Mg II absorbers with millions of sources from the SDSS (optical), WISE (IR), and GALEX (UV) surveys we effectively extract about 2000 galaxy-absorber pairs at z ∼ 0.5 and probe relations between absorption strength and galaxy type, impact parameter and azimuthal angle. We find that cool gas traced by Mg II absorbers exists around both star-forming and passive galaxies with a similar incidence rate on scales greater than 100 kpc but each galaxy type exhibits a different behavior on smaller scales: Mg II equivalent width does not correlate with the presence of passive galaxies whereas stronger Mg II absorbers tend to be found in the vicinity of star-forming galaxies. This effect is preferentially seen along the minor axis of these galaxies, suggesting that some of the gas is associated with outflowing material. In contrast, the distribution of cool gas around passive galaxies is consistent with being isotropic on the same scales. We quantify the average excess Mg II equivalent width 〈δW0Mg II〉 as a function of galaxy properties and find 〈δW0Mg II〉∝SFR1.2, sSFR0.5, and M∗0.4 for star-forming galaxies. This work demonstrates that the dichotomy between star-forming and passive galaxies is reflected in the circumgalactic medium traced by low-ionized gas. We also measure the covering fraction of Mg II absorption and find it to be about 2-10 times higher for star-forming galaxies than passive ones within 50 kpc. We estimate the amount of neutral gas in the halo of (log M */M ☉) ∼ 10.8 galaxies to be a few × 109 M ☉ for both types of galaxies. Finally, we find that correlations between absorbers and sources detected in the UV and IR lead to physical trends consistent with those measured in the optical.

  18. The SDSS-IV in 2015: Report of the Committee on the Participation of Women in the Sloan Digital Sky Survey

    Science.gov (United States)

    Diamond-Stanic, Aleksandar M.; Lucatello, Sara; Aragon-Salamanca, Alfonso; Cherinka, Brian; Cunha, Katia M. L.; Gillespie, Bruce Andrew; Hagen, Alex; Jones, Amy; Kinemuchi, Karen; Lundgren, Britt; Myers, Adam D.; Roman, Alexandre; Zasowski, Gail; SDSS-IV Collaboration

    2016-01-01

    Given that many astronomers now participate in large international scientific collaborations, it is important to examine whether these structures foster a healthy scientific climate that is inclusive and diverse. The Committee on the Participation of Women in the Sloan Digital Sky Survey (CPWS) was formed to evaluate the climate and demographics within the SDSS collaboration and to make recommendations for how best to establish the scientific and technical leadership team for SDSS-IV. Building on the work described in Lundgren et al. (2015), the CPWS conducted a demographic survey in Spring 2015 that included questions about career and leadership status, racial / ethnic identity, gender identity, identification with the LGBT community, disability, partnership status, and level of parental education. For example, 71% of survey respondents identify as male and 81% do not identify as a racial or ethnic minority at their current institution. This reflects the under-representation of women and men from minority groups (e.g., people of color in the United States) and women from majority groups (e.g., white women in the United States) in the field of astronomy. We have focused our analysis on the representation of scientists from these groups among the SDSS-IV leadership and the full collaboration. Our goal is to use these quantitative data to track the demographics of SDSS-IV membership and leadership over time as we work to assess and improve the climate of SDSS-IV.

  19. Type II-P Supernovae from the SDSS-II Supernova Survey and the Standardized Candle Method

    CERN Document Server

    D'Andrea, Chris B; Dilday, Benjamin; Frieman, Joshua A; Holtzman, Jon; Kessler, Richard; Konishi, Kohki; Schneider, Donald P; Sollerman, Jesper; Wheeler, J C; Yasuda, Naoki; Cinabro, David; Jha, Saurabh; Nichol, Robert C; Lampeitl, Hubert; Smith, Mathew; Atlee, David W; Basset, Bruce; Castander, Francisco J; Goobar, Ariel; Miquel, Ramon; Nordin, Jakob; Östman, Linda; Prieto, Jose Luis; Quimby, Robert; Riess, Adam G; Stritzinger, Maximilian

    2009-01-01

    We apply the Standardized Candle Method (SCM) for Type II Plateau supernovae (SNe II-P), which relates the velocity of the ejecta of a SN to its luminosity during the plateau, to 15 SNe II-P discovered over the three season run of the Sloan Digital Sky Survey - II Supernova Survey. The redshifts of these SNe - 0.027 0.01) as all of the current literature on the SCM combined. We find that the SDSS SNe have a very small intrinsic I-band dispersion (0.22 mag), which can be attributed to selection effects. When the SCM is applied to the combined SDSS-plus-literature set of SNe II-P, the dispersion increases to 0.29 mag, larger than the scatter for either set of SNe separately. We show that the standardization cannot be further improved by eliminating SNe with positive plateau decline rates, as proposed in Poznanski et al. (2009). We thoroughly examine all potential systematic effects and conclude that for the SCM to be useful for cosmology, the methods currently used to determine the Fe II velocity at day 50 mus...

  20. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Analysis of potential systematics

    CERN Document Server

    Ross, Ashley J; Sanchez, Ariel G; Samushia, Lado; Ho, Shirley; Kazin, Eyal; Manera, Marc; Reid, Beth; White, Martin; Tojeiro, Rita; McBride, Cameron K; Xu, Xiaoying; Wake, David A; Strauss, Michael A; Montesano, Francesco; Swanson, Molly E C; Bailey, Stephen; Bolton, Adam S; Dorta, Antonio Montero; Eisenstein, Daniel J; Guo, Hong; Hamilton, Jean-Christophe; Nichol, Robert C; Padmanabhan, Nikhil; Prada, Francisco; Schlegel, David J; Magana, Mariana Vargas; Zehavi, Idit; Blanton, Michael; Bizyaev, Dmitry; Brewington, Howard; Cuesta, Antonio J; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Parejko, John; Pan, Kaike; Shelden, Donald P Schneider Alaina; Simmons, Audrey; Snedden, Stephanie; Zhao, Gong-bo

    2012-01-01

    We analyze the density field of galaxies observed by the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Nine (DR9). DR9 includes spectroscopic redshifts for over 400,000 galaxies spread over a footprint of 3,275 deg^2. We identify, characterize, and mitigate the impact of sources of systematic uncertainty on large-scale clustering measurements, both for angular moments of the redshift-space correlation function and the spherically averaged power spectrum, P(k), in order to ensure that robust cosmological constraints will be obtained from these data. A correlation between the projected density of stars and the higher redshift (0.43 120h^-1Mpc or k < 0.01hMpc^-1. We find that these errors can be ameliorated by weighting galaxies based on their surface brightness and the local stellar density. We use mock galaxy catalogs that simulate the CMASS selection function to determine that randomly selecting galaxy redshifts in order to simulate th...

  1. Local SDSS galaxies in the Herschel Stripe82 survey: A critical assessment of optically-derived star-formation rates

    CERN Document Server

    Rosario, D J; Ellison, S L; Lutz, D; Trump, J R

    2016-01-01

    We study a set of 3319 galaxies in the redshift interval 0.04 < z < 0.15 with far-infrared (FIR) coverage from the Herschel Stripe 82 survey (HerS), and emission-line measurements, redshifts, stellar masses and star-formation rates (SFRs) from the SDSS (DR7) MPA/JHU database. About 40% of the sample are detected in the Herschel/SPIRE 250 micron band. Total infrared (TIR) luminosities derived from HerS and ALLWISE photometry allow us to compare infrared and optical estimates of SFR with unprecedented statistics for diverse classes of galaxies. We find excellent agreement between TIR-derived and emission line-based SFRs for H II galaxies. Other classes, such as active galaxies and evolved galaxies, exhibit systematic discrepancies between optical and TIR SFRs. We demonstrate that these offsets are attributable primarily to survey biases and the large intrinsic uncertainties of the D4000- and colour-based optical calibrations used to estimate the SDSS SFRs of these galaxies. Using a classification scheme w...

  2. SDSS-III Baryon Oscillation Spectroscopic Survey: Analysis of Potential Systematics in Fitting of Baryon Acoustic Feature

    CERN Document Server

    Magaña, Mariana Vargas; Xu, Xiaoying; Sánchez, Ariel G; O'Connell, Ross; Eisenstein, Daniel J; Cuesta, Antonio J; Percival, Will J; Ross, Ashley J; Aubourg, Eric; Kirkby, Stéphanie Escoffier David; Manera, Marc; Schneider, Donald P; Tinker, Jeremy L; Weaver, Benjamin A

    2013-01-01

    Extraction of the Baryon Acoustic Oscillations (BAO) to percent level accuracy is challenging and demands an understanding of many potential systematic to an accuracy well below 1 per cent, in order ensure that they do not combine significantly when compared to statistical error of the BAO measurement. Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) SDSS Data Release Eleven (DR11) reaches a distance measurement with $\\sim 1\\%$ statistical error and this prompts an extensive search for all possible sub-percent level systematic errors which could be safely ignored previously. In this paper, we analyze the potential systematics in BAO fitting methodology using mocks and data from BOSS DR10 and DR11. We demonstrate the robustness of the fiducial multipole fitting methodology to be at $0.1\\%-0.2\\%$ level with a wide range of tests in mock galaxy catalogs pre- and post-reconstruction. We also find the DR10 and DR11 data from BOSS to be robust against changes in methodology at simi...

  3. VizieR Online Data Catalog: Swift AGN and Cluster Survey (SWCL). II. SDSS (Griffin+, 2016)

    Science.gov (United States)

    Griffin, R. D.; Dai, X.; Kochanek, C. S.; Bregman, J. N.

    2016-02-01

    We downloaded all swift/XRT "GRB" observations before 2013 Jul 27, and reprocessed the data as described in Dai et al. (2015, Paper I, J/ApJS/218/8). From this, we made images and corresponding exposure maps in different energy ranges: total (0.2-10keV), soft (0.5-2keV), and hard (2-10keV). SDSS DR8 provides the optical data for this study. (1 data file).

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: combining correlated Gaussian posterior distributions

    CERN Document Server

    Sanchez, Ariel G; Salazar-Albornoz, Salvador; Alam, Shadab; Beutler, Florian; Ross, Ashley J; Brownstein, Joel R; Chuang, Chia-Hsun; Cuesta, Antonio J; Eisenstein, Daniel J; Kitaura, Francisco-Shu; Percival, Will J; Prada, Francisco; Rodriguez-Torres, Sergio; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Vazquez, Jose A; Zhao, Gong-Bo

    2016-01-01

    The cosmological information contained in anisotropic galaxy clustering measurements can often be compressed into a small number of parameters whose posterior distribution is well described by a Gaussian. We present a general methodology to combine these estimates into a single set of consensus constraints that encode the total information of the individual measurements, taking into account the full covariance between the different methods. We illustrate this technique by applying it to combine the results obtained from different clustering analyses, including measurements of the signature of baryon acoustic oscillations (BAO) and redshift-space distortions (RSD), based on a set of mock catalogues of the final SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Our results show that the region of the parameter space allowed by the consensus constraints is smaller than that of the individual methods, highlighting the importance of performing multiple analyses on galaxy surveys even when the measurements a...

  5. Local SDSS galaxies in the Herschel Stripe 82 survey: a critical assessment of optically derived star formation rates

    Science.gov (United States)

    Rosario, D. J.; Mendel, J. T.; Ellison, S. L.; Lutz, D.; Trump, J. R.

    2016-04-01

    We study a set of 3319 galaxies in the redshift interval 0.04 star formation rates (SFRs) from the Sloan Digital Sky Survey (SDSS) (DR7) MPA/JHU data base. About 40 per cent of the sample are detected in the Herschel/SPIRE 250 μm band. Total infrared (TIR) luminosities derived from HerS and Wide-field Infrared Survey Explorer (WISE) photometry allow us to compare infrared and optical estimates of SFR with unprecedented statistics for diverse classes of galaxies. We find excellent agreement between TIR-derived and emission line-based SFRs for H II galaxies. Other classes, such as active galaxies and evolved galaxies, exhibit systematic discrepancies between optical and TIR SFRs. We demonstrate that these offsets are attributable primarily to survey biases and the large intrinsic uncertainties of the Dn4000- and colour-based optical calibrations used to estimate the SDSS SFRs of these galaxies. Using a classification scheme which expands upon popular emission-line methods, we demonstrate that emission-line galaxies with uncertain classifications include a population of massive, dusty, metal-rich star-forming systems that are frequently neglected in existing studies. We also study the capabilities of infrared selection of star-forming galaxies. FIR selection reveals a substantial population of galaxies dominated by cold dust which are missed by the long-wavelength WISE bands. Our results demonstrate that Herschel large-area surveys offer the means to construct large, relatively complete samples of local star-forming galaxies with accurate estimates of SFR that can be used to study the interplay between nuclear activity and star formation.

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: the low redshift sample

    CERN Document Server

    Parejko, John K; Padmanabhan, Nikhil; Wake, David A; Berlind, Andreas A; Bizyaev, Dmitry; Blanton, Michael; Bolton, Adam S; Bosch, Frank van den; Brinkmann, Jon; Brownstein, Joel R; da Costa, Luiz Alberto Nicolaci; Eisenstein, Daniel J; Guo, Hong; Kazin, Eyal; Maia, Marcio; Malanushenko, Elena; Maraston, Claudia; McBride, Cameron K; Nichol, Robert C; Oravetz, Daniel J; Pan, Kaike; Percival, Will J; Prada, Francisco; Ross, Ashley J; Ross, Nicholas P; Schlegel, David J; Schneider, Don; Simmons, Audrey E; Skibba, Ramin; Tinker, Jeremy; Tojeiro, Rita; Weaver, Benjamin A; Wetzel, Andrew; White, Martin; Weinberg, David H; Thomas, Daniel; Zehavi, Idit; Zheng, Zheng

    2012-01-01

    We report on the small scale (0.5Survey (BOSS), to be released as part of SDSS Data Release 9 (DR9). We describe the sample selection, basic properties of the galaxies, and caveats for working with the data. We calculate the real- and redshift-space two-point correlation functions of these galaxies, fit these measurements using Halo Occupation Distribution (HOD) modeling within dark matter cosmological simulations, and estimate the errors using mock catalogs. These galaxies lie in massive halos, with a mean halo mass of 5.2x10^13 h^-1 M_sun, a large scale bias of ~2.0, and a satellite fraction of 12+/-2%. Thus, these galaxies occupy halos with average masses in between those of the higher redshift BOSS CMASS sample and the original SDSS I/II LRG sample.

  7. Mock Quasar-Lyman-{\\alpha} Forest Data-sets for the SDSS-III Baryon Oscillation Spectroscopic Survey

    CERN Document Server

    Bautista, Julian E; Font-Ribera, Andreu; Pieri, Matthew M; Busca, Nicolás G; Miralda-Escudé, Jordi; Palanque-Delabrouille, Nathalie; Rich, James; Dawson, Kyle; Feng, Yu; Ge, Jian; Gontcho, Satya Gontcho A; Ho, Shirley; Goff, Jean Marc Le; Noterdaeme, Pasquier; Pâris, Isabelle; Rossi, Graziano; Schlegel, David

    2014-01-01

    We describe mock data-sets generated to simulate the high-redshift quasar sample in Data Release 11 (DR11) of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). The mock spectra contain Ly{\\alpha} forest correlations useful for studying the 3D correlation function including Baryon Acoustic Oscillations (BAO). They also include astrophysical effects such as quasar continuum diversity and high-density absorbers, instrumental effects such as noise and spectral resolution, as well as imperfections introduced by the SDSS pipeline treatment of the raw data. The Ly{\\alpha} forest BAO analysis of the BOSS collaboration, described in Delubac et al. 2014, has used these mock data-sets to develop and cross-check analysis procedures prior to performing the BAO analysis on real data, and for continued systematic cross checks. Tests presented here show that the simulations reproduce sufficiently well important characteristics of real spectra. These mock data-sets will be made available together with the data at t...

  8. Overview of the SDSS-IV MaNGA Survey: Mapping nearby Galaxies at Apache Point Observatory

    Science.gov (United States)

    Bundy, Kevin; Bershady, Matthew A.; Law, David R.; Yan, Renbin; Drory, Niv; MacDonald, Nicholas; Wake, David A.; Cherinka, Brian; Sánchez-Gallego, José R.; Weijmans, Anne-Marie; Thomas, Daniel; Tremonti, Christy; Masters, Karen; Coccato, Lodovico; Diamond-Stanic, Aleksandar M.; Aragón-Salamanca, Alfonso; Avila-Reese, Vladimir; Badenes, Carles; Falcón-Barroso, Jésus; Belfiore, Francesco; Bizyaev, Dmitry; Blanc, Guillermo A.; Bland-Hawthorn, Joss; Blanton, Michael R.; Brownstein, Joel R.; Byler, Nell; Cappellari, Michele; Conroy, Charlie; Dutton, Aaron A.; Emsellem, Eric; Etherington, James; Frinchaboy, Peter M.; Fu, Hai; Gunn, James E.; Harding, Paul; Johnston, Evelyn J.; Kauffmann, Guinevere; Kinemuchi, Karen; Klaene, Mark A.; Knapen, Johan H.; Leauthaud, Alexie; Li, Cheng; Lin, Lihwai; Maiolino, Roberto; Malanushenko, Viktor; Malanushenko, Elena; Mao, Shude; Maraston, Claudia; McDermid, Richard M.; Merrifield, Michael R.; Nichol, Robert C.; Oravetz, Daniel; Pan, Kaike; Parejko, John K.; Sanchez, Sebastian F.; Schlegel, David; Simmons, Audrey; Steele, Oliver; Steinmetz, Matthias; Thanjavur, Karun; Thompson, Benjamin A.; Tinker, Jeremy L.; van den Bosch, Remco C. E.; Westfall, Kyle B.; Wilkinson, David; Wright, Shelley; Xiao, Ting; Zhang, Kai

    2015-01-01

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 Å at R ~ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (Å-1 per 2'' fiber) at 23 AB mag arcsec-2, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M * >~ 109 M ⊙ using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr.

  9. OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY

    Energy Technology Data Exchange (ETDEWEB)

    Bundy, Kevin [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); Bershady, Matthew A.; Wake, David A.; Tremonti, Christy; Diamond-Stanic, Aleksandar M. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Law, David R.; Cherinka, Brian [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Yan, Renbin; Sánchez-Gallego, José R. [Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055 (United States); Drory, Niv [McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); MacDonald, Nicholas [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Weijmans, Anne-Marie [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Thomas, Daniel; Masters, Karen; Coccato, Lodovico [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth (United Kingdom); Aragón-Salamanca, Alfonso [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Avila-Reese, Vladimir [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico D.F. (Mexico); Badenes, Carles [Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, 3941 OHara St, Pittsburgh, PA 15260 (United States); Falcón-Barroso, Jésus [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Belfiore, Francesco [Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); and others

    2015-01-01

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 Å at R ∼ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (Å{sup –1} per 2'' fiber) at 23 AB mag arcsec{sup –2}, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M {sub *} ≳ 10{sup 9} M {sub ☉} using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr.

  10. OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY

    International Nuclear Information System (INIS)

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 Å at R ∼ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (Å–1 per 2'' fiber) at 23 AB mag arcsec–2, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M * ≳ 109 M ☉ using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr

  11. The 2XMMi/SDSS Galaxy Cluster Survey I. The first cluster sample and X-ray luminosity-temperature relation

    CERN Document Server

    Takey, A; Lamer, G

    2011-01-01

    We present a catalogue of X-ray selected galaxy clusters and groups as a first release of the 2XMMi/SDSS Galaxy Cluster Survey. The survey is a search for galaxy clusters detected serendipitously in observations with XMM-Newton in the footprint of the Sloan Digital Sky Survey (SDSS). The main aims of the survey are to identify new X-ray galaxy clusters, investigate their X-ray scaling relations, identify distant cluster candidates and study the correlation of the X-ray and optical properties. In this paper we describe the basic strategy to identify and characterize the X-ray cluster candidates that currently comprise 1180 objects selected from the second XMM-Newton serendipitous source catalogue (2XMMi-DR3). Cross-correlation of the initial catalogue with recently published optically selected SDSS galaxy cluster catalogues yields photometric redshifts for 275 objects. Of these, 182 clusters have at least one member with a spectroscopic redshift from existing public data (SDSS-DR8). Here we present the X-ray p...

  12. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: weighing the neutrino mass using the galaxy power spectrum of the CMASS sample

    OpenAIRE

    Zhao, G. -B.; Saito, S.; Percival, W J; Ross, A. J.; Montesano, F.; M. Viel(INAF-Osservatorio Astronomico di Trieste, Italy); Schneider, D. P.; Manera, M; Miralda-Escude, J.; Palanque-Delabrouille, N.; Ross, N. P.; Samushia, L.; Sanchez, A. G.; Swanson, M. E. C.; D. Thomas

    2013-01-01

    We measure the sum of the neutrino particle masses using the three-dimensional galaxy power spectrum of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) CMASS galaxy sample. Combined with the cosmic microwave background (CMB), supernova (SN) and additional baryonic acoustic oscillation (BAO) data, we find upper 95 percent confidence limits of the neutrino mass $\\Sigma m_{\

  13. SDSS-III Baryon Oscillation Spectroscopic Survey Data Release 12: galaxy target selection and large-scale structure catalogues

    Science.gov (United States)

    Reid, Beth; Ho, Shirley; Padmanabhan, Nikhil; Percival, Will J.; Tinker, Jeremy; Tojeiro, Rita; White, Martin; Eisenstein, Daniel J.; Maraston, Claudia; Ross, Ashley J.; Sánchez, Ariel G.; Schlegel, David; Sheldon, Erin; Strauss, Michael A.; Thomas, Daniel; Wake, David; Beutler, Florian; Bizyaev, Dmitry; Bolton, Adam S.; Brownstein, Joel R.; Chuang, Chia-Hsun; Dawson, Kyle; Harding, Paul; Kitaura, Francisco-Shu; Leauthaud, Alexie; Masters, Karen; McBride, Cameron K.; More, Surhud; Olmstead, Matthew D.; Oravetz, Daniel; Nuza, Sebastián E.; Pan, Kaike; Parejko, John; Pforr, Janine; Prada, Francisco; Rodríguez-Torres, Sergio; Salazar-Albornoz, Salvador; Samushia, Lado; Schneider, Donald P.; Scóccola, Claudia G.; Simmons, Audrey; Vargas-Magana, Mariana

    2016-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target catalogue caused by changes either in the targeting algorithm or properties of the data used, the pattern of spectroscopic observations, the spatial distribution of targets for which redshifts were not obtained, and variations in the target sky density due to observational systematics. We document here the target selection algorithms used to create the galaxy samples that comprise BOSS. We also present the algorithms used to create large-scale structure catalogues for the final Data Release (DR12) samples and the associated random catalogues that quantify the survey mask. The algorithms are an evolution of those used by the BOSS team to construct catalogues from earlier data, and have been designed to accurately quantify the galaxy sample. The code used, designated MKSAMPLE, is released with this paper.

  14. Correlations among the properties of galaxies found in a blind HI survey, which also have SDSS optical data

    CERN Document Server

    Garcia-Appadoo, Diego A; Dalcanton, Julianne J; Cortese, Luca; Disney, Michael J

    2008-01-01

    We have used the Parkes Multibeam system and the Sloan Digital Sky Survey (SDSS) to assemble a sample of 195 galaxies selected originally from their HI signature to avoid biases against unevolved or low surface brightness objects. For each source 9 intrinsic properties are measured homogeneously, as well as inclination and an optical spectrum. The sample, which should be almost entirely free of either misidentification or confusion, includes a wide diversity of galaxies ranging from inchoate, low surface brightness dwarfs to giant spirals. Despite this diversity there are 5 clear correlations among their properties. They include a common dynamical mass-to-light ratio within their optical radii, a correlation between surface-brightness and Luminosity and a common HI surface-density. Such correlation should provide strong constrains on models of galaxy formation and evolution.

  15. The Rise and Fall of Type Ia Supernova Light Curves in the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, Brian T.; /Notre Dame U.; Garnavich, Peter M.; /Notre Dame U.; Kessler, Richard; /KICP, Chicago /Chicago U., EFI; Frieman, Joshua A.; /KICP, Chicago /Chicago U. /Fermilab; Jha, Saurabh W.; /Stanford U., Phys. Dept. /Rutgers U., Piscataway; Bassett, Bruce; /Cape Town U., Dept. Math. /South African Astron. Observ.; Cinabro, David; /Wayne State U.; Dilday, Benjamin; /Rutgers U., Piscataway; Kasen, Daniel; /UC, Santa Cruz; Marriner, John; /Fermilab; Nichol, Robert C.; /Portsmouth U., ICG /Baltimore, Space Telescope Sci. /Johns Hopkins U.

    2010-01-01

    We analyze the rise and fall times of Type Ia supernova (SN Ia) light curves discovered by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. From a set of 391 light curves k-corrected to the rest-frame B and V bands, we find a smaller dispersion in the rising portion of the light curve compared to the decline. This is in qualitative agreement with computer models which predict that variations in radioactive nickel yield have less impact on the rise than on the spread of the decline rates. The differences we find in the rise and fall properties suggest that a single 'stretch' correction to the light curve phase does not properly model the range of SN Ia light curve shapes. We select a subset of 105 light curves well observed in both rise and fall portions of the light curves and develop a '2-stretch' fit algorithm which estimates the rise and fall times independently. We find the average time from explosion to B-band peak brightness is 17.38 {+-} 0.17 days, but with a spread of rise times which range from 13 days to 23 days. Our average rise time is shorter than the 19.5 days found in previous studies; this reflects both the different light curve template used and the application of the 2-stretch algorithm. The SDSS-II supernova set and the local SNe Ia with well-observed early light curves show no significant differences in their average rise-time properties. We find that slow-declining events tend to have fast rise times, but that the distribution of rise minus fall time is broad and single peaked. This distribution is in contrast to the bimodality in this parameter that was first suggested by Strovink (2007) from an analysis of a small set of local SNe Ia. We divide the SDSS-II sample in half based on the rise minus fall value, t{sub r} - t{sub f} {approx}< 2 days and t{sub r} - t{sub f} > 2 days, to search for differences in their host galaxy properties and Hubble residuals; we find no difference in host galaxy properties or Hubble

  16. A survey of luminous high-redshift quasars with SDSS and WISE. I. target selection and optical spectroscopy

    CERN Document Server

    Wang, Feige; Fan, Xiaohui; Yang, Jinyi; Yi, Weimin; Bian, Fuyan; McGreer, Ian D; Yang, Qian; Ai, Yanli; Dong, Xiaoyi; Zuo, Wenwen; Jiang, Linhua; Green, Richard; Wang, Shu; Cai, Zheng; Wang, Ran; Yue, Minghao

    2016-01-01

    High-redshift quasars are important tracers of structure and evolution in the early universe. However, they are very rare and difficult to find when using color selection because of contamination from late-type dwarfs. High-redshift quasar surveys based on only optical colors suffer from incompleteness and low identification efficiency, especially at $z\\gtrsim4.5$. We have developed a new method to select $4.7\\lesssim z \\lesssim 5.4$ quasars with both high efficiency and completeness by combining optical and mid-IR Wide-field Infrared Survey Explorer (WISE) photometric data, and are conducting a luminous $z\\sim5$ quasar survey in the whole Sloan Digital Sky Survey (SDSS) footprint. We have spectroscopically observed 99 out of 110 candidates with $z$-band magnitudes brighter than 19.5 and 64 (64.6\\%) of them are quasars with redshifts of $4.4\\lesssim z \\lesssim 5.5$ and absolute magnitudes of $-29\\lesssim M_{1450} \\lesssim -26.4$. In addition, we also observed 14 fainter candidates selected with the same crite...

  17. Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory

    CERN Document Server

    Bundy, Kevin; Law, David R; Yan, Renbin; Drory, Niv; MacDonald, Nicholas; Wake, David A; Cherinka, Brian; Sánchez-Gallego, José R; Weijmans, Anne-Marie; Thomas, Daniel; Tremonti, Christy; Masters, Karen; Coccato, Lodovico; Diamond-Stanic, Aleksandar M; Aragón-Salamanca, Alfonso; Avila-Reese, Vladimir; Badenes, Carles; Falcón-Barroso, Jésus; Belfiore, Francesco; Bizyaev, Dmitry; Blanc, Guillermo A; Bland-Hawthorn, Joss; Blanton, Michael R; Brownstein, Joel R; Byler, Nell; Cappellari, Michele; Conroy, Charlie; Dutton, Aaron A; Emsellem, Eric; Etherington, James; Frinchaboy, Peter M; Fu, Hai; Gunn, James E; Harding, Paul; Johnston, Evelyn J; Kauffmann, Guinevere; Kinemuchi, Karen; Klaene, Mark A; Knapen, Johan H; Leauthaud, Alexie; Li, Cheng; Lin, Lihwai; Maiolino, Roberto; Malanushenko, Viktor; Malanushenko, Elena; Mao, Shude; Maraston, Claudia; McDermid, Richard M; Merrifield, Michael R; Nichol, Robert C; Oravetz, Daniel; Pan, Kaike; Parejko, John K; Sanchez, Sebastian F; Schlegel, David; Simmons, Audrey; Steele, Oliver; Steinmetz, Matthias; Thanjavur, Karun; Thompson, Benjamin A; Tinker, Jeremy L; Bosch, Remco C E van den; Westfall, Kyle B; Wilkinson, David; Wright, Shelley; Xiao, Ting; Zhang, Kai

    2014-01-01

    We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12" (19 fibers) to 32" (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 A at R~2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (per A, per 2" fiber) at 23 AB mag per sq. arcsec, which is typical for the outskirts of ...

  18. Mass Functions of the Active Black Holes in Distant Quasars from the Large Bright Quasar Survey, the Bright Quasar Survey, and the Color-Selected Sample of the SDSS Fall Equatorial Stripe

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Osmer, Patrick S.

    2009-01-01

    We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey, the Bright Quasar Survey, and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts (0...... functions at similar redshifts based on the SDSS Data Release 3 quasar catalog presented by Vestergaard et al. We see clear evidence of cosmic downsizing in the comoving space density distribution of active black holes in the LBQS sample alone. In forthcoming papers, further analysis, comparison......, and discussion of these mass functions will be made with other existing black hole mass functions, notably that based on the SDSS DR3 quasar catalog. We present the relationships used to estimate the black hole mass based on the MgII emission line; the relations are calibrated to the Hbeta and CIV relations...

  19. The Optical Luminosity Function of Void Galaxies in the SDSS and ALFALFA Surveys

    CERN Document Server

    Moorman, Crystal M; Hoyle, Fiona; Pan, Danny C; Haynes, Martha P; Giovanelli, Riccardo

    2015-01-01

    We measure the r-band galaxy luminosity function (LF) across environments over the redshift range 0<$z$<0.107 using the SDSS. We divide our sample into galaxies residing in large scale voids (void galaxies) and those residing in denser regions (wall galaxies). The best fitting Schechter parameters for void galaxies are: log$\\Phi^*$= -3.40$\\pm$0.03 log(Mpc$^{-3}$), $M^*$= -19.88$\\pm$0.05, and $\\alpha$=-1.20$\\pm$0.02. For wall galaxies, the best fitting parameters are: log$\\Phi^*$=-2.86$\\pm$0.02 log(Mpc$^{-3}$), $M^*$=-20.80$\\pm$0.03, and $\\alpha$=-1.16$\\pm$0.01. We find a shift in the characteristic magnitude, $M^*$, towards fainter magnitudes for void galaxies and find no significant difference between the faint-end slopes of the void and wall galaxy LFs. We investigate how low surface brightness selections effects can affect the galaxy LF. To attempt to examine a sample of galaxies that is relatively free of surface brightness selection effects, we compute the optical galaxy LF of galaxies detected by ...

  20. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    CERN Document Server

    Dilday, Benjamin; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A; Galbany, Lluís; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; Ihara, Yutaka; Jha, Saurabh W; Kessler, Richard; Lampeitl, Hubert; Marriner, John; Miquel, Ramon; Mollá, Mercedes; Nichol, Robert C; Nordin, Jakob; Riess, Adam G; Sako, Masao; Schneider, Donald P; Smith, Mathew; Sollerman, Jesper; Wheeler, J Craig; Östman, Linda; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie

    2010-01-01

    ABRIDGED We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z <0.17 and 27 SN events in 492 maxBCG clusters at 0.1 < z < 0.3$. We find values for the cluster SN Ia rate of $({0.37}^{+0.17+0.01}_{-0.12-0.01}) \\mathrm{SNu}r h^{2}$ and $({0.55}^{+0.13+0.02}_{-0.11-0.01}) \\mathrm{SNu}r h^{2}$ ($\\mathrm{SNu}x = 10^{-12} L_{x\\sun}^{-1} \\mathrm{yr}^{-1}$) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be $({0.31}^{+0.18+0.01}_{-0.12-0.01}) \\mathrm{SNu}r h^{2}$ and $({0.49}^{+0.15+0.02}_{-0.11-0.01})$ $\\mathrm{SNu}r h^{2}$ in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be $({2.04}^{+1.99+0.07}_{-1.11-0.04}) \\mathrm{SNu}r h^{2}$ and $({0.36}^{+0.84+0.01}_...

  1. The Open Cluster Chemical Analysis and Mapping Survey: Local Galactic Metallicity Gradient with APOGEE using SDSS DR10

    CERN Document Server

    Frinchaboy, Peter M; Jackson, Kelly M; O'Connell, Julia; Meyer, Brianne; Zasowski, Gail; Majewski, Steven R; Chojnowksi, S Drew; Johnson, Jennifer A; Prieto, Carlos Allende; Beers, Timothy C; Bizyaev, Dmitry; Brewington, Howard; Cunha, Katia; Ebelke, Garrett; Perez, Ana Elia Garcia; Hearty, Frederick R; Holtzman, Jon; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Marchante, Moses; Meszaros, Szabolcs; Muna, Demitri; Nidever, David L; Oravetz, Daniel; Pan, Kaike; Schiavon, Ricardo P; Schneider, Donald P; Shetrone, Matthew; Simmons, Audrey; Snedden, Stephanie; Smith, Verne V; Wilson, John C

    2013-01-01

    The Open Cluster Chemical Analysis and Mapping (OCCAM) Survey aims to produce a comprehensive, uniform, infrared-based dataset for hundreds of open clusters, and constrain key Galactic dynamical and chemical parameters from this sample. This first contribution from the OCCAM survey presents analysis of 141 members stars in 28 open clusters with high-resolution metallicities derived from a large uniform sample collected as part of the SDSS-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE). This sample includes the first high-resolution metallicity measurements for 22 open clusters. With this largest ever uniformly observed sample of open cluster stars we investigate the Galactic disk gradients of both [M/H] and [alpha/M]. We find basically no gradient across this range in [alpha/M], but [M/H] does show a gradient for R_{GC} < 10 kpc and a significant flattening beyond R_{GC} = 10 kpc. In particular, whereas fitting a single linear trend yields an [M/H] gradient of -0.09 +/- 0.03$ dex/kpc -...

  2. The SDSS-IV extended Baryonic Oscillation Spectroscopic Survey: selecting Emission Line Galaxies using the Fisher Discriminant

    CERN Document Server

    Raichoor, A; Delubac, T; Kneib, J -P; Yèche, C; Zou, H; Abdalla, F B; Dawson, K; Fan, X; Fan, Z; Jiang, Z; Jing, Y; Jouvel, S; Lang, D; Lesser, M; Li, C; Ma, J; Newman, J A; Nie, J; Olszewski, E; Palanque-Delabrouille, N; Percival, W; Prada, F; Shen, S; Wang, J; Wu, Z; Zhang, T; Zhou, X; Zhou, Z

    2015-01-01

    We present a new selection technique to produce spectroscopic target catalogues for massive spectroscopic surveys for cosmology. This work was conducted in the context of the extended Baryon Oscillation Spectroscopic Survey (eBOSS), which will use 200,000 emission line galaxies (ELGs) at 0.6SDSS spectroscopy to quantify the redshift distribution and [Oii] flux of our ELG target selections. We demonstrate that two of our selections fulfill the initial eBOSS/ELG redshift requirements: for a target density of 180 d...

  3. FIRST RESULTS FROM THE SWARMS SURVEY. SDSS 1257+5428: A NEARBY, MASSIVE WHITE DWARF BINARY WITH A LIKELY NEUTRON STAR OR BLACK HOLE COMPANION

    International Nuclear Information System (INIS)

    We present the first results from the SWARMS survey, an ongoing project to identify compact white dwarf (WD) binaries in the spectroscopic catalog of the Sloan Digital Sky Survey (SDSS). The first object identified by SWARMS, SDSS 1257+5428, is a single-lined spectroscopic binary in a circular orbit with a period of 4.56 hr and a semiamplitude of 322.7 ± 6.3 km s-1. From the spectrum and photometry, we estimate a WD mass of 0.92+0.28-0.32 Msun. Together with the orbital parameters of the binary, this implies that the unseen companion must be more massive than 1.62+0.20-0.25 Msun, and is in all likelihood either a neutron star or a black hole. At an estimated distance of 48+10-19 pc, this would be the closest known stellar remnant of a supernova explosion.

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Observational systematics and baryon acoustic oscillations in the correlation function

    OpenAIRE

    Ross, Ashley J.; Beutler, Florian; Chuang, Chia-Hsun; Pellejero-Ibanez, Marcos; Seo, Hee-Jong; Vargas-Magana, Mariana; Cuesta, Antonio J.; Percival, Will J.; Burden, Angela; Sanchez, Ariel G.; Grieb, Jan Niklas; Reid, Beth; Brownstein, Joel R.; Dawson, Kyle S.; Eisenstein, Daniel J.

    2016-01-01

    We present baryon acoustic oscillation (BAO) scale measurements determined from the clustering of 1.2 million massive galaxies with redshifts 0.2 < z < 0.75 distributed over 9300 square degrees, as quantified by their redshift-space correlation function. In order to facilitate these measurements, we define, describe, and motivate the selection function for galaxies in the final data release (DR12) of the SDSS III Baryon Oscillation Spectroscopic Survey (BOSS). This includes the observational ...

  5. At the survey limits: discovery of the Aquarius 2 dwarf galaxy in the VST ATLAS and the SDSS data

    CERN Document Server

    Torrealba, G; Belokurov, V; Irwin, M; Collins, M; Spencer, M; Ibata, R; Mateo, M; Bonaca, A; Jethwa, P

    2016-01-01

    We announce the discovery of the Aquarius~2 dwarf galaxy, a new distant satellite of the Milky Way, detected on the fringes of the VST ATLAS and the SDSS surveys. The object was originally identified as an overdensity of Red Giant Branch stars, but chosen for subsequent follow-up based on the presence of a strong Blue Horizontal Branch, which was also used to measure its distance of $\\sim 110$ kpc. Using deeper imaging from the IMACS camera on the 6.5m Baade and spectroscopy with DEIMOS on Keck, we measured the satellite's half-light radius $5.1\\pm 0.8$ arcmin, or $\\sim 160$ pc at this distance, and its stellar velocity dispersion of $5.4^{+3.4}_{-0.9}$ km s$^{-1}$. With $\\mu=30.4$ mag arcsec$^{-2}$ and $M_V=-4.2$, the new satellite lies close to two important detection limits: one in surface brightness; and one in luminosity at a given distance, thereby making Aquarius~2 one of the hardest dwarfs to find.

  6. At the survey limits: discovery of the Aquarius 2 dwarf galaxy in the VST ATLAS and the SDSS data

    Science.gov (United States)

    Torrealba, G.; Koposov, S. E.; Belokurov, V.; Irwin, M.; Collins, M.; Spencer, M.; Ibata, R.; Mateo, M.; Bonaca, A.; Jethwa, P.

    2016-08-01

    We announce the discovery of the Aquarius 2 dwarf galaxy, a new distant satellite of the Milky Way, detected on the fringes of the VST ATLAS and the SDSS surveys. The object was originally identified as an overdensity of Red Giant Branch stars, but chosen for subsequent follow-up based on the presence of a strong Blue Horizontal Branch, which was also used to measure its distance of ˜110 kpc. Using deeper imaging from the IMACS camera on the 6.5m Baade and spectroscopy with DEIMOS on Keck, we measured the satellite's half-light radius 5.1 ± 0.8 arcmin, or ˜160 pc at this distance, and its stellar velocity dispersion of 5.4^{+3.4}_{-0.9} km s-1. With μ = 30.2 mag arcsec-2 and MV = -4.36, the new satellite lies close to two important detection limits: one in surface brightness; and one in luminosity at a given distance, thereby making Aquarius 2 one of the hardest dwarfs to find.

  7. Multifractal analysis and lacunarity spectrum of the galaxies of the ninth Sloan Digital Sky Survey (SDSS) data release

    CERN Document Server

    Chacón-Cardona, César A

    2012-01-01

    In this work, we develop a statistical analysis of the large-scale clustering of matter in the Universe from the fractal point of view using galaxies from the Ninth Sloan Digital Sky Survey (SDSS) Data Release (DR9). From the total set of galaxies, a magnitude-limited sample of galaxies with redshifts in the range 0 < z < 0.15 was created. The sample covers the largest completely connected area of the celestial sphere within the catalogue, with limits in right ascension from 120 to 240 degrees and declination from 0 to 60 degrees, which is a region that includes the largest galactic samples that have been studied from the fractal viewpoint to date. The sample contains 164,168 galaxies. Using the sliding-window technique, the multifractal dimension spectrum and its dependence on radial distance are determined. This generalisation of the concept of fractal dimension is used to analyse large-scale clustering of matter in complex systems. Likewise, the lacunarity spectrum, which is a quantity that complemen...

  8. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey:Overview and Early Data

    OpenAIRE

    Dawson, Kyle S.; Kneib, Jean-Paul,; Percival, Will J.; Alam, Shadab; Albareti, Franco D.; Anderson, Scott F.; Armengaud, Eric; Aubourg, Eric; Bailey, Stephen; Bautista, Julian. E.; Andreas A. Berlind(Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA); Bershady, Matthew A.; Beutler, Florian; Bizyaev, Dmitry; Blanton, Michael R.

    2016-01-01

    The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. Observations will be simultaneous with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. eBOSS will use four different tracers to measure the distance-redshift relation with baryon acoustic osci...

  9. Arecibo Observations of Parkes Multibeam Pulsars

    Indian Academy of Sciences (India)

    N. D. R. Bhat; F. Camilo; J. M. Cordes; D. J. Nice; D. R. Lorimer; S. Chatterjee

    2002-03-01

    The on-going Parkes multibeam survey has been astoundingly successful (Manchester et al. 2001), and its discovery of over 600 pulsars has opened up new avenues for probing the Galaxy’s electron content and magnetic field. Here we report on recent observations made with the Arecibo 305-m telescope, where 80 distant, high dispersion measure pulsars (of which 35 are from the multibeam survey) were studied at multiple frequency bands in the range 0.4–2.4 GHz, in order to determine their scattering properties, rotation measures and spectral indices. The results will be used to meet a variety of science goals; viz., creating an improved model of the electron density, mapping out the Galactic magnetic field, and modeling the pulsar population.

  10. The SDSS-DR5 Survey for Proximate Damped Lya Systems

    OpenAIRE

    Prochaska, Jason X.; Hennawi, Joseph F.; Herbert-Fort, Stephane

    2007-01-01

    Using the Sloan Digital Sky Survey, Data Release 5, we survey proximate damped Lya systems (PDLAs): absorption line systems with HI column density N(HI)> 2x10^20 cm^{-2} at velocity separation dv < 3000 km/s from their background quasar. These absorbers are physically associated with their background quasars, and their statistics allow us to study quasar environments out to z~5. However, the large ionizing flux emitted by a quasar can ionize the neutral gas in a nearby galaxy possibly giving ...

  11. Origin of 12 μm Emission across Galaxy Populations from WISE and SDSS Surveys

    OpenAIRE

    Donoso, E; Yan, Lin; Tsai, C. -W.; Eisenhardt, P.; Stern, D; Assef, R.; Leisawitz, D.; Jarrett, T. H.; Stanford, S A

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer sources brighter than 1 mJy at 12 μm with the Sloan Digital Sky Survey galaxy spectroscopic catalog to produce a sample of ~10^5 galaxies at = 0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range ~10^(8)-10^(12) L_☉. We identify which stellar populations are responsible for most of the 12 μm emission. We find that most (~80%) of the 12 μm...

  12. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection

    OpenAIRE

    Myers, Adam D.; Palanque-Delabrouille, Nathalie; Prakash, Abhishek; Pâris, Isabelle; Yeche, Christophe,; Dawson, Kyle S.; Bovy, Jo; Lang, Dustin; Schlegel, David J.; Newman, Jeffrey A.; Petitjean, Patrick; Kneib, Jean Paul; Laurent, Pierre; Percival, Will J.; Ross, Ashley J.

    2015-01-01

    As part of the Sloan Digital Sky Survey IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 sq. deg. First, a "CORE" quasar sample will combine optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color-cut. eBOSS CORE selection (to g < 22 OR r...

  13. The clustering of galaxies in the SDSS-III DR10 Baryon Oscillation Spectroscopic Survey: no detectable colour dependence of distance scale or growth rate measurements

    Science.gov (United States)

    Ross, Ashley J.; Samushia, Lado; Burden, Angela; Percival, Will J.; Tojeiro, Rita; Manera, Marc; Beutler, Florian; Brinkmann, J.; Brownstein, Joel R.; Carnero, Aurelio; da Costa, Luiz A. N.; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; Maia, Marcio A. G.; Montesano, Francesco; Muna, Demitri; Nichol, Robert C.; Nuza, Sebastián E.; Sánchez, Ariel G.; Schneider, Donald P.; Skibba, Ramin A.; Sobreira, Flávia; Streblyanska, Alina; Swanson, Molly E. C.; Thomas, Daniel; Tinker, Jeremy L.; Wake, David A.; Zehavi, Idit; Zhao, Gong-bo

    2014-01-01

    We study the clustering of galaxies, as a function of their colour, from Data Release Ten (DR10) of the Sloan Digital Sky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey. DR10 contains 540 505 galaxies with 0.43 comb = 0.443 ± 0.055. This result compares favourably to that of the full 0.43 tests on mock samples, which predict that any colour-dependent systematic uncertainty on the measured BAO position is less than 0.5 per cent.

  14. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Release 9 spectroscopic galaxy sample

    OpenAIRE

    Anderson, Lauren; de Putter, Roland; Mena Requejo, Olga

    2012-01-01

    We present measurements of galaxy clustering from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). These use the Data Release 9 (DR9) CMASS sample, which contains 264 283 massive galaxies covering 3275 square degrees with an effective redshift z = 0.57 and redshift range 0.43 < z < 0.7. Assuming a concordance Lambda CDM cosmological model, this sample covers an effective volume of 2.2 Gpc(3), and represents the largest sample of...

  15. First-Year Spectroscopy for the SDSS-II Supernova Survey

    CERN Document Server

    Zheng, Chen; Sako, Masao; Marriner, John; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L; Dilday, Ben; Doi, Mamoru; Frieman, Joshua A; Garnavich, Peter M; Hogan, Craig J; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert; Marshall, Jennifer L; McGinnis, David; Miknaitis, Gajus; Nichol, Robert C; Prieto, Jose Luis; Riess, Adam G; Richmond, Michael W; Schneider, Donald P; Smith, Mathew; Takanashi, Naohiro; Tokita, Kouichi; van der Heyden, Kurt; Yasuda, Naoki; Assef, Roberto J; Barentine, John; Bender, Ralf; Blandford, Roger D; Bremer, Malcolm; Brewington, Howard; Collins, Chris A; Crotts, Arlin; Dembicky, Jack; Eastman, Jason; Edge, Alastair; Elson, Ed; Eyler, Michael E; Filippenko, Alexei V; Foley, Ryan J; Frank, Stephan; Goobar, Ariel; Harvanek, Michael; Hopp, Ulrich; Ihara, Yutaka; Kahn, Steven; Ketzeback, William; Kleinman, Scott J; Kollatschny, Wolfram; Krzesiński, Jurek; Leloudas, Giorgos; Long, Daniel C; Lucey, John; Malanushenko, Elena; Malanushenko, Viktor; McMillan, Russet J; Morgan, Christopher W; Morokuma, Tomoki; Nitta, Atsuko; Ostman, Linda; Pan, Kaike; Romer, A Kathy; Saurage, Gabrelle; Schlesinger, Katie; Snedden, Stephanie A; Sollerman, Jesper; Stritzinger, Maximilian; Watson, Linda C; Watters, Shannon; Wheeler, J Craig; York, Donald

    2008-01-01

    This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existi...

  16. First-Year Spectroscopy for the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Chen; Romani, Roger W.; Sako, Masao; Marriner, John; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Frieman, Joshua A.; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert

    2008-03-25

    This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05-0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.

  17. HOMOGENEOUS UGRIZ PHOTOMETRY FOR ACS VIRGO CLUSTER SURVEY GALAXIES: A NON-PARAMETRIC ANALYSIS FROM SDSS IMAGING

    International Nuclear Information System (INIS)

    We present photometric and structural parameters for 100 ACS Virgo Cluster Survey (ACSVCS) galaxies based on homogeneous, multi-wavelength (ugriz), wide-field SDSS (DR5) imaging. These early-type galaxies, which trace out the red sequence in the Virgo Cluster, span a factor of nearly ∼103 in g-band luminosity. We describe an automated pipeline that generates background-subtracted mosaic images, masks field sources and measures mean shapes, total magnitudes, effective radii, and effective surface brightnesses using a model-independent approach. A parametric analysis of the surface brightness profiles is also carried out to obtain Sersic-based structural parameters and mean galaxy colors. We compare the galaxy parameters to those in the literature, including those from the ACSVCS, finding good agreement in most cases, although the sizes of the brightest, and most extended, galaxies are found to be most uncertain and model dependent. Our photometry provides an external measurement of the random errors on total magnitudes from the widely used Virgo Cluster Catalog, which we estimate to be σ(BT )∼ 0.13 mag for the brightest galaxies, rising to ∼ 0.3 mag for galaxies at the faint end of our sample (BT ∼ 16). The distribution of axial ratios of low-mass (dwarf) galaxies bears a strong resemblance to the one observed for the higher-mass (giant) galaxies. The global structural parameters for the full galaxy sample-profile shape, effective radius, and mean surface brightness-are found to vary smoothly and systematically as a function of luminosity, with unmistakable evidence for changes in structural homology along the red sequence. As noted in previous studies, the ugriz galaxy colors show a nonlinear but smooth variation over a ∼7 mag range in absolute magnitude, with an enhanced scatter for the faintest systems that is likely the signature of their more diverse star formation histories.

  18. Voids in the SDSS DR9: observations, simulations, and the impact of the survey mask

    CERN Document Server

    Sutter, P M; Wandelt, Benjamin D; Weinberg, David H; Warren, Michael S

    2013-01-01

    We present and study cosmic voids identified using the watershed void finder ZOBOZ in the Sloan Digital Sky Survey Data Release 9, compare these voids to ones identified in mock catalogs, and assess the impact of the survey mask on void statistics such as number functions, ellipticity distributions, and radial density profiles. The nearly 1,000 identified voids span three volume-limited samples from redshift z=0.43 to 0.7. For comparison we use 98 of the publicly available 2LPT-based mock galaxy catalogs of Manera et al. (2012), and also generate our own mock catalogs by applying a Halo Occupation Distribution model to an N-body simulation. We find that the mask reduces the number density of voids at all scales by a factor of three and slightly skews the relative size distributions. This engenders an increase in the mean ellipticity by roughly 30%. However, we find that radial density profiles are largely robust to the effects of the mask. We see excellent agreement between the data and both mock catalogs, an...

  19. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Overview and Early Data

    CERN Document Server

    Dawson, Kyle S; Percival, Will J; Alam, Shadab; Albareti, Franco D; Anderson, Scott F; Armengaud, Eric; Aubourg, Eric; Bailey, Stephen; Bautista, Julian E; Berlind, Andreas A; Bershady, Matthew A; Beutler, Florian; Bizyaev, Dmitry; Blanton, Michael R; Blomqvist, Michael; Bolton, Adam S; Bovy, Jo; Brandt, W N; Brinkmann, Jon; Brownstein, Joel R; Burtin, Etienne; Busca, N G; Cai, Zheng; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Cope, Frances; Croft, Rupert A C; Cruz-Gonzalez, Irene; da Costa, Luiz N; Cousinou, Marie-Claude; Darling, Jeremy; de la Torre, Sylvain; Delubac, Timothee; Bourboux, Helion du Mas des; Dwelly, Tom; Ealet, Anne; Eisenstein, Daniel J; Eracleous, Michael; Escoffier, S; Fan, Xiaohui; Finoguenov, Alexis; Font-Ribera, Andreu; Frinchaboy, Peter; Gaulme, Patrick; Georgakakis, Antonis; Green, Paul; Guo, Hong; Guy, Julien; Ho, Shirley; Holder, Diana; Huehnerhoff, Joe; Hutchinson, Timothy; Jing, Yipeng; Jullo, Eric; Kamble, Vikrant; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco-Shu; Klaene, Mark A; Laher, Russ R; Lang, Dustin; Laurent, Pierre; Goff, Jean-Marc Le; Li, Cheng; Liang, Yu; Lima, Marcos; Lin, Qiufan; Lin, Weipeng; Lin, Yen-Ting; Long, Daniel C; Lundgren, Britt; MacDonald, Nicholas; Maia, Marcio Antonio Geimba; Malanushenko, Elena; Malanushenko, Viktor; Mariappan, Vivek; McBride, Cameron K; McGreer, Ian D; Menard, Brice; Merloni, Andrea; Meza, Andres; Montero-Dorta, Antonio D; Muna, Demitri; Myers, Adam D; Nandra, Kirpal; Naugle, Tracy; Newman, Jeffrey A; Noterdaeme, Pasquier; Nugent, Peter; Ogando, Ricardo; Olmstead, Matthew D; Oravetz, Audrey; Oravetz, Daniel J; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K; Paris, Isabelle; Peacock, John A; Petitjean, Patrick; Pieri, Matthew M; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Raichoor, Anand; Reid, Beth; Rich, James; Ridl, Jethro; Rodriguez-Torres, Sergio; Rosell, Aurelio Carnero; Ross, Ashley J; Rossi, Graziano; Ruan, John; Salvato, Mara; Sayres, Conor; Schneider, Donald P; Schlegel, David J; Seljak, Uros; Seo, Hee-Jong; Sesar, Branimir; Shandera, Sarah; Shu, Yiping; Slosar, Anze; Sobreira, Flavia; Strauss, Michael A; Streblyanska, Alina; Suzuki, Nao; Tao, Charling; Tinker, Jeremy L; Tojeiro, Rita; Vargas-Magana, Mariana; Wang, Yuting; Weaver, Benjamin A; Weinberg, David H; White, Martin; Wood-Vasey, W M; Yeche, Christophe; Zhai, Zhongxu; Zhao, Cheng; Zhao, Gong-bo; Zheng, Zheng; Zhu, Guangtun Ben; Zou, Hu

    2015-01-01

    The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. Observations will be simultaneous with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. eBOSS will use four different tracers to measure the distance-redshift relation with baryon acoustic oscillations (BAO) in the clustering of matter. Using more than 250,000 new, spectroscopically confirmed luminous red galaxies at a median redshift z=0.72, we project that eBOSS will yield measurements of $d_A(z)$ to an accuracy of 1.2% and measurements of H(z) to 2.1% when combined with the z>0.6 sample of BOSS galaxies. With ~195,000 new emission line galaxy redshifts, we expect BAO measurements of $d_A(z)$ to an accuracy of 3.1% and H(z) to 4.7% at an effective redshift of z= 0.87. A sample of more than 500,000 spectroscop...

  20. Measurements of the Rate of Type Ia Supernovae at Redshift z < ~0.3 from the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Dilday, Benjamin; /Rutgers U., Piscataway /Chicago U. /KICP, Chicago; Smith, Mathew; /Cape Town U., Dept. Math. /Portsmouth U.; Bassett, Bruce; /Cape Town U., Dept. Math. /South African Astron. Observ.; Becker, Andrew; /Washington U., Seattle, Astron. Dept.; Bender, Ralf; /Munich, Tech. U. /Munich U. Observ.; Castander, Francisco; /Barcelona, IEEC; Cinabro, David; /Wayne State U.; Filippenko, Alexei V.; /UC, Berkeley; Frieman, Joshua A.; /Chicago U. /Fermilab; Galbany, Lluis; /Barcelona, IFAE; Garnavich, Peter M.; /Notre Dame U. /Stockholm U., OKC /Stockholm U.

    2010-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey. The adopted sample of supernovae (SNe) includes 516 SNe Ia at redshift z {approx}< 0.3, of which 270 (52%) are spectroscopically identified as SNe Ia. The remaining 246 SNe Ia were identified through their light curves; 113 of these objects have spectroscopic redshifts from spectra of their host galaxy, and 133 have photometric redshifts estimated from the SN light curves. Based on consideration of 87 spectroscopically confirmed non-Ia SNe discovered by the SDSS-II SN Survey, we estimate that 2.04{sub -0.95}{sup +1.61}% of the photometric SNe Ia may be misidentified. The sample of SNe Ia used in this measurement represents an order of magnitude increase in the statistics for SN Ia rate measurements in the redshift range covered by the SDSS-II Supernova Survey. If we assume a SN Ia rate that is constant at low redshift (z < 0.15), then the SN observations can be used to infer a value of the SN rate of r{sub V} = (2.69{sub -0.30-0.01}{sup +0.34+0.21}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} at a mean redshift of {approx} 0.12, based on 79 SNe Ia of which 72 are spectroscopically confirmed. However, the large sample of SNe Ia included in this study allows us to place constraints on the redshift dependence of the SN Ia rate based on the SDSS-II Supernova Survey data alone. Fitting a power-law model of the SN rate evolution, r{sub V} (z) = A{sub p} x ((1+z)/(1+z{sub 0})){sup {nu}}, over the redshift range 0.0 < z < 0.3 with z{sub 0} = 0.21, results in A{sub p} = (3.43{sub -0.15}{sup +0.15}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} and {nu} = 2.04{sub -0.89}{sup +0.90}.

  1. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Overview and Early Data

    Science.gov (United States)

    Dawson, Kyle S.; Kneib, Jean-Paul; Percival, Will J.; Alam, Shadab; Albareti, Franco D.; Anderson, Scott F.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Bautista, Julian E.; Berlind, Andreas A.; Bershady, Matthew A.; Beutler, Florian; Bizyaev, Dmitry; Blanton, Michael R.; Blomqvist, Michael; Bolton, Adam S.; Bovy, Jo; Brandt, W. N.; Brinkmann, Jon; Brownstein, Joel R.; Burtin, Etienne; Busca, N. G.; Cai, Zheng; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Cope, Frances; Croft, Rupert A. C.; Cruz-Gonzalez, Irene; da Costa, Luiz N.; Cousinou, Marie-Claude; Darling, Jeremy; de la Macorra, Axel; de la Torre, Sylvain; Delubac, Timothée; du Mas des Bourboux, Hélion; Dwelly, Tom; Ealet, Anne; Eisenstein, Daniel J.; Eracleous, Michael; Escoffier, S.; Fan, Xiaohui; Finoguenov, Alexis; Font-Ribera, Andreu; Frinchaboy, Peter; Gaulme, Patrick; Georgakakis, Antonis; Green, Paul; Guo, Hong; Guy, Julien; Ho, Shirley; Holder, Diana; Huehnerhoff, Joe; Hutchinson, Timothy; Jing, Yipeng; Jullo, Eric; Kamble, Vikrant; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco-Shu; Klaene, Mark A.; Laher, Russ R.; Lang, Dustin; Laurent, Pierre; Le Goff, Jean-Marc; Li, Cheng; Liang, Yu; Lima, Marcos; Lin, Qiufan; Lin, Weipeng; Lin, Yen-Ting; Long, Daniel C.; Lundgren, Britt; MacDonald, Nicholas; Geimba Maia, Marcio Antonio; Malanushenko, Elena; Malanushenko, Viktor; Mariappan, Vivek; McBride, Cameron K.; McGreer, Ian D.; Ménard, Brice; Merloni, Andrea; Meza, Andres; Montero-Dorta, Antonio D.; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Naugle, Tracy; Newman, Jeffrey A.; Noterdaeme, Pasquier; Nugent, Peter; Ogando, Ricardo; Olmstead, Matthew D.; Oravetz, Audrey; Oravetz, Daniel J.; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Peacock, John A.; Petitjean, Patrick; Pieri, Matthew M.; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Raichoor, Anand; Reid, Beth; Rich, James; Ridl, Jethro; Rodriguez-Torres, Sergio; Carnero Rosell, Aurelio; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Salvato, Mara; Sayres, Conor; Schneider, Donald P.; Schlegel, David J.; Seljak, Uros; Seo, Hee-Jong; Sesar, Branimir; Shandera, Sarah; Shu, Yiping; Slosar, Anže; Sobreira, Flavia; Streblyanska, Alina; Suzuki, Nao; Taylor, Donna; Tao, Charling; Tinker, Jeremy L.; Tojeiro, Rita; Vargas-Magaña, Mariana; Wang, Yuting; Weaver, Benjamin A.; Weinberg, David H.; White, Martin; Wood-Vasey, W. M.; Yeche, Christophe; Zhai, Zhongxu; Zhao, Cheng; Zhao, Gong-bo; Zheng, Zheng; Ben Zhu, Guangtun; Zou, Hu

    2016-02-01

    In a six-year program started in 2014 July, the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. These observations will be conducted simultaneously with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. In particular, eBOSS will measure with percent-level precision the distance-redshift relation with baryon acoustic oscillations (BAO) in the clustering of matter. eBOSS will use four different tracers of the underlying matter density field to vastly expand the volume covered by BOSS and map the large-scale-structures over the relatively unconstrained redshift range 0.6 yield measurements of the angular diameter distance dA(z) to an accuracy of 1.2% and measurements of H(z) to 2.1% when combined with the z > 0.6 sample of BOSS galaxies. With ∼195,000 new emission line galaxy redshifts, we expect BAO measurements of dA(z) to an accuracy of 3.1% and H(z) to 4.7% at an effective redshift of z = 0.87. A sample of more than 500,000 spectroscopically confirmed quasars will provide the first BAO distance measurements over the redshift range 0.9 2.1 these new data will enhance the precision of dA(z) and H(z) at z > 2.1 by a factor of 1.44 relative to BOSS. Furthermore, eBOSS will provide improved tests of General Relativity on cosmological scales through redshift-space distortion measurements, improved tests for non-Gaussianity in the primordial density field, and new constraints on the summed mass of all neutrino species. Here, we provide an overview of the cosmological goals, spectroscopic target sample, demonstration of spectral quality from early data, and projected cosmological constraints from eBOSS.

  2. Type 1 Active Galactic Nucleus Fraction in SDSS/FIRST Survey

    CERN Document Server

    Lu, Yu; Dong, Xiao-Bo; Zhou, Hong-Yan

    2010-01-01

    In the unification scheme, narrow-lined (type 2) active galactic nuclei (AGN) are intrinsically similar to broad-lined (type 1) AGN with the exception that the line of sight to the broad emission line region and accretion disk is blocked by a dusty torus. The fraction of type 1 AGN measures the average covering factor of the torus. In this paper, we explore the dependence of this fraction on nuclear properties for a sample of low redshift (z 10^{23}W/Hz) AGN selected by matching the spectroscopic catalog of Sloan Digital Sky Survey and the radio source catalog of Faint Image of Radio Sky at Twenty cm. After correcting for several selection effects, we find that : (1) type 1 fraction $f_1$ keeps at a constant of ~20 per cent in the [O III] 5007 luminosity range of 40.7< log(L_{[O III]}/ erg/s) <43.5 . This result is significantly different from previous studies, and the difference can be explained by extinction correction and different treatment of selection effects. (2) $f_1$ rises with black hole mass ...

  3. Detecting active comets with SDSS

    Energy Technology Data Exchange (ETDEWEB)

    Solontoi, Michael; Ivezic, Zeljko; /Washington U., Seattle, Astron. Dept.; West, Andrew A.; /MIT, MKI; Claire, Mark; /Washington U., Seattle, Astron. Dept.; Juric, Mario; /Princeton U. Observ.; Becker, Andrew; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; Hall, Patrick B.; /York U., Canada; Kent, Steve; /Fermilab; Lupton, Robert H.; /Princeton U. Observ.; Quinn, Tom; /Washington U., Seattle, Astron. Dept. /Princeton U. Observ.

    2010-12-01

    Using a sample of serendipitously discovered active comets in the Sloan Digital Sky Survey (SDSS), we develop well-controlled selection criteria for greatly increasing the efficiency of comet identification in the SDSS catalogs. After follow-up visual inspection of images to reject remaining false positives, the total sample of SDSS comets presented here contains 19 objects, roughly one comet per 10 million other SDSS objects. The good understanding of selection effects allows a study of the population statistics, and we estimate the apparent magnitude distribution to r {approx} 18, the ecliptic latitude distribution, and the comet distribution in SDSS color space. The most surprising results are the extremely narrow range of colors for comets in our sample (e.g. root-mean-square scatter of only {approx}0.06 mag for the g-r color), and the similarity of comet colors to those of jovian Trojans. We discuss the relevance of our results for upcoming deep multi-epoch optical surveys such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope (LSST), and estimate that LSST may produce a sample of about 10,000 comets over its 10-year lifetime.

  4. The Clustering of Galaxies in the Completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmic Flows and Cosmic Web from Luminous Red Galaxies

    OpenAIRE

    Ata, Metin; Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E.; Ferraro, Simone; McDonald, Patrick; Monteagudo, Carlos Hernández; Müller, Volker; Yepes, Gustavo; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R.; Burden, Angela; Eisenstein, Daniel J

    2016-01-01

    We present a Bayesian phase space reconstruction of the cosmic large-scale matter density and velocity fields from the SDSS-III Baryon Oscillations Spectroscopic Survey Data Release 12 (BOSS DR12) CMASS galaxy clustering catalogue. We rely on a given $\\Lambda$CDM cosmology, a mesh resolution in the range of 6-10 $h^{-1}$ Mpc, and a lognormal-Poisson model with a redshift dependent nonlinear bias. The bias parameters are derived from the data and a general renormalised perturbation theory appr...

  5. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:mock galaxy catalogues for the BOSS Final Data Release

    OpenAIRE

    Kitaura, Francisco-Shu; Rodriguez-Torres, Sergio; Chuang, Chia-Hsun; Zhao, Cheng; Prada, Francisco; Gil-Marin, Hector; Guo, Hong; Yepes, Gustavo; Klypin, Anatoly; Scoccola, Claudia G.; Tinker, Jeremy; McBride, Cameron; Reid, Beth; Sanchez, Ariel G.; Salazar-Albornoz, Salvador

    2016-01-01

    We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillation Spectroscopic Survey Final Data Release (BOSS DR11&DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated (6,000) 12,288 MultiDark PATCHY BOSS (DR11) DR12 light-cones corresponding to an effective volume of $\\sim192,000\\,[h^{-1}\\,{\\rm Gpc}]^3$ (the largest ever simulated volume), including cosmic evolut...

  6. The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment

    CERN Document Server

    Ahn, Christopher P; Prieto, Carlos Allende; Anders, Friedrich; Anderson, Scott F; Anderton, Timothy; Andrews, Brett H; Aubourg, Éric; Bailey, Stephen; Bastien, Fabienne A; Bautista, Julian E; Beers, Timothy C; Beifiori, Alessandra; Bender, Chad F; Berlind, Andreas A; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C; Bizyaev, Dmitry; Blake, Cullen H; Blanton, Michael R; Blomqvist, Michael; Bochanski, John J; Bolton, Adam S; Borde, Arnaud; Bovy, Jo; Bradley, Alaina Shelden; Brandt, W N; Brauer, Dorothée; Brinkmann, J; Brownstein, Joel R; Busca, Nicolás G; Carithers, William; Carlberg, Joleen K; Carnero, Aurelio R; Carr, Michael A; Chiappini, Cristina; Chojnowski, S Drew; Chuang, Chia-Hsun; Comparat, Johan; Crepp, Justin R; Cristiani, Stefano; Croft, Rupert A C; Cuesta, Antonio J; Cunha, Katia; da Costa, Luiz N; Dawson, Kyle S; De Lee, Nathan; Dean, Janice D R; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L; Edmondson, Edward M; Eisenstein, Daniel J; Epstein, Courtney R; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L; Fabbian, D; Fan, Xiaohui; Favole, Ginevra; Castellá, Bruno Femen\\'\\ia; Alvar, Emma Fernández; Feuillet, Diane; Ak, Nurten Filiz; Finley, Hayley; Fleming, Scott W; Font-Ribera, Andreu; Frinchaboy, Peter M; Galbraith-Frew, J G; Garc\\'\\ia-Hernández, D A; Pérez, Ana E Garc\\'\\ia; Ge, Jian; Génova-Santos, R; Gillespie, Bruce A; Girardi, Léo; Hernández, Jonay I González; Gott, J Richard; Gunn, James E; Guo, Hong; Halverson, Samuel; Harding, Paul; Harris, David W; Hasselquist, Sten; Hawley, Suzanne L; Hayden, Michael; Hearty, Frederick R; Ho, Shirley; Hogg, David W; Holtzman, Jon A; Honscheid, Klaus; Huehnerhoff, Joseph; Ivans, Inese I; Jackson, Kelly M; Jiang, Peng; Johnson, Jennifer A; Kirkby, David; Kinemuchi, K; Klaene, Mark A; Kneib, Jean-Paul; Koesterke, Lars; Lan, Ting-Wen; Lang, Dustin; Goff, Jean-Marc Le; Lee, Khee-Gan; Lee, Young Sun; Long, Daniel C; Loomis, Craig P; Lucatello, Sara; Lupton, Robert H; Ma, Bo; Mahadevan, Suvrath; Maia, Marcio A G; Majewski, Steven R; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A; Manera, Marc; Maraston, Claudia; Margala, Daniel; Martell, Sarah L; Masters, Karen L; McBride, Cameron K; McGreer, Ian D; McMahon, Richard G; Ménard, Brice; Mészáros, Sz; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D; Montesano, Francesco; More, Surhud; Morrison, Heather L; Muna, Demitri; Munn, Jeffrey A; Myers, Adam D; Nguyen, Duy Cuong; Nichol, Robert C; Nidever, David L; Noterdaeme, Pasquier; Nuza, Sebastián E; O'Connell, Julia E; O'Connell, Robert W; O'Connell, Ross; Olmstead, Matthew D; Oravetz, Daniel J; Owen, Russell; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K; Pâris, Isabelle; Pepper, Joshua; Percival, Will J; Pérez-Ràfols, Ignasi; Perottoni, Hélio Dotto; Petitjean, Patrick; Pieri, Matthew M; Pinsonneault, M H; Prada, Francisco; Price-Whelan, Adrian M; Raddick, M Jordan; Rahman, Mubdi; Rebolo, Rafael; Reid, Beth A; Richards, Jonathan C; Riffel, Rogério; Robin, Annie C; Rocha-Pinto, H J; Rockosi, Constance M; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Rossi, Graziano; Roy, Arpita; Rubiño-Martin, J A; Sabiu, Cristiano G; Sánchez, Ariel G; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P; Schlegel, David J; Schlesinger, Katharine J; Schmidt, Sarah J; Schneider, Donald P; Schultheis, Mathias; Sellgren, Kris; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Simmons, Audrey E; Skrutskie, M F; Slosar, Anže; Smith, Verne V; Snedden, Stephanie A; Sobeck, Jennifer S; Sobreira, Flavia; Stassun, Keivan G; Steinmetz, Matthias; Strauss, Michael A; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E C; Terrien, Ryan C; Thakar, Aniruddha R; Thomas, Daniel; Thompson, Benjamin A; Tinker, Jeremy L; Tojeiro, Rita; Troup, Nicholas W; Vandenberg, Jan; Magaña, Mariana Vargas; Viel, Matteo; Vogt, Nicole P; Wake, David A; Weaver, Benjamin A; Weinberg, David H; Weiner, Benjamin J; White, Martin; White, Simon D M; Wilson, John C; Wisniewski, John P; Wood-Vasey, W M; Yèche, Christophe; York, Donald G; Zamora, O; Zasowski, Gail; Zehavi, Idit; Zheng, Zheng; Zhu, Guangtun

    2013-01-01

    The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the tenth public data release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July. The APOGEE instrument is a near-infrared R~22,500 300-fiber spectrograph covering 1.514--1.696 microns. The APOGEE survey is studying the chemical abundances and radial velocities of roughly 100,000 red giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10 includes 178,397 spectra of 57,454 stars, each typically observed three or more times, from APOGEE. Derived quantities from these spectra (radial velocities, effective temperatures, surface gravities, and metallicities) are also included.DR10 also roughly doubles the number of BOSS spectra over those included in the ninth data r...

  7. The Arecibo Observatory Space Academy

    Science.gov (United States)

    Rodriguez-Ford, Linda A.; Zambrano-Marin, Luisa; Petty, Bryan M.; Sternke, Elizabeth; Ortiz, Andrew M.; Rivera-Valentin, Edgard G.

    2015-11-01

    The Arecibo Observatory Space Academy (AOSA) is a ten (10) week pre-college research program for students in grades 9-12. Our mission is to prepare students for academic and professional careers by allowing them to receive an independent and collaborative research experience on topics related to space and aide in their individual academic and social development. Our objectives are to (1) Supplement the student’s STEM education via inquiry-based learning and indirect teaching methods, (2) Immerse students in an ESL environment, further developing their verbal and written presentation skills, and (3) To foster in every student an interest in science by exploiting their natural curiosity and knowledge in order to further develop their critical thinking and investigation skills. AOSA provides students with the opportunity to share lectures with Arecibo Observatory staff, who have expertise in various STEM fields. Each Fall and Spring semester, selected high school students, or Cadets, from all over Puerto Rico participate in this Saturday academy where they receive experience designing, proposing, and carrying out research projects related to space exploration, focusing on four fields: Physics/Astronomy, Biology, Engineering, and Sociology. Cadets get the opportunity to explore their topic of choice while practicing many of the foundations of scientific research with the goal of designing a space settlement, which they present at the NSS-NASA Ames Space Settlement Design Contest. At the end of each semester students present their research to their peers, program mentors, and Arecibo Observatory staff. Funding for this program is provided by NASA SSERVI-LPI: Center for Lunar Science and Exploration with partial support from the Angel Ramos Visitor Center through UMET and management by USRA.

  8. The 2dF-SDSS LRG and QSO Survey: the QSO luminosity function at 0.4

    CERN Document Server

    Croom, Scott M; Shanks, Tom; Boyle, Brian J; Strauss, Michael A; Myers, Adam D; Nichol, Robert C; Pimbblet, Kevin A; Ross, Nicholas P; Schneider, Donald P; Sharp, Robert G; Wake, David A

    2009-01-01

    We present the QSO luminosity function of the completed 2dF-SDSS LRG and QSO (2SLAQ) survey, based on QSOs photometrically selected from Sloan Digital Sky Survey imaging data and then observed spectroscopically using the 2dF instrument on the Anglo-Australian Telescope. We analyse 10637 QSOs in the redshift range 0.420.0, as found previously by Richards et al. (2005). The luminosity function is consistent with other previous, much smaller, samples produced to the depth of 2SLAQ. By combining the 2SLAQ and SDSS QSO samples we produce a QSO luminosity function with an unprecedented combination of precision and dynamic range. With this we are able to accurately constrain both the bright and faint ends of the QSO LF. While the overall trends seen in the evolution of the QSO LF appear similar to pure luminosity evolution, the data show very significant departures from such a model. Most notably we see clear evidence that the number density of faint QSOs peaks at lower redshift than bright QSOs : QSOs with Mg>-23 h...

  9. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Dilday, Benjamin; /Rutgers U., Piscataway /Chicago U. /KICP, Chicago; Bassett, Bruce; /Cape Town U., Dept. Math. /South African Astron. Observ.; Becker, Andrew; /Washington U., Seattle, Astron. Dept.; Bender, Ralf; /Munich, Tech. U. /Munich U. Observ.; Castander, Francisco; /Barcelona, IEEC; Cinabro, David; /Wayne State U.; Frieman, Joshua A.; /Chicago U. /Fermilab; Galbany, Lluis; /Barcelona, IFAE; Garnavich, Peter; /Notre Dame U.; Goobar, Ariel; /Stockholm U., OKC /Stockholm U.; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  10. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Observational systematics and baryon acoustic oscillations in the correlation function

    CERN Document Server

    Ross, Ashley J; Chuang, Chia-Hsun; Pellejero-Ibanez, Marcos; Seo, Hee-Jong; Vargas-Magana, Mariana; Cuesta, Antonio J; Percival, Will J; Burden, Angela; Sanchez, Ariel G; Grieb, Jan Niklas; Reid, Beth; Brownstein, Joel R; Dawson, Kyle S; Eisenstein, Daniel J; Ho, Shirley; Kitaura, Francisco-Shu; Nichol, Robert C; Olmstead, Matthew D; Prada, Francisco; Rodriguez-Torres, Sergio A; Saito, Shun; Salazar-Albornoz, Salvador; Schneider, Donald P; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Wang, Yuting; White, Martin; Zhao, Gong-bo

    2016-01-01

    We present baryon acoustic oscillation (BAO) scale measurements determined from the clustering of 1.2 million massive galaxies with redshifts 0.2 < z < 0.75 distributed over 9300 square degrees, as quantified by their redshift-space correlation function. In order to facilitate these measurements, we define, describe, and motivate the selection function for galaxies in the final data release (DR12) of the SDSS III Baryon Oscillation Spectroscopic Survey (BOSS). This includes the observational footprint, masks for image quality and Galactic extinction, and weights to account for density relationships intrinsic to the imaging and spectroscopic portions of the survey. We simulate the observed systematic trends in mock galaxy samples and demonstrate that they impart no bias on baryon acoustic oscillation (BAO) scale measurements and have a minor impact on the recovered statistical uncertainty. We measure transverse and radial BAO distance measurements in 0.2 < z < 0.5, 0.5 < z < 0.75, and (overla...

  11. Identifying Thematic Variations in SDSS research.

    OpenAIRE

    Chen, Chaomei; Ibekwe-Sanjuan, Fidelia; Sanjuan, Eric; Vogeley, Michael

    2008-01-01

    The Sloan Digital Sky Survey (SDSS) is the largest ongoing sky survey. It regularly makes data releases to the astronomical community. From a macroscopic point of view, a profound question is: what is the role of SDSS data releases in the evolution of the relevant scientific fields? In this paper, we introduce an integrated approach by combining statistical, information-theoretical, and symbolic methods for text data analysis and show how this combined approach can distinguish thematic variat...

  12. MASS FUNCTIONS OF THE ACTIVE BLACK HOLES IN DISTANT QUASARS FROM THE LARGE BRIGHT QUASAR SURVEY, THE BRIGHT QUASAR SURVEY, AND THE COLOR-SELECTED SAMPLE OF THE SDSS FALL EQUATORIAL STRIPE

    International Nuclear Information System (INIS)

    We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey (LBQS), the Bright Quasar Survey (BQS), and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts from the local universe to z = 5 and were subject to different selection criteria and flux density limits. This makes these samples complementary and can help us gain additional insight on the true underlying black hole mass distribution free from selection effects and mass estimation errors through future studies. By comparing these quasar samples, we see evidence that the active black hole population at redshift four is somewhat different than that at lower redshifts, including that in the nearby universe. In particular, there is a sharp increase in the space density of the detected active black holes (M BH ∼>108 M sun) between redshifts ∼4 and ∼2.5. Also, the mass function of the SDSS quasars at 3.6 ≤ z ≤ 5 has a somewhat flatter high-mass-end slope of β = -1.75 ± 0.56, compared to the mass functions based on quasars below z of 3 (BQS and LBQS quasars), which display typical slopes of β ∼ -3.3; the latter are consistent with the mass functions at similar redshifts based on the SDSS Data Release 3 quasar catalog presented by Vestergaard et al. We see clear evidence of cosmic downsizing in the comoving space density distribution of active black holes in the LBQS sample alone. In forthcoming papers, further analysis, comparison, and discussion of these mass functions will be made with other existing black hole mass functions, notably that based on the SDSS DR3 quasar catalog. We present the relationships used to estimate the black hole mass based on the Mg II emission line; the relations are calibrated to the Hβ and C IV relations by means of several thousand high-quality SDSS spectra. Mass estimates of the individual black holes of these

  13. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 10 and 11 galaxy samples

    CERN Document Server

    Anderson, Lauren; Bailey, Stephen; Beutler, Florian; Bhardwaj, Vaishali; Blanton, Michael; Bolton, Adam S; Brinkmann, J; Brownstein, Joel R; Burden, Angela; Chuang, Chia-Hsun; Cuesta, Antonio J; Dawson, Kyle S; Eisenstein, Daniel J; Escoffier, Stephanie; Gunn, James E; Guo, Hong; Ho, Shirley; Honscheid, Klaus; Howlett, Cullan; Kirkby, David; Lupton, Robert H; Manera, Marc; Maraston, Claudia; McBride, Cameron K; Mena, Olga; Montesano, Francesco; Nichol, Robert C; Nuza, Sebastian E; Olmstead, Matthew D; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Parejko, John; Percival, Will J; Petitjean, Patrick; Prada, Francisco; Price-Whelan, Adrian M; Reid, Beth; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Sabiu, Cristiano G; Saito, Shun; Samushia, Lado; Sanchez, Ariel G; Schlegel, David J; Schneider, Donald P; Scoccola, Claudia G; Seo, Hee-Jong; Skibba, Ramin A; Strauss, Michael A; Swanson, Molly E C; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Magana, Mariana Vargas; Verde, Licia; Wake, David A; Weaver, Benjamin A; Weinberg, David H; White, Martin; Xu, Xiaoying; Yeche, Christophe; Zehavi, Idit; Zhao, Gong-Bo

    2013-01-01

    We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range $0.2surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the baryon acoustic oscillation (BAO) feature. The acoustic features are detected at a significance of over $7\\sigma$ in both the correlation function and power spectrum. Fitting for the position of the ...

  14. Finding binary active galactic nuclei candidates by the centroid shift in imaging surveys II. Testing the method with SDSS J233635.75-010733.7

    CERN Document Server

    Liu, Yuan

    2016-01-01

    In Liu (2015), we propose selecting binary active galactic nuclei (AGNs) candidates using the centroid shift of the images, which is induced by the non-synchronous variations of the two nuclei. In this paper, a known binary AGN (SDSS J233635.75-010733.7) is employed to verify the ability of this method. Using 162 exposures in the $R$ band of \\textit{Palomar Transient Factory} (PTF), an excess of dispersion in the positional distribution of the binary AGN is detected, though the two nuclei cannot be resolved in the images of PTF. We also propose a new method to compare the position of the binary AGN in PTF $g$ and $R$ band and find the difference is highly significant even only with 20 exposures. This new method is efficient for two nuclei with different spectral energy distributions, e.g., type I + type II AGN or off-set AGN. Large-scale surveys, e.g., the Panoramic Survey Telescope and Rapid Response System and the Large Synoptic Survey Telescope, are expected to discover a large sample of binary AGN candida...

  15. HI Observations of the Ca II absorbing galaxies Mrk 1456 and SDSS J211701.26-002633.7

    CERN Document Server

    Cherinka, Brian; Rosenberg, Jessica

    2009-01-01

    In an effort to study Damped Lyman Alpha galaxies at low redshift, we have been using the Sloan Digital Sky Survey to identify galaxies projected onto QSO sightlines and to characterize their optical properties. For low redshift galaxies, the HI 21cm emission line can be used as an alternate tool for identifying possible DLA galaxies, since HI emitting galaxies typically exhibit HI columns that are larger than the classical DLA limit. Here we report on follow-up HI 21 cm emission line observations of two DLA candidates that are both low-redshift spiral galaxies, Mrk 1456 and SDSS J211701.26-002633.7. The observations were made using the Green Bank and Arecibo Telescopes, respectively. Analysis of their HI properties reveal the galaxies to be about one and two M_HI* galaxies, respectively, and to have average HI mass, gas-richness, and gas mass fraction for their morphological types. We consider Mrk 1456 and SDSS J211701.26-002633.7 to be candidate DLA systems based upon the strength of the CaII absorption lin...

  16. A deep / wide 1-2 GHz snapshot survey of SDSS Stripe 82 using the Karl G. Jansky Very Large Array in a compact hybrid configuration

    CERN Document Server

    Heywood, I; Baker, A J; Bannister, K W; Carvalho, C S; Hardcastle, M; Hilton, M; Moodley, K; Smirnov, O M; Smith, D J B; White, S V; Wollack, E J

    2016-01-01

    We have used the Karl G. Jansky Very Large Array to image ~100 sq. deg. of SDSS Stripe 82 at 1-2 GHz. The survey consists of 1,026 snapshot observations of 2.5 minutes duration, using the hybrid CnB configuration. The survey has good sensitivity to diffuse, low surface brightness structures and extended radio emission, making it highly synergistic with existing 1.4 GHz radio observations of the region. The principal data products are continuum images, with 16 x 10 arcsecond resolution, and a catalogue containing 11,782 point and Gaussian components resulting from fits to the thresholded Stokes-I brightness distribution, forming approximately 8,948 unique radio sources. The typical effective 1{\\sigma} noise level is 88 {\\mu}Jy / beam. Spectral index estimates are included, as derived from the 1 GHz of instantaneous bandwidth. Astrometric and photometric accuracy are in excellent agreement with existing narrowband observations. A large-scale simulation is used to investigate clean bias, which we extend into the...

  17. A survey of luminous high-redshift quasars with SDSS and WISE II. the bright end of the quasar luminosity function at z ~ 5

    CERN Document Server

    Yang, Jinyi; Wu, Xue-Bing; Fan, Xiaohui; McGreer, Ian D; Bian, Fuyan; Yi, Weimin; Yang, Qian; Ai, Yanli; Dong, Xiaoyi; Zuo, Wenwen; Green, Richard; Jiang, Linhua; Wang, Shu; Wang, Ran; Yue, Minghao

    2016-01-01

    This is the second paper in a series on a new luminous z ~ 5 quasar survey using optical and near-infrared colors. Here we present a new determination of the bright end of the quasar luminosity function (QLF) at z ~ 5. Combined our 45 new quasars with previously known quasars that satisfy our selections, we construct the largest uniform luminous z ~ 5 quasar sample to date, with 99 quasars in the range 4.7 <= z < 5.4 and -29 < M1450 <= -26.8, within the Sloan Digital Sky Survey (SDSS) footprint. We use a modified 1/Va method including flux limit correction to derive a binned QLF, and we model the parametric QLF using maximum likelihood estimation. With the faint-end slope of the QLF fixed as alpha = -2.03 from previous deeper samples, the best fit of our QLF gives a flatter bright end slope beta = -3.58+/-0.24 and a fainter break magnitude M*1450 = -26.98+/-0.23 than previous studies at similar redshift. Combined with previous work at lower and higher redshifts, our result is consistent with a lum...

  18. Abundance analysis of SDSS J134338.67+484426.6; an extremely metal-poor star from the MARVELS pre-survey

    CERN Document Server

    Rani, A Susmitha; Beers, T C; Fleming, S; Mahadevan, S; Ge, J

    2016-01-01

    We present an elemental-abundance analysis of an extremely metal-poor (EMP; [Fe/H] < -3.0) star, SDSS J134338.67+484426.6, identified during the course of the MARVELS spectroscopic pre-survey of some 20000 stars to identify suitable candidates for exoplanet searches. This star, with an apparent magnitude V = 12.14, is the lowest metallicity star found in the pre-survey, and is one of only ~20 known EMP stars that are this bright or brighter. Our high-resolution spectroscopic analysis shows that this star is a subgiant with [Fe/H] = -3.42, having "normal" carbon and no enhancement of neutron-capture abundances. Strontium is under-abundant, [Sr/Fe] =-0.47, but the derived lower limit on [Sr/Ba] indicates that Sr is likely enhanced relative to Ba. This star belongs to the sparsely populated class of alpha-poor EMP stars that exhibit low ratios of [Mg/Fe], [Si/Fe], and [Ca/Fe] compared to typical halo stars at similar metallicity. The observed variations in radial velocity from several epochs of (low- and high...

  19. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in Fourier space

    CERN Document Server

    Zhao, Gong-Bo; Saito, Shun; Wang, Dandan; Ross, Ashley J; Beutler, Florian; Grieb, Jan Niklas; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Rodriguez-Torres, Sergio; Percival, Will J; Brownstein, Joel R; Cuesta, Antonio J; Eisenstein, Daniel J; Gil-Marín, Héctor; Kneib, Jean-Paul; Nichol, Robert C; Olmstead, Matthew D; Prada, Francisco; Rossi, Graziano; Salazar-Albornoz, Salvador; Samushia, Lado; Sánchez, Ariel G; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Weinberg, David H; Zhu, Fangzhou

    2016-01-01

    We perform a tomographic baryon acoustic oscillations (BAO) analysis using the monopole, quadrupole and hexadecapole of the redshift-space galaxy power spectrum measured from the pre-reconstructed combined galaxy sample of the completed Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) Data Release (DR)12 covering the redshift range of $0.20

  20. The SDSS White Dwarf - M Star Library

    CERN Document Server

    Heller, René; Østensen, Roy H

    2011-01-01

    The Sloan Digital Sky Survey (SDSS), originally targeted at quasi-stellar objects, has provided us with a wealth of astronomical byproducts through the last decade. Since then, the number of white dwarfs (WDs) with physically bound main-sequence star companions (mostly dM stars) has increased radically, allowing for fundamentally new insights into stellar physics. Different methods for the retrieval and follow-up analysis of SDSS WD-dM binaries have been applied in the literature, leading to a rising number of WD-dM catalogs. Here we present a detailed literature search, coupled with our own hunting for SDSS WD-dMs by color selection, the outcome being named the "SDSS White Dwarf - M Star Library". We also explain improvements of our automated spectral analysis method.

  1. THE WIRED SURVEY. III. AN INFRARED EXCESS AROUND THE ECLIPSING POST-COMMON ENVELOPE BINARY SDSS J030308.35+005443.7

    Energy Technology Data Exchange (ETDEWEB)

    Debes, John H. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Hoard, D. W. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Farihi, Jay [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Wachter, Stefanie [IPAC, California Institute of Technology, Pasadena, CA (United States); Leisawitz, David T. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Cohen, Martin [Monterey Institute for Research in Astronomy, Marina, CA 93933 (United States)

    2012-11-01

    We present the discovery with WISE of a significant infrared excess associated with the eclipsing post-common envelope binary SDSS J030308.35+005443.7, the first excess discovered around a non-interacting white dwarf+main-sequence M dwarf binary. The spectral energy distribution of the white dwarf+M dwarf companion shows significant excess longward of 3 {mu}m. A T {sub eff} of 8940 K for the white dwarf is consistent with a cooling age >2 Gyr, implying that the excess may be due to a recently formed circumbinary dust disk of material that extends from the tidal truncation radius of the binary at 1.96 R {sub Sun} out to <0.8 AU, with a total mass of {approx}10{sup 20} g. We also construct WISE and follow-up ground-based near-infrared light curves of the system and find variability in the K band that appears to be in phase with ellipsoidal variations observed in the visible. The presence of dust might be due to (1) material being generated by the destruction of small rocky bodies that are being perturbed by an unseen planetary system or (2) dust condensing from the companion's wind. The high inclination of this system and the presence of dust make it an attractive target for M dwarf transit surveys and long-term photometric monitoring.

  2. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Mock galaxy catalogues for the final BOSS Data Release

    CERN Document Server

    Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Zhao, Cheng; Prada, Francisco; Gil-Marin, Hector; Guo, Hong; Yepes, Gustavo; Klypin, Anatoly; Scoccola, Claudia G; Tinker, Jeremy; McBride, Cameron; Reid, Beth; Sanchez, Ariel G; Salazar-Albornoz, Salvador; Grieb, Jan Niklas; Vargas-Magana, Mariana; Cuesta, Antonio J; Neyrinck, Mark; Beutler, Florian; Comparat, Johan; Percival, Will; Ross, Ashley

    2015-01-01

    We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillations Spectroscopic Survey Data Release 12 (BOSS DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated 12,288 MultiDark patchy light-cones corresponding to an effective volume of ~192,000 [Gpc/h]^3 (the largest ever simulated volume), including cosmic evolution in the range from 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the Halo Abundance Matching modelling of the BOSS DR12 galaxy clustering data and on the data themselves. The production of the MultiDark PATCHY BOSS DR12 mocks follows three steps. First, we apply the PATCHY-code to generate a dark matter field and an object distribution including nonlinear stochastic galaxy bias. Second, we run the halo/stellar distribution reconstruction HADRON-code to assign masses to the various objects. This step uses the mass distribution...

  3. The Clustering of Galaxies in the Completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmic Flows and Cosmic Web from Luminous Red Galaxies

    CERN Document Server

    Ata, Metin; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E; Ferraro, Simone; McDonald, Patrick; Monteagudo, Carlos Hernández; Müller, Volker; Yepes, Gustavo; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R; Burden, Angela; Eisenstein, Daniel J; Guo, Hong; Ho, Shirley; McBride, Cameron; Neyrinck, Mark; Olmstead, Matthew D; Padmanabhan, Nikhil; Perciva, Will J; Prada, Francisco; Rossi, Graziano; Sánchez, Ariel G; Schlege, David; Schneider, Donald P; Seo, Hee-Jong; Streblyanska, Alina; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana

    2016-01-01

    We present a Bayesian phase space reconstruction of the cosmic large-scale matter density and velocity fields from the SDSS-III Baryon Oscillations Spectroscopic Survey Data Release 12 (BOSS DR12) CMASS galaxy clustering catalogue. We rely on a given $\\Lambda$CDM cosmology, a mesh resolution in the range of 6-10 $h^{-1}$ Mpc, and a lognormal-Poisson model with a redshift dependent nonlinear bias. The bias parameters are derived from the data and a general renormalised perturbation theory approach. We use combined Gibbs and Hamiltonian sampling, implemented in the \\textsc{argo} code, to iteratively reconstruct the dark matter density field and the coherent peculiar velocities of individual galaxies, correcting hereby for coherent redshift space distortions (RSD). Our tests relying on accurate $N$-body based mock galaxy catalogues, show unbiased real space power spectra of the nonlinear density field up to $k\\sim0.2\\, h$ Mpc$^{-1}$, and vanishing quadrupoles down to $\\sim20\\,h^{-1}$ Mpc. We also demonstrate tha...

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological implications of the configuration-space clustering wedges

    CERN Document Server

    Sanchez, Ariel G; Crocce, Martin; Grieb, Jan Niklas; Salazar-Albornoz, Salvador; DallaVecchia, Claudio; Lippich, Martha; Beutler, Florian; Brownstein, Joel R; Chuang, Chia-Hsun; Eisenstein, Daniel J; Kitaura, Francisco-Shu; Olmstead, Matthew D; Percival, Will J; Prada, Francisco; Rodriguez-Torres, Sergio; Ross, Ashley J; Samushia, Lado; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Wang, Yuting; Zhao, Gong-Bo

    2016-01-01

    We explore the cosmological implications of anisotropic clustering measurements in configuration space of the final galaxy samples from Data Release 12 of the SDSS-III Baryon Oscillation Spectroscopic Survey. We implement a new detailed modelling of the effects of non-linearities, galaxy bias and redshift-space distortions that can be used to extract unbiased cosmological information from our measurements for scales $s \\gtrsim 20\\,h^{-1}{\\rm Mpc}$. We combined the galaxy clustering information from BOSS with the latest cosmic microwave background (CMB) observations and Type Ia supernovae samples and found no significant evidence for a deviation from the $\\Lambda$CDM cosmological model. In particular, these data sets can constrain the dark energy equation of state parameter to $w_{\\rm DE}=-0.996\\pm0.042$ when assumed time-independent, the curvature of the Universe to $\\Omega_{k}=-0.0007\\pm 0.0030$ and the sum of the neutrino masses to $\\sum m_{\

  5. SDSS J2222+2745: A GRAVITATIONALLY LENSED SEXTUPLE QUASAR WITH A MAXIMUM IMAGE SEPARATION OF 15.''1 DISCOVERED IN THE SLOAN GIANT ARCS SURVEY

    International Nuclear Information System (INIS)

    We report the discovery of a unique gravitational lens system, SDSS J2222+2745, producing five spectroscopically confirmed images of a zs = 2.82 quasar lensed by a foreground galaxy cluster at zl = 0.49. We also present photometric and spectroscopic evidence for a sixth lensed image of the same quasar. The maximum separation between the quasar images is 15.''1. Both the large image separations and the high image multiplicity are in themselves rare among known lensed quasars, and observing the combination of these two factors is an exceptionally unlikely occurrence in present data sets. This is only the third known case of a quasar lensed by a cluster, and the only one with six images. The lens system was discovered in the course of the Sloan Giant Arcs Survey, in which we identify candidate lenses in the Sloan Digital Sky Survey and target these for follow-up and verification with the 2.56 m Nordic Optical Telescope. Multi-band photometry obtained over multiple epochs from 2011 September to 2012 September reveals significant variability at the ∼10%-30% level in some of the quasar images, indicating that measurements of the relative time delay between quasar images will be feasible. In this lens system, we also identify a bright (g = 21.5) giant arc corresponding to a strongly lensed background galaxy at zs = 2.30. We fit parametric models of the lens system, constrained by the redshift and positions of the quasar images and the redshift and position of the giant arc. The predicted time delays between different pairs of quasar images range from ∼100 days to ∼6 yr

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release

    Science.gov (United States)

    Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio; Chuang, Chia-Hsun; Zhao, Cheng; Prada, Francisco; Gil-Marín, Héctor; Guo, Hong; Yepes, Gustavo; Klypin, Anatoly; Scóccola, Claudia G.; Tinker, Jeremy; McBride, Cameron; Reid, Beth; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Grieb, Jan Niklas; Vargas-Magana, Mariana; Cuesta, Antonio J.; Neyrinck, Mark; Beutler, Florian; Comparat, Johan; Percival, Will J.; Ross, Ashley

    2016-03-01

    We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillation Spectroscopic Survey Final Data Release (BOSS DR11&DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated (6000) 12 288 MultiDark PATCHY BOSS (DR11) DR12 light cones corresponding to an effective volume of ˜192 000 [h-1 Gpc]3 (the largest ever simulated volume), including cosmic evolution in the redshift range from 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the halo abundance matching modelling of the BOSS DR11&DR12 galaxy clustering data and on the data themselves. The production follows three steps. First, we apply the PATCHY code to generate a dark matter field and an object distribution including non-linear stochastic galaxy bias. Secondly, we run the halo/stellar distribution reconstruction HADRON code to assign masses to the various objects. This step uses the mass distribution as a function of local density and non-local indicators (i.e. tidal field tensor eigenvalues and relative halo exclusion separation for massive objects) from the reference simulation applied to the corresponding patchy dark matter and galaxy distribution. Finally, we apply the SUGAR code to build the light cones. The resulting MultiDarkPATCHY mock light cones reproduce the number density, selection function, survey geometry, and in general within 1σ, for arbitrary stellar mass bins, the power spectrum up to k = 0.3 h Mpc-1, the two-point correlation functions down to a few Mpc scales, and the three-point statistics of the BOSS DR11&DR12 galaxy samples.

  7. A self-consistent public catalogue of voids and superclusters in the SDSS Data Release 7 galaxy surveys

    CERN Document Server

    Nadathur, Seshadri

    2013-01-01

    The study of the interesting cosmological properties of voids in the Universe depends on the efficient and robust identification of such voids in galaxy redshift surveys. Recently, Sutter et al. (2012) have published a public catalogue of voids in the Sloan Digital Sky Survey Data Release 7 main galaxy and luminous red galaxy samples, using the void-finding algorithm ZOBOV, which is based on the watershed transform. We examine the properties of this catalogue and show that it suffers from several inconsistencies and errors, including the identification of some extremely overdense regions as voids. As a result, cosmological results obtained using this catalogue need to be reconsidered. We provide instead an alternative, self-consistent, public catalogue of voids in the same galaxy data, obtained from using an improved version of the same watershed transform algorithm. We provide a more robust method of dealing with survey boundaries and masks, as well as with a radially varying selection function, which means ...

  8. A public void catalog from the SDSS DR7 Galaxy Redshift Surveys based on the watershed transform

    CERN Document Server

    Sutter, P M; Wandelt, Benjamin D; Weinberg, David H

    2012-01-01

    We produce the most comprehensive public void catalog to date using the Sloan Digital Sky Survey Data Release 7 main sample out to redshift z=0.2 and the Luminous Red Galaxy sample out to z=0.44. Using a modified version of the parameter-free void finder ZOBOV, we fully take into account the presence of the survey boundary and masks. Our strategy for finding voids is thus appropriate for any survey configuration. We produce two distinct catalogs: a complete catalog including voids near any masks, which would be appropriate for void galaxy surveys, and a bias-free catalog of voids away from any masks, which is necessary for analyses that require a fair sampling of void shapes and alignments. Our discovered voids have effective radii from 5 to 135 h^-1 Mpc. We discuss basic catalog statistics such as number counts and redshift distributions and describe some additional data products derived from our catalog, such as radial density profiles and projected density maps. We find that radial profiles of stacked void...

  9. A PUBLIC VOID CATALOG FROM THE SDSS DR7 GALAXY REDSHIFT SURVEYS BASED ON THE WATERSHED TRANSFORM

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, P. M.; Wandelt, Benjamin D. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Lavaux, Guilhem [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Weinberg, David H. [Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)

    2012-12-10

    We produce the most comprehensive public void catalog to date using the Sloan Digital Sky Survey Data Release 7 main sample out to redshift z = 0.2 and the luminous red galaxy sample out to z = 0.44. Using a modified version of the parameter-free void finder ZOBOV, we fully take into account the presence of the survey boundary and masks. Our strategy for finding voids is thus appropriate for any survey configuration. We produce two distinct catalogs: a complete catalog including voids near any masks, which would be appropriate for void galaxy surveys, and a bias-free catalog of voids away from any masks, which is necessary for analyses that require a fair sampling of void shapes and alignments. Our discovered voids have effective radii from 5 to 135 h {sup -1} Mpc. We discuss basic catalog statistics such as number counts and redshift distributions and describe some additional data products derived from our catalog, such as radial density profiles and projected density maps. We find that radial profiles of stacked voids show a qualitatively similar behavior across nearly two decades of void radii and throughout the full redshift range.

  10. Chemical tagging in the SDSS-III/APOGEE survey: new identifications of halo stars with globular cluster origins

    CERN Document Server

    Martell, Sarah; Lucatello, Sara; Schiavon, Ricardo; Meszaros, Szabolcs; Prieto, Carlos Allende; Hernandez, Anibal Garcia; Beers, Tim; Nidever, David

    2016-01-01

    We present new identifications of five red giant stars in the Galactic halo with chemical abundance patterns that indicate they originally formed in globular clusters. Using data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Survey available through Sloan Digital Sky Survey Data Release 12 (DR12), we first identify likely halo giants, and then search those for the well-known chemical tags associated with globular clusters, specifically enrichment in nitrogen and aluminum. We find that 2% of the halo giants in our sample have this chemical signature, in agreement with previous results. Following the interpretation in our previous work on this topic, this would imply that at least 13% of halo stars originally formed in globular clusters. Recent developments in the theoretical understanding of globular cluster formation raise questions about that interpretation, and we concede the possibility that these migrants represent a small fraction of the halo field. There are roughly as many st...

  11. THE OPEN CLUSTER CHEMICAL ANALYSIS AND MAPPING SURVEY: LOCAL GALACTIC METALLICITY GRADIENT WITH APOGEE USING SDSS DR10

    International Nuclear Information System (INIS)

    The Open Cluster Chemical Analysis and Mapping (OCCAM) survey aims to produce a comprehensive, uniform, infrared-based data set for hundreds of open clusters, and constrain key Galactic dynamical and chemical parameters from this sample. This first contribution from the OCCAM survey presents analysis of 141 members stars in 28 open clusters with high-resolution metallicities derived from a large uniform sample collected as part of the Sloan Digital Sky Survey III/Apache Point Observatory Galactic Evolution Experiment. This sample includes the first high-resolution metallicity measurements for 22 open clusters. With this largest ever uniformly observed sample of open cluster stars we investigate the Galactic disk gradients of both [M/H] and [α/M]. We find basically no gradient in [α/M] across 7.9 kpc ≤ R GC ≤ 14.5 kpc, but [M/H] does show a gradient for R GC GC = 10 kpc. In particular, whereas fitting a single linear trend yields an [M/H] gradient of –0.09 ± 0.03 dex kpc–1—similar to previously measure gradients inside 13 kpc—by independently fitting inside and outside 10 kpc separately we find a significantly steeper gradient near the Sun (7.9 ≤ R GC ≤ 10) than previously found (–0.20 ± 0.08 dex kpc–1) and a nearly flat trend beyond 10 kpc (–0.02 ± 0.09 dex kpc–1)

  12. Type Ia Supernova Properties as a Function of the Distance to the Host Galaxy in the SDSS-II SN Survey

    Energy Technology Data Exchange (ETDEWEB)

    Galbany, Lluis [Institut de Fisica d' Altes Energies (IFAE), Barcelona (Spain); et al.

    2012-08-20

    We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to search for dependencies between SN Ia properties and the projected distance to the host galaxy center, using the distance as a proxy for local galaxy properties (local star-formation rate, local metallicity, etc.). The sample consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at redshifts below 0.25. The sample is split into two groups depending on the morphology of the host galaxy. We fit light-curves using both MLCS2k2 and SALT2, and determine color (AV, c) and light-curve shape (delta, x1) parameters for each SN Ia, as well as its residual in the Hubble diagram. We then correlate these parameters with both the physical and the normalized distances to the center of the host galaxy and look for trends in the mean values and scatters of these parameters with increasing distance. The most significant (at the 4-sigma level) finding is that the average fitted AV from MLCS2k2 and c from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies. We also find indications that SNe in elliptical galaxies tend to have narrower light-curves if they explode at larger distances, although this may be due to selection effects in our sample. We do not find strong correlations between the residuals of the distance moduli with respect to the Hubble flow and the galactocentric distances, which indicates a limited correlation between SN magnitudes after standardization and local host metallicity.

  13. SDSS DR6 Data for Photometric Redshift Calculations

    Data.gov (United States)

    National Aeronautics and Space Administration — Subject Area: Astronomical data Description: The Sloan Digital Sky Survey (SDSS) is a multi-organization effort to gather deep, multi-color images covering more...

  14. Magnetic White Dwarf Stars in the SDSS

    CERN Document Server

    Kepler, S O; Jordan, Stefan; Kleinman, Scot J; Kulebi, Baybars; Koester, Detlev; Peçanha, Viviane; Castanheira, Bárbara G; Nitta, Atsuko; Costa, José Eduardo da Silveira; Winget, Don Earl; Kanaan, Antonio; Fraga, Luciano

    2012-01-01

    To obtain a better statistics on the occurrence of magnetism among white dwarfs, we searched the spectra of the hydrogen atmosphere white dwarf stars (DAs) in the Data Release 7 of the Sloan Digital Sky Survey (SDSS) for Zeeman splittings and estimated the magnetic fields. We found 521 DAs with detectable Zeeman splittings, with fields in the range from around 1 MG to 733 MG, which amounts to 4% of all DAs observed. As the SDSS spectra have low signal-to-noise ratios, we carefully investigated by simulations with theoretical spectra how reliable our detection of magnetic field was.

  15. A Serendipitous XMM Survey of the SDSS: the evolution of the colour-magnitude diagram of X-ray AGN from z=0.8 to z=0.1

    CERN Document Server

    Georgakakis, Antonis

    2011-01-01

    A new serendipitous XMM survey in the area of the Sloan Digital Sky Survey is described (XMM/SDSS), which includes features such as the merging of overlapping fields to increase the sensitivity to faint sources, the use of a new parametrisation of the XMM point spread function for the source detection and photometry, the accurate estimation of the survey sensitivity. About 40,000 X-ray point sources are detected over a total area of 122deg2. A subsample of 209 sources detected in the 2-8keV spectral band with SDSS spectroscopic redshifts in the range 0.0341.5 (erg/s) are selected to explore their distribution on the colour magnitude diagram. This is compared with the colour-magnitude diagram of X-ray AGN in the AEGIS field at z~0.8. We find no evidence for evolution of the rest-frame colours of X-ray AGN hosts from z=0.8 to z=0.1. This suggests that the dominant accretion mode of the AGN population, which is expected to imprint on the properties of their host galaxies, does not change since z=0.8. This argues...

  16. A Systematic Search for Changing-Look Quasars in SDSS

    Science.gov (United States)

    Macleod, C.

    2015-09-01

    AGN are known to be variable phenomena. However, it is only relatively recently that multiple spectra of the same AGN at high redshift have become available, mainly in part due to large spectroscopic surveys such as the SDSS. I present results from a search for significant Broad Emission Line (BEL) changes in quasars selected based on their light curves in SDSS and PanSTARRS. Such changing-look quasars can provide direct observational evidence for the physical processes happening within the AGN.

  17. Modeling Galaxy-Galaxy Weak Lensing with SDSS Groups

    OpenAIRE

    Li, Ran; Mo, H. J.; Fan, Zuhui; Cacciato, Marcello; Bosch, Frank C. van den; Yang, Xiaohu; More, Surhud

    2008-01-01

    We use galaxy groups selected from the Sloan Digital Sky Survey (SDSS) together with mass models for individual groups to study the galaxy-galaxy lensing signals expected from galaxies of different luminosities and morphological types. We compare our model predictions with the observational results obtained from the SDSS by Mandelbaum et al. (2006) for the same samples of galaxies. The observational results are well reproduced in a $\\Lambda$CDM model based on the WMAP 3-year data, but a $\\Lam...

  18. A Precision Photometric Comparison between SDSS-II and CSP Type Ia Supernova Data

    DEFF Research Database (Denmark)

    Mosher, J.; Sako, M.; Corlies, L.;

    2012-01-01

    Consistency between Carnegie Supernova Project (CSP) and SDSS-II Supernova Survey ugri measurements has been evaluated by comparing Sloan Digital Sky Survey (SDSS) and CSP photometry for nine spectroscopically confirmed Type Ia supernova observed contemporaneously by both programs. The CSP data...

  19. The Arecibo Observatory as an MST radar

    Science.gov (United States)

    Woodman, R. F.

    1983-01-01

    The radars and other systems at the Arecibo Observatory were designed and built, originally, for incoherent-scatter and radio-astronomy research. More recently, important additions have been made for planetary radar and artificial RF heating of the ionosphere. Although designed and built for a different application, these systems have shown to be very powerful tools for tropospheric, stratospheric and mesospheric research. The Observatory at present has two main radars: one at 430 and the other at 2380 MHz. In addition, 50-MHz MST radar work has been done using portable transmitters brought to the Observatory for this purpose. This capability will become permanent with the recent acquisition of a transmitter at this frequency. Furthermore, control and data processing systems have been developed to use the powerful HF transmitter and antennas of the HF-heating facility as an HF bistatic radar. A brief description of the four radars available at the Observatory is presented.

  20. Molecular hydrogen absorption systems in SDSS

    CERN Document Server

    Balashev, S A; Ivanchik, A V; Varshalovich, D A; Petitjean, P; Noterdaeme, P

    2014-01-01

    We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS) II Data Release 7 and SDSS-III Data Release 9. We have selected candidates using a modified profile fitting technique taking into account that the Ly$\\alpha$ forest can effectively mimic H$_2$ absorption systems at the resolution of SDSS data. To estimate the confidence level of the detections, we use two methods: a Monte-Carlo sampling and an analysis of control samples. The analysis of control samples allows us to define regions of the spectral quality parameter space where H$_2$ absorption systems can be confidently identified. We find that H$_2$ absorption systems with column densities $\\log {\\rm N_{H_2}} > 19$ can be detected in only less than 3% of SDSS quasar spectra. We estimate the upper limit on the detection rate of saturated H$_2$ absorption systems ($\\log {\\rm N_{H_2}} > 19$) in Damped Ly-$\\alpha$ (DLA) systems to be about 7%. We provide a sample of ...

  1. GALEX-SDSS CATALOGS FOR STATISTICAL STUDIES

    International Nuclear Information System (INIS)

    We present a detailed study of the Galaxy Evolution Explorer's (GALEX) photometric catalogs with special focus on the statistical properties of the All-sky and Medium Imaging Surveys. We introduce the concept of primaries to resolve the issue of multiple detections and follow a geometric approach to define clean catalogs with well understood selection functions. We cross-identify the GALEX sources (GR2+3) with Sloan Digital Sky Survey (SDSS; DR6) observations, which indirectly provides an invaluable insight into the astrometric model of the UV sources and allows us to revise the band merging strategy. We derive the formal description of the GALEX footprints as well as their intersections with the SDSS coverage along with analytic calculations of their areal coverage. The crossmatch catalogs are made available for the public. We conclude by illustrating the implementation of typical selection criteria in SQL for catalog subsets geared toward statistical analyses, e.g., correlation and luminosity function studies.

  2. Arecibo, Puerto Rico Tsunami Forecast Grids for MOST Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Arecibo, Puerto Rico Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST) model....

  3. The SDSS-IV in 2014: A Demographic Snapshot

    CERN Document Server

    Lundgren, Britt; Zasowski, Gail; Lucatello, Sara; Diamond-Stanic, Aleksandar M; Tremonti, Christy A; Myers, Adam D; Aragon-Salamanca, Alfonso; Gillespie, Bruce; Ho, Shirley; Gallagher, John S

    2015-01-01

    Many astronomers now participate in large international collaborations, and it is important to examine whether these structures foster a scientific climate that is inclusive and diverse. The Committee on the Participation of Women in the Sloan Digital Sky Survey (CPWS) was formed to evaluate the demographics and gender climate within SDSS-IV, one of the largest and most geographically distributed astronomical collaborations. In April 2014, the CPWS administered a demographic survey to establish a baseline for the incipient SDSS-IV. We received responses from 250 participants (46% of the active membership). Half of the survey respondents were located in the US or Canada and 30% were based in Europe. Eleven percent of survey respondents considered themselves to be an ethnic minority at their current institution. Twenty-five percent of the SDSS-IV collaboration members are women, a fraction that is consistent with the US astronomical community, but substantially higher than the fraction of women in the IAU (16%)...

  4. Direct Minkowski Functional analysis of large redshift surveys: a new high-speed code tested on the LRG SDSS-DR7 catalogue

    CERN Document Server

    Wiegand, Alexander; Ostermann, Matthias

    2013-01-01

    As deeper galaxy catalogues are soon to come, it becomes even more important to measure large-scale fluctuations in the catalogues with robust statistics that cover all moments of the galaxy distribution. In this paper we reinforce a direct analysis of galaxy data by employing the Germ-Grain method to calculate the family of Minkowski Functionals. We introduce a new code, suitable for the analysis of large data sets without smoothing and without the construction of excursion sets. We provide new tools to measure correlation properties, putting emphasis on explicitly isolating non-Gaussian correlations with the help of integral--geometric relations. As a first application we present the analysis of large-scale fluctuations in the LRG sample of SDSS DR7 data. We find significant (more than 2-sigma) deviations from the simulated mock catalogues on samples as large as $500h^{-1}$Mpc and $700h^{-1}$Mpc, respectively, and we investigate possible sources of these deviations.

  5. Abundance analysis of SDSS J134338.67+484426.6; an extremely metal-poor star from the MARVELS pre-survey

    Science.gov (United States)

    Susmitha Rani, A.; Sivarani, T.; Beers, T. C.; Fleming, S.; Mahadevan, S.; Ge, J.

    2016-05-01

    We present an elemental-abundance analysis of an extremely metal-poor (EMP; [Fe/H] carbon and no enhancement of neutron-capture abundances. Strontium is underabundant, [Sr/Fe] = -0.47, but the derived lower limit on [Sr/Ba] indicates that Sr is likely enhanced relative to Ba. This star belongs to the sparsely populated class of α-poor EMP stars that exhibit low ratios of [Mg/Fe], [Si/Fe], and [Ca/Fe] compared to typical halo stars at similar metallicity. The observed variations in radial velocity from several epochs of (low- and high-resolution) spectroscopic follow-up indicate that SDSS J134338.67+484426.6 is a possible long-period binary. We also discuss the abundance trends in EMP stars for r-process elements, and compare with other magnesium-poor stars.

  6. WISE photometry for 400 million SDSS sources

    CERN Document Server

    Lang, Dustin; Schlegel, David J

    2014-01-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE; Wright et al. 2010) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS; York et al. 2000). We use a "forced photometry" technique, using measured SDSS source positions, star-galaxy separation and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our "unWISE" coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero. However, for many sources we get three- or four-sigma measurements; these sources would not be reported by the WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements...

  7. Arecibo/Magellan Composite of Quetzalpetlatl Corona

    Science.gov (United States)

    1990-01-01

    This composite image was created by inserting approximately 70 orbits of Magellan data into an image obtained at the Arecibo, Puerto Rico radiotelescope and shows a geologically complex region in the southern hemisphere of Venus. The region is centered on 65 degrees south, 359 degrees east and is about 1500 x 1500 km (900 x 900 miles) in extent. The large oval feature in the lower half of the image is Quetzalpetlatl Corona, approximately 700 km (420 miles) in diameter. Coronae are circular to oval regions defined by an annulus of ridges and are centers for tectonic and volcanic activity. Tectonic activity is largely observed in a relatively narrow rim region, which in this image is defined by a complex lineated terrain that surrounds much of the corona. Bright and dark volcanic flows are seen throughout the corona and surrounding terrain. Small shield volcanoes, 1-20 km (0.6-12 miles) in diameter, are seen near the southern limit of the Magellan data image. Narrow linear troughs (seen in the image as bright lines) trend to the north-northwest of Quetzalpetlatl.

  8. Principal Component Analysis of SDSS Stellar Spectra

    CERN Document Server

    McGurk, Rosalie C; Ivezic, Zeljko

    2010-01-01

    We apply Principal Component Analysis (PCA) to ~100,000 stellar spectra obtained by the Sloan Digital Sky Survey (SDSS). In order to avoid strong non-linear variation of spectra with effective temperature, the sample is binned into 0.02 mag wide intervals of the g-r color (-0.20SDSS. The SDSS stellar spect...

  9. A short history of geophysical radar at Arecibo Observatory

    Directory of Open Access Journals (Sweden)

    J. D. Mathews

    2013-03-01

    Full Text Available As Arecibo Observatory (AO approaches its 50th anniversary, it is appropriate to review the many radars and ionospheric heaters that have been deployed on or near the 305 m dish and to summarize some of the innovative radar-based geophysical research that has resulted. The reasons William E. (Bill Gordon developed the 305 m Arecibo dish are well known but are briefly reviewed. The early and then more recent radar/feed designs are reviewed as geophysical uses of Arecibo have evolved and as the full potential of the dish and nearby facilities was and is being realized from HF through S-band frequencies. This history surely has some gaps and there are a few mysteries. The community is encouraged to fill these gaps and to help complete the history.

  10. BOSS DR12 combined galaxy sample: The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: On the measurement of growth rate using galaxy correlation functions

    CERN Document Server

    Satpathy, Siddharth; Ho, Shirley; White, Martin; Bahcall, Neta A; Beutler, Florian; Brownstein, Joel R; Chuang, Chia-Hsun; Eisenstein, Daniel J; Grieb, Jan Niklas; Kitaura, Francisco; Olmstead, Matthew D; Percival, Will J; Salazar-Albornoz, Salvador; Sánchez, Ariel G; Seo, Hee-Jong; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita

    2016-01-01

    We present a measurement of the linear growth rate of structure, \\textit{f} from the Sloan Digital Sky Survey III (SDSS III) Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 (DR12) using Convolution Lagrangian Perturbation Theory (CLPT) with Gaussian Streaming Redshift-Space Distortions (GSRSD) to model the two point statistics of BOSS galaxies in DR12. The BOSS-DR12 dataset includes 1,198,006 massive galaxies spread over the redshift range $0.2 < z < 0.75$. These galaxy samples are categorized in three redshift bins. Using CLPT-GSRSD in our analysis of the combined sample of the three redshift bins, we report measurements of $f \\sigma_8$ for the three redshift bins. We find $f \\sigma_8 = 0.430 \\pm 0.054$ at $z_{\\rm eff} = 0.38$, $f \\sigma_8 = 0.452 \\pm 0.057$ at $z_{\\rm eff} = 0.51$ and $f \\sigma_8 = 0.457 \\pm 0.052$ at $z_{\\rm eff} = 0.61$. Our results are consistent with the predictions of Planck $\\Lambda$CDM-GR. Our constraints on the growth rates of structure in the Universe at differ...

  11. SDSS, LSST, and Gaia: Lessons and Synergies

    CERN Document Server

    Juric, Mario

    2011-01-01

    The advent of deep, wide, accurate, digital photometric surveys exemplified by the Sloan Digital Sky Survey (SDSS) has had a profound impact on studies of the Milky Way. In the past decade, we have transitioned from a scarcity to an (over)abundance of precise, well calibrated, observations of stars over a large fraction of the Galaxy. The avalanche of data will continue throughout this decade, culminating with Gaia and LSST. This new reality will necessitate changes in methodology, habits, and expectations both on the side of the large survey projects as well as the astrophysics community at large. We argue, based on the experience with SDSS, that surveys should release data as early and often as possible incorporating incremental improvements in each subsequent release, as opposed to holding off for a single, big, final release. The scientific community will need to reciprocate by performing analyses and (re-analyses) appropriate to the current fidelity of the released data, understanding that these are cont...

  12. The SDSS Coadd: A Galaxy Photometric Redshift Catalog

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Ribamar R.R.; /Fermilab /Rio de Janeiro Federal U.; Soares-Santos, Marcelle; /Fermilab /Inst. Geo. Astron., Havana /Sao Paulo U.; Annis, James; /Fermilab; Dodelson, Scott; /Fermilab /Chicago U. /Chicago U., KICP; Hao, Jiangang; /Fermilab; Johnston, David; /Fermilab; Kubo, Jeffrey; /Fermilab; Lin, Huan; /Fermilab; Seo, Hee-Jong; /UC, Berkeley; Simet, Melanie; /Chicago U.

    2011-11-01

    We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for {approx} 13 million objects classified as galaxies in the coadd with r < 24.5. The photo-z and photo-z error estimators are trained and validated on a sample of {approx} 89, 000 galaxies that have SDSS photometry and spectroscopic redshifts measured by the SDSS Data Release 7 (DR7), the Canadian Network for Observational Cosmology Field Galaxy Survey (CNOC2), the Deep Extragalactic Evolutionary Probe Data Release 3(DEEP2 DR3), the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS), the Visible imaging Multi-Object Spectrograph - Very Large Telescope Deep Survey (VVDS) and the WiggleZ Dark Energy Survey. For the best ANN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than {sigma}{sub 68} = 0.036. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

  13. Type Ia supernova rate studies from the SDSS-II Supernova Study

    Energy Technology Data Exchange (ETDEWEB)

    Dilday, Benjamin [Univ. of Chicago, IL (United States)

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  14. Type Ia supernova rate studies from the SDSS-II Supernova Study

    Energy Technology Data Exchange (ETDEWEB)

    Dilday, Benjamin; /Chicago U.

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered {approx} 500 spectroscopically confirmed SNe Ia with densely sampled (once every {approx} 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents {approx} 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  15. Measuring Quasar Variability with Pan-STARRS1 and SDSS

    CERN Document Server

    Morganson, E; Chambers, K C; Green, P J; Kaiser, N; Magnier, E A; Marshall, P J; Morgan, J S; Price, P A; Rix, H -W; Chlafly, E F S; Tonry, J L; Walter, F

    2014-01-01

    We measure quasar variability using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1 or PS1) and the Sloan Digital Sky Survey (SDSS) and establish a method of selecting quasars via their variability in 10,000 square degree surveys. We use 100,000 spectroscopically confirmed quasars that have been well measured in both PS1 and SDSS and take advantage of the decadal time scales that separate SDSS measurements and PS1 measurements. A power law model fits the data well over the entire time range tested, 0.01 to 10 years. Variability in the current PS1-SDSS dataset can efficiently distinguish between quasars and non-varying objects. It improves the purity of a griz quasar color cut from 4.1% to 48% while maintaining 67% completeness. Variability will be very effective at finding quasars in datasets with no u band and in redshift ranges where exclusively photometric selection is not efficient. We show that quasars' rest-frame ensemble variability, measured as a root mean squared in del...

  16. Robust detection of CID double stars in SDSS

    CERN Document Server

    Pourbaix, D; Gunn, J E; Lupton, R H; Ivezic, Z; Siopis, C; Rigaux, M; Rubbens, A

    2016-01-01

    Aims. The Sloan Digital Sky Survey (SDSS) offers a unique possibility of not only detecting Colour Induced Displacement (CID) double stars but also confirming these detections. Methods. Successive cuts are applied to the SDSS DR12 database in order to reduce the size of the sample to be considered. The resulting dataset is then screened with a criterion based on the distance and orientation of the photocentres in different photometric bands. Results. About 3 200 distinct objects are classified as CID double stars, 40 of which are confirmed with at least a second detection. A consistency check further validates these detections.

  17. Measuring the matter density using baryon oscillations in the SDSS

    OpenAIRE

    Percival, Will J.; Nichol, Robert C.; Eisenstein, Daniel J.; Weinberg, David H.; Fukugita, Masataka; Pope, Adrian C.; Schneider, Donald P.; Szalay, Alex S.; Vogeley, Michael S.; Zehavi, Idit; Bahcall, Neta A.; Brinkmann, Jon; Connolly, Andrew J; Loveday, Jon; Meiksin, Avery

    2006-01-01

    We measure the cosmological matter density by observing the positions of baryon acoustic oscillations in the clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We jointly analyse the main galaxies and LRGs in the SDSS DR5 sample, using over half a million galaxies in total. The oscillations are detected with 99.74% confidence (3.0sigma assuming Gaussianity) compared to a smooth power spectrum. When combined with the observed scale of the peaks within the CMB, we find a best-fit va...

  18. Measuring the matter density using baryon oscillations in the SDSS

    OpenAIRE

    Percival, Will J.; Nichol, Robert C.; Eisenstein, Daniel J.; Weinberg, David H.; Fukugita, Masataka; Pope, Adrian C.; Schneider, Donald P.; Szalay, Alex S.; Vogeley, Michael S.; Zehavi, Idit; Bahcall, Neta A.; Brinkmann, Jon; Connolly, Andrew J; Loveday, Jon; Meiksin, Avery

    2007-01-01

    We measure the cosmological matter density by observing the positions of baryon acoustic oscillations in the clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We jointly analyze the main galaxies and LRGs in the SDSS DR5 sample, using over half a million galaxies in total. The oscillations are detected with 99.74% confidence (3.0 σ assuming Gaussianity) compared to a smooth power spectrum. When combined with the observed scale of the peaks within the CMB, we find a best-fit value...

  19. The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766

    OpenAIRE

    Shin, Min-Su; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Emilio E. Falco; Broadhurst, Tom; Gunn, James E.

    2008-01-01

    We present the first result of a survey for strong galaxy-galaxy lenses in Sloan Digital Sky Survey (SDSS) images. SDSS J082728.70+223256.4 was selected as a lensing candidate using selection criteria based on the color and positions of objects in the SDSS photometric catalog. Follow-up imaging and spectroscopy showed this object to be a lensing system. The lensing galaxy is an elliptical at z = 0.349 in a galaxy cluster. The lensed galaxy has the spectrum of a post-starburst galaxy at z = 0....

  20. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological implications of the full shape of the clustering wedges in the data release 10 and 11 galaxy samples

    CERN Document Server

    Sanchez, Ariel G; Kazin, Eyal A; Aubourg, Eric; Beutler, Florian; Brinkmann, Jon; Brownstein, Joel R; Cuesta, Antonio J; Dawson, Kyle S; Eisenstein, Daniel J; Ho, Shirley; Honscheid, Klaus; Manera, Marc; Maraston, Claudia; McBride, Cameron K; Percival, Will J; Ross, Ashley J; Samushia, Lado; Schlegel, David J; Schneider, Donald P; Skibba, Ramin; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Wake, David A; Weaver, Benjamin A; White, Martin; Zehavi, Idit

    2013-01-01

    We explore the cosmological implications of the angle-averaged correlation function, xi(s), and the clustering wedges, xi_perp(s) and xi_para(s), of the LOWZ and CMASS galaxy samples from Data Release 10 and 11 of the SDSS-III Baryon Oscillation Spectroscopic Survey. Our results show no significant evidence for a deviation from the standard LCDM model. The combination of the information from our clustering measurements with recent data from the cosmic microwave background is sufficient to constrain the curvature of the Universe to Omega_k = 0.0010 +- 0.0029, the total neutrino mass to Sum m_nu < 0.23 eV (95% confidence level), the effective number of relativistic species to N_eff=3.31 +- 0.27, and the dark energy equation of state to w_DE = -1.051 +- 0.076. These limits are further improved by adding information from type Ia supernovae and baryon acoustic oscillations from other samples. In particular, this data set combination is completely consistent with a time-independent dark energy equation of state,...

  1. A Survey of Metal Lines at High Redshift. II. SDSS Absorption Line Studies—O VI Line Density, Space Density, and Gas Metallicity at z abs ~ 3.0

    Science.gov (United States)

    Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

    2010-09-01

    We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N >=5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0.19 Å for the O VI 1032 Å component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs >= 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the "incompleteness and S/N-corrected" redshift number densities of O VI absorbers: ΔN O VI,c /Δzc (2.8 4.0) = 8.4 ± 2.9. We can place a secure lower limit for the contribution of O VI to the closure mass density at the redshifts probed here: ΩO VI (2.8 = 1.9 × 10-8 h -1. We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, {O VI}/{O}, and adopting the Anders & Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 = 3.6 × 10-4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

  2. The Size Distribution of Arecibo Interstellar Particles and Its Implications

    Science.gov (United States)

    Meisel, David D.; Janches, Diego; Mathews, John D.

    2002-11-01

    Size histograms of all Arecibo ultra-high-frequency radar micrometeors detected in 1997-1998 whose radii were measured by atmospheric drag are presented. Most can be fitted with either a lognormal function or, alternatively, one or more power-law functions. Either form is indicative of significant fragmentation. The interplanetary dust particle (IDP) histogram results are discussed and compared with those considered to be extrasolar particles, including a subset of those deemed to be true interstellar particles (ISPs). The Arecibo IDP power-law results are shown to agree well with those derived from IRAS dust bands and Long-Duration Exposure Facility cratering, thus confirming the applicability of the sample to the derivation of mass estimates. A dichotomy between size histograms of particles with preperihelion Earth encounters and those with postperihelion encounters is evidence that significant size histogram change occurs when the smallest particles, including all ISPs, pass close to the Sun, even if only once. A small sample of previously undetected Arecibo postperihelion ISPs coming from the direction of the known Ulysses gas and dust flow are shown to have a size distribution and solar system dynamical properties similar to other Arecibo ISPs and therefore can be combined with previous ISP results to obtain a more robust sample. Derived mass flux points for the Arecibo ISPs agree well (over 5 orders of magnitude of mass) with a previously derived mass flux distribution function for Ulysses/Galileo spacecraft dust. This combined spacecraft and ground-based mass flux function is then used to infer a number of interesting mass-related solar system and astrophysical quantities.

  3. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Signs of neutrino mass in current cosmological datasets

    OpenAIRE

    Beutler, Florian; Saito, Shun; Brownstein, Joel R.; Chuang, Chia-Hsun; Cuesta, Antonio J.; Percival, Will J.; Ross, Ashley J.; Ross, Nicholas P.; Schneider, Donald P.; Samushia, Lado; Sanchez, Ariel G.; Seo, Hee-Jong; Tinker, Jeremy L.; Wagner, Christian; Weaver, Benjamin A.

    2014-01-01

    We investigate the cosmological implications of the latest growth of structure measurement from the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 with particular focus on the sum of the neutrino masses, $\\sum m_{\

  4. The 2dF-SDSS LRG and QSO Survey: The z<2.1 Quasar Luminosity Function from 5645 Quasars to g=21.85

    CERN Document Server

    Richards, G T; Anderson, S F; Bland-Hawthorn, J; Boyle, B J; De Propris, R; Drinkwater, M J; Fan, X; Gunn, J E; Ivezic, Z; Jester, S; Loveday, J; Meiksin, A; Miller, L; Myers, A; Nichol, R C; Outram, P J; Pimbblet, K A; Roseboom, I G; Ross, N; Schneider, D P; Shanks, T; Sharp, R G; Stoughton, C; Strauss, M A; Szalay, A S; Vanden Berk, Daniel E; York, D G

    2005-01-01

    We have used the 2dF instrument on the AAT to obtain redshifts of a sample of z21 deep surveys. The 2SLAQ data exhibit no well defined ``break'' but do clearly flatten with increasing magnitude. The shape of the quasar luminosity function derived from 2SLAQ is in good agreement with that derived from type I quasars found in hard X-ray surveys. [Abridged

  5. ALFABURST: A realtime fast radio burst monitor for the Arecibo telescope

    CERN Document Server

    Chennamangalam, Jayanth; MacMahon, David; Armour, Wes; Cobb, Jeff; Lorimer, Duncan; Rajwade, Kaustubh; Siemion, Andrew; Werthimer, Dan; Williams, Christopher

    2015-01-01

    Fast radio bursts (FRBs) constitute an emerging class of fast radio transient whose origin continues to be a mystery. Realizing the importance of increasing coverage of the search parameter space, we have designed, built, and deployed a realtime monitor for FRBs at the 305-m Arecibo radio telescope. Named 'ALFABURST', it is a commensal instrument that is triggered whenever the 1.4 GHz seven-beam Arecibo $L$-Band Feed Array (ALFA) receiver commences operation. The ongoing commensal survey we are conducting using ALFABURST has an instantaneous field of view of 0.02 sq. deg. within the FWHM of the beams, with the realtime software configurable to use up to 300 MHz of bandwidth. We search for FRBs with dispersion measure up to 2560 cm$^{-3}$ pc and pulse widths ranging from 0.128 ms to 16.384 ms. Commissioning observations performed over the past few months have demonstrated the capability of the instrument in detecting single pulses from known pulsars. In this paper, I describe the instrument and the associated ...

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:galaxy clustering measurements in the low-redshift sample of Data Release 11

    OpenAIRE

    Tojeiro, R.; Ross, A. J.; Burden, A; Samushia, L.; Manera, M; Percival, W J; Beutler, F.; Brinkmann, J.; Brownstein, J. R.; Cuesta, A. J.; Dawson, K.; Eisenstein, D. J.; Ho, S.; Howlett, C.; Mcbride, C. K.

    2014-01-01

    RT is thankful for support from the European Research Council and the Science & Technology Facilities Council. We present the distance measurement to z = 0.32 using the eleventh data release (DR) of the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey (BOSS). We use 313 780 galaxies of the low-redshift (LOWZ) sample over 7341 square degrees to compute DV=(1264 ± 25)(rd/rd,fid}) - a sub 2 per cent measurement - using the baryon acoustic feature measured in the galaxy two-poin...

  7. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : mock galaxy catalogues for the low-redshift sample

    OpenAIRE

    Manera, Marc; Samushia, Lado; Tojeiro, Rita; Howlett, Cullan; Ross, Ashley J.; Percival, Will J.; Gil-Marín, Hector; Brownstein, Joel R.; Burden, Angela; Montesano, Francesco

    2015-01-01

    MM and WJP acknowledge support from European Research Council, through grant ‘MDEPUGS’. We present 1000 mock galaxy catalogues (mocks) for the analysis of the low-redshift sample (LOWZ; effective redshift z ˜ 0.32) of the Baryon Oscillation Spectroscopic Survey (BOSS) Data Releases 10 and 11. These mocks have been created following the PTHalos method revised to include new developments. The main improvement is the introduction of a redshift dependence in the halo occupation distribution in...

  8. The SDSS-IV in 2014: A Demographic Snapshot

    Science.gov (United States)

    Lundgren, Britt; Kinemuchi, Karen; Zasowski, Gail; Lucatello, Sara; Diamond-Stanic, Aleksandar M.; Tremonti, Christy A.; Myers, Adam D.; Aragón-Salamanca, Alfonso; Gillespie, Bruce; Ho, Shirley; Gallagher, John S.

    2015-08-01

    Many astronomers now participate in large international scientific collaborations, and it is important to examine whether these structures foster a healthy scientific climate that is inclusive and diverse. The Committee on the Participation of Women in the Sloan Digital Sky Survey (CPWS) was formed to evaluate the demographics and gender climate within SDSS-IV, one of the largest and most geographically distributed astronomical collaborations. In 2014 April, the CPWS administered a voluntary demographic survey to establish a baseline for the incipient SDSS-IV, which began observations in 2014 July. We received responses from 250 participants (46% of the active membership). Half of the survey respondents were located in the United States or Canada and 30% were based in Europe. Approximately 65% were faculty or research scientists and 31% were postdocs or graduate students. Eleven percent of survey respondents considered themselves to be an ethnic minority at their current institution. Twenty-five percent of the SDSS-IV collaboration members are women, a fraction that is consistent with the U.S. astronomical community, but substantially higher than the fraction of women in the International Astronomical Union (16%). Approximately equal fractions of men and women report holding positions of leadership in the collaboration. When binned by academic age and career level, men and women also assume leadership roles at approximately equal rates, in a way that increases steadily for both genders with increasing seniority. In this sense, SDSS-IV has been successful in recruiting leaders that are representative of the collaboration. That said, it is clear that more progress needs to be made toward achieving gender balance and increasing diversity in the field of astronomy, and there is still room for improvement in the membership and leadership of SDSS-IV. For example, at the highest level of SDSS-IV leadership, women disproportionately assume roles related to education and

  9. A Monte-Carlo Method for Making SDSS $u$-Band Magnitude more accurate

    CERN Document Server

    Gu, Jiayin; Zuo, Wenbo; Jing, Yingjie; Wu, Zhenyu; Ma, Jun; Zhou, Xu

    2016-01-01

    We develop a new Monte-Carlo-based method to convert the SDSS (Sloan Digital Sky Survey) $u$-band magnitude to the SCUSS (South Galactic Cap of $u$-band Sky Survey) $u$-band magnitude. Due to more accuracy of SCUSS $u$-band measurements, the converted $u$-band magnitude becomes more accurate comparing with the original SDSS $u$-band magnitude, in particular at the faint end. The average $u$ (both SDSS and SCUSS) magnitude error of numerous main-sequence stars with $0.2SDSS $u$ is 0.11. When $g=20.5$, the average SDSS $u$ error is up to 0.22. However, at this magnitude, the average magnitude error of SCUSS $u$ is just half as much as that of SDSS $u$. The SDSS $u$-band magnitudes of main-sequence stars with $0.2

  10. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies

    OpenAIRE

    Gil-Marín, Héctor; Will J. Percival(Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK); Verde, Licia; Brownstein, Joel R.; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio A.; Olmstead, Matthew D.

    2016-01-01

    We measure and analyse the bispectrum of the final, Data Release 12, galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS galaxies. The LOWZ sample contains 361762 galaxies with an effective redshift of $z_{\\rm LOWZ}=0.32$, and the CMASS sample 777202 galaxies with an effective redshift of $z_{\\rm CMASS}=0.57$. Combining the power spectrum, measured relative to the line-of-sight, with the spherically averaged bispectrum, w...

  11. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Testing gravity with redshift-space distortions using the power spectrum multipoles

    OpenAIRE

    Beutler, Florian; Saito, Shun; Seo, Hee-Jong; Brinkmann, Jon; Dawson, Kyle S.; Eisenstein, Daniel J.; Font-Ribera, Andreu; Ho, Shirley; McBride, Cameron K.; Montesano, Francesco; Percival, Will J.; Ross, Ashley J.; Ross, Nicholas P.; Samushia, Lado; Schlegel, David J.

    2013-01-01

    We analyse the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 (DR11) sample, which consists of $690\\,827$ galaxies in the redshift range $0.43 < z < 0.7$ and has a sky coverage of $8\\,498\\,\\text{deg}^2$. We perform our analysis in Fourier space using a power spectrum estimator suggested by Yamamoto et al. (2006). We measure the multipole power spectra in a self-consistent manner for the first time in the sense that we provide a proper way to...

  12. The Arecibo Remote Command Center: Students Doing Science

    Science.gov (United States)

    Miller, Andy; Jenet, F. A.; Rodriguez-Zermeno, A.; Stovall, K.

    2010-01-01

    The University of Texas-Brownsville (UTB) is home to the Center for Gravitational Wave Astronomy (CGWA) which is, in turn, the home of the Arecibo Remote Command Center (ARCC). The ARCC is a virtual control room where researchers and undergraduate students--with the assistance of local high school students--control in real time the Arecibo Observatory--the world's largest single dish radio telescope. This poster presents a general outline of ARCC programs and recent accomplishments. Several notable accomplishments include: 1) the direct involvement of high school students in the PALFA pulsar search project at the Arecibo Observatory; 2) ARCC Scholars (undergraduate physics majors at UTB) led observations for a significant percentage of PALFA observing runs; 3) a summer astronomy academy for local high school students was held for the fifth consecutive year; 4) a second cohort of ARCC Scholars brings to ten the number of undergraduate physics majors specializing in astrophysics at UTB; 5) two members of the second cohort of ARCC Scholars, along with four summer academy high school students, attended the Pulsar Search Collaboratory program at the Green Bank Observatory; 6) specialized astrophysics programs are being expanded into a number of local high schools to stimulate interest in astrophysics research.

  13. The infra-red luminosities of ~332,000 SDSS galaxies predicted from artificial neural networks and the Herschel Stripe 82 survey

    CERN Document Server

    Ellison, Sara L; Rosario, David J; Mendel, J Trevor

    2015-01-01

    The total infra-red (IR) luminosity (L_IR) can be used as a robust measure of a galaxy's star formation rate (SFR), even in the presence of an active galactic nucleus (AGN), or when optical emission lines are weak. Unfortunately, existing all sky far-IR surveys, such as the Infra-red Astronomical Satellite (IRAS) and AKARI, are relatively shallow and are biased towards the highest SFR galaxies and lowest redshifts. More sensitive surveys with the Herschel Space Observatory are limited to much smaller areas. In order to construct a large sample of L_IR measurements for galaxies in the nearby universe, we employ artificial neural networks (ANNs), using 1136 galaxies in the Herschel Stripe 82 sample as the training set. The networks are validated using two independent datasets (IRAS and AKARI) and demonstrated to predict the L_IR with a scatter sigma ~ 0.23 dex, and with no systematic offset. Importantly, the ANN performs well for both star-forming galaxies and those with an AGN. A public catalog is presented wi...

  14. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Anisotropic galaxy clustering in Fourier-space

    CERN Document Server

    Beutler, Florian; Saito, Shun; Chuang, Chia-Hsun; Cuesta, Antonio J; Eisenstein, Daniel J; Gil-Marín, Héctor; Grieb, Jan Niklas; Hand, Nick; Kitaura, Francisco-Shu; Modi, Chirag; Nichol, Robert C; Olmstead, Matthew D; Percival, Will J; Prada, Francisco; Sánchez, Ariel G; Rodriguez-Torres, Sergio; Ross, Ashley J; Ross, Nicholas P; Schneider, Donald P; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana

    2016-01-01

    We investigate the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 (DR12) sample, which consists of $1\\,198\\,006$ galaxies in the redshift range $0.2 < z < 0.75$ and a sky coverage of $10\\,252\\,$deg$^2$. We analyse this dataset in Fourier space, using the power spectrum multipoles to measure Redshift-Space Distortions (RSD) simultaneously with the Alcock-Paczynski (AP) effect and the Baryon Acoustic Oscillation (BAO) scale. We include the power spectrum monopole, quadrupole and hexadecapole in our analysis and compare our measurements with a perturbation theory based model, while properly accounting for the survey window function. To evaluate the reliability of our analysis pipeline we participate in a mock challenge, which resulted in systematic uncertainties significantly smaller than the statistical uncertainties. While the high-redshift constraint on $f\\sigma_8$ at $z_{\\rm eff}=0.61$ indicates a small ($\\sim 1.4\\sigma$) deviation from the prediction of th...

  15. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample

    CERN Document Server

    Alam, Shadab; Bailey, Stephen; Beutler, Florian; Bizyaev, Dmitry; Blazek, Jonathan A; Bolton, Adam S; Brownstein, Joel R; Burden, Angela; Chuang, Chia-Hsun; Comparat, Johan; Cuesta, Antonio J; Dawson, Kyle S; Eisenstein, Daniel J; Escoffier, Stephanie; Gil-Marín, Héctor; Grieb, Jan Niklas; Hand, Nick; Ho, Shirley; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Malanushenko, Elena; Malanushenko, Viktor; Maraston, Claudia; McBride, Cameron K; Nichol, Robert C; Olmstead, Matthew D; Oravetz, Daniel; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pellejero-Ibanez, Marcos; Percival, Will J; Petitjean, Patrick; Prada, Francisco; Price-Whelan, Adrian M; Reid, Beth A; Rodríguez-Torres, Sergio A; Roe, Natalie A; Ross, Ashley J; Ross, Nicholas P; Rossi, Graziano; Rubiño-Martín, Jose Alberto; Sánchez, Ariel G; Saito, Shun; Salazar-Albornoz, Salvador; Samushia, Lado; Satpathy, Siddharth; Scóccola, Claudia G; Schlegel, David J; Schneider, Donald P; Seo, Hee-Jong; Simmons, Audrey; Slosar, Anže; Strauss, Michael A; Swanson, Molly E C; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Magaña, Mariana Vargas; Vazquez, Jose Alberto; Verde, Licia; Wake, David A; Wang, Yuting; Weinberg, David H; White, Martin; Wood-Vasey, W Michael; Yèche, Christophe; Zehavi, Idit; Zhai, Zhongxu; Zhao, Gong-Bo

    2016-01-01

    We present cosmological results from the final galaxy clustering data set of the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey III. Our combined galaxy sample comprises 1.2 million massive galaxies over an effective area of 9329 deg^2 and volume of 18.7 Gpc^3, divided into three partially overlapping redshift slices centred at effective redshifts 0.38, 0.51, and 0.61. We measure the angular diameter distance DM and Hubble parameter H from the baryon acoustic oscillation (BAO) method after applying reconstruction to reduce non-linear effects on the BAO feature. Using the anisotropic clustering of the pre-reconstruction density field, we measure the product DM*H from the Alcock-Paczynski (AP) effect and the growth of structure, quantified by f{\\sigma}8(z), from redshift-space distortions (RSD). We combine measurements presented in seven companion papers into a set of consensus values and likelihoods, obtaining constraints that are tighter and more robust than those from any one m...

  16. SDSS-III/APOGEE: Detailed Abundances of Galactic Star Clusters

    CERN Document Server

    Frinchaboy, Peter M; Jackson, Kelly; Johnson, Jennifer A; Majewski, Steven R; Shetrone, Matthew; Rocha, Aaron

    2010-01-01

    The Sloan Digital Sky Survey III/Apache Point Observatory Galactic Evolution Experiment (SDSS-III/APOGEE) is a large-scale spectroscopic survey of Galactic stars and star clusters. The SDSS-III/APOGEE survey is designed to produce high-S/N, R = 27,500-31,000 spectra that cover a wavelength range of 1.51 to 1.68 microns. By utilizing APOGEE's excellent kinematics (error <= 0.5 km/s) and abundances (errors ~ 0.1 dex), we will be able to study star cluster kinematics and chemical properties in detail. Over the course of the 3-year survey beginning in 2011, APOGEE will target 25-30 key open and globular clusters. In addition, the large area coverage of the SDSS focal plane will also allow us to target stars in 100-200 additional star clusters during the main survey observations. We present the strength of APOGEE for both open and globular star cluster studies and the methods of identifying probable clusters members utilizing 2MASS and IRAC/WISE data.

  17. The UV Properties of SDSS Selected Quasars

    CERN Document Server

    Trammell, G B; Schneider, D P; Richards, G T; Hall, P B; Anderson, S F; Brinkmann, J; Trammell, George B.; Berk, Daniel E. Vanden; Schneider, Donald P.; Richards, Gordon T.; Hall, Patrick B.; Anderson, Scott F.

    2006-01-01

    We present an analysis of the broadband UV/optical properties of z<3.4 quasars matched in the Galaxy Evolution Explorer (GALEX) General Data Release 1 (GR1) and the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Of the 6371 DR3 quasars covered by 204 GR1 tiles, 5380 have near-UV detections, while 3034 have both near-UV and far-UV detections using a matching radius of 7". Most of the DR3 sample quasars are detected in the near-UV until z~1.7, with the near-UV detection fraction dropping to ~50% by z~2. Statistical tests performed on the distributions of non-detections indicate that the optically-selected quasars missed in the UV tend to be optically faint or at high redshift. The GALEX positions are shown to be consistent with the SDSS astrometry to within an rms scatter of 0.6-0.7" in each coordinate, and empirically determined photometric errors from multi-epoch GALEX observations significantly exceed the Poissonian errors quoted in the GR1 object catalogs. The UV-detected quasars are well separated ...

  18. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmological implications of the Fourier space wedges of the final sample

    CERN Document Server

    Grieb, Jan Niklas; Salazar-Albornoz, Salvador; Scoccimarro, Román; Crocce, Martín; Vecchia, Claudio Dalla; Montesano, Francesco; Gil-Marín, Héctor; Ross, Ashley J; Beutler, Florian; Rodríguez-Torres, Sergio; Chuang, Chia-Hsun; Prada, Francisco; Kitaura, Francisco-Shu; Cuesta, Antonio J; Eisenstein, Daniel J; Percival, Will J; Vargas-Magana, Mariana; Tinker, Jeremy L; Tojeiro, Rita; Brownstein, Joel R; Maraston, Claudia; Nichol, Robert C; Olmstead, Matthew D; Samushia, Lado; Seo, Hee-Jong; Streblyanska, Alina; Zhao, Gong-bo

    2016-01-01

    We extract cosmological information from the anisotropic power spectrum measurements from the recently completed Baryon Oscillation Spectroscopic Survey (BOSS), extending the concept of clustering wedges to Fourier space. Making use of new FFT-based estimators, we measure the power spectrum clustering wedges of the BOSS sample by filtering out the information of Legendre multipoles l > 4. Our modelling of these measurements is based on novel approaches to describe non-linear evolution, bias, and redshift-space distortions, which we test using synthetic catalogues based on large-volume N-body simulations. We are able to include smaller scales than in previous analyses, resulting in tighter cosmological constraints. Using three overlapping redshift bins, we measure the angular diameter distance, the Hubble parameter, and the cosmic growth rate, and explore the cosmological implications of our full shape clustering measurements in combination with CMB and SN Ia data. Assuming a {\\Lambda}CDM cosmology, we constra...

  19. Properties of galaxies in SDSS Quasar environments at z < 0.2

    OpenAIRE

    Coldwell, Georgina V.; Lambas, Diego G.

    2006-01-01

    We analyse the environment of low redshift, z < 0.2, SDSS quasars using the spectral and photometric information of galaxies from the Sloan Digital Sky Survey Third Data Release (SDSS-DR3). We compare quasar neighbourhoods with field and high density environments through an analysis on samples of typical galaxies and groups. We compute the surrounding surface number density of galaxies finding that quasar environments systematically avoid high density regions. Their mean environments correspo...

  20. The SDSS and e-science archiving at the University of Chicago Library

    OpenAIRE

    Kern, Barbara; Armstrong, Dean; Blair, Charles; Farley, David; Feeney, Kathleen; Ielmini, Eileen; Long, Elisabeth; Meyer, Daniel; Wilkins, Peggy

    2010-01-01

    The Sloan Digital Sky Survey (SDSS) is a co-operative scientific project involving over 25 institutions worldwide and managed by the Astrophysical Research Consortium (ARC) to map one- quarter of the entire sky in detail, determining the positions and absolute brightness of hundreds of millions of celestial objects. The project was completed in October 2008 and produced over 100 terabytes of data comprised of object catalogs, images, and spectra. While the project remained active, SDSS data w...

  1. Applying the Support Vector Machine Method to Matching IRAS and SDSS Catalogues

    OpenAIRE

    Cao, Chen

    2007-01-01

    This paper presents results of applying a machine learning technique, the Support Vector Machine (SVM), to the astronomical problem of matching the Infra-Red Astronomical Satellite (IRAS) and Sloan Digital Sky Survey (SDSS) object catalogues. In this study, the IRAS catalogue has much larger positional uncertainties than those of the SDSS. A model was constructed by applying the supervised learning algorithm (SVM) to a set of training data. Validation of the model shows a good identification ...

  2. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    CERN Document Server

    Gil-Marín, Héctor; Cuesta, Antonio J; Brownstein, Joel R; Chuang, Chia-Hsun; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashely J; Schlegel, David J; Schneider, Donald P; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Magaña, Mariana Vargas; Zhao, Gong-Bo

    2015-01-01

    [abridged] We present an anisotropic analysis of the baryonic acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryonic Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains contains 361\\,762 galaxies with an effective redshift of $z_{\\rm LOWZ}=0.32$, and the CMASS sample consists of 777\\,202 galaxies with an effective redshift of $z_{\\rm CMASS}=0.57$. We extract the BAO peak position from the monopole power spectrum moment, $\\alpha_0$, and from the $\\mu^2$ moment, $\\alpha_2$. We report $H(z_{\\rm LOWZ})r_s(z_d)=(11.64\\pm0.62)\\cdot10^3\\,{\\rm km}s^{-1}$ and $D_A(z_{\\rm LOWZ})/r_s(z_d)=6.85\\pm0.17$ with a cross-correlation coefficient of $r_{HD_A}=0.42$, for the LOWZ sample; and $H(z_{\\rm CMASS})r_s(z_d)=(14.56\\pm0.38)\\cdot10^3\\,{\\rm km}s^{-1}$ and $D_A(z_{\\rm CMASS})/r_s(z_d)=9.42\\pm0.13$ with a cross-correlation coefficient of $r_{HD_A}=0.51$, for the CMASS sample. We combine these results with the measurements...

  3. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    CERN Document Server

    Gil-Marín, Héctor; Brownstein, Joel R; Chuang, Chia-Hsun; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J; Samushia, Lado; Schlegel, David J; Thomas, Daniel; Tinker, Jeremy L; Zhao, Gong-Bo

    2015-01-01

    We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line-of-sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12 (DR12). The LOWZ sample contains 361\\,762 galaxies with an effective redshift of $z_{\\rm lowz}=0.32$, and the CMASS sample 777\\,202 galaxies with an effective redshift of $z_{\\rm cmass}=0.57$. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter $f$ times the amplitude of dark matter density fluctuations $\\sigma_8$ by modeling the Redshift-Space Distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on $f\\sigma_8$, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch $H(z)r_s(z_d)$, and the angular distance parameter divided by the sound horizon $D_A(z)/r_s(z_d)$. We find $f(z_{\\rm lowz})\\sigma_8(z_{\\rm lowz})=0.394\\pm0.062$, $D_A(z_{\\rm l...

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

    CERN Document Server

    Beutler, Florian; Ross, Ashley J; McDonald, Patrick; Saito, Shun; Bolton, Adam S; Brownstein, Joel R; Chuang, Chia-Hsun; Cuesta, Antonio J; Eisenstein, Daniel J; Font-Ribera, Andreu; Grieb, Jan Niklas; Hand, Nick; Kitaura, Francisco-Shu; Modi, Chirag; Nichol, Robert C; Percival, Will J; Prada, Francisco; Rodriguez-Torres, Sergio; Roe, Natalie A; Ross, Nicholas P; Salazar-Albornoz, Salvador; Sánchez, Ariel G; Schneider, Donald P; Slosar, Anže; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana; Vazquez, Jose A

    2016-01-01

    We analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes $1\\,198\\,006$ galaxies over the redshift range $0.2 < z < 0.75$. We divide this dataset into three (overlapping) redshift bins with the effective redshifts $\\zeff = 0.38$, $0.51$ and $0.61$. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as $\\sim 1000$ MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density field reconstruction to enhance the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can separate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance $D_A(z)$ and the Hubble parameter $H(z)$ separately. We obtain two independent $1.6\\%$ and $1.5\\%$ constraints on $D_A(z)$ and $2.9\\%$ and $2.3\\%$ constraints...

  5. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies

    CERN Document Server

    Gil-Marín, Héctor; Verde, Licia; Brownstein, Joel R; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio A; Olmstead, Matthew D

    2016-01-01

    We measure and analyse the bispectrum of the final, Data Release 12, galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS galaxies. The LOWZ sample contains 361762 galaxies with an effective redshift of $z_{\\rm LOWZ}=0.32$, and the CMASS sample 777202 galaxies with an effective redshift of $z_{\\rm CMASS}=0.57$. Combining the power spectrum, measured relative to the line-of-sight, with the spherically averaged bispectrum, we are able to constrain the product of the growth of structure parameter, $f$, and the amplitude of dark matter density fluctuations, $\\sigma_8$, along with the geometric Alcock-Paczynski parameters, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch, $H(z)r_s(z_d)$, and the angular distance parameter divided by the sound horizon, $D_A(z)/r_s(z_d)$. We find $f(z_{\\rm LOWZ})\\sigma_8(z_{\\rm LOWZ})=0.460\\pm 0.066$, $D_A(z_{\\rm LOWZ})/r_s(z_d)=6.74 \\pm 0.22$, $H(z_{\\rm LOWZ})r_s(z_d)=(1...

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    Science.gov (United States)

    Gil-Marín, Héctor; Percival, Will J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Grieb, Jan Niklas; Ho, Shirley; Shu Kitaura, Francisco-; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Samushia, Lado; Schlegel, David J.; Thomas, Daniel; Tinker, Jeremy L.; Zhao, Gong-Bo

    2016-05-01

    We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line-of-sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12 (DR12). The LOWZ sample contains 361 762 galaxies with an effective redshift of zlowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of zcmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations σ8 by modeling the Redshift-Space Distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on fσ8, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch H(z)rs(zd), and the angular distance parameter divided by the sound horizon DA(z)/rs(zd). We find f(zlowz)σ8(zlowz) = 0.394 ± 0.062, DA(zlowz)/rs(zd) = 6.35 ± 0.19, H(zlowz)rs(zd) = (11.41 ± 0.56) 103kms-1 for the LOWZ sample, and f(zcmass)σ8(zcmass) = 0.444 ± 0.038, DA(zcmass)/rs(zd) = 9.42 ± 0.15, H(z_cmass)r_s(z_d)=(13.92 ± 0.44) {10^3km}s^{-1} for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial ΛCDM values, we find f(zlowz)σ8(zlowz) = 0.485 ± 0.044 and f(zcmass)σ8(zcmass) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.

  7. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    Science.gov (United States)

    Gil-Marín, Héctor; Percival, Will J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Samushia, Lado; Schlegel, David J.; Thomas, Daniel; Tinker, Jeremy L.; Zhao, Gong-Bo

    2016-08-01

    We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line of sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12. The LOWZ sample contains 361 762 galaxies with an effective redshift of zlowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of zcmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations σ8 by modelling the redshift-space distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on fσ8, the product of the Hubble constant and the comoving sound horizon at the baryon-drag epoch H(z)rs(zd), and the angular distance parameter divided by the sound horizon DA(z)/rs(zd). We find f(zlowz)σ8(zlowz) = 0.394 ± 0.062, DA(zlowz)/rs(zd) = 6.35 ± 0.19, H(zlowz)rs(zd) = (11.41 ± 0.56) 103 km s- 1 for the LOWZ sample, and f(zcmass)σ8(zcmass) = 0.444 ± 0.038, DA(zcmass)/rs(zd) = 9.42 ± 0.15, H(zcmass)rs(zd) = (13.92 ± 0.44) 103 km s- 1 for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial Λcold dark matter values, we find f(zlowz)σ8(zlowz) = 0.485 ± 0.044 and f(zcmass)σ8(zcmass) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.

  8. THE LICK/SDSS LIBRARY. I. SYNTHETIC INDEX DEFINITION AND CALIBRATION

    International Nuclear Information System (INIS)

    A new synthetic library of spectral feature indices, Lick/Sloan Digital Sky Survey (SDSS), for stellar population studies is presented. Lick/SDSS is computed from synthetic spectra with resolving power R = 1800 to fully exploit the content of the spectroscopic SDSS-DR7 stellar database. The Lick/SDSS system is based on the Lick/IDS one complemented with a UV index in the wavelength region of Ca II H and K lines. The system is well suited to study α-element abundances in F, G, and K stars. The reliability of synthetic indices in reproducing the behaviors of observational ones with effective temperature, surface gravity, overall metallicity, and α-element abundances is tested by using empirical stellar libraries (ELODIE, INDO-U.S., and MILES) and the SDSS-DR7 spectroscopic database. The importance of using the same temperature scale in comparing theoretical and observational indices is discussed. The full consistency between Lick/SDSS and observational indices derived from the above mentioned stellar libraries is assessed. The comparison with indices computed from SDSS-DR7 spectra evidences good consistency for 'dwarf' stars and significant disagreement for 'giant' stars due to systematic overestimation of the stellar T eff by the SEGUE Stellar Parameter Pipeline.

  9. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    Science.gov (United States)

    Gil-Marín, Héctor; Percival, Will J.; Cuesta, Antonio J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Ho, Shirley; Shu Kitaura, Francisco-; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Schlegel, David J.; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Vargas Magaña, Mariana; Zhao, Gong-Bo

    2016-05-01

    We present an anisotropic analysis of the baryonic acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryonic Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains contains 361 762 galaxies with an effective redshift of zLOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of zCMASS = 0.57. We extract the BAO peak position from the monopole power spectrum moment, α0, and from the μ2 moment, α2, where μ is the cosine of the angle to the line-of-sight. The μ2-moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ2-moment, which are related to radial and angular shifts in scale. We report H(zLOWZ)rs(zd) = (11.60 ± 0.60) · 103 kms-1 and DA(zLOWZ)/rs(zd) = 6.66 ± 0.16 with a cross-correlation coefficient of r_{HD_A}=0.41, for the LOWZ sample; and H(zCMASS)rs(zd) = (14.56 ± 0.37) · 103 kms-1 and DA(zCMASS)/rs(zd) = 9.42 ± 0.13 with a cross-correlation coefficient of r_{HD_A}=0.47, for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same dataset (Cuesta et al. 2016, companion paper) and report the consensus values: H(zLOWZ)rs(zd) = (11.63 ± 0.69) · 103 kms-1 and DA(zLOWZ)/rs(zd) = 6.67 ± 0.15 with r_{HD_A}=0.35 for the LOWZ sample; H(zCMASS)rs(zd) = (14.67 ± 0.42) · 103 kms-1 and DA(zCMASS)/rs(zd) = 9.47 ± 0.12 with r_{HD_A}=0.52 for the CMASS sample.

  10. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    Science.gov (United States)

    Gil-Marín, Héctor; Percival, Will J.; Cuesta, Antonio J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Schlegel, David J.; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Vargas Magaña, Mariana; Zhao, Gong-Bo

    2016-08-01

    We present an anisotropic analysis of the baryon acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361 762 galaxies with an effective redshift of zLOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of zCMASS = 0.57. We extract the BAO peak position from the monopole power-spectrum moment, α0, and from the μ2 moment, α2, where μ is the cosine of the angle to the line of sight. The μ2-moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ2-moment, which are related to radial and angular shifts in scale. We report H(zLOWZ)rs(zd) = (11.60 ± 0.60) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.66 ± 0.16 with a cross-correlation coefficient of r_{HD_A}=0.41, for the LOWZ sample; and H(zCMASS)rs(zd) = (14.56 ± 0.37) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.42 ± 0.13 with a cross-correlation coefficient of r_{HD_A}=0.47, for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same data set (Cuesta et al. 2016, companion paper) and report the consensus values: H(zLOWZ)rs(zd) = (11.63 ± 0.69) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.67 ± 0.15 with r_{HD_A}=0.35 for the LOWZ sample; H(zCMASS)rs(zd) = (14.67 ± 0.42) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.47 ± 0.12 with r_{HD_A}=0.52 for the CMASS sample.

  11. SDSS Plate Packets - From Artifact to Teaching Tool

    Science.gov (United States)

    Meredith, Kate K.; Masters, Karen; Lundgren, Britt; Fraser, Oliver; MacDonald, Nick

    2015-08-01

    For almost two decades the Sloan Digital Sky Survey (SDSS) has been producing aluminum plates that precisely align fiber optic cables to spectroscopic targets on the sky in order to capture thousands of spectra each night. Until recently the majority of these feats of engineering have ended as aluminum scrap. A few however, have found their way into classrooms in the US. The feedback has been overwhelmingly positive. We are building off the success of these experiences in a collaboration-wide effort to use this resource and send plates to educational institutions along with a variety of teaching materials that will be a useful science and engineering teaching tools and raise awareness for the varied surveys that are part of the SDSS. Each plate will arrive with a black and white print of the targeted section of sky to motivate students and resources to aid their exploration beginning in the September 2015.

  12. Stellar Metallicity Gradients in SDSS galaxies

    CERN Document Server

    Roig, Benjamin; Yan, Renbin

    2015-01-01

    We infer stellar metallicity and abundance ratio gradients for a sample of red galaxies in the Sloan Digital Sky Survey (SDSS) Main galaxy sample. Because this sample does not have multiple spectra at various radii in a single galaxy, we measure these gradients statistically. We separate galaxies into stellar mass bins, stack their spectra in redshift bins, and calculate the measured absorption line indices in projected annuli by differencing spectra in neighboring redshift bins. After determining the line indices, we use stellar population modeling from the EZ\\_Ages software to calculate ages, metallicities, and abundance ratios within each annulus. Our data covers the central regions of these galaxies, out to slightly higher than $1 R_{e}$. We find detectable gradients in metallicity and relatively shallow gradients in abundance ratios, similar to results found for direct measurements of individual galaxies. The gradients are only weakly dependent on stellar mass, and this dependence is well-correlated with...

  13. The SDSS Coadd: A Galaxy Photometric Redshift Catalog

    International Nuclear Information System (INIS)

    We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for ∼ 13 million objects classified as galaxies in the coadd with r 68 = 0.036. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

  14. Measuring quasar variability with Pan-STARRS1 and SDSS

    International Nuclear Information System (INIS)

    We measure quasar variability using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1 or PS1) and the Sloan Digital Sky Survey (SDSS) and establish a method of selecting quasars via their variability in 104 deg2 surveys. We use 105 spectroscopically confirmed quasars that have been well measured in both PS1 and SDSS and take advantage of the decadal timescales that separate SDSS measurements and PS1 measurements. A power law model fits the data well over the entire time range tested, 0.01-10 yr. Variability in the current PS1-SDSS data set can efficiently distinguish between quasars and nonvarying objects. It improves the purity of a griz quasar color cut from 4.1% to 48% while maintaining 67% completeness. Variability will be very effective at finding quasars in data sets with no u band and in redshift ranges where exclusively photometric selection is not efficient. We show that quasars' rest-frame ensemble variability, measured as a root mean squared in Δ magnitudes, is consistent with V(z, L, t) = A 0(1 + z)0.37(L/L 0)–0.16(t/1 yr)0.246, where L 0 = 1046 erg s–1 and A 0 = 0.190, 0.162, 0.147, or 0.141 in the g P1, r P1, i P1, or z P1filter, respectively. We also fit across all four filters and obtain median variability as a function of z, L, and λ as V(z, L, λ, t) = 0.079(1 + z)0.15(L/L 0)–0.2(λ/1000 nm)–0.44(t/1 yr)0.246.

  15. Dynamical Studies of Micrometeorites Detected at the Arecibo Observatory

    Science.gov (United States)

    Meisel, D. D.; Allen, T. S.; Getman, V. S.; Mathews, J. D.; Zhou, Q.

    1997-07-01

    A dynamical and orbital analysis of micrometeors detected with the Arecibo 430 MHz radar (and some dual frequency with 50 MHz) has been carried out which includes radiation pressure as well as perturbations by Jupiter and Saturn. Since these objects are apparently a new class of micrometeoroid (Mathews et al., Icarus, 1997), accurate orbital analysis is essential to determine their origin. The hypothesis that all of these small, dense particles originated from outside the solar system is explored in some detail. Alternatives to this view are briefly considered and will be the subject of future dynamical investigations.

  16. SDSS Pre-Burst Observations of Recent Gamma-Ray Burst Fields

    CERN Document Server

    Cool, R J; Brinkmann, J; Eisenstein, D J; Hogg, D W; Schlegel, D J; Schneider, D P; Vanden Berk, Daniel E; Berk, Daniel E. Vanden; Blanton, Michael R.; Cool, Richard J.; Eisenstein, Daniel J.; Hogg, David W.; Schlegel, David J.; Schneider, Donald P.

    2006-01-01

    In this paper, we present Sloan Digital Sky Survey (SDSS) photometry and spectroscopy in the fields of 24 gamma-ray bursts (GRBs) observed by Swift, including bursts localized by Swift, HETE-2, and INTEGRAL, after December 2004. After this bulk release, we plan to provide individual releases of similar data shortly after the localization of future bursts falling in the SDSS survey area. These data provide a solid basis for the astrometric and photometric calibration of follow-up afterglow searches and monitoring. Furthermore, the images provided with this release will allow observers to find transient objects up to a magnitude fainter than possible with Digitized Sky Survey image comparisons.

  17. THE HALO OCCUPATION DISTRIBUTION OF SDSS QUASARS

    International Nuclear Information System (INIS)

    We present an estimate of the projected two-point correlation function (2PCF) of quasars in the Sloan Digital Sky Survey (SDSS) over the full range of one- and two-halo scales, 0.02 h–1 Mpc p –1 Mpc. This was achieved by combining data from SDSS DR7 on large scales and Hennawi et al. (with appropriate statistical corrections) on small scales. Our combined clustering sample is the largest spectroscopic quasar clustering sample to date, containing ∼48, 000 quasars in the redshift range 0.4 ∼sat = (7.4 ± 1.4) × 10–4, be satellites in dark matter halos. At z ∼ 1.4, the median masses of the host halos of central and satellite quasars are constrained to be Mcen = 4.1+0.3–0.4 × 1012 h–1 M☉ and Msat = 3.6+0.8–1.0 × 1014 h–1 M☉, respectively. To investigate the redshift evolution of the quasar-halo relationship, we also perform HOD modeling of the projected 2PCF measured by Shen et al. for SDSS quasars with median redshift 3.2. We find tentative evidence for an increase in the mass scale of quasar host halos—the inferred median mass of halos hosting central quasars at z ∼ 3.2 is Mcen = 14.1+5.8–6.9 × 1012 h–1 M☉. The cutoff profiles of the mean occupation functions of central quasars reveal that quasar luminosity is more tightly correlated with halo mass at higher redshifts. The average quasar duty cycle around the median host halo mass is inferred to be fq = 7.3+0.6–1.5 × 10–4 at z ∼ 1.4 and fq = 8.6+20.4–7.2 × 10–2 at z ∼ 3.2. We discuss the implications of our results for quasar evolution and quasar-galaxy co-evolution.

  18. NTT and NOT spectroscopy of SDSS-II supernovae

    CERN Document Server

    Ostman, L; Goobar, A; Amanullah, R; Smith, M; Sollerman, J; Stanishev, V; Stritzinger, M D; Bassett, B A; Davis, T M; Edmondson, E; Frieman, J A; Garnavich, P M; Lampeitl, H; Leloudas, G; Marriner, J; Nichol, R C; Romer, K; Sako, M; Schneider, D P; Zheng, C

    2010-01-01

    Context. The SDSS-II Supernova Survey, conducted between 2005 and 2007, was designed to detect a large number of Type Ia supernovae (SNe Ia) around z~0.2, the redshift “gap” between low-z and high-z SN searches. The survey has provided multi-band photometric lightcurves for variable targets, and SN candidates were scheduled for spectroscopic observations, primarily to provide SN classification and accurate redshifts. We present SN spectra obtained in 2006 and 2007 using the NTT and the NOT. Aims. We provide an atlas of SN spectra in the range z =0.03-0.32 that complements the well-sampled lightcurves from SDSS-II in the forthcoming three-year SDSS SN cosmology analysis. The sample can, for example, be used for spectral studies of SNe Ia, which are critical for understanding potential systematic effects when SNe are used to determine cosmological distances. Methods. The spectra were reduced in a uniform manner, and special care was taken in estimating the uncertainties for the different processing st...

  19. Photometric redshifts for the SDSS Data Release 12

    Science.gov (United States)

    Beck, Róbert; Dobos, László; Budavári, Tamás; Szalay, Alexander S.; Csabai, István

    2016-08-01

    We present the methodology and data behind the photometric redshift data base of the Sloan Digital Sky Survey (SDSS) Data Release 12. We adopt a hybrid technique, empirically estimating the redshift via local regression on a spectroscopic training set, then fitting a spectrum template to obtain K-corrections and absolute magnitudes. The SDSS spectroscopic catalogue was augmented with data from other, publicly available spectroscopic surveys to mitigate target selection effects. The training set is comprised of 1976 978 galaxies, and extends up to redshift z ≈ 0.8, with a useful coverage of up to z ≈ 0.6. We provide photometric redshifts and realistic error estimates for the 208 474 076 galaxies of the SDSS primary photometric catalogue. We achieve an average bias of overline{Δ z_{norm}} = {5.84 × 10^{-5}}, a standard deviation of σ(Δznorm) = 0.0205, and a 3σ outlier rate of Po = 4.11 per cent when cross-validating on our training set. The published redshift error estimates and photometric error classes enable the selection of galaxies with high-quality photometric redshifts. We also provide a supplementary error map that allows additional, sophisticated filtering of the data.

  20. A Large Sample of BL Lacs from SDSS and FIRST

    CERN Document Server

    Plotkin, Richard M; Hall, Patrick B; Margon, Bruce; Voges, Wolfgang; Schneider, Donald P; Stinson, Gregory; York, Donald G

    2008-01-01

    We present a large sample of 501 radio-selected BL Lac candidates from the combination of the Sloan Digital Sky Survey (SDSS) Data Release 5 optical spectroscopy and from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio survey; this is one of the largest BL Lac samples yet assembled, and each object emerges with homogeneous data coverage. Each candidate is detected in the radio from FIRST and confirmed in SDSS optical spectroscopy to have: (1) no emission feature with measured rest equivalent width larger than 5 Angstroms; and (2) no measured Ca II H/K depression larger than 40%. We subdivide our sample into 426 higher confidence candidates and 75 lower confidence candidates. We argue that contamination from other classes of objects that formally pass our selection criteria is small, and we identify a few very rare radio AGN with unusual spectra that are probably related to broad absorption line quasars. About one-fifth of our sample were known BL Lacs prior to the SDSS. A preliminary ana...

  1. Photometric redshifts for the SDSS Data Release 12

    CERN Document Server

    Beck, Róbert; Budavári, Tamás; Szalay, Alexander S; Csabai, István

    2016-01-01

    We present the methodology and data behind the photometric redshift database of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). We adopt a hybrid technique, empirically estimating the redshift via local regression on a spectroscopic training set, then fitting a spectrum template to obtain K-corrections and absolute magnitudes. The SDSS spectroscopic catalog was augmented with data from other, publicly available spectroscopic surveys to mitigate target selection effects. The training set is comprised of $1,976,978$ galaxies, and extends up to redshift $z\\approx 0.8$, with a useful coverage of up to $z\\approx 0.6$. We provide photometric redshifts and realistic error estimates for the $208,474,076$ galaxies of the SDSS primary photometric catalog. We achieve an average bias of $\\overline{\\Delta z_{\\mathrm{norm}}} = -0.0012$, a standard deviation of $\\sigma \\left(\\Delta z_{\\mathrm{norm}}\\right)=0.0249$, and a $3\\sigma$ outlier rate of $P_o=1.6\\%$ when cross-validating on our training set. The published...

  2. A systematic search for changing-look quasars in SDSS

    Science.gov (United States)

    MacLeod, Chelsea L.; Ross, Nicholas P.; Lawrence, Andy; Goad, Mike; Horne, Keith; Burgett, William; Chambers, Ken C.; Flewelling, Heather; Hodapp, Klaus; Kaiser, Nick; Magnier, Eugene; Wainscoat, Richard; Waters, Christopher

    2016-03-01

    We present a systematic search for changing-look quasars based on repeat photometry from Sloan Digital Sky Survey (SDSS) and Pan-STARRS1, along with repeat spectra from SDSS and SDSS-III Baryon Oscillation Spectroscopic Survey. Objects with large, |Δg| > 1 mag photometric variations in their light curves are selected as candidates to look for changes in broad emission line (BEL) features. Out of a sample of 1011 objects that satisfy our selection criteria and have more than one epoch of spectroscopy, we find 10 examples of quasars that have variable and/or `changing-look' BEL features. Four of our objects have emerging BELs, five have disappearing BELs, and one object shows tentative evidence for having both emerging and disappearing BELs. With redshifts in the range 0.20 15 per cent of strongly variable luminous quasars display changing-look BEL features on rest-frame time-scales of 8 to 10 yr. Plausible time-scales for variable dust extinction are factors of 2-10 too long to explain the dimming and brightening in these sources, and simple dust reddening models cannot reproduce the BEL changes. On the other hand, an advancement such as disc reprocessing is needed if the observed variations are due to accretion rate changes.

  3. The galaxy counts-in-cells distribution from the SDSS

    CERN Document Server

    Yang, Abel

    2010-01-01

    We determine the galaxy counts-in-cells distribution from the Sloan Digital Sky Survey (SDSS) for 3D spherical cells in redshift space as well as for 2D projected cells. We find that cosmic variance in the SDSS causes the counts-in-cells distributions in different quadrants to differ from each other by up to 20%. We also find that within this cosmic variance, the overall galaxy counts-in-cells distribution agrees with both the gravitational quasi-equilibrium distribution and the negative binomial distribution. We also find that brighter galaxies are more strongly clustered than if they were randomly selected from a larger complete sample that includes galaxies of all luminosities. The results suggest that bright galaxies could be in dark matter haloes separated by less than ~10 Mpc/h.

  4. Robust detection of CID double stars in SDSS

    Science.gov (United States)

    Pourbaix, D.; Knapp, G. R.; Gunn, J. E.; Lupton, R. H.; Ivezić, Ž.; Siopis, C.; Rigaux, M.; Rubbens, A.

    2016-06-01

    Aims: The Sloan Digital Sky Survey (SDSS) offers a unique possibility of not only detecting colour induced displacement (CID) double stars but also confirming these detections. Methods: Successive cuts are applied to the SDSS data release (DR) 12 database to reduce the size of the sample under consideration. The resulting dataset is then screened with a criterion based on the distance and orientation of the photocentres in different photometric bands. Results: About 3200 distinct objects are classified as CID double stars, 40 of which are confirmed with at least a second detection. A consistency check further validates these detections. Full Tables 1 and 2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A96

  5. SDSS-IV: The Clustering of eBOSS LRGs using photometric redshifts

    Science.gov (United States)

    Prakash, Abhishek; SDSS-IV/eBOSS

    2016-01-01

    SDSS-IV/eBOSS is producing an exciting data set for cosmology which will add to our understanding of the large-scale structure of the Universe. The Luminous Red Galaxy (LRG) component of this survey will cover a redshift regime barely explored by SDSS-III/BOSS and will allow a ˜1% measurement of the Baryon Acoustic Oscillation (BAO) scale and a 4.0% Redshift Space Distortion (RSD) measurement using a relatively uniform set of luminous, early-type galaxies in the redshift range 0.6 Digital Sky Survey (SDSS), using photometric redshifts. Although spectroscopic redshifts provide stronger constraints on large scale measurements, these results demonstrate the ability to make precise clustering measurements with photometric surveys.

  6. VizieR Online Data Catalog: Quasar from SDSS and UKIDSS (Wu+, 2010)

    Science.gov (United States)

    Wu, X.-B.; Jia, Z.

    2011-02-01

    We cross-identify all quasars in SDSS Data Release 7 (DR7) with the UKIDSS DR3, by finding the closest counterparts within 3-arcsec between the positions in two surveys and requesting all detections in both SDSS ugriz and UKIDSS YJHK bands for each quasar. To do the cross-identifications, we use the CrossID form available at the UKIDSS WFCAM Science Archive web site (http://surveys.roe.ac.uk:8080/wsa/crossID_form.jsp/) and use only the data in UKIDSS Large Area Survey (LAS) in order to avoid the misidentifications in the crowded fields with lower Galactic latitudes. This results in a sample of 8498 quasars with both SDSS and UKIDSS data. (1 data file).

  7. The UV, Optical, and IR Properties of SDSS Sources Detected by GALEX

    CERN Document Server

    Agüeros, M A; Covey, Kevin R; Obric, M; Hao, L; Walkowicz, L M; West, A A; Vanden Berk, Daniel E; Lupton, R H; Knapp, G R; Gunn, J E; Richards, G T; Bochanski, J J; Brooks, A; Claire, M; Haggard, D; Kaib, N; Kimball, A; Gogarten, S M; Seth, A; Solontoi, M; Agueros, Marcel A.; Ivezic, Zeljko; Covey, Kevin R.; Obric, Mirela; Hao, Lei; Walkowicz, Lucianne M.; West, Andrew A.; Berk, Daniel E. Vanden; Lupton, Robert H.; Knapp, Gillian R.; Gunn, James E.; Richards, Gordon T.; Bochanski, John; Brooks, Alyson; Claire, Mark; Haggard, Daryl; Kaib, Nathan; Kimball, Amy; Gogarten, Stephanie M.; Seth, Anil; Solontoi, Michael

    2005-01-01

    We discuss the UV, optical, and IR properties of the SDSS sources detected by GALEX as part of its All-sky Imaging Survey Early Release Observations. Virtually all of the GALEX sources in the overlap region are detected by SDSS. GALEX sources represent ~2.5% of all SDSS sources within these fields and about half are optically unresolved. Most unresolved GALEX/SDSS sources are bright blue turn-off thick disk stars and are typically detected only in the GALEX near-UV band. The remaining unresolved sources include low-redshift quasars, white dwarfs, and white dwarf/M dwarf pairs, and these dominate the optically unresolved sources detected in both GALEX bands. Almost all the resolved SDSS sources detected by GALEX are fainter than the SDSS 'main' spectroscopic limit. These sources have colors consistent with those of blue (spiral) galaxies (u-r<2.2), and most are detected in both GALEX bands. Measurements of their UV colors allow much more accurate and robust estimates of star-formation history than are possi...

  8. Extragalactic HI Surveys

    OpenAIRE

    Giovanelli, Riccardo; Haynes, Martha P.

    2015-01-01

    We review the results of HI line surveys of extragalactic sources in the local Universe. In the last two decades major efforts have been made in establishing on firm statistical grounds the properties of the HI source population, the two most prominent being the HI Parkes All Sky Survey (HIPASS) and the Arecibo Legacy Fast ALFA survey (ALFALFA). We review the choices of technical parameters in the design and optimization of spectro-photometric "blind" HI surveys, which for the first time prod...

  9. THE 5 GHz ARECIBO SEARCH FOR RADIO FLARES FROM ULTRACOOL DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Route, Matthew; Wolszczan, Alexander, E-mail: mroute@astro.psu.edu, E-mail: alex@astro.psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2013-08-10

    We present the results of a 4.75 GHz survey of 33 brown dwarfs and one young exoplanetary system for flaring radio emission, conducted with the 305 m Arecibo radio telescope. The goal of this program was to detect and characterize the magnetic fields of objects cooler than spectral type L3.5, the coolest brown dwarf detected prior to our survey. We have also attempted to detect flaring radio emission from the HR 8799 planetary system, guided by theoretical work indicating that hot, massive exoplanets may have strong magnetic fields capable of generating radio emission at GHz frequencies. We have detected and confirmed radio flares from the T6.5 dwarf 2MASS J10475385+2124234. This detection dramatically extends the temperature range over which brown dwarfs appear to be at least sporadic radio-emitters, from 1900 K (L3.5) down to 900 K (T6.5). It also demonstrates that the utility of radio detection as a unique tool to study the magnetic fields of substellar objects extends to the coolest dwarfs, and, plausibly to hot, massive exoplanets. We have also identified a single, 3.6{sigma} flare from the L1 dwarf, 2MASS J1439284+192915. This detection is tentative and requires confirmation by additional monitoring observations.

  10. The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs

    CERN Document Server

    Route, Matthew

    2016-01-01

    We describe our second installment of the 4.75 GHz survey of ultracool dwarfs (UCDs) conducted with the Arecibo radio telescope, which has observed 27 such objects and resulted in the detection of sporadic flaring from the T6 dwarf, WISEPC J112254.73+255021.5. We also present follow up observations of the first radio-emitting T dwarf, 2MASS J10475385+2124234, a tentatively identified radio emitting L1 dwarf, 2MASS J1439284+192915, and the known radio-flaring source, 2MASS J13142039+132011 AB. Our new data indicate that 2MASS J1439284+192915 is not a radio flaring source. The overall detection rate of our unbiased survey for radio-flaring UCDs is ~5% for new sources, with a detection rate for each spectral class of ~5-10%. Evidently, radio luminosity of the UCDs does not appear to monotonically decline with spectral type from M7 dwarfs to giant planets, in contradiction to theories of the magnetic field generation and internal structure of these objects. Along with other, recently published results, our data e...

  11. Statistical Properties of Bright Galaxies in the SDSS Photometric System

    CERN Document Server

    Shimasaku, K; Doi, M; Hamabe, M; Ichikawa, T; Okamura, S; Sekiguchi, M; Yasuda, N

    2001-01-01

    We investigate the photometric properties of 456 bright galaxies using imaging data recorded during the commissioning phase of the Sloan Digital Sky Survey (SDSS). Morphological classification is carried out by correlating results of several human classifiers. Our purpose is to examine the statistical properties of color indices, scale lengths, and concentration indices as functions of morphology for the SDSS photometric system. We find that $u'-g'$, $g'-r'$, and $r'-i'$ colors of SDSS galaxies match well with those expected from the synthetic calculation of spectroscopic energy distribution of template galaxies and with those transformed from $UBVR_CI_C$ color data of nearby galaxies. The agreement is somewhat poor, however, for $i'-z'$ color band with a discrepancy of $0.1-0.2$ mag. With the aid of the relation between surface brightness and radius obtained by Kent (1985), we estimate the averages of the effective radius of early type galaxies and the scale length of exponential disks both to be 2.6 kpc for...

  12. Extremely metal-poor star candidates in the SDSS

    Science.gov (United States)

    Xu, Si-Yao; Zhang, Hua-Wei; Liu, Xiao-Wei

    2013-03-01

    For a sample of metal-poor stars (-3.3 Digital Sky Survey (SDSS), calculated effective temperatures from (g - z)0 color, deduced stellar surface gravities by fitting stellar isochrones, and determined metallicities based on the aforementioned quantities. Metallicities thus derived from the Ca II K line are in much better agreement with the results determined from high-resolution spectra than the values given in the SDSS Data Release 7. The metallicities derived from the Mg I b lines have a large dispersion owing to the large measurement errors, whereas those deduced from the Ca II triplet lines are too high due to both non-local thermodynamical equilibrium (NLTE) effects and measurement errors. Abundances after correction for the NLTE effect for the Mg I b lines and Ca II triplet lines are also presented. Following this method, we have identified six candidates of ultra-metal-poor stars with [Fe/H] ~ -4.0 from a sample of 166 metal-poor star candidates. One of them, SDSS J102915+172927, was recently confirmed to be an ultra-metal-poor ([Fe/H] 4.0) star with the lowest metallicity ever measured. Follow-up high-resolution spectroscopy for the other five ultra-metal-poor stars in our sample will therefore be of great interest.

  13. Color-Induced Displacement double stars in SDSS

    CERN Document Server

    Pourbaix, D; Knapp, G R; Gunn, J E

    2004-01-01

    We report the first successful application of the astrometric color-induced displacement technique (CID, the displacement of the photocenter between different bandpasses due to a varying contribution of differently colored components to the total light), originally proposed by Wielen (1996) for discovering unresolved binary stars. Using the Sloan Digital Sky Survey (SDSS) Data Release 1 with 2.5 million stars brighter than 21m in the u and g bands, we select 419 candidate binary stars with CID greater than 0.5 arcsec. The SDSS colors of the majority of these candidates are consistent with binary systems including a white dwarf and any main sequence star with spectral type later than ~K7. The astrometric CID method discussed here is complementary to the photometric selection of binary stars in SDSS discussed by Smolcic et al. (2004), but there is considerable overlap (15%) between the two samples of selected candidates. This overlap testifies both to the physical soundness of both methods, as well as to the as...

  14. Galaxy-Galaxy Weak Lensing Measurements from SDSS: I. Image Processing and Lensing signals

    CERN Document Server

    Luo, Wentao; Zhang, Jun; Tweed, Dylan; Fu, Liping; Mo, H J; Bosch, Frank C van den; Shu, Chenggang; Li, Ran; Li, Nan; Liu, Xiangkun; Pan, Chuzhong; Wang, Yiran; Radovich, Mario

    2016-01-01

    As the first paper in a series on the study of the galaxy-galaxy lensing from Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our image processing pipeline that corrects the systematics primarily introduced by the Point Spread Function (PSF). Using this pipeline, we processed SDSS DR7 imaging data in $r$ band and generated a background galaxy catalog containing the shape information of each galaxy. Based on our own shape measurements of the galaxy images from SDSS DR7, we extract the galaxy-galaxy (GG) lensing signals around foreground spectroscopic galaxies binned in different luminosity and stellar mass. The overall signals are in good agreement with those obtained by \\citet{Mandelbaum2005, Mandelbaum2006} from the SDSS DR4. The results in this paper with higher signal to noise ratio is due to the larger survey area than SDSS DR4, confirm that more luminous/massive galaxies bear stronger GG lensing signal. We also divide the foreground galaxies into red/blue and star forming/quenched subsampl...

  15. The Arecibo Remote Command Center: Undergraduate and High School Students Exploring Astrophysics

    Science.gov (United States)

    Miller, Andy

    2012-01-01

    The University of Texas-Brownsville (UTB) is home to the Arecibo Remote Command Center (ARCC). The ARCC is a virtual control room where researchers and undergraduate students_with the assistance of local high school students_control in real time the Arecibo Observatory_the world's largest single dish radio telescope. This poster presents a general outline of ARCC programs and recent accomplishments.

  16. THE z = 5 QUASAR LUMINOSITY FUNCTION FROM SDSS STRIPE 82

    Energy Technology Data Exchange (ETDEWEB)

    McGreer, Ian D.; Fan Xiaohui [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Jiang Linhua [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Ross, Nicholas P.; White, Martin [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Schneider, Donald P.; Brandt, W. Niel [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); DeGraf, Colin [McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Glikman, Eilat [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Ge Jian [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Streblyanska, Alina, E-mail: imcgreer@as.arizona.edu [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain)

    2013-05-10

    We present a measurement of the Type I quasar luminosity function at z = 5 using a large sample of spectroscopically confirmed quasars selected from optical imaging data. We measure the bright end (M{sub 1450} < -26) with Sloan Digital Sky Survey (SDSS) data covering {approx}6000 deg{sup 2}, then extend to lower luminosities (M{sub 1450} < -24) with newly discovered, faint z {approx} 5 quasars selected from 235 deg{sup 2} of deep, coadded imaging in the SDSS Stripe 82 region (the celestial equator in the Southern Galactic Cap). The faint sample includes 14 quasars with spectra obtained as ancillary science targets in the SDSS-III Baryon Oscillation Spectroscopic Survey, and 59 quasars observed at the MMT and Magellan telescopes. We construct a well-defined sample of 4.7 < z < 5.1 quasars that is highly complete, with 73 spectroscopic identifications out of 92 candidates. Our color selection method is also highly efficient: of the 73 spectra obtained, 71 are high-redshift quasars. These observations reach below the break in the luminosity function (M{sub 1450}{sup *}{approx}-27). The bright-end slope is steep ({beta} {approx}< -4), with a constraint of {beta} < -3.1 at 95% confidence. The break luminosity appears to evolve strongly at high redshift, providing an explanation for the flattening of the bright-end slope reported previously. We find a factor of {approx}2 greater decrease in the number density of luminous quasars (M{sub 1450} < -26) from z = 5 to z = 6 than from z = 4 to z = 5, suggesting a more rapid decline in quasar activity at high redshift than found in previous surveys. Our model for the quasar luminosity function predicts that quasars generate {approx}30% of the ionizing photons required to keep hydrogen in the universe ionized at z = 5.

  17. Clustering and Bias Measurements of SDSS Voids

    CERN Document Server

    Clampitt, Joseph; Sánchez, Carles

    2015-01-01

    Using a void catalog from the SDSS survey, we present the first measurements of void clustering and the corresponding void bias. Over the range 30-200 Mpc/h the void auto-correlation is detected at 5-sigma significance for voids of radius 15-20 Mpc/h. We also measure the void-galaxy cross-correlation at higher signal-to-noise and compare the inferred void bias with the autocorrelation results. Void bias is constant with scale for voids of a given size, but its value falls from 5.6 +/- 1.0 to below zero as the void radius increases from 15 to 30 Mpc/h. The comparison of our measurements with carefully matched galaxy mock catalogs, with no free parameters related to the voids, shows that model predictions can be reliably made for void correlations. We study the dependence of void bias on tracer density and void size with a view to future applications. In combination with our previous lensing measurements of void mass profiles, these clustering measurements provide another step towards using voids as cosmologica...

  18. SDSS QUASARS IN THE WISE PRELIMINARY DATA RELEASE AND QUASAR CANDIDATE SELECTION WITH OPTICAL/INFRARED COLORS

    International Nuclear Information System (INIS)

    We present a catalog of 37,842 quasars in the Sloan Digital Sky Survey (SDSS) Data Release 7, which have counterparts within 6'' in the Wide-field Infrared Survey Explorer (WISE) Preliminary Data Release. The overall WISE detection rate of the SDSS quasars is 86.7%, and it decreases to less than 50.0% when the quasar magnitude is fainter than i = 20.5. We derive the median color-redshift relations based on this SDSS-WISE quasar sample and apply them to estimate the photometric redshifts of the SDSS-WISE quasars. We find that by adding the WISE W1- and W2-band data to the SDSS photometry we can increase the photometric redshift reliability, defined as the percentage of sources with photometric and spectroscopic redshift difference less than 0.2, from 70.3% to 77.2%. We also obtain the samples of WISE-detected normal and late-type stars with SDSS spectroscopy, and present a criterion in the z – W1 versus g – z color-color diagram, z – W1 > 0.66(g – z) + 2.01, to separate quasars from stars. With this criterion we can recover 98.6% of 3089 radio-detected SDSS-WISE quasars with redshifts less than four and overcome the difficulty in selecting quasars with redshifts between 2.2 and 3 from SDSS photometric data alone. We also suggest another criterion involving the WISE color only, W1 – W2 > 0.57, to efficiently separate quasars with redshifts less than 3.2 from stars. In addition, we compile a catalog of 5614 SDSS quasars detected by both WISE and UKIDSS surveys and present their color-redshift relations in the optical and infrared bands. By using the SDSS ugriz, UKIDSS, YJHK, and WISE W1- and W2-band photometric data, we can efficiently select quasar candidates and increase the photometric redshift reliability up to 87.0%. We discuss the implications of our results on the future quasar surveys. An updated SDSS-WISE quasar catalog consisting of 101,853 quasars with the recently released WISE all-sky data is also provided.

  19. Sagittarius stream 3-d kinematics from SDSS Stripe 82

    OpenAIRE

    Koposov, Sergey E.; Belokurov, Vasily; Evans, N. Wyn

    2013-01-01

    Using multi-epoch observations of the Stripe 82 region done by Sloan Digital Sky Survey, we measure precise statistical proper motions of the stars in the Sagittarius stellar stream. The multi-band photometry and SDSS radial velocities allow us to efficiently select Sgr members and thus enhance the proper motion precision to ~0.1 mas/yr. We measure separately the proper motion of a photometrically selected sample of the main sequence turn-off stars, as well as of a spectroscopically selected ...

  20. Measuring quasar variability with Pan-STARRS1 and SDSS

    Energy Technology Data Exchange (ETDEWEB)

    Morganson, E.; Rix, H.-W.; Schlafly, E. F.; Walter, F. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Burgett, W. S.; Chambers, K. C.; Kaiser, N.; Magnier, E. A.; Morgan, J. S.; Tonry, J. L. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Green, P. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Marshall, P. J. [Department of Astrophysics, Oxford University, Denys Wilkinson Building, Kemble Road, Oxford, OX1 3RH (United Kingdom); Price, P. A., E-mail: morganson@mpia.de [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2014-04-01

    We measure quasar variability using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1 or PS1) and the Sloan Digital Sky Survey (SDSS) and establish a method of selecting quasars via their variability in 10{sup 4} deg{sup 2} surveys. We use 10{sup 5} spectroscopically confirmed quasars that have been well measured in both PS1 and SDSS and take advantage of the decadal timescales that separate SDSS measurements and PS1 measurements. A power law model fits the data well over the entire time range tested, 0.01-10 yr. Variability in the current PS1-SDSS data set can efficiently distinguish between quasars and nonvarying objects. It improves the purity of a griz quasar color cut from 4.1% to 48% while maintaining 67% completeness. Variability will be very effective at finding quasars in data sets with no u band and in redshift ranges where exclusively photometric selection is not efficient. We show that quasars' rest-frame ensemble variability, measured as a root mean squared in Δ magnitudes, is consistent with V(z, L, t) = A {sub 0}(1 + z){sup 0.37}(L/L {sub 0}){sup –0.16}(t/1 yr){sup 0.246}, where L {sub 0} = 10{sup 46} erg s{sup –1} and A {sub 0} = 0.190, 0.162, 0.147, or 0.141 in the g {sub P1}, r {sub P1}, i {sub P1}, or z {sub P1}filter, respectively. We also fit across all four filters and obtain median variability as a function of z, L, and λ as V(z, L, λ, t) = 0.079(1 + z){sup 0.15}(L/L {sub 0}){sup –0.2}(λ/1000 nm){sup –0.44}(t/1 yr){sup 0.246}.

  1. PTSS: Discovery of a Probable Supernova in SDSS J150350.43+482250.7

    Science.gov (United States)

    Yang, Zesheng; Li, Bin; Li, Wenxiong; Wang, Xiaofeng; Zhao, Baibin; Wang, Lifang

    2016-03-01

    During the PMO-Tsinghua Supernova Survey (PTSS), using the 1.04-m schmidt telescope at Xuyi, China, we discovered a supernova candidate in the galaxy SDSS J150350.43+482250.7 (with a redshift of 0.026).

  2. A Cosmic Void Catalog of SDSS DR12 BOSS Galaxies

    CERN Document Server

    Mao, Qingqing; Scherrer, Robert J; Scoccimarro, Roman; Tinker, Jeremy L; McBride, Cameron K; Neyrinck, Mark C; Schneider, Donald P; Pan, Kaike; Bizyaev, Dmitry; Malanushenko, Elena; Malanushenko, Viktor

    2016-01-01

    We present a cosmic void catalog using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Release 12 and is the final catalog of SDSS-III. We take into account the survey boundaries, masks, and angular and radial selection functions, and apply the ZOBOV void finding algorithm to the galaxy catalog. After making quality cuts to ensure that the voids represent real underdense regions, we identify 1228 voids with effective radii spanning the range 20-100Mpc/h and with central densities that are, on average, 30% of the mean sample density. We discuss the basic statistics of voids, such as their size and redshift distributions, and measure the radial density profile of the voids via a stacking technique. In addition, we construct mock void catalogs from 1000 mock galaxy catalogs, and find that the properties of BOSS voids are in good agreement with those in the mock catalogs. We compare the stella...

  3. Constraining RRc candidates using SDSS colours

    CERN Document Server

    Bányai, E; Molnár, L; Dobos, L; Szabó, R

    2016-01-01

    The light variations of first-overtone RR Lyrae stars and contact eclipsing binaries can be difficult to distinguish. The Catalina Periodic Variable Star catalog contains several misclassified objects, despite the classification efforts by Drake et al. (2014). They used metallicity and surface gravity derived from spectroscopic data (from the SDSS database) to rule out binaries. Our aim is to further constrain the catalog using SDSS colours to estimate physical parameters for stars that did not have spectroscopic data.

  4. Acoustic scale from the angular power spectra of SDSS-III DR8 photometric luminous galaxies

    CERN Document Server

    Seo, Hee-Jong; White, Martin; Cuesta, Antonio; Ross, Ashley; Saito, Shun; Reid, Beth; Padmanabhan, Nikhil; Percival, Will J; de Putter, Roland; Schlegel, David; Eisenstein, Daniel; Xu, Xiaoying; Schneider, Donald; Skibba, Ramin; Verde, Licia; Nichol, Robert; Bizyaev, Dmitry; Brewington, Howard; Brinkmann, J; Costa, Luiz; Gott, J; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Palanque-Delabrouille, Nathalie; Pan, Kaike; Prada, Francisco; Ross, Nicholas; Simmons, Audrey; Simoni, Fernando; Shelden, Alaina; Snedden, Stephanie; Zehavi, Idit

    2012-01-01

    We measure the acoustic scale from the angular power spectra of the Sloan Digital Sky Survey III (SDSS-III) Data Release 8 imaging catalog that includes 872,921 galaxies over ~ 10,000 deg^2 between 0.45~ 0.35. We report constraints on cosmological parameters from our measurement in combination with the WMAP7 data and the previous spectroscopic BAO measurements of SDSS (Percival et al. 2010) and WiggleZ (Blake et al. 2011). We refer to our companion papers (Ho et al. 2011; de Putter et al. 2011) for investigations on information of the full power spectrum.

  5. The structure of the Galactic halo: SDSS versus SuperCOSMOS

    OpenAIRE

    Xu, Y; Deng, L. C.; Hu, J Y

    2007-01-01

    The halo structure at high Galactic latitudes near both the north and south poles is studied using SDSS and SuperCOSMOS data. For the south cap halo, the archive of the SuperCOSMOS photographic photometry sky survey is used. The coincident source rate between SuperCOSMOS data in $B_J$ band from $16^m.5$ to $20^m.5$ and SDSS data is about 92%, in a common sky area in the south. While that in the $R_F$ band is about 85% from $16^m.5$ to $19^m.5$. Transformed to the SuperCOSMOS system and downgr...

  6. The Arecibo Fast Radio Burst: Dense Circum-burst Medium

    CERN Document Server

    Kulkarni, S R; Neill, J D

    2015-01-01

    The nature of fast radio bursts (FRB) has been extensively debated. Here we investigate FRB121102, detected at Arecibo telescope and remarkable for its unusually large spectral index. After extensive study we conclude that the spectral index is caused by a nebula with free-free absorption. We find that putative nebula must lie beyond the Milky Way. We conclude that FRBs are of extra-galactic origin and that they arise in dense star-forming regions. The challenge with extra-galactic models is the the high volumetric rate of FRBs. This high rate allows us to eliminate all models of catastrophic stellar deaths. Hyper-giant flares from young magnetars emerge as the most likely progenitors. Some of the consequences are: (i) Intergalactic FRB models can be safely ignored. (ii) The rich ISM environment of young magnetars can result in significant contribution to DM, Rotation Measure (RM) and in some cases to significant free-free optical depth. (iii) The star-forming regions in the host galaxies can contribute signi...

  7. SDSS quasars in the WISE preliminary data release and quasar candidate selection with the optical/infrared colors

    CERN Document Server

    Wu, Xue-Bing; Jia, Zhendong; Zhang, Yanxia; Peng, Nanbo

    2012-01-01

    We present a catalog of 37842 quasars in the Sloan Digital Sky Survey (SDSS) Data Release 7, which have counterparts within 6$"$ in the Wide-field Infrared Survey Explorer (WISE) Preliminary Data Release. The overall WISE detection rate of the SDSS quasars is 86.7%, and it decreases to less than 50.0% when the quasar magnitude is fainter than $i=20.5$. We derive the median color-redshift relations based on this SDSS-WISE quasar sample and apply them to estimate the photometric redshifts of the SDSS-WISE quasars. We find that by adding the WISE W1 and W2-band data to the SDSS photometry we can increase the photometric redshift reliability, defined as the percentage of sources with the photometric and spectroscopic redshift difference less than 0.2, from 70.3% to 77.2%. We also obtain the samples of WISE detected normal and late-type stars with SDSS spectroscopy, and present a criterion in the $z-W1$ vs. $g-z$ color-color diagram, $z-W1>0.66(g-z)+2.01$, to separate quasars from stars. With this criterion we can...

  8. THE z = 5 QUASAR LUMINOSITY FUNCTION FROM SDSS STRIPE 82

    International Nuclear Information System (INIS)

    We present a measurement of the Type I quasar luminosity function at z = 5 using a large sample of spectroscopically confirmed quasars selected from optical imaging data. We measure the bright end (M1450 2, then extend to lower luminosities (M1450 2 of deep, coadded imaging in the SDSS Stripe 82 region (the celestial equator in the Southern Galactic Cap). The faint sample includes 14 quasars with spectra obtained as ancillary science targets in the SDSS-III Baryon Oscillation Spectroscopic Survey, and 59 quasars observed at the MMT and Magellan telescopes. We construct a well-defined sample of 4.7 1450*∼-27). The bright-end slope is steep (β ∼1450 < –26) from z = 5 to z = 6 than from z = 4 to z = 5, suggesting a more rapid decline in quasar activity at high redshift than found in previous surveys. Our model for the quasar luminosity function predicts that quasars generate ∼30% of the ionizing photons required to keep hydrogen in the universe ionized at z = 5.

  9. Properties of optically selected BL Lac candidates from the SDSS

    CERN Document Server

    Kügler, S D; Heidt, J; Esser, J; Schultz, T

    2014-01-01

    \\textbf{Context.} Deep optical surveys open the avenue for find large numbers of BL Lac objects that are hard to identify because they lack the unique properties classifying them as such. While radio or X-ray surveys typically reveal dozens of sources, recent compilations based on optical criteria alone have increased the number of BL Lac candidates considerably. However, these compilations are subject to biases and may contain a substantial number of contaminating sources. \\textbf{Aims.} In this paper we extend our analysis of 182 optically selected BL Lac object candidates from the SDSS with respect to an earlier study. The main goal is to determine the number of bona fide BL Lac objects in this sample. \\textbf{Methods.} We examine their variability characteristics, determine their broad-band radio-UV SEDs, and search for the presence of a host galaxy. In addition we present new optical spectra for 27 targets with improved S/N with respect to the SDSS spectra. \\textbf{Results.} At least 59% of our targets h...

  10. Radio OH Observations of Recent Bright Comets from Arecibo

    Science.gov (United States)

    Lovell, Amy J.; Howell, Ellen S.

    2014-11-01

    We obtained OH spectra of recent comets with the Arecibo 305m radiotelescope. C/2012 X1 LINEAR was observed between 03 November 2013 and 13 January 2014, C/2014 E2 Jacques on 14 dates between 10 May and 31 July 2014, and C/2012 K1 PANSTARRS on 12 dates between 16 June and 23 August 2014. Spectra at 1667 and 1665 MHz (18cm wavelength) were obtained with an on-sky beam size of 2.9 arcminutes, mapping 7 positions of the OH within 4 arcminutes of the nucleus when the coma is sufficiently large. Radio OH spectra are seen via a Λ-doublet, with the excitation of the lines depending on the heliocentric velocity of the comet. We interpret the spectra via a Monte Carlo model, taking into account the OH inversion predictions of Despois et al. (1981) or Schleicher & A'Hearn (1988). In highly productive comets, high densities thermalize the lines, reducing the line strength near the nucleus. Models of mapping observations can directly constrain the radius within which quenching is active, and thus yield a more accurate estimate of the gas production rate, while radio observations at high spectral resolution place excellent constraints on the gas outflow velocity whether or not the coma is resolved. We present gas production rates, quenching radius estimates and outflow velocities for comets C/2012 X1 LINEAR, C/2014 E2 Jacques and C/2012 K1 PANSTARRS. Near its noteworthy sungrazing perihelion, comet C/2012 S1 ISON presented too small a gas coma for mapping observations, so we present only estimated gas production rates and outflow velocities for these unresolved observations.

  11. Orbital Properties of the Arecibo Micrometeoroids at Earth Interception

    Science.gov (United States)

    Janches, D.; Meisel, D. D.; Mathews, J. D.

    2001-04-01

    Using the Arecibo Observatory (AO) 430-MHz Radar we have developed a Doppler technique to measure very precise micrometeor instantaneous velocities directly from the meteor head echo. In addition, a large number of the observed meteoroids show deceleration. With the velocity, the deceleration, and the assumptions of a spherical shape and a mean micrometeoroid mass density, we have obtained estimates of in-atmosphere particle sizes. The size estimate, the MSIS model atmosphere, and the measured deceleration are used to obtain the meteor extra-atmospheric speeds, assuming these particles undergo little mass-loss prior to and during the time we detect them (Janches et al. 2000b, Icarus145, 53-63). Orbital elements at 1 AU are presented and discussed. These results have not been corrected for perturbation effects such as radiation pressure, Poynting-Robertson drag, attraction by the giant planets, and photoelectric charging effects. So far, over 7700 detections obtained during November 1997 and 3500 during the November 1998 observation campaigns have been analyzed. The observing periods included the Leonids meteor shower, but none of the orbits are recently derived from it. Out of these detections, we present details of over 1500 orbits with eccentricities less than unity. These orbits show (a) a depletion of postperihelion particles with small perihelion distance, suggesting the possibility of collisional and thermal destruction, and (b) an enhancement of particles with perihelia in the zone between Mercury and Venus. Also discussed are 40 β-meteoroids (with radii less than 0.5 μm) dynamically related to the elliptical orbit population with q<0.7 AU. We interpret the latter results on the basis of Poynting-Robertson drag and the electromagnetic resonant effects proposed by G. E. Morfill and E. Grün (1979, Planet. Space Sci.27, 1269-1282). Comparison with previous data sets indicates that most of the AO micrometeoroid orbits are well randomized and that association

  12. Improved Spectrophotometric Calibration of the SDSS-III BOSS Quasar Sample

    OpenAIRE

    Margala, Daniel; Kirkby, David; Dawson, Kyle; Bailey, Stephen; Blanton, Michael; Schneider, Donald P.

    2015-01-01

    We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) and describe the correction procedure we have developed and applied to this sample. Calibration errors are primarily due to atmospheric differential refraction and guiding offsets during each exposure. The corrections potentially reduce the systematics for any studies of BOSS quasars, includi...

  13. Seasonal dependence of MSTIDs obtained from 630.0 nm airglow imaging at Arecibo

    Science.gov (United States)

    Martinis, C.; Baumgardner, J.; Wroten, J.; Mendillo, M.

    2010-06-01

    All-sky imaging data of 630.0 nm airglow emissions are used to study the seasonal and solar activity dependence of medium-scale traveling ionospheric disturbances (MSTIDs) over Arecibo, Puerto Rico (18.3° N, 66.7° W, 28° N mag lat). MSTIDs are typical F-region signatures at midlatitudes, yet limited statistical results in the American sector hindered the progress in our understanding of these dynamical structures. This study compiles data from 2002 to 2007 and shows for the first time that optically-determined MSTIDs at Arecibo present a semiannual pattern with peak occurrence at both solstices. In the Japanese longitude sector, a similar pattern has been found, but one with a main peak during local summer. This paper explains the high occurrence rate during local winter at Arecibo via E-layer/F-layer coupling and inter-hemispheric coupling, thus accounting for a consistent morphology between the two longitude sectors.

  14. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Modeling the clustering and halo occupation distribution of BOSS-CMASS galaxies in the Final Data Release

    CERN Document Server

    Rodríguez-Torres, Sergio A; Chuang, Chia-Hsun; Guo, Hong; Klypin, Anatoly; Behroozi, Peter; Hahn, Chang Hoon; Comparat, Johan; Yepes, Gustavo; Montero-Dorta, Antonio D; Brownstein, Joel R; Maraston, Claudia; McBride, Cameron K; Tinker, Jeremy; Gottlöber, Stefan; Favole, Ginevra; Shu, Yiping; Kitaura, Francisco-Shu; Bolton, Adam; Scoccimarro, Román; Samushia, Lado; Schlegel, David; Schneider, Donald P; Thomas, Daniel

    2015-01-01

    We present a study of the clustering and halo occupation distribution of BOSS CMASS galaxies in the redshift range 0.43 < z < 0.7 drawn from the Final SDSS-III Data Release. We compare the BOSS results with the predictions of a halo abundance matching (HAM) clustering model that assigns galaxies to dark matter halos selected from the large BigMultiDark N-body simulation of a flat $\\Lambda$CDM Planck cosmology. We compare the observational data with the simulated ones on a light-cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fiber collisions are included in the model, which reproduces within 1-$\\sigma$ errors the observed monopole of the 2-point correlation function at all relevant scales{: --} from the smallest scales, 0.5 $h^{-1}$Mpc , up to scales beyond the Baryonic Acoustic Oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to $k\\sim1$ $h$ Mpc$^{-1}$), and the three...

  15. The Data Release of the Sloan Digital Sky Survey-II Supernova Survey

    DEFF Research Database (Denmark)

    Sako, Masao; Bassett, Bruce; C. Becker, Andrew;

    2014-01-01

    This paper describes the data release of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey conducted between 2005 and 2007. Light curves, spectra, classifications, and ancillary data are presented for 10,258 variable and transient sources discovered through repeat ugriz imaging of SDSS S...

  16. The Arecibo Remote Command Center: Undergraduates and High School Students Exploring Astrophysics

    Science.gov (United States)

    Miller, Andy; Jenet, F.; Price, R. H.; Rodriguez-Zermeno, A.; Creighton, T. D.; Benacquista, M.; Guerrero-miller, A.; Romano, J. D.; Quetschke, V.

    2013-01-01

    The University of Texas-Brownsville (UTB) is home to the Arecibo Remote Command Center (ARCC). The ARCC is a virtual control room where researchers and undergraduate students—and local high school students—control in real time the Arecibo Observatory—the world’s largest single dish radio telescope. This poster presents a general outline of ARCC programs and recent accomplishments—including pulsar discoveries, construction of our own telescope array named the Low Frequency All Sky Monitor (LoFASM), the graduation of our first cohort of ARCC Scholars, and the establishment of the Center for Advanced Radio Astronomy (CARA).

  17. The rate of stellar tidal disruption flares from SDSS data

    Directory of Open Access Journals (Sweden)

    van Velzen S.

    2012-12-01

    Full Text Available We have searched for flares due to the tidal disruption of stars by supermassive black holes in archival Sloan Digital Sky Survey (SDSS multi-epoch imaging data. Our pipeline takes advantage of the excellent astrometry of SDSS to separate nuclear flares from supernovae. The 10 year baseline and the high cadence of the observations facilitate a clear-cut identification of variable active galactic nuclei. We found 186 nuclear flares, of which two are strong stellar tidal disruption flare (TDF candidates. To compute the rate of these events, we simulated our entire pipeline to obtain the efficiency of detection for a given light curve. We compute a model-independent upper limit to the TDF rate of Ṅ < 3 × 10−4 yr−1galaxy−1 (90% CL. Using a simple model to extrapolate the observed light curve forward and backward in time, we find our best-estimate of the rate: Ṅ = 3-3+5 × 10−5 yr−1galaxy−1.

  18. The Alignment effect of brightest cluster galaxies in the SDSS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Rita S.J.; Annis, Jim; Strauss, Michael A.; Lupton, Robert H.; Bahcall, Neta A.; Gunn, James E.; Kepner, Jeremy V.; Postman, Marc

    2001-10-01

    One of the most vital observational clues for unraveling the origin of Brightest Cluster Galaxies (BCG) is the observed alignment of the BCGs with their host cluster and its surroundings. We have examined the BCG-cluster alignment effect, using clusters of galaxies detected from the Sloan Digital Sky Survey (SDSS). We find that the BCGs are preferentially aligned with the principal axis of their hosts, to a much higher redshift (z >~ 0.3) than probed by previous studies (z <~ 0.1). The alignment effect strongly depends on the magnitude difference of the BCG and the second and third brightest cluster members: we find a strong alignment effect for the dominant BCGs, while less dominant BCGs do not show any departure from random alignment with respect to the cluster. We therefore claim that the alignment process originates from the same process that makes the BCG grow dominant, be it direct mergers in the early stage of cluster formation, or a later process that resembles the galactic cannibalism scenario. We do not find strong evidence for (or against) redshift evolution between 0SDSS cluster catalogs, which will provide us with better statistics for systematic investigations of the alignment with redshift, richness and morphology of both the cluster and the BCG.

  19. SDSS Observations of Kuiper Belt Objects: Colors and Variability

    CERN Document Server

    Ofek, Eran O

    2012-01-01

    Colors of Trans Neptunian Objects (TNOs) are used to study the evolutionary processes of bodies in the outskirts of the Solar System, and to test theories regarding their origin. Here I describe a search for serendipitous Sloan Digital Sky Survey (SDSS) observations of known TNOs and Centaurs. I present a catalog of SDSS photometry, colors and astrometry of 388 measurements of 42 outer Solar-System objects. I find a weak evidence, at the ~2-sigma level (per trial), for a correlation between the g-r color and inclination of scattered disk objects and hot classical KBOs. I find a correlation between the g-r color and the angular momentum in the z direction of all the objects in this sample. Light curves as a function of phase angle are constructed for 13 objects. The steepness of the slopes of these light curves suggests that the coherent backscatter mechanism plays a major role in the reflectivity of outer Solar-System small objects at small phase angles. I find a weak evidence for an anti-correlation, signifi...

  20. Census of blue stars in SDSS DR8

    CERN Document Server

    Scibelli, Samantha; Carlin, Jeffrey L; Yanny, Brian

    2014-01-01

    We present a census of the 12,060 spectra of blue objects ($(g-r)_0<-0.25$) in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). As part of the data release, all of the spectra were cross-correlated with 48 template spectra of stars, galaxies and QSOs to determine the best match. We compared the blue spectra by eye to the templates assigned in SDSS DR8. 10,856 of the objects matched their assigned template, 170 could not be classified due to low signal-to-noise (S/N), and 1034 were given new classifications. We identify 7458 DA white dwarfs, 1145 DB white dwarfs, 273 rarer white dwarfs (including carbon, DZ, DQ, and magnetic), 294 subdwarf O stars, 648 subdwarf B stars, 679 blue horizontal branch stars, 1026 blue stragglers, 13 cataclysmic variables, 129 white dwarf - M dwarf binaries, 36 objects with spectra similar to DO white dwarfs, 179 QSOs, and 10 galaxies. We provide two tables of these objects, sample spectra that match the templates, figures showing all of the spectra that were grouped by ...

  1. Vertical Mining of SDSS Spectra - Constraining Dust Extinction

    Science.gov (United States)

    Poznanski, Dovi; Prochaska, J. X.; Bloom, J. S.; Baron, D.

    2013-01-01

    Dust extinction is most likely the leading systematic uncertainty in current cosmological and astrophysical measurements. By both absorbing and reddening radiation, it impedes distance and color measurements, as well as biasing any method that relies on statistics of samples. In a recent publication, we took about a million spectra from the Sloan Digital Sky Survey (SDSS), and used them in a novel way. Every object in SDSS is observed through the gas and dust in the Milky Way. While a single spectrum does not offer the signal to noise to recover this imprint, stacking many of them recovers the signature in absorption. We stacked thousands of spectra with a similar expected extinction (as derived from the maps of Schlegel et al. 1998). Our approach allowed us to beat down the ample noise and original signal from every source, recovering just the imprint of the Galaxy’s ISM with very high signal-to-noise. We showed that there is indeed a strong correlation between the sodium lines and extinction, and that high resolution spectra have the potential to leverage this correlation well. We will further show additional results using the methods.

  2. Mapping stellar content to dark matter halos using galaxy clustering and galaxy-galaxy lensing in the SDSS DR7

    CERN Document Server

    Zu, Ying

    2015-01-01

    The mapping between the distributions of the observed galaxy stellar mass and the underlying dark matter halos provides the crucial link from theories of large-scale structure formation to interpreting the complex phenomena of galaxy formation and evolution. We develop a novel statistical method, based on the Halo Occupation Distribution model (HOD), to solve for this mapping by jointly fitting the galaxy clustering and the galaxy-galaxy lensing measured from the Sloan Digital Sky Survey (SDSS). The method, called the iHOD model, extracts maximum information from the survey by including ~80% more galaxies than the traditional HOD methods, and takes into account the incompleteness of the stellar mass samples in a statistically consistent manner. The derived stellar-to-halo mass relation not only explains the clustering and lensing of SDSS galaxies over almost four decades in stellar mass, but also successfully predicts the stellar mass functions observed in SDSS. Due to its capability of modelling significantl...

  3. Spectral Energy Distributions of SDSS Blazars

    Indian Academy of Sciences (India)

    H. Z. Li; L. E. Chen

    2014-09-01

    We compiled the radio, optical and X-ray data for SDSS sample, and presented broad band spectral index. The broad band energy distribution reveals that FSRQs and LBLs objects have similar spectral properties. However, HBLs have a separate distinct property. Even so, a unified scheme was also revealed from colour–colour diagram.

  4. The Arecibo Remote Command Center: Involving Students in Major Astronomical Research

    Science.gov (United States)

    Miller, Andy; Rodriguez-Zermeno, A.; Jenet, F.

    2006-12-01

    At the Center for Gravitational Wave Astronomy (CGWA) at the University of Texas-Brownsville (UTB), we are developing the first Arecibo Remote Command Center (ARCC). The ARCC will be a virtual control room where researchers and students will control the world’s largest single dish radio telescope at the Arecibo observatory. Web cams at Arecibo and digital projectors in the ARCC will provide students with a visually spectacular view of the instrument as they control it. Projections of instrument readouts and monitor screens will give controllers a virtual view of what is happening at Arecibo from the ARCC in Brownsville. Students and research scientists of all levels will be working together in teams to perform actual observations and data analysis. In this talk we describe the current implementation of the ARCC project, plans for student research, prototype projects conducted by students during summer of 2006, recent achievements and successes of student participants, and future plans for the establishment of the ARCC program as an ongoing enterprise.

  5. The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Min-Su; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Falco, Emilio E.; Broadhurst, Tom; Gunn, James E.

    2008-09-30

    We present the first result of a survey for strong galaxy-galaxy lenses in Sloan Digital Sky Survey (SDSS) images. SDSS J082728.70+223256.4 was selected as a lensing candidate using selection criteria based on the color and positions of objects in the SDSS photometric catalog. Follow-up imaging and spectroscopy showed this object to be a lensing system. The lensing galaxy is an elliptical at z = 0.349 in a galaxy cluster. The lensed galaxy has the spectrum of a post-starburst galaxy at z = 0.766. The lensing galaxy has an estimated mass of {approx} 1.2 x 10{sup 12} M{sub {circle_dot}} and the corresponding mass to light ratio in the B-band is {approx} 26 M{sub {circle_dot}}/L{sub {circle_dot}} inside 1.1 effective radii of the lensing galaxy. Our study shows how catalogs drawn from multi-band surveys can be used to find strong galaxy-galaxy lenses having multiple lens images. Our strong lensing candidate selection based on photometry-only catalogs will be useful in future multi-band imaging surveys such as SNAP and LSST.

  6. The Sloan Digital Sky Survey Data Transfer Infrastructure

    Science.gov (United States)

    Weaver, Benjamin A.; Blanton, Michael R.; Brinkmann, Jon; Brownstein, Joel R.; Stauffer, Fritz

    2015-04-01

    The Sloan Digital Sky Survey (SDSS) has been active for approximately 15 years as of this writing. SDSS continues to produce large amounts of data, effectively daily. SDSS needs an effective system for data transfer and management that can operate essentially free of human intervention. In 2008, with the commencement of the third phase of SDSS, SDSS-III, new needs and opportunities motivated a fresh look at the data transfer infrastructure. We have constructed and are releasing a Python package, transfer, that contains all the automation needed for daily data transfer operations. This package has been tested and used successfully for several years. Significant portions of this code will continue to be used as SDSS transitions to its fourth phase, SDSS-IV.

  7. Capability of Quasar Selection by Combining the SCUSS and SDSS Observations

    CERN Document Server

    Zou, Hu; Zhou, Xu; Wang, Shu; Jiang, Linhua; Fan, Xiaohui; Fan, Zhou; Jiang, Zhaoji; Jing, Yipeng; Lesser, Michael; Li, Cheng; Ma, Jun; Nie, Jundan; Shen, Shiyin; Wang, Jiali; Wu, Zhenyu; Zhang, Tianmeng; Zhou, Zhimin

    2015-01-01

    The South Galactic Cap $u$-band Sky Survey (SCUSS) provides a deep $u$-band imaging of about 5000 deg$^2$ in south Galactic cap. It is about 1.5 mag deeper than the SDSS $u$-band. In this paper we evaluate the capability of quasar selection using both SCUSS and SDSS data, based on considerations of the deep SCUSS $u$-band imaging and two-epoch $u$-band variability. We find that the combination of the SCUSS $u$-band and the SDSS $griz$ band allows us to select more faint quasars and more quasars at redshift around 2.2 than the selection only with the SDSS $ugriz$ data. Quasars have significant $u$-band variabilities. The fraction of quasars with large two-epoch variability is much higher than that of stars. The selection by variability can select both low-redshift quasars with ultraviolet excess and mid-redshift ($2 < z <3.5$) quasars where quasar selection by optical colors is inefficient. The above two selections are complementary and make full use of the SCUSS u-band advantages.

  8. Orbital periods of cataclysmic variables identified by the SDSS. VII. Four new eclipsing systems

    CERN Document Server

    Southworth, John; Gansicke, B T; Pyrzas, S

    2009-01-01

    We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital periods. The light curves of three of the eclipsing systems are also analysed using the LCURVE code, and their mass ratios and orbital inclinations determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 +/- 0.0008 min, making it a useful object with which to investigate the evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a period of 131.2432 +/- 0.0014 min and is probably magnetic. The white dwarf ingress and egress phases are very deep and short, and there is no clear evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 +/- 0.4 and 93.6 +/- 0.5 min and mass ratios of 0.14 +/- 0.03 and 0.17 +/- 0.03, respectively. Their eclipses have w...

  9. On the Nature of the Apparent Ring Galaxy SDSS J075234.33+292049.8

    CERN Document Server

    Brosch, Noah; Moiseev, Alexei; Pustilnik, Simon A

    2009-01-01

    (abridged) An object classified as a galaxy in on-line data bases and revealed on sky survey images as a distant ring galaxy is a rare case of polar ring galaxy where the ring is only slightly inclined to the equatorial plane of the central body. SDSS imaging indicates that the diameter of the ring is about 36 kpc. The SDSS data was combined with long-slit spectroscopic observations and with Fabry-Perot Interferometer H-beta mapping obtained at the Russian Academy of Sciences 6-m telescope. We derived the complex morphologies of this presumed ring galaxy from a combination of SDSS images and from the kinematical behaviour of the central body and of the ring, and determined the stellar population compositions of the two components from SDSS colours, spectroscopy, and evolutionary stellar synthesis models. The ring metallicity is slightly under-abundant. The total luminosity and the total mass of the system are not extreme, but the rather high M/L~20 indicates the presence of large amounts of dark matter. Two a...

  10. Finishing and Commissioning the New Arecibo HF Facility

    Science.gov (United States)

    Sulzer, M. P.; Gonzalez, S. A.

    2011-12-01

    The imminent completion of the major tasks in the construction of the New Arecibo HF facility means that we must verify that the components are working as intended. The antenna system and the transmitters must be separately commissioned before they can be connected together so that we an be sure it will provide 83 dbW at 8.175 MHz, and 80 dbW at 5.1 MHz. The antenna system will be ready for initial testing in September. It Illuminates the 305 meter dish using dipoles near the surface of the dish transmitting upward to a wire mesh sub-reflector. There are three crossed dipoles for each of the two frequencies. The dipoles are supported on towers mounted on concrete pads underneath the dish. Each dipole element is connected to a transmitter through a three inch coax line. The tower foundations are nearly complete, and the towers will be erected in early September, and we expect to have at least one crossed dipole in place for initial testing by the end of September. We will need to make some measurements on the antenna system to ensure that it meets our requirements. One requirement is to match the antenna impedance to the transmission line and the transmitter closely enough to meet the transmitter specifications, the closer, the better. We have additional requirements; for example, it is necessary for efficient use of the facility that the polarization be close to circular. In most experiments, we want O mode excitation. If we were to transmit linear only half the power would reach the reflection height. The symmetry of the system assures that most of the conditions for achieving accurate circular polarization are met, but one condition is not: that exciting the transmitters driving the orthogonal elements at 90 degrees assures 90 degree separation in the corresponding antenna currents. One of the dipoles of each pair points toward the center of the array. If we think of the three crossed dipoles as consisting of a reference and two that are excited relative to it

  11. COMPARING H{alpha} AND H I SURVEYS AS MEANS TO A COMPLETE LOCAL GALAXY CATALOG IN THE ADVANCED LIGO/VIRGO ERA

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, Brian D. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08542 (United States); Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Berger, Edo, E-mail: bmetzger@astro.princeton.edu, E-mail: kaplan@uwm.edu, E-mail: eberger@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-02-20

    Identifying the electromagnetic counterparts of gravitational wave (GW) sources detected by upcoming networks of advanced ground-based interferometers will be challenging, due in part to the large number of unrelated astrophysical transients within the {approx}10-100 deg{sup 2} sky localizations. A potential way to greatly reduce the number of such false positives is to limit detailed follow-up to only those candidates near galaxies within the GW sensitivity range of {approx}200 Mpc for binary neutron star mergers. Such a strategy is currently hindered by the fact that galaxy catalogs are grossly incomplete within this volume. Here, we compare two methods for completing the local galaxy catalog: (1) a narrowband H{alpha} imaging survey and (2) an H I emission line radio survey. Using H{alpha} fluxes, stellar masses (M {sub *}), and star formation rates (SFRs) from galaxies in the Sloan Digital Sky Survey (SDSS), combined with H I data from the GALEX Arecibo SDSS Survey and the Herschel Reference Survey, we estimate that an H{alpha} survey with a luminosity sensitivity of L {sub H{alpha}} = 10{sup 40} erg s{sup -1} at 200 Mpc could achieve a completeness of f {sup H{alpha}} {sub SFR} Almost-Equal-To 75% with respect to total SFR, but only f{sub M* Star-Operator }{sup H{alpha}} approx. 33% with respect to M {sub *} (due to lack of sensitivity to early-type galaxies). These numbers are significantly lower than those achieved by an idealized spectroscopic survey due to the loss of H{alpha} flux resulting from resolving out nearby galaxies and the inability to correct for the underlying stellar continuum. An H I survey with sensitivity similar to the proposed WALLABY survey on ASKAP could achieve f{sub SFR}{sup H{sub I}} Almost-Equal-To 80% and f{sub M Star-Operator }{sup H{sub I}} Almost-Equal-To 50%, somewhat higher than that of the H{alpha} survey. Finally, both H{alpha} and H I surveys should achieve {approx}> 50% completeness with respect to the host galaxies of

  12. The milky way tomography with sdss

    Energy Technology Data Exchange (ETDEWEB)

    Juric, Mario; Ivezic, Zeljko; Brooks, Alyson; Lupton, Robert H.; Schlegel, David; Finkbeiner, Douglas; Padmanabhan, Nikhil; Bond, Nicholas; Rockosi, Constance M.; Knapp,; Gunn, James E.; Sumi, Takahiro; Schneider, Donald; Barentine, J.C.; Brewington, Howard J.; Brinkmann, J.; Fukugita, Masataka; Harvanek, Michael; Kleinman, S.J.; Krzesinski, Jurek; Long, Dan; /Princeton U. Observ. /Washington U., Seattle, Astron. Dept. /Princeton U. /Penn State U., Astron. Astrophys. /Apache Point Observ. /Tokyo U., ICRR

    2005-10-01

    Using the photometric parallax method, we estimate the distances to {approx}48 million stars detected by the Sloan Digital Sky Survey (SDSS), and map their three-dimensional number density distribution in the Galaxy. The currently available data sample the distance range from 100 pc to 15 kpc and cover 6,500 deg{sup 2} of sky, mostly at high galactic latitudes (|b| > 25). These stellar number density maps allow an investigation of the Galactic structure without any a priori assumptions about its components. The data show strong evidence for a Galaxy consisting of an oblate halo, disk components, and a number of localized overdensities. The number density distribution of stars in the Solar neighborhood (D < 1.5kpc) favors a model having a ''thin'' and a ''thick'' exponential disk, with scale heights and lengths of H{sub 1} {approx} 280 pc and L{sub 1} {approx} 2400pc, and H{sub 2} {approx} 1200pc and L{sub 2} {approx} 3500pc, respectively, and local thick-to-thin disk normalization {rho}{sub thick} (R{sub {circle_dot}})/{rho}{sub thin}(R{sub {circle_dot}}) = 4%. Fits applied to the entire dataset are significantly more uncertain due to the presence of clumps and overdensities. The halo power law index is very poorly constrained, but we find an oblate halo with c/a {approx} 0.5 to be strongly preferred. While roughly consistent with this simple model, the measured density distribution shows a number of statistically significant deviations from the model predictions. In addition to known features, such as the Monoceros stream, a remarkable density enhancement covering over a thousand square degrees of sky is detected towards the constellation of Virgo, at distances of {approx} 5-15 kpc. Compared to counts in a region symmetric with respect to the l = 0 line and with the same Galactic latitude, it is responsible for a factor of 2 number density excess, and may be a nearby tidal stream or a low-surface brightness dwarf galaxy

  13. Cosmological Constraints from the SDSS Luminous Red Galaxies

    CERN Document Server

    Tegmark, M; Strauss, M; Weinberg, D; Blanton, M; Frieman, J A; Fukugita, M; Gunn, J; Hamilton, A; Knapp, G; Nichol, R; Ostriker, J; Padmanabhan, N; Percival, W; Schlegel, D J; Schneider, D; Scoccimarro, R; Seljak, U; Seo, H; Swanson, M; Szalay, A S; Vogeley, M; Yoo, J; Zehavi, I; Abazajian, Kevork N; Anderson, S; Annis, J; Bahcall, Neta A; Bassett, B; Berlind, A; Brinkmann, J; Budavari, T; Castander, F; Connolly, A; Csabai, I; Doi, M; Finkbeiner, D; Gillespie, B; Glazebrook, K; Hennessy, G; Hogg, D; Ivezic, Z; Jain, B; Johnston, D; Kent, S; Lamb, D; Lee, B; Lin, H; Loveday, J; Lupton, R; Munn, J A; Pan, K; Park, C; Peoples, John; Pier, J; Pope, A; Richmond, M; Rockosi, C M; Scranton, R; Sheth, R; Stebbins, A; Stoughton, C; Szapudi, I; Tucker, D; Vanden Berk, Daniel E; Yanny, B; York, D

    2006-01-01

    We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01h/Mpc 0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial.

  14. Feature importance for machine learning redshifts applied to SDSS galaxies

    CERN Document Server

    Hoyle, Ben; Zitlau, Roman; Steiz, Stella; Weller, Jochen

    2014-01-01

    We present an analysis of importance feature selection applied to photometric redshift estimation using the machine learning architecture Random Decision Forests (RDF) with the ensemble learning routine Adaboost. We select a list of 85 easily measured (or derived) photometric quantities (or 'features') and spectroscopic redshifts for almost two million galaxies from the Sloan Digital Sky Survey Data Release 10. After identifying which features have the most predictive power, we use standard artificial Neural Networks (aNN) to show that the addition of these features, in combination with the standard magnitudes and colours, improves the machine learning redshift estimate by 18% and decreases the catastrophic outlier rate by 32%. We further compare the redshift estimate from RDF using the ensemble learning routine Adaboost with those from two different aNNs, and with photometric redshifts available from the SDSS. We find that the RDF requires orders of magnitude less computation time than the aNNs to obtain a m...

  15. Automated Morphological Classification of SDSS Red Sequence Galaxies

    CERN Document Server

    Cheng, Judy Y; Simard, Luc; Graves, Genevieve J; Lopez, Eric D; Yan, Renbin; Cooper, Michael C

    2010-01-01

    (abridged) In the last decade, the advent of enormous galaxy surveys has motivated the development of automated morphological classification schemes to deal with large data volumes. Existing automated schemes can successfully distinguish between early and late type galaxies and identify merger candidates, but are inadequate for studying detailed morphologies of red sequence galaxies. To fill this need, we present a new automated classification scheme that focuses on making finer distinctions between early types roughly corresponding to Hubble types E, S0, and Sa. We visually classify a sample of 984 non-starforming SDSS galaxies with apparent sizes >14". We then develop an automated method to closely reproduce the visual classifications, which both provides a check on the visual results and makes it possible to extend morphological analysis to much larger samples. We visually classify the galaxies into three bulge classes (BC) by the shape of the light profile in the outer regions: discs have sharp edges and ...

  16. First measurement of gravitational lensing by cosmic voids in SDSS

    CERN Document Server

    Melchior, Peter; Sheldon, Erin S; Krause, Elisabeth; Wandelt, Benjamin D

    2013-01-01

    We report the first measurement of the diminutive lensing signal arising from matter underdensities associated with cosmic voids. While undetectable individually, by stacking the weak gravitational shear estimates around 901 voids detected in SDSS DR7 by Sutter et al. (2012b), we find substantial evidence for a depression of the lensing signal compared to the cosmic mean. This depression is most pronounced at the void radius, in agreement with analytical models of void matter profiles. Even with the largest void sample and imaging survey available today, we cannot put useful constraints on the radial dark-matter void profile. We invite independent investigations of our findings by releasing data and analysis code to the public at https://github.com/pmelchior/void-lensing.

  17. Oxygen Abundance Methods in SDSS: View from Modern Statistics

    Indian Academy of Sciences (India)

    Fei Shi; Gang Zhao; James Wicker

    2010-09-01

    Our purpose is to find which is the most reliable one among various oxygen abundance determination methods. We will test the validity of several different oxygen abundance determination methods using methods of modern statistics. These methods include Bayesian analysis and information scoring. We will analyze a sample of ∼ 6000 HII galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release four. All methods that we used drew the same conclusion that the method is a more reliable oxygen abundance determination method than the Bayesian metallicity method under the existing telescope ability. The ratios of the likelihoods between the different kinds of methods tell us that the , , and 32 methods are consistent with each other because the and 32 methods are calibrated by method. The Bayesian and 23 methods are consistent with each other because both are calibrated by a galaxy model. In either case, the 2 method is an unreliable method.

  18. VizieR Online Data Catalog: Halo red giants from the SEGUE survey (Martell+, 2011)

    Science.gov (United States)

    Martell, S. L.; Smolinski, J. P.; Beers, T. C.; Grebel, E. K.

    2011-09-01

    Table 1 lists SDSS identifiers, astrometry and photometry, stellar parameters and survey name for 2519 stars observed as part of the SDSS-II/SEGUE-1 and SDSS-III/SEGUE-2 surveys. The stars in this table were selected as red giants with halo-like metallicities (-1.8bandstrength indices, CN bandstrength class, absolute r magnitudes, heliocentric and Galactocentric distances, and survey name, for the same stars as in Table 1. (2 data files).

  19. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling the clustering and halo occupation distribution of BOSS CMASS galaxies in the Final Data Release

    Science.gov (United States)

    Rodríguez-Torres, Sergio A.; Chuang, Chia-Hsun; Prada, Francisco; Guo, Hong; Klypin, Anatoly; Behroozi, Peter; Hahn, Chang Hoon; Comparat, Johan; Yepes, Gustavo; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Maraston, Claudia; McBride, Cameron K.; Tinker, Jeremy; Gottlöber, Stefan; Favole, Ginevra; Shu, Yiping; Kitaura, Francisco-Shu; Bolton, Adam; Scoccimarro, Román; Samushia, Lado; Schlegel, David; Schneider, Donald P.; Thomas, Daniel

    2016-08-01

    We present a study of the clustering and halo occupation distribution of Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies in the redshift range 0.43 relation for the CMASS sample measured using weak lensing in the Canada-France-Hawaii Telescope Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1σ. The BigMD-BOSS light cone including properties of BOSS galaxies and halo properties is made publicly available.

  20. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Measuring D_A and H at z=0.57 from the Baryon Acoustic Peak in the Data Release 9 Spectroscopic Galaxy Sample

    OpenAIRE

    Anderson, Lauren; Mena Requejo, Olga

    2013-01-01

    We present measurements of the angular diameter distance to and Hubble parameter at z = 0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264 283 galaxies over 3275 square degrees in the redshift range 0.43 

  1. Variability-based AGN selection using image subtraction in the SDSS and LSST era

    OpenAIRE

    Choi, Yumi; Gibson, Robert R.; Becker, Andrew C.; Ivezić, Željko; Connolly, Andrew J.; MacLeod, Chelsea L.; Ruan, John J.; Anderson, Scott F

    2013-01-01

    With upcoming all sky surveys such as LSST poised to generate a deep digital movie of the optical sky, variability-based AGN selection will enable the construction of highly-complete catalogs with minimum contamination. In this study, we generate $g$-band difference images and construct light curves for QSO/AGN candidates listed in SDSS Stripe 82 public catalogs compiled from different methods, including spectroscopy, optical colors, variability, and X-ray detection. Image differencing excels...

  2. A DESCRIPTION OF QUASAR VARIABILITY MEASURED USING REPEATED SDSS AND POSS IMAGING

    International Nuclear Information System (INIS)

    We provide a quantitative description and statistical interpretation of the optical continuum variability of quasars. The Sloan Digital Sky Survey (SDSS) has obtained repeated imaging in five UV-to-IR photometric bands for 33,881 spectroscopically confirmed quasars. About 10,000 quasars have an average of 60 observations in each band obtained over a decade along Stripe 82 (S82), whereas the remaining ∼25,000 have 2-3 observations due to scan overlaps. The observed time lags span the range from a day to almost 10 years, and constrain quasar variability at rest-frame time lags of up to 4 years, and at rest-frame wavelengths from 1000 Å to 6000 Å. We publicly release a user-friendly catalog of quasars from the SDSS Data Release 7 that have been observed at least twice in SDSS or once in both SDSS and the Palomar Observatory Sky Survey, and we use it to analyze the ensemble properties of quasar variability. Based on a damped random walk (DRW) model defined by a characteristic timescale and an asymptotic variability amplitude that scale with the luminosity, black hole mass, and rest wavelength for individual quasars calibrated in S82, we can fully explain the ensemble variability statistics of the non-S82 quasars such as the exponential distribution of large magnitude changes. All available data are consistent with the DRW model as a viable description of the optical continuum variability of quasars on timescales of ∼5-2000 days in the rest frame. We use these models to predict the incidence of quasar contamination in transient surveys such as those from the Palomar Transient Factory and Large Synoptic Survey Telescope.

  3. Estimation of stellar atmospheric parameters from SDSS/SEGUE spectra

    Science.gov (United States)

    Re Fiorentin, P.; Bailer-Jones, C. A. L.; Lee, Y. S.; Beers, T. C.; Sivarani, T.; Wilhelm, R.; Allende Prieto, C.; Norris, J. E.

    2007-06-01

    We present techniques for the estimation of stellar atmospheric parameters (T_eff, log~g, [Fe/H]) for stars from the SDSS/SEGUE survey. The atmospheric parameters are derived from the observed medium-resolution (R = 2000) stellar spectra using non-linear regression models trained either on (1) pre-classified observed data or (2) synthetic stellar spectra. In the first case we use our models to automate and generalize parametrization produced by a preliminary version of the SDSS/SEGUE Spectroscopic Parameter Pipeline (SSPP). In the second case we directly model the mapping between synthetic spectra (derived from Kurucz model atmospheres) and the atmospheric parameters, independently of any intermediate estimates. After training, we apply our models to various samples of SDSS spectra to derive atmospheric parameters, and compare our results with those obtained previously by the SSPP for the same samples. We obtain consistency between the two approaches, with RMS deviations on the order of 150 K in T_eff, 0.35 dex in log~g, and 0.22 dex in [Fe/H]. The models are applied to pre-processed spectra, either via Principal Component Analysis (PCA) or a Wavelength Range Selection (WRS) method, which employs a subset of the full 3850-9000Å spectral range. This is both for computational reasons (robustness and speed), and because it delivers higher accuracy (better generalization of what the models have learned). Broadly speaking, the PCA is demonstrated to deliver more accurate atmospheric parameters when the training data are the actual SDSS spectra with previously estimated parameters, whereas WRS appears superior for the estimation of log~g via synthetic templates, especially for lower signal-to-noise spectra. From a subsample of some 19 000 stars with previous determinations of the atmospheric parameters, the accuracies of our predictions (mean absolute errors) for each parameter are T_eff to 170/170 K, log~g to 0.36/0.45 dex, and [Fe/H] to 0.19/0.26 dex, for methods (1

  4. The SDSS spectroscopic catalogue of white dwarf-main-sequence binaries: new identifications from DR 9-12

    Science.gov (United States)

    Rebassa-Mansergas, A.; Ren, J. J.; Parsons, S. G.; Gänsicke, B. T.; Schreiber, M. R.; García-Berro, E.; Liu, X.-W.; Koester, D.

    2016-06-01

    We present an updated version of the spectroscopic catalogue of white dwarf-main-sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS). We identify 938 WDMS binaries within the data releases (DR) 9-12 of SDSS plus 40 objects from DR 1-8 that we missed in our previous works, 646 of which are new. The total number of spectroscopic SDSS WDMS binaries increases to 3294. This is by far the largest and most homogeneous sample of compact binaries currently available. We use a decomposition/fitting routine to derive the stellar parameters of all systems identified here (white dwarf effective temperatures, surface gravities and masses, and secondary star spectral types). The analysis of the corresponding stellar parameter distributions shows that the SDSS WDMS binary population is seriously affected by selection effects. We also measure the Na I λλ 8183.27, 8194.81 absorption doublet and H α emission radial velocities (RV) from all SDSS WDMS binary spectra identified in this work. 98 objects are found to display RV variations, 62 of which are new. The RV data are sufficient enough to estimate the orbital periods of three close binaries.

  5. The SDSS spectroscopic catalogue of white dwarf-main sequence binaries: new identifications from DR9-12

    CERN Document Server

    Rebassa-Mansergas, A; Parsons, S G; Gaensicke, B T; Schreiber, M R; Garcia-Berro, E; Liu, X -W; Koester, D

    2016-01-01

    We present an updated version of the spectroscopic catalogue of white dwarf-main sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS). We identify 939 WDMS binaries within the data releases (DR) 9-12 of SDSS plus 40 objects from DR 1-8 that we missed in our previous works, 646 of which are new. The total number of spectroscopic SDSS WDMS binaries increases to 3294. This is by far the largest and most homogeneous sample of compact binaries currently available. We use a decomposition/fitting routine to derive the stellar parameters of all systems identified here (white dwarf effective temperatures, surface gravities and masses, and secondary star spectral types). The analysis of the corresponding stellar parameter distributions shows that the SDSS WDMS binary population is seriously affected by selection effects. We also measure the NaI 8183.27, 8194.81 absorption doublet and Halpha emission radial velocities (RV) from all SDSS WDMS binary spectra identified in this work. 98 objects are found to di...

  6. Robust Machine Learning Applied to Astronomical Datasets I: Star-Galaxy Classification of the SDSS DR3 Using Decision Trees

    CERN Document Server

    Ball, N M; Myers, A D; Tcheng, D; Ball, Nicholas M.; Brunner, Robert J.; Myers, Adam D.; Tcheng, David

    2006-01-01

    We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that these star/galaxy classifications are expected to be reliable for approximately 22 million objects with r < ~20. The general machine learning environment Data-to-Knowledge and supercomputing resources enabled extensive investigation of the decision tree parameter space. This work presents the first public release of objects classified in this way for an entire SDSS data release. The objects are classified as either galaxy, star or nsng (neither star nor galaxy), with an associated probability for each class. To demonstrate how to effectively make use of these classifications, we perform several important tests. First, we detail selection criteria within the probability space defined by the three classes to extract samples of stars and galaxies to a given completeness an...

  7. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling the clustering and halo occupation distribution of BOSS CMASS galaxies in the Final Data Release

    Science.gov (United States)

    Rodríguez-Torres, Sergio A.; Chuang, Chia-Hsun; Prada, Francisco; Guo, Hong; Klypin, Anatoly; Behroozi, Peter; Hahn, Chang Hoon; Comparat, Johan; Yepes, Gustavo; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Maraston, Claudia; McBride, Cameron K.; Tinker, Jeremy; Gottlöber, Stefan; Favole, Ginevra; Shu, Yiping; Kitaura, Francisco-Shu; Bolton, Adam; Scoccimarro, Román; Samushia, Lado; Schlegel, David; Schneider, Donald P.; Thomas, Daniel

    2016-08-01

    We present a study of the clustering and halo occupation distribution of Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies in the redshift range 0.43 baryon acoustic oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to k ˜ 1 h Mpc-1), and the three-point correlation function. The quadrupole of the correlation function presents some tensions with observations. We discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. We compare the stellar-to-halo mass relation for the CMASS sample measured using weak lensing in the Canada-France-Hawaii Telescope Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1σ. The BigMD-BOSS light cone including properties of BOSS galaxies and halo properties is made publicly available.

  8. The micrometeoroid mass flux into the upper atmosphere: Arecibo results and a comparison with prior estimates

    Science.gov (United States)

    Mathews, J. D.; Janches, D.; Meisel, D. D.; Zhou, Q.-H.

    Radar micrometeor observations at Arecibo Observatory have enabled direct estimates of the meteoroid mass flux into the upper atmosphere. We report mass flux determinations from November 1997/1998 observations that are based on the observed number of meteor events per day in the 300-m diameter Arecibo beam and on particle mass determinations from that fraction of all particles for which deceleration is measured. The average mass of the Arecibo micrometeoroids that manifest observable deceleration is ˜0.32/0.76 µgm/particle with a resultant annual whole-Earth mass flux of 1.6 × 106/2.7 × 106 kg/yr over the ˜10-5-10² µgm mass range for 1997/1998, respectively. The annual whole-earth mass flux per decade of particle mass is calculated and compared with that of Ceplecha et al. [1998] (3.7 × 106 kg/yr) and with that derived by Love and Brownlee [1993] (LB) from small particle impact craters on the orbital Long Duration Exposure Facility (LDEF). We also give the LDEF results as significantly modified using the Arecibo-determined average particle velocity of ˜50 km/sec—much larger than the effective value of 12 km/sec used by LB. This modification results in a net LDEF mass flux of 1.8×106 kg/yr—7% of the value we determined from reanalysis of the LB data using their original 12 km/sec mean impact speed. These results may provoke some debate.

  9. The intrinsic shape of galaxies in SDSS/Galaxy Zoo

    Science.gov (United States)

    Rodríguez, Silvio; Padilla, Nelson D.

    2013-09-01

    By modelling the axis ratio distribution of Sloan Digital Sky Survey (SDSS) Data Release 8 galaxies, we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of shapes, while taking into account dust extinction. We measure the dust extinction of the full sample of spiral galaxies and find a smaller value than previous estimations, with an edge-on extinction of E_0 = 0.284^{+0.015}_{-0.026} in the SDSS r band. We also find that the distribution of minor to major axis ratio has a mean value of 0.267 ± 0.009, slightly larger than previous estimates mainly due to the lower extinction used; the same affects the circularity of galactic discs, which are found to be less round in shape than in previous studies, with a mean ellipticity of 0.215 ± 0.013. For elliptical galaxies, we find that the minor to major axis ratio, with a mean value of 0.584 ± 0.006, is larger than previous estimations due to the removal of spiral interlopers present in samples with morphological information from photometric profiles. These interlopers are removed when selecting ellipticals using Galaxy Zoo data. We find that the intrinsic shapes of galaxies and their dust extinction vary with absolute magnitude, colour and physical size. We find that bright elliptical galaxies are more spherical than faint ones, a trend that is also present with galaxy size, and that there is no dependence of elliptical galaxy shape with colour. For spiral galaxies, we find that the reddest ones have higher dust extinction as expected, due to the fact that this reddening is mainly due to dust. We also find that the thickness of discs increases with luminosity and size, and that brighter, smaller and redder galaxies have less round discs.

  10. Photometric Separation of Stellar Properties Using SDSS Filters

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, D.D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Newberg, H.J. [Fermi National Accelerator Laboratory, Kirk Road and Pine Street, Batavia, IL 60510 (United States); Rosner, R. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Richards, G.T. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Stoughton, C. [Fermi National Accelerator Laboratory, Kirk Road and Pine Street, Batavia, IL 60510 (United States)

    1998-12-01

    Using synthetic photometry of Kurucz model spectra, we explore the colors of stars as a function of temperature, metallicity, and surface gravity with Sloan Digital Sky Survey (SDSS) filters, {ital u}{prime}{ital g}{prime}{ital r}{prime}{ital i}{prime}{ital z}{prime}. The synthetic colors show qualitative agreement with the few published observations in these filters. We find that the locus of synthetic stars is basically two-dimensional for 4500 {lt} {ital T} {lt} 8000 K, which precludes simultaneous color separation of the three basic stellar characteristics we consider. Colors including {ital u}{prime} contain the most information about normal stellar properties; measurements in this filter are also important for selecting white dwarfs. We identify two different subsets of the locus in which the loci separate by either metallicity or surface gravity. For 0.5 {lt} {ital g}{prime} {minus} {ital r}{prime} {lt} 0.8 (corresponding roughly to G stars), the locus separates by metallicity; for photometric error of a few percent, we estimate metallicity to within {approximately}0.5 dex in this range. In the range {minus}0.15 {lt} {ital g}{prime} {minus} {ital r}{prime} {lt} 0.00 (corresponding roughly to A stars), the locus shows separation by surface gravity. In both cases, we show that it is advantageous to use more than two colors when determining stellar properties by color. Strategic observations in SDSS filters are required to resolve the source of a {approximately}5{percent} discrepancy between synthetic colors of Gunn-Stryker stars, Kurucz models, and external determinations of the metallicities and surface gravities. The synthetic star colors can be used to investigate the properties of any normal star and to construct analytic expressions for the photometric prediction of stellar properties in special cases. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

  11. The Arecibo Remote Command Center: Inspiring the Next Generation of Astrophysicists

    Science.gov (United States)

    Jenet, Fredrick; Miller, A.; Rodriguez-Zermeno, A.; Stovall, K.; van Straten, W.

    2007-12-01

    At the Center for Gravitational Wave Astronomy at the University of Texas-Brownsville (UTB) we have developed the first Arecibo Remote Command Center (ARCC). The ARCC is a virtual control room where researchers and students from the high school level and higher have real time control of the world's largest single dish radio telescope at the Arecibo observatory. Here we give an overview of the project and the progress made over the past year. Several notable accomplishments include 1) the direct involvement of high school students in the PALFA pulsar search project at the Arecibo Observatory; 2) the first remote observations conducted with the Parkes Observatory in New South Wales, Australia; 3) development of a web-based pulsar search interface which students have used to identify potential pulsar candidates; 4) completion of the ARCC room facility at the UTB campus, a state of the art professionally designed room that looks like the bridge of a starship; 5) building the second ARCC project at the University of Wisconsin-Milwaukee (ARCC@UWM).

  12. The Arecibo Remote Command Center: Creating an Inspiring Environment for Astrophysics

    Science.gov (United States)

    Miller, Andy F.; Jenet, F. A.; Zermeno, A.; Stovall, K.

    2009-01-01

    At the Center for Gravitational Wave Astronomy at the University of Texas-Brownsville (UTB) we have developed the first Arecibo Remote Command Center (ARCC). The ARCC is a virtual control room where researchers and students from the high school level and higher have real time control of the world's largest single dish radio telescope at the Arecibo observatory. Here we give an overview of the project and the progress made over the past four years. Several notable accomplishments include: 1) the direct involvement of high school students in the PALFA pulsar search project at the Arecibo Observatory; 2) development of a web-based pulsar search interface which students have used to identify potential pulsar candidates; 3) completion of the ARCC room facility at the UTB campus, a state of the art room that looks like the bridge of a starship; 4) establishment of the ARCC Scholars_a program that provides undergraduate physics majors at UTB the opportunity to specialize in astrophysics and begin research early in their careers.

  13. SDSS J102347.6+003841: A Millisecond Radio Pulsar Binary That Had A Hot Disk

    CERN Document Server

    Wang, Zhongxiang; Thorstensen, John R; Kaspi, Victoria M; Lorimer, Duncan R; Stairs, Ingrid; Ransom, Scott M

    2009-01-01

    The Sloan Digital Sky Survey (SDSS) source J102347.6+003841 is a binary star with a 4.75 hr orbital period. A recent radio pulsar survey showed that its primary is a millisecond pulsar (MSP). Here we analyze the SDSS spectrum of the source in detail. The spectrum was taken on 2001 February 1, when the source was in a bright state and showed broad, double-peaked hydrogen and helium lines -- dramatically different from the G-type absorption spectrum seen from 2003 onward. The lines are consistent with emission from a disk around the compact primary. We derive properties of the disk by fitting the SDSS continuum with a simple disk model, and find a temperature range of 2000--34000 K from the outer to inner edge of the disk. The disk inner and outer radii were approximately 10^9 and 5.7x10^10 cm, respectively. These results further emphasize the unique feature of the source: it is evidently a system at the beginning of its life as a recycled radio pulsar. The disk mass is estimated to have been ~10^23 g, most of ...

  14. Globular and Open Clusters Observed by SDSS/SEGUE: the Giant Stars

    CERN Document Server

    Morrison, Heather L; Clem, James L; An, Deokkeun; Connor, Thomas; Schechtman-Rook, Andrew; Harding, Paul; Casagrande, Luca; Rockosi, Constance; Yanny, Brian; Beers, Timothy C; Johnson, Jennifer A; Schneider, Donald P

    2015-01-01

    We present griz observations for the clusters M92, M13 and NGC 6791 and gr photometry for M71, Be 29 and NGC 7789. In addition we present new membership identifications for all these clusters, which have been observed spectroscopically as calibrators for the SDSS/SEGUE survey; this paper focuses in particular on the red giant branch stars in the clusters. In a number of cases, these giants were too bright to be observed in the normal SDSS survey operations, and we describe the procedure used to obtain spectra for these stars. For M71, also present a new variable reddening map and a new fiducial for the gr giant branch. For NGC 7789, we derived a transformation from Teff to g-r for giants of near solar abundance, using IRFM Teff measures of stars with good ugriz and 2MASS photometry and SEGUE spectra. The result of our analysis is a robust list of known cluster members with correctly dereddened and (if needed) transformed gr photometry for crucial calibration efforts for SDSS and SEGUE.

  15. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:Baryon Acoustic Oscillations in the correlation function of LOWZ and CMASS galaxies in Data Release 12

    OpenAIRE

    Cuesta, Antonio J.; Vargas-Magaña, Mariana; Beutler, Florian; Bolton, Adam S.; Brownstein, Joel R.; Eisenstein, Daniel J.; Gil-Marín, Héctor; Ho, Shirley; McBride, Cameron K.; Maraston, Claudia; Padmanabhan, Nikhil; Percival, Will J.; Reid, Beth A.; Ross, Ashley J.; Ross, Nicholas P.

    2016-01-01

    AJC and LV are supported by supported by the European Research Council under the European Community's Seventh Framework Programme FP7-IDEAS-Phys.LSS 240117. Funding for this work was partially provided by the Spanish MINECO under projects AYA2014-58747-P and MDM-2014-0369 of ICCUB (Unidad de Excelencia ‘María de Maeztu’). The Science, Technology and Facilities Council is acknowledged for support through the Survey Cosmology and Astrophysics consolidated grant, ST/I001204/1. We present dist...

  16. Properties of galaxies in SDSS Quasar environments at z < 0.2

    CERN Document Server

    Coldwell, G V; Coldwell, Georgina V.; Lambas, Diego G.

    2006-01-01

    We analyse the environment of low redshift, z < 0.2, SDSS quasars using the spectral and photometric information of galaxies from the Sloan Digital Sky Survey Third Data Release (SDSS-DR3). We compare quasar neighbourhoods with field and high density environments through an analysis on samples of typical galaxies and groups. We compute the surrounding surface number density of galaxies finding that quasar environments systematically avoid high density regions. Their mean environments correspond to galaxy density enhancements similar to those of typical galaxies. We have also explored several galaxy properties in these environments, such as spectral types, specific star formation rates, concentration indexes, colours and active nuclei activity. We conclude that low redshift quasar neighbourhoods (r_p < 1 Mpc h^-1, Delta V < 500 km/s) are populated by bluer and more intense star forming galaxies of disk-type morphology than galaxies in groups and in the field. Although star formation activity is though...

  17. Satellite Galaxy Velocity Dispersions in the SDSS and Modified Gravity Models

    Directory of Open Access Journals (Sweden)

    John W. Moffat

    2014-05-01

    Full Text Available The Sloan Digital Sky Survey (SDSS provides data on several hundred thousand galaxies. The precise location of these galaxies in the sky, along with information about their luminosities and line-of-sight (Doppler velocities, allows one to construct a three-dimensional map of their location and estimate their line-of-sight velocity dispersion. This information, in principle, allows one to test dynamical gravity models, specifically models of satellite galaxy velocity dispersions near massive hosts. A key difficulty is the separation of true satellites from interlopers. We sidestep this problem by not attempting to derive satellite galaxy velocity dispersions from the data, but instead incorporate an interloper background into the mathematical models and compare the result to the actual data. We find that due to the presence of interlopers, it is not possible to exclude several gravitational theories on the basis of the SDSS data.

  18. Spectral Variability of Quasar SDSS J030639.57+000343.1

    Indian Academy of Sciences (India)

    Hengxiao Guo; Minfeng Gu

    2014-09-01

    In a sample of 60 quasars selected from the Sloan Digital Sky Survey (SDSS) with at least six-epoch spectroscopy, we investigated the variability of emission lines and continuum luminosity. In this paper, we present the results of SDSS J030639.57+000343.1. We found a strong anticorrelation between the continuum luminosity at 5100 Å and the spectral index, implying a bluer-when-brighter trend. The luminosity of the broad line is in proportion to the continuum luminosity at 5100 Å. Correspondingly, we did not find a strong correlation between the equivalent width of broad and the continuum luminosity, i.e. no Baldwin effect of broad in this source.

  19. Physical properties of galaxies: toward a consistent comparison between hydrodynamical simulations and SDSS

    CERN Document Server

    Guidi, Giovanni; Walcher, C Jakob; Gallazzi, Anna

    2016-01-01

    We study the effects of applying observational techniques to derive the properties of simulated galaxies, with the aim of making an unbiased comparison between observations and simulations. For our study, we used fifteen galaxies simulated in a cosmological context using three different feedback and chemical enrichment models, and compared their z=0 properties with data from the Sloan Digital Sky Survey (SDSS). We show that the physical properties obtained directly from the simulations without post-processing can be very different to those obtained mimicking observational techniques. In order to provide simulators a way to reliably compare their galaxies with SDSS data, for each physical property that we studied - colours, magnitudes, gas and stellar metallicities, mean stellar ages and star formation rates - we give scaling relations that can be easily applied to the values extracted from the simulations. These scalings have in general a high correlation, except for the galaxy mean stellar ages and gas oxyge...

  20. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Measuring D_A and H at z=0.57 from the Baryon Acoustic Peak in the Data Release 9 Spectroscopic Galaxy Sample

    CERN Document Server

    Anderson, Lauren; Bailey, Stephen; Beutler, Florian; Bolton, Adam S; Brinkmann, J; Brownstein, Joel R; Chuang, Chia-Hsun; Cuesta, Antonio J; Dawson, Kyle S; Eisenstein, Daniel J; Honscheid, Klaus; Kazin, Eyal A; Kirkby, David; Manera, Marc; McBride, Cameron K; Mena, O; Nichol, Robert C; Olmstead, Matthew D; Padmanabhan, Nikhil; Palanque-Delabrouille, N; Percival, Will J; Prada, Francisco; Ross, Ashley J; Ross, Nicolas P; Sanchez, Ariel G; Samushia, Lado; Schlegel, David J; Schneider, Donald P; Seo, Hee-Jong; Strauss, Michael A; Thomas, Daniel; Tinker, Jeremy L; Tojeiro, Rita; Verde, Licia; Weinberg, David H; Xu, Xiaoying; Yeche, Christophe

    2013-01-01

    We present measurements of the angular diameter distance to and Hubble parameter at z=0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264,283 galaxies over 3275 square degrees in the redshift range 0.43

  1. SDSS-IV MaNGA: Data Products, Quality, and Initial Public Release

    Science.gov (United States)

    Law, David R.; Cherinka, Brian; MaNGA Team

    2016-01-01

    As a spectroscopic imaging survey, MaNGA presents a host of technical challenges ranging from spectrophotometic calibration to image reconstruction. I will present an overview of the MaNGA data reduction pipeline (DRP) and the algorithms used to process the MaNGA data. Additionally, I will describe the format and quality of the MaNGA data products, and the means by which the first year of survey data will be made publicly available in SDSS Data Release 13 (DR-13).

  2. The Milky Way Tomography with SDSS. 2. Stellar Metallicity

    Energy Technology Data Exchange (ETDEWEB)

    Ivezic, Zeljko; /Washington U., Seattle; Sesar, Branimir; /Washington U., Seattle; Juric, Mario; /Princeton, Inst. Advanced Study; Bond, Nicholas; /Princeton U.; Dalcanton, Julianne; /Washington U., Seattle; Rockosi, Constance M.; /UC, Santa Cruz; Yanny, Brian; /Fermilab; Newberg, Heidi J.; /Rensselaer Poly.; Beers, Timothy C.; /Michigan State U.; Prieto, Carlos Allende; /Texas U.; Wilhelm, Ron; /Texas Tech. /Michigan State U.

    2008-04-01

    In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is producing a massive spectroscopic database which already contains over 280,000 stellar spectra. Using effective temperature and metallicity derived from SDSS spectra for {approx}60,000 F and G type main sequence stars (0.2 < g-r < 0.6), we develop polynomial models, reminiscent of traditional methods based on the UBV photometry, for estimating these parameters from the SDSS u-g and g-r colors. These estimators reproduce SDSS spectroscopic parameters with a root-mean-square scatter of 100 K for effective temperature, and 0.2 dex for metallicity (limited by photometric errors), which are similar to random and systematic uncertainties in spectroscopic determinations. We apply this method to a photometric catalog of coadded SDSS observations and study the photometric metallicity distribution of {approx}200,000 F and G type stars observed in 300 deg{sup 2} of high Galactic latitude sky. These deeper (g < 20.5) and photometrically precise ({approx}0.01 mag) coadded data enable an accurate measurement of the unbiased metallicity distribution for a complete volume-limited sample of stars at distances between 500 pc and 8 kpc. The metallicity distribution can be exquisitely modeled using two components with a spatially varying number ratio, that correspond to disk and halo. The best-fit number ratio of the two components is consistent with that implied by the decomposition of stellar counts profiles into exponential disk and power-law halo components by Juric et al. (2008). The two components also possess the kinematics expected for disk and halo stars. The metallicity of the halo component can be modeled as a spatially invariant Gaussian distribution with a mean of [Fe/H] = -1.46 and a standard deviation of {approx}0.3 dex. The disk metallicity distribution is non-Gaussian, with a remarkably small scatter (rms {approx}0.16 dex) and the median smoothly decreasing with distance

  3. SDSS-IV/MaNGA: Spectrophotometric Calibration Technique

    CERN Document Server

    Yan, Renbin; Bershady, Matthew A; Law, David R; Schlegel, David J; Bundy, Kevin; Drory, Niv; MacDonald, Nicholas; Bizyaev, Dmitry; Blanc, Guillermo A; Blanton, Michael R; Cherinka, Brian; Eigenbrot, Arthur; Gunn, James E; Harding, Paul; Hogg, David W; Sánchez-Gallego, José R; Sánchez, Sebastian F; Wake, David A; Weijmans, Anne-Marie; Xiao, Ting; Zhang, Kai

    2015-01-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV (SDSS-IV), is an integral-field spectroscopic (IFS) survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2 arcsec fibers to obtain resolved spectroscopy over a wide wavelength range of 3,600-10,300A. To map the internal variations within each galaxy, we need to perform accurate {\\it spectral surface photometry}, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to v...

  4. Magnetic White Dwarfs from the SDSS. The First Data Release

    CERN Document Server

    Schmidt, G D

    2003-01-01

    Beyond its goals related to the extragalactic universe, the Sloan Digital Sky Survey (SDSS) is an effective tool for identifying stellar objects with unusual spectral energy distributions. Here we report on the 53 new magnetic white dwarfs discovered during the first two years of the survey, including 38 whose data are made public in the 1500 square-degree First Data Release. Discoveries span the magnitude range 16.3 3 MG and g > 15. The new objects nearly double the total number of known magnetic white dwarfs, and include examples with polar field strengths B > 500 MG as well as several with exotic atmospheric compositions. The improved sample statistics and uniformity indicate that the distribution of magnetic white dwarfs has a broad peak in the range ~5-30 MG and a tail extending to nearly 10^9 G. Degenerates with polar fields B > 50 MG are consistent with being descendents of magnetic Ap/Bp main-sequence stars, but low- and moderate-field magnetic white dwarfs appear to imply another origin. Yet-undetec...

  5. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: double-probe measurements from BOSS galaxy clustering \\& Planck data -- towards an analysis without informative priors

    CERN Document Server

    Pellejero-Ibanez, Marcos; Rubiño-Martín, J A; Cuesta, Antonio J; Wang, Yuting; Zhao, Gong-bo; Ross, Ashley J; Rodríguez-Torres, Sergio; Prada, Francisco; Slosar, Anže; Vazquez, Jose A; Alam, Shadab; Beutler, Florian; Eisenstein, Daniel J; Gil-Marín, Héctor; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Percival, Will J; Rossi, Graziano; Salazar-Albornoz, Salvador; Samushia, Lado; Sánchez, Ariel G; Satpathy, Siddharth; Seo, Hee-Jong; Tinker, Jeremy L; Tojeiro, Rita; Vargas-Magaña, Mariana; Brownstein, Joel R; Nichol, Robert C; Olmstead, Matthew D

    2016-01-01

    We develop a new methodology called double-probe analysis with the aim of minimizing informative priors in the estimation of cosmological parameters. We extract the dark-energy-model-independent cosmological constraints from the joint data sets of Baryon Oscillation Spectroscopic Survey (BOSS) galaxy sample and Planck cosmic microwave background (CMB) measurement. We measure the mean values and covariance matrix of $\\{R$, $l_a$, $\\Omega_b h^2$, $n_s$, $log(A_s)$, $\\Omega_k$, $H(z)$, $D_A(z)$, $f(z)\\sigma_8(z)\\}$, which give an efficient summary of Planck data and 2-point statistics from BOSS galaxy sample, where $R=\\sqrt{\\Omega_m H_0^2}\\,r(z_*)$, and $l_a=\\pi r(z_*)/r_s(z_*)$, $z_*$ is the redshift at the last scattering surface, and $r(z_*)$ and $r_s(z_*)$ denote our comoving distance to $z_*$ and sound horizon at $z_*$ respectively. The advantage of this method is that we do not need to put informative priors on the cosmological parameters that galaxy clustering is not able to constrain well, i.e. $\\Omega_b...

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the correlation function of LOWZ and CMASS galaxies in Data Release 12

    Science.gov (United States)

    Cuesta, Antonio J.; Vargas-Magaña, Mariana; Beutler, Florian; Bolton, Adam S.; Brownstein, Joel R.; Eisenstein, Daniel J.; Gil-Marín, Héctor; Ho, Shirley; McBride, Cameron K.; Maraston, Claudia; Padmanabhan, Nikhil; Percival, Will J.; Reid, Beth A.; Ross, Ashley J.; Ross, Nicholas P.; Sánchez, Ariel G.; Schlegel, David J.; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Verde, Licia; White, Martin

    2016-04-01

    We present distance scale measurements from the baryon acoustic oscillation signal in the constant stellar mass and low-redshift sample samples from the Data Release 12 of the Baryon Oscillation Spectroscopic Survey. The total volume probed is 14.5 Gpc3, a 10 per cent increment from Data Release 11. From an analysis of the spherically averaged correlation function, we infer a distance to z = 0.57 of D_V(z)r^fid_d/r_d = 2028± 21 Mpc and a distance to z = 0.32 of D_V(z)r^fid_d/r_d = 1264± 22 Mpc assuming a cosmology in which r^fid_d = 147.10 Mpc. From the anisotropic analysis, we find an angular diameter distance to z = 0.57 of D_A(z)r^fid_d/r_d = 1401± 21 Mpc and a distance to z = 0.32 of 981 ± 20 Mpc, a 1.5 and 2.0 per cent measurement, respectively. The Hubble parameter at z = 0.57 is H(z)r_d/r^fid_d = 100.3± 3.7 km s-1 Mpc-1 and its value at z = 0.32 is 79.2 ± 5.6 km s-1 Mpc-1, a 3.7 and 7.1 per cent measurement, respectively. These cosmic distance scale constraints are in excellent agreement with a Λ cold dark matter model with cosmological parameters released by the recent Planck 2015 results.

  7. Recovering isolated galaxies from large scale surveys: problems and strategies

    CERN Document Server

    Santander-Vela, Juan de Dios; Verdes-Montenegro, Lourdes

    2009-01-01

    The large survey programs being performed nowadays, being the SDSS their flagship, provide us with morphological parameters which allow for extraction of large galaxy samples. We will analyze the methodology for obtaining an AMIGA-like catalogue of isolated galaxies from the SDSS DR5 photometric catalogue of galaxy objects, together with the roadblocks found in the process, and suggested workarounds.

  8. An unobscured type II quasar candidate: SDSS J012032.19-005501.9

    International Nuclear Information System (INIS)

    We report the finding of an unobscured type II active galactic nucleus (AGN) candidate, SDSS J012032.19-005501.9, at a relatively high redshift of 0.601, which shows a number of unusual properties. It varies significantly on timescales of years, typical of type I AGNs, and marginally on timescales of weeks. The color–magnitude relation and the structure function are also consistent with that of type I AGNs, which implies that its variability likely originates from the black hole accretion system. However, no broad emission line (BEL) is detected in the Sloan Digital Sky Survey spectrum, and the upper limit of the equivalent width of the Hβ BEL is much less than that of type I AGNs. These properties suggest that SDSS J012032.19-005501.9 may be an unobscured quasar without intrinsically broad emission lines, namely, an unobscured type II AGN or “true” type II AGN. Furthermore, its continuum luminosity is at least one order of magnitude fainter than the average value over the past century from the [O iii] emission line. This indicates that SDSS J012032.19-005501.9 may be switching off. Additional possible scenarios to explain this intriguing source are also discussed. Future deep observations at multiwavelengths are needed to reveal the nature of this peculiar and intriguing AGN.

  9. An unobscured type II quasar candidate: SDSS J012032.19-005501.9

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Yuan, W.; Komossa, S. [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012 (China); Zhou, H. Y.; Liu, W. J. [Key Laboratory for Research in Galaxies and Cosmology, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Ai, Y. L. [Department of Astronomy, Peking University, Beijing 100871 (China); Boisvert, J. H., E-mail: liye@nao.cas.cn [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2015-02-01

    We report the finding of an unobscured type II active galactic nucleus (AGN) candidate, SDSS J012032.19-005501.9, at a relatively high redshift of 0.601, which shows a number of unusual properties. It varies significantly on timescales of years, typical of type I AGNs, and marginally on timescales of weeks. The color–magnitude relation and the structure function are also consistent with that of type I AGNs, which implies that its variability likely originates from the black hole accretion system. However, no broad emission line (BEL) is detected in the Sloan Digital Sky Survey spectrum, and the upper limit of the equivalent width of the Hβ BEL is much less than that of type I AGNs. These properties suggest that SDSS J012032.19-005501.9 may be an unobscured quasar without intrinsically broad emission lines, namely, an unobscured type II AGN or “true” type II AGN. Furthermore, its continuum luminosity is at least one order of magnitude fainter than the average value over the past century from the [O iii] emission line. This indicates that SDSS J012032.19-005501.9 may be switching off. Additional possible scenarios to explain this intriguing source are also discussed. Future deep observations at multiwavelengths are needed to reveal the nature of this peculiar and intriguing AGN.

  10. The real space clustering of galaxies in SDSS DR7: I. Two point correlation functions

    CERN Document Server

    Shi, Feng; Wang, Huiyuan; Zhang, Youcai; Mo, H J; Bosch, Frank C van den; Li, Shijie; Liu, Chengze; Lu, Yi; Tweed, Dylan; Yang, Lei

    2016-01-01

    Using a method to correct redshift space distortion (RSD) for individual galaxies, we present the measurements of real space two-point correlation functions (2PCFs) of galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7). Galaxy groups selected from the SDSS are used as proxies of dark matter halos to correct the virial motions of galaxies in dark matter halos, and to reconstruct the large-scale velocity field. We use an ensemble of mock catalogs to demonstrate the reliability of our method. Over the range $0.2 < r < 20 h^{-1}{\\rm {Mpc}}$, the 2PCF measured directly in reconstructed real space is better than the measurement error due to cosmic variance, if the reconstruction uses the correct cosmology. Applying the method to the SDSS DR7, we construct a real space version of the main galaxy catalog, which contains 396,068 galaxies in the North Galactic Cap with redshifts in the range $0.01 \\leq z \\leq 0.12$. The Sloan Great Wall, the largest known structure in the nearby Universe, is not...

  11. A Radio Search For Pulsar Companions To SDSS Low-Mass White Dwarfs

    CERN Document Server

    Agueros, Marcel A; Silvestri, Nicole M; Kleinman, S J; Anderson, Scott F; Liebert, James W

    2009-01-01

    We have conducted a search for pulsar companions to 15 low-mass white dwarfs (LMWDs; M < 0.4 M_Sun) at 820 MHz with the NRAO Green Bank Telescope (GBT). These LMWDs were spectroscopically identified in the Sloan Digital Sky Survey (SDSS), and do not show the photometric excess or spectroscopic signature associated with a companion in their discovery data. However, LMWDs are believed to evolve in binary systems and to have either a more massive WD or a neutron star as a companion. Indeed, evolutionary models of low-mass X-ray binaries, the precursors of millisecond pulsars (MSPs), produce significant numbers of LMWDs (e.g., Benvenuto & De Vito 2005), suggesting that the SDSS LMWDs may have neutron star companions. No convincing pulsar signal is detected in our data. This is consistent with the findings of van Leeuwen et al. (2007), who conducted a GBT search for radio pulsations at 340 MHz from unseen companions to eight SDSS WDs (five are still considered LMWDs; the three others are now classified as "...

  12. Death of a cluster: the destruction of M67 as seen by the SDSS

    CERN Document Server

    Davenport, James R A

    2010-01-01

    We probe the spatial and dynamical structure of the old open cluster M67 using photometric data from the Sloan Digital Sky Survey's sixth data release. Making use of an optimal contrast, or matched filter, algorithm, we map the distribution of high probability members of M67. We find an extended and elongated halo of likely members to a radius of nearly 60'. Our measured core radius of Rcore = 8.'24+/-0.'60 is somewhat larger than that of previous estimates. We attribute the larger core radius measurement to the SDSS probing lower mass main sequence stars than has been done before for similar studies of M67, and the exclusion of post main sequence M67 members in the SDSS sample. We estimate the number of M67 members in our SDSS sample to be 1385+/-67 stars. A lower limit on the binary fraction in M67 is measured to be 45%. A higher fraction of binary stars is measured in the core as compared to the halo, and the luminosity function of the core is found to be more depleted of low-mass stars. Thus the halo is c...

  13. VizieR Online Data Catalog: Photometric Classification Catalogue of SDSS DR7 (Abraham+, 2012)

    Science.gov (United States)

    Abraham, S.; Philip, N. S.; Kembhavi, A.; Wadadekar, Y. G.; Sinha, R.

    2012-04-01

    We present a catalogue of about six million unresolved photometric detections in the Sloan Digital Sky Survey (SDSS) Seventh Data Release, classifying them into stars, galaxies and quasars. We use a machine learning classifier trained on a subset of spectroscopically confirmed objects from 14th to 22nd magnitude in the SDSS i band. Our catalogue consists of 2430625 quasars, 3544036 stars and 63586 unresolved galaxies from 14th to 24th magnitude in the SDSS i-band. Our algorithm recovers 99.96 per cent of spectroscopically confirmed quasars and 99.51 per cent of stars to i~21.3 in the colour window that we study. The level of contamination due to data artefacts for objects beyond i=21.3 is highly uncertain and all mention of completeness and contamination in the paper are valid only for objects brighter than this magnitude. However, a comparison of the predicted number of quasars with the theoretical number counts shows reasonable agreement. (2 data files).

  14. A Search for Planetary Nebulae With the SDSS: the outer regions of M31

    CERN Document Server

    Kniazev, A Y; Zucker, D B; Rix, H-W; Martinez-Delgado, D; Snedden, S A

    2013-01-01

    We have developed a method to identify planetary nebula (PN) candidates in imaging data of the Sloan Digital Sky Survey (SDSS). This method exploits the SDSS' five-band sampling of emission lines in PN spectra, which results in a color signature distinct from that of other sources. Selection criteria based on this signature can be applied to nearby galaxies in which PNe appear as point sources. We applied these criteria to the whole area of M31 as scanned by the SDSS, selecting 167 PN candidates that are located in the outer regions of M31. The spectra of 80 selected candidates were then observed with the 2.2m telescope at Calar Alto Observatory. These observations and cross-checks with literature data show that our method has a selection rate efficiency of about 90%, but the efficiency is different for the different groups of PNe candidates. In the outer regions of M31, PNe trace different well-known morphological features like the Northern Spur, the NGC205 Loop, the G1 Clump, etc. In general, the distributi...

  15. Orbital periods of cataclysmic variables identified by the SDSS. VII. Four new eclipsing systems

    Science.gov (United States)

    Southworth, J.; Copperwheat, C. M.; Gänsicke, B. T.; Pyrzas, S.

    2010-02-01

    We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital periods. The light curves of three of the eclipsing systems are also analysed using the lcurve code, and their mass ratios and orbital inclinations determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 ± 0.0008 min, making it a useful object with which to investigate the evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a period of 131.2432 ± 0.0014 min and is probably magnetic. The white dwarf ingress and egress phases are very deep and short, and there is no clear evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 ± 0.4 and 93.6 ± 0.5 min and mass ratios of 0.14 ± 0.03 and 0.17 ± 0.03, respectively. Their eclipses have well-defined white dwarf and bright spot ingress and egress features, making them excellent candidates for detailed study. All four of the orbital periods presented here are shorter than the 2-3 h period gap observed in the known population of cataclysmic variables. The reduced observational data presented in this work are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A100 and at http://www.astro.keele.ac.uk/ jkt/.

  16. Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

    Energy Technology Data Exchange (ETDEWEB)

    Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Chen, Yan-Mei; Wake, David [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States); Bolton, Adam; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Leauthaud, Alexie [Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8582 (Japan); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Skibba, Ramin [Department of Physics, Center for Astrophysics and Space Sciences, University of California, 9500 Gilman Drive, San Diego, CA 92093 (United States); Pan, Kaike, E-mail: beifiori@mpe.mpg.de [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); and others

    2014-07-10

    We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M{sub *} ∼2 × 10{sup 11} M{sub ☉}. We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M{sub dyn}/M{sub *} ∼(1 + z){sup –0.30±0.12}, further strengthening the evidence for an increase of M{sub dyn}/M{sub *} with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

  17. Report of the Committee on the Participation of Women in the Sloan Digital Sky Survey

    Science.gov (United States)

    Myers, Adam D.; Diamond-Stanic, Aleks; Gallagher, John S.; Gillespie, Bruce Andrew; Ho, Shirley; Kinemuchi, Karen; Lucatello, Sara; Lundgren, Britt; Tremonti, Christina A.; Zasowski, Gail; SDSS-III Collaboration, SDSS-IV Collaboration

    2015-01-01

    The Committee on the Participation of Women in the SDSS (CPWS) was formed by the SDSS to evaluate the gender climate within the collaboration. The CPWS seeks to foster gender balance in our collaboration by fielding concerns from our members and by recommending best practices for establishing the SDSS leadership team. An important aspect of the mission of the CPWS is to regularly assess gender diversity and inclusiveness within the SDSS. Against the backdrop of the transition from SDSS-III to SDSS-IV, the CPWS has been collecting data relevant to gender issues through interviews and surveys. In April, 2014, the CPWS surveyed 251 SDSS-IV members (~50% of active membership) regarding gender and leadership. Broad findings from this survey include that the male-to-female ratio in SDSS-IV is about 3:1 and that the male-to-female ratio among those that identify themselves as being in an SDSS-IV leadership role is also close to 3:1. About 35% of those surveyed self-identify as an SDSS-IV "leader," though we recognize the possibility that active stakeholders might be more likely to respond to a demographics survey. About 80% of those that self-identify as leaders consider their leadership role within SDSS-IV to be officially acknowledged, regardless of gender. The fraction of women in SDSS leadership roles appears to be a weak function of current job position in that 6 of 32 (19%) senior faculty that are SDSS leaders are women, compared to 4 of 13 (31%) postdocs. Similarly, the fraction of SDSS leaders who are women is highest (32%) amongst those leaders who received their PhDs 6-10 years ago, while the fraction of female leaders amongst other age demographics is somewhat lower (20%). Although these are small sample sizes, this hints at a trend where women are most likely to fill SDSS leadership roles at certain stages of their lives and careers. The CPWS intends to use this initial survey data to establish a baseline for tracking SDSS-IV demographics, and thus hopes to

  18. Observed diurnal and seasonal behavior of the micrometeor flux using the Arecibo and Jicamarca radars

    Science.gov (United States)

    Janches, D.; Chau, J. L.

    2005-09-01

    In this paper, we present results from meteor head-echo observations using the 430 MHz dual beam Arecibo radar in Puerto Rico and the 50 MHz Jicamarca radar in Peru. We show that the seasonal behavior reflected in the fast component of the micrometeor velocity distributions measured at Arecibo can be well explained by a micrometeor radiant distribution centered at the Earth's apex as measured by Jicamarca Radio Observatory (JRO). We conclude that these radars, as probably every other high power and large aperture radar, detect this micrometeor population that show good agreement with the so-called South and North Apex sources reported by Jones and Brown [1993. Monthly Notices of the Royal Astronomical Society]. However, these radars do not seem to detect particles from any other source reported by those authors. We also showed that in order to explain the diurnal and seasonal behavior of the meteor rate detected at Arecibo, based on the results determined by the Jicamarca radar, a strong atmospheric filtering effect must exist. This effect is produced by the early and higher ablation of micrometeors, which enter the atmosphere a low elevation angles, probably reaching high temperature at higher altitudes and depositing some or all their material before they penetrate deep into the Mesosphere/Lower Thermosphere region. These results explain at some level the missing mass inconsistency raised by the comparison of meteor fluxes derived from satellite and traditional meteor radar observations. They also may be the source of the observed high altitude ions and metallic layers observed by radars and lidars, respectively.

  19. Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

    OpenAIRE

    Janches, D.; Nolan, M. C.; Sulzer, M.

    2004-01-01

    Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO) micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR) meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam and finally seen in...

  20. Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

    OpenAIRE

    Janches, D.; Nolan, M. C.; Sulzer, M.

    2004-01-01

    Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO) micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR) meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam a...

  1. Eigenspectra of the SDSS DR1 quasars

    CERN Document Server

    Yip, C W; Vanden Berk, Daniel E; Ma, Z; Frieman, Joshua A; Subba-Rao, M; Szalay, A S; Yip, Ching-Wa; Connolly, Andrew; Berk, Daniel Vanden; Ma, Zhaoming; Frieman, Joshua; Rao, Mark Subba; Szalay, Alex

    2004-01-01

    We construct eigenspectra from the DR1 quasars in the SDSS using the Karhunen-Lo\\`eve (KL) transform (or Principal Component Analysis, PCA) in different redshift and luminosity bins. We find that the quasar spectra can be classified, by the first two eigenspectra, into a continuous sequence in the variation of the spectral slope. We also find a dependence on redshift and luminosity in the eigencoefficients. The dominant redshift effect is the evolution of the blended Fe~II emission (optical) and the Balmer continuum (the ``small-bump'', $\\lambda_{rest} \\approx 2000-4000$\\AA), while the luminosity effect is related to the Baldwin effect. Correlations among several major broad emission lines are found, including the well-known ``Eigenvector-1''.

  2. Subdwarf O Stars from SDSS and SPY

    OpenAIRE

    Hirsch, H. A.; Heber, U.; O'Toole, S. J.

    2008-01-01

    We present the results of quantitative spectral analysis of sdOs from the SDSS database. Fitting the Balmer, HeI and HeII lines to non-LTE model spectra, we derived their effective temperatures, surface gravities and helium abundances. We find the helium-enriched sdO stars to rally in a small intervall of Teff = 40,000K to 50,000K and log(g) = 5.5 to 6.0. We conclude, that the sdB stars are linked with the helium-deficient sdO stars, i.e. the sdBs are predecessors for the helium-deficient sdO...

  3. Cosmological constraints from the SDSS luminous red galaxies

    International Nuclear Information System (INIS)

    We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01h/Mpcm and the baryon fraction in good agreement with WMAP. Within the context of flat ΛCDM models, our LRG measurements complement WMAP by sharpening the constraints on the matter density, the neutrino density and the tensor amplitude by about a factor of 2, giving Ωm=0.24±0.02 (1σ) (95%) and rtot=1.05±0.05 from WMAP alone to Ωtot=1.003±0.010. Assuming Ωtot=1, the equation of state parameter is constrained to w=-0.94±0.09, indicating the potential for more ambitious future LRG measurements to provide precision tests of the nature of dark energy. All these constraints are essentially independent of scales k>0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial

  4. The Alignment Effect of Brightest Cluster Galaxies in the SDSS

    CERN Document Server

    Kim, R S J; Strauss, M A; Lupton, R H; Bahcall, Neta A; Gunn, J E; Kepner, J V; Postman, M; Kim, Rita S. J.; Annis, Jim; Strauss, Michael A.; Lupton, Robert H.; Bahcall, Neta A.; Gunn, James E.; Kepner, Jeremy V.; Postman, Marc

    2002-01-01

    One of the most vital observational clues for unraveling the origin of Brightest Cluster Galaxies (BCG) is the observed alignment of the BCGs with their host cluster and its surroundings. We have examined the BCG-cluster alignment effect, using clusters of galaxies detected from the Sloan Digital Sky Survey (SDSS). We find that the BCGs are preferentially aligned with the principal axis of their hosts, to a much higher redshift (z >~ 0.3) than probed by previous studies (z <~ 0.1). The alignment effect strongly depends on the magnitude difference of the BCG and the second and third brightest cluster members: we find a strong alignment effect for the dominant BCGs, while less dominant BCGs do not show any departure from random alignment with respect to the cluster. We therefore claim that the alignment process originates from the same process that makes the BCG grow dominant, be it direct mergers in the early stage of cluster formation, or a later process that resembles the galactic cannibalism scenario. We...

  5. M Dwarf Flares from Time-Resolved SDSS Spectra

    CERN Document Server

    Hilton, Eric J; Hawley, Suzanne L; Kowalski, Adam F

    2010-01-01

    We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey using a novel measurement of emission line strength called the Flare Line Index. Each of the ~38,000 M dwarfs in the SDSS low mass star spectroscopic sample of West et al. was observed several times (usually 3-5) in exposures that were typically 9-25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong H-alpha and H-beta emission line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This sug...

  6. The Angular Power Spectra of Photometric SDSS LRGs

    CERN Document Server

    Thomas, Shaun A; Lahav, Ofer

    2010-01-01

    We construct new galaxy angular power spectra based on the extended, updated and final SDSS II Luminous Red Galaxy (LRG) photometric redshift survey: MegaZ DR7. Encapsulating 7746 deg^{2} we utilise 723,556 photometrically determined LRGs between 0.45 < z < 0.65 in a 3.3 (Gpc h^{-1})^3 spherical harmonic analysis of the galaxy distribution. By combining four photometric redshift bins we find preliminary parameter constraints of f_{b} = \\Omega_{b}/\\Omega_{m} = 0.173 +/- 0.046 and \\Omega_{m} = 0.260 +/- 0.035 assuming H_{0} = 75 km s^{-1} Mpc^{-1}, n_{s}=1 and \\Omega_{k} = 0. These limits are consistent with the CMB and the previous data release (DR4). The C_{\\ell} are sensitive to redshift space distortions and therefore we also recast our constraints into a measurement of \\beta ~ \\Omega_{m}^{0.55}/b in different redshift shells. The robustness of these power spectra with respect to a number of potential systematics such as extinction, photometric redshift and ANNz training set extrapolation are examined...

  7. Large SDSS quasar groups and their statistical significance

    CERN Document Server

    Park, Changbom; Einasto, Maret; Lietzen, Heidi; Heinamaki, Pekka

    2015-01-01

    We use a volume-limited sample of quasars in the Sloan Digital Sky Survey (SDSS) DR7 quasar catalog to identify quasar groups and address their statistical significance. This quasar sample has a uniform selection function on the sky and nearly a maximum possible contiguous volume that can be drawn from the DR7 catalog. Quasar groups are identified by using the Friend-of-Friend algorithm with a set of fixed comoving linking lengths. We find that the richness distribution of the richest 100 quasar groups or the size distribution of the largest 100 groups are statistically equivalent with those of randomly-distributed points with the same number density and sky coverage when groups are identified with the linking length of 70 h-1Mpc. It is shown that the large-scale structures like the huge Large Quasar Group (U1.27) reported by Clowes et al. (2013) can be found with high probability even if quasars have no physical clustering, and does not challenge the initially homogeneous cosmological models. Our results are...

  8. Clustering Property of Wolf-Rayet Galaxies in the SDSS

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Xu Kong; Fu-Zhen Cheng

    2008-01-01

    We have analysed, for the first time, the clustering properties of Wolf-Rayet (W-R) galaxies, using a large sample of 846 W-R galaxies selected from the Data Release 4 (DR4) of the Sloan Digital Sky Survey (SDSS). We compute the cross-correlation function between W- R galaxies and a reference sample of galaxies drawn from the DR4. We compare the function to the results for control samples of non-W-R star-forming galaxies that are matched closely in redshift, luminosity, concentration, 4000-A break strength and specific star formation rate (SSFR). On scales larger than a few Mpc, W-R galaxies have almost the same clustering amplitude as the control samples, indicating that W-R galaxies and non-W-R control galax- ies populate dark matter haloes of similar masses. On scales between 0.1-1 h-1 Mpc, W-R galaxies are less clustered than the control samples, and the size of the difference depends on the SSFR. Based on both observational and theoretical considerations, we speculate that this negative bias can be interpreted by W-R galaxies residing preferentially at the centers of their dark matter haloes. We examine the distribution of W-R galaxies more closely using the SDSS galaxy group catalogue of Yang et al., and find that ~82% of our W-R galaxies are the central galaxies of groups, compared to ~74% for the corresponding control galaxies. We find that W-R galaxies are hosted, on average, by dark matter haloes of masses of 1012,3 M☉, compared to 1012,1 M? For centrally-located W-R galaxies and 1012,7 M☉ For satellite ones. We would like to point out that this finding, which provides a direct observational support to our conjecture, is really very crude due to the small number of W-R galaxies and the incom- pleteness of the group catalogue, and needs more work in future with larger samples.

  9. THE LICK/SDSS LIBRARY. II. [Ca/Fe] AND [Mg/Fe] IN F, G, AND K STARS FROM SDSS-DR7

    International Nuclear Information System (INIS)

    We analyzed the spectra of 17,600 F, G, and K stars extracted from the seventh Sloan Digital Sky Survey Data Release (SDSS-DR7) database in order to derive ([α/Fe]), [Ca/Fe], and [Mg/Fe] ratios. Particular attention has been devoted to estimating homogeneous and self-consistent atmospheric parameter values, Teff, log g, and [Fe/H], by comparing synthetic and observational Lick/SDSS indices. We present results for the sub-sample of more than 4000 spectra whose overall quality allowed us to derive fairly accurate stellar atmospheric parameter values and, therefore, reliable abundance ratios. A Monte Carlo approach was adopted to evaluate both the errors in the observational Lick/SDSS indices and in the derived parameter estimates. The analysis of the trends of [Ca/Fe] and [Mg/Fe] versus [Fe/H] pointed out that (1) the [Ca/Fe] and [Mg/Fe] ratios increase with decreasing [Fe/H] with different slopes reaching maximum average levels of +0.25 and +0.40 dex at [Fe/H] ≅ -1.75, respectively; (2) our sample contains, at a given [Fe/H], stars characterized by significantly different amounts of α-enhancement, thus belonging to different Galactic populations; and (3) the analyzed sample shows a predominance of thick disk stars for [Fe/H] > - 0.5 and the presence of stars belonging to the high-αhalo population for -2.0 < [Fe/H] <-0.5.

  10. Environmental dependence of galaxy age in the Main galaxy sample of SDSS DR10

    OpenAIRE

    Deng, Xin-Fa

    2014-01-01

    Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10), I investigate the environmental dependence of galaxy age, and get the same conclusions in two volume-limited Main galaxy samples: old galaxies exist preferentially in the densest regions of the universe, while young galaxies are located preferentially in low density regions. Such an age-density relation is likely a combination of a strong age-stellar mass relation and the stellar mass-den...

  11. ENVIRONMENT AND MASS DEPENDENCIES OF GALACTIC A SPIN PARAMETER: COSMOLOGICAL SIMULATIONS AND SDSS GALAXIES COMPARED

    OpenAIRE

    Cervantes-Sodi, B.; X. Hernández; Ch. Park; Kim, J

    2008-01-01

    Empleamos una muestra de galaxias del Sloan Digital Sky Survey (SDSS) para buscar correlaciones entre el parámetro de espín ¿ y el medio ambiente y la masa de las galaxias. Para calcular el valor total de ¿ de cada galaxia observada, empleamos un modelo sencillo de la estructura dinámica de las galaxias el cual nos permite una estimación a primer orden del valor de ¿ usando únicamente observables fácilmente medibles de galaxias luminosas. El uso de una muestra extensa limitada por volumen (má...

  12. Acoustic oscillations in the SDSS DR4 Luminous Red Galaxy sample power spectrum

    OpenAIRE

    Huetsi, Gert

    2005-01-01

    We calculate the redshift-space power spectrum of the Sloan Digital Sky Survey (SDSS) Data Release 4 (DR4) Luminous Red Galaxy (LRG) sample, finding evidence for a full series of acoustic features down to the scales of \\sim 0.2 hMpc^{-1}. This corresponds up to the 7th peak in the CMB angular power spectrum. The acoustic scale derived, (105.4 \\pm 2.3) h^{-1}Mpc, agrees very well with the ``concordance'' model prediction and also with the one determined via the analysis of the spatial two-poin...

  13. Quantifying the coherent outflows of galaxies around voids in the SDSS DR7

    OpenAIRE

    Patiri, Santiago G.; Betancort-Rijo, Juan; Prada, Francisco

    2012-01-01

    We report the detection, with a high level of confidence, of coherent outflows around voids found in the seventh data release of the Sloan Digital Sky Survey (SDSS DR7). In particular, we developed a robust statistical test to quantify the strength of redshift-space distortions (RSD) associated with extended coherent velocity fields. We consistently find that the vector that joins void centers with galaxies that lie in shells around them is more likely to be perpendicular to the line-of-sigh...

  14. The Expansion of Arecibo in Summer 2008: A Receiver at 600-1200 MHz

    Science.gov (United States)

    Jones, Kristen; Rajagopalan, G.; Whitlow, D.

    2009-01-01

    The purpose of this project is to investigate the radio frequency interference (RFI) environment seen through the Arecibo telescope and recommend necessary limits for a cooled receiver in the 600-1200 MHz regime. Preliminary discriminatory measurements were made using the Hilltop RFI Monitoring system. Strong TV and cell phone signals dominate the band from 450 to 1200 MHz. We seek to overcome this RFI for a number of reasons. It is feasible that the dish will see less troublesome RFI than the Hilltop Monitoring sees. Additionally, this region is astronomically essential, as it is ideal for both pulsar research and high z HI studies. We have constructed an antenna and receiver optimized in the 600-1200 MHz band and have installed them in the Gregorian Dome. We are currently working to focus and calibrate the receiver and to produce spectra across the band from sample regions of the entire Arecibo beam. This information will guide the limits and filters necessary to make a cooled receiver functional in this useful region. We graciously thank the National Science Foundation's Research Experience for Undergraduates program for funding this research.

  15. Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity

    Science.gov (United States)

    Raizada, S.; Tepley, C. A.; Janches, D.; Friedman, J. S.; Zhou, Q.; Mathews, J. D.

    2004-04-01

    We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.

  16. Six New Millisecond Pulsars from Arecibo Searches of Fermi Gamma-Ray Sources

    CERN Document Server

    Cromartie, H T; Kerr, M; Deneva, J S; Ransom, S M; Ray, P S; Ferrara, E C; Michelson, P F; Wood, K S

    2016-01-01

    We have discovered six radio millisecond pulsars (MSPs) in a search with the Arecibo telescope of 34 unidentified gamma-ray sources from the Fermi Large Area Telescope (LAT) 4-year point source catalog. Among the 34 sources, we also detected two MSPs previously discovered elsewhere. Each source was observed at a center frequency of 327 MHz, typically at three epochs with individual integration times of 15 minutes. The new MSP spin periods range from 1.99 to 4.66 ms. Five of the six pulsars are in interacting compact binaries (period < 8.1 hr), while the sixth is a more typical neutron star-white dwarf binary with an 83-day orbital period. This is a higher proportion of interacting binaries than for equivalent Fermi-LAT searches elsewhere. The reason is that Arecibo's large gain afforded us the opportunity to limit integration times to 15 minutes, which significantly increased our sensitivity to these highly accelerated systems. Seventeen of the remaining 26 gamma-ray sources are still categorized as strong...

  17. THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III

    OpenAIRE

    Dawson, Kyle; Génova-Santos, Ricardo; Pérez-Fournon, Ismael; Rebolo López, Rafael; J.A. Rubino-Martin; Scoccola, C. G.; Streblyanska, Alina; Prada, Francisco; Mena, Olga

    2013-01-01

    The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort fromthe technical and administrative staff in Malarg¨ue. The authors are very grateful to the following agencies and organizations for financial support: Comisi´on Nacional de Energ´ıa At´omica, Fundaci ´on Antorchas, Gobierno De La Provincia de Mendoza, Municipalidad de Malarg¨ue, NDM Holdings and Valle Las Le˜...

  18. The XMM-Newton/SDSS galaxy cluster survey

    OpenAIRE

    Takey, Ali Said Ahmed

    2014-01-01

    Galaxy clusters are the largest known gravitationally bound objects, their study is important for both an intrinsic understanding of their systems and an investigation of the large scale structure of the universe. The multi- component nature of galaxy clusters offers multiple observable signals across the electromagnetic spectrum. At X-ray wavelengths, galaxy clusters are simply identified as X-ray luminous, spatially extended, and extragalactic sources. X-ray observations offer the most powe...

  19. Genus statistics using the Delaunay tessellation field estimation method: (I) tests with the Millennium Simulation and the SDSS DR7

    OpenAIRE

    Zhang, Youcai; Springel, Volker; Yang, Xiaohu

    2010-01-01

    We study the topology of cosmic large-scale structure through the genus statistics, using galaxy catalogues generated from the Millennium Simulation and observational data from the latest Sloan Digital Sky Survey Data Release (SDSS DR7). We introduce a new method for constructing galaxy density fields and for measuring the genus statistics of its isodensity surfaces. It is based on a Delaunay tessellation field estimation (DTFE) technique that allows the definition of a piece-wise continuous ...

  20. Extremely Red Quasars from SDSS, BOSS and WISE: Classification of Optical Spectra

    CERN Document Server

    Ross, Nicholas P; Zakamska, Nadia L; Richards, Gordon T; Villforth, Carolin; Strauss, Michael A; Greene, Jenny E; Alexandroff, Rachael; Brandt, W Niel; Liu, Guilin; Myers, Adam D; Paris, Isabelle; Schneider, Donald P

    2014-01-01

    Quasars with extremely red colours are an interesting population that can test ideas about quasar evolution as well as orientation and geometric effects in the so-called AGN unified model. To identify such a population we search the quasar catalogs of the Sloan Digital Sky Survey (SDSS), the Baryon Oscillation Spectroscopic Survey (BOSS) and the Wide-Field Infrared Survey Explorer (WISE) for quasars with extremely high infrared-to-optical ratios. We identify 65 objects with r(AB)-W4(Vega)>14 mag (i.e., F_nu(22um)/F_nu(r) > ~1000). This sample spans a redshift range of 0.282.6 objects that are detected in the W4-band but not W1 or W2 (i.e., "W1W2-dropouts"). The SDSS/BOSS spectra show that the majority of the objects are reddened Type 1 quasars, Type 2 quasars (both at low and high redshift) or objects with deep low-ionization broad absorption lines (BALs) that suppress the observed r-band flux. In addition, we identify a class of Type 1 permitted broad-emission line objects at z~2-3 which are characterized by...

  1. A search for optical variability of type 2 quasars in SDSS stripe 82

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Aaron J.; Carson, Daniel J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Voevodkin, Alexey [Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997 (Russian Federation); Woźniak, Przemysław, E-mail: barth@uci.edu [Los Alamos National Laboratory, MS-D466, Los Alamos, NM 87545 (United States)

    2014-01-01

    Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active galactic nuclei (AGNs). A straightforward expectation of unified models is that highly obscured Type 2 AGNs should show little or no optical variability on timescales of days to years. As a test of this prediction, we have carried out a search for variability in Type 2 quasars in SDSS Stripe 82 using difference-imaging photometry. Starting with the Type 2 AGN catalogs of Zakamska et al. and Reyes et al., we find evidence of significant g-band variability in 17 out of 173 objects for which light curves could be measured from the Stripe 82 data. To determine the nature of this variability, we obtained new Keck spectropolarimetry observations for seven of these variable AGNs. The Keck data show that these objects have low continuum polarizations (p ≲ 1% in most cases) and all seven have broad Hα and/or Mg II emission lines in their total (unpolarized) spectra, indicating that they should actually be classified as Type 1 AGNs. We conclude that the primary reason variability is found in the SDSS-selected Type 2 AGN samples is that these samples contain a small fraction of Type 1 AGNs as contaminants, and it is not necessary to invoke more exotic possible explanations such as a population of 'naked' or unobscured Type 2 quasars. Aside from misclassified Type 1 objects, the Type 2 quasars do not generally show detectable optical variability over the duration of the Stripe 82 survey.

  2. A search for optical variability of type 2 quasars in SDSS stripe 82

    International Nuclear Information System (INIS)

    Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active galactic nuclei (AGNs). A straightforward expectation of unified models is that highly obscured Type 2 AGNs should show little or no optical variability on timescales of days to years. As a test of this prediction, we have carried out a search for variability in Type 2 quasars in SDSS Stripe 82 using difference-imaging photometry. Starting with the Type 2 AGN catalogs of Zakamska et al. and Reyes et al., we find evidence of significant g-band variability in 17 out of 173 objects for which light curves could be measured from the Stripe 82 data. To determine the nature of this variability, we obtained new Keck spectropolarimetry observations for seven of these variable AGNs. The Keck data show that these objects have low continuum polarizations (p ≲ 1% in most cases) and all seven have broad Hα and/or Mg II emission lines in their total (unpolarized) spectra, indicating that they should actually be classified as Type 1 AGNs. We conclude that the primary reason variability is found in the SDSS-selected Type 2 AGN samples is that these samples contain a small fraction of Type 1 AGNs as contaminants, and it is not necessary to invoke more exotic possible explanations such as a population of 'naked' or unobscured Type 2 quasars. Aside from misclassified Type 1 objects, the Type 2 quasars do not generally show detectable optical variability over the duration of the Stripe 82 survey.

  3. Extragalactic HI Surveys

    CERN Document Server

    Giovanelli, Riccardo

    2015-01-01

    We review the results of HI line surveys of extragalactic sources in the local Universe. In the last two decades major efforts have been made in establishing on firm statistical grounds the properties of the HI source population, the two most prominent being the HI Parkes All Sky Survey (HIPASS) and the Arecibo Legacy Fast ALFA survey (ALFALFA). We review the choices of technical parameters in the design and optimization of spectro-photometric "blind" HI surveys, which for the first time produced extensive HI-selected data sets. Particular attention is given to the relationship between optical and HI populations, the differences in their clustering properties and the importance of HI-selected samples in contributing to the understanding of apparent conflicts between observation and theory on the abundance of low mass halos. The last section of this paper provides an overview of currently ongoing and planned surveys which will explore the cosmic evolution of properties of the HI population.

  4. Extragalactic HI surveys

    Science.gov (United States)

    Giovanelli, Riccardo; Haynes, Martha P.

    2015-12-01

    We review the results of HI line surveys of extragalactic sources in the local Universe. In the last two decades major efforts have been made in establishing on firm statistical grounds the properties of the HI source population, the two most prominent being the HI Parkes All Sky Survey and the Arecibo Legacy Fast ALFA survey. We review the choices of technical parameters in the design and optimization of spectro-photometric "blind" HI surveys, which for the first time produced extensive HI-selected data sets. Particular attention is given to the relationship between optical and HI populations, the differences in their clustering properties and the importance of HI-selected samples in contributing to the understanding of apparent conflicts between observation and theory on the abundance of low mass halos. The last section of this paper provides an overview of currently ongoing and planned surveys which will explore the cosmic evolution of properties of the HI population.

  5. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    International Nuclear Information System (INIS)

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of ∼100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you want

  6. New lensed quasars from the MUSCLES survey

    CERN Document Server

    Jackson, Neal; Ofek, Eran O; Shin, Min-Su

    2011-01-01

    Gravitational lens systems containing lensed quasars are important as cosmological probes, as diagnostics of structural properties of the lensing galaxies and as tools to study the quasars themselves. The largest lensed quasar sample is the SDSS Quasar Lens Search, drawn from the Sloan Digital Sky Survey (SDSS). We are attempting to extend this survey using observations of lens candidates selected from a combination of the quasar sample from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). This adds somewhat higher image quality together with a wider range of wavelength for the selection process. In previous pilot surveys we observed 5 objects, finding 2 lenses; here we present further observations of 20 objects in which we find 4 lenses, of which 2 are independently discovered in SQLS (in preparation). Following earlier work on the combination of these two surveys, we have refined our method and find that use of a colour-separation diagnostic, where we select for separations between components which...

  7. Galaxy And Mass Assembly (GAMA): detection of low-surface-brightness galaxies from SDSS data

    CERN Document Server

    Williams, R P; Kelvin, L S; James, P A; Driver, S P; Prescott, M; Brough, S; Brown, M J I; Davies, L J M; Holwerda, B W; Liske, J; Norberg, P; Moffett, A J; Wright, A H

    2016-01-01

    We report on a search for new low-surface-brightness galaxies (LSBGs) using Sloan Digital Sky Survey (SDSS) data within the GAMA equatorial fields. The search method consisted of masking objects detected with SDSS photo, combining gri images weighted to maximise the expected signal-to-noise ratio (SNR), and smoothing the images. The processed images were then run through a detection algorithm that finds all pixels above a set threshold and groups them based on their proximity to one another. The list of detections was cleaned of contaminants such as diffraction spikes and the faint wings of masked objects. From these, selecting potentially the brightest in terms of total flux, a list of 343 LSBGs was produced having been confirmed using VISTA Kilo-degree Infrared Galaxy Survey (VIKING) imaging. The photometry of this sample was refined using the deeper VIKING Z band as the aperture-defining band. Measuring their $g-i$ and $J-K$ colours shows that most are consistent with being at redshifts less than 0.2. The ...

  8. Higher Order Moments of the Angular Distribution of Galaxies from Early SDSS Data

    CERN Document Server

    Szapudi, I; Scoccimarro, R; Szalay, A S; Connolly, A J; Dodelson, S; Eisenstein, D J; Gunn, J E; Johnston, D; Kent, S; Loveday, J; Meiksin, A; Nichol, R C; Scranton, R; Stebbins, A; Vogeley, M S; Szapudi, Istv\\'an; Frieman, Joshua A.; Scoccimarro, Roman; Szalay, Alexander S.; Connolly, Andrew J.; Dodelson, Scott; Eisenstein, Daniel J.; Gunn, James E.; Johnston, David; Kent, Stephen; Loveday, Jon; Meiksin, Avery; Nichol, Robert C.; Scranton, Ryan; Stebbins, Albert; Vogeley, Michael S.

    2002-01-01

    We present initial results for counts in cells statistics of the angular distribution of galaxies in early data from the Sloan Digital Sky Survey (SDSS). We analyze a rectangular stripe $2.5^\\circ$ wide, covering approximately 160 sq. degrees, containing over $10^6$ galaxies in the apparent magnitude range $18 < r^\\prime < 22$, with areas of bad seeing, contamination from bright stars, ghosts, and high galactic extinction masked out. This survey region, which forms part of the SDSS Early Data Release, is the same as that for which two-point angular clustering statistics have recently been computed. The third and fourth moments of the cell counts, $s_3$ (skewness) and $s_4$ (kurtosis), constitute the most accurate measurements to date of these quantities (for $r^\\prime < 21$) over angular scales $0.015^\\circ-0.3^\\circ$. They display the approximate hierarchical scaling expected from non-linear structure formation models and are in reasonable agreement with the predictions of $\\Lambda$-dominated cold d...

  9. Cosmic Voids in the SDSS DR12 BOSS Galaxy Sample: The Alcock-Paczynski Test

    CERN Document Server

    Mao, Qingqing; Scherrer, Robert J; Neyrinck, Mark C; Scoccimarro, Roman; Tinker, Jeremy L; McBride, Cameron K

    2016-01-01

    We apply the Alcock-Paczynski (AP) test to the stacked voids identified using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Release 12 and is the final catalog of SDSS-III. We also use 1000 mock galaxy catalogs that match the geometry, density, and clustering properties of the BOSS sample in order to characterize the statistical uncertainties of our measurements and take into account systematic errors such as redshift space distortions. For both BOSS data and mock catalogs, we use the ZOBOV algorithm to identify voids, we stack together all voids with effective radii of 30-100Mpc/h in the redshift range 0.43-0.7, and we accurately measure the shape of the stacked voids. Our tests with the mock catalogs show that we measure the stacked void ellipticity with a statistical precision of 2.6%. We find that the stacked voids in redshift space are slightly squashed along the line of sight, whic...

  10. MAPPING THE LOCAL HALO: STATISTICAL PARALLAX ANALYSIS OF SDSS LOW-MASS SUBDWARFS

    International Nuclear Information System (INIS)

    We present a statistical parallax study of nearly 2000 M subdwarfs with photometry and spectroscopy from the Sloan Digital Sky Survey (SDSS). Statistical parallax analysis yields the mean absolute magnitudes, mean velocities, and velocity ellipsoids for homogenous samples of stars. We selected homogeneous groups of subdwarfs based on their photometric colors and spectral appearance. We examined the color-magnitude relations of low-mass subdwarfs and quantified their dependence on the newly refined metallicity parameter, ζ. We also developed a photometric metallicity parameter, δ(g–r), based on the g – r and r – z colors of low-mass stars and used it to select stars with similar metallicities. The kinematics of low-mass subdwarfs as a function of color and metallicity were also examined and compared to main-sequence M dwarfs. We find that the SDSS subdwarfs share similar kinematics to the inner halo and thick disk. The color-magnitude relations derived in this analysis will be a powerful tool for identifying and characterizing low-mass metal-poor subdwarfs in future surveys such as Gaia and LSST, making them important and plentiful tracers of the stellar halo.

  11. Automated physical classification in the SDSS DR10. A catalogue of candidate quasars

    Science.gov (United States)

    Brescia, M.; Cavuoti, S.; Longo, G.

    2015-07-01

    We discuss whether modern machine learning methods can be used to characterize the physical nature of the large number of objects sampled by the modern multiband digital surveys. In particular, we applied the MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) method to the optical data of the Sloan Digital Sky Survey (SDSS) Data Release 10, investigating whether photometric data alone suffice to disentangle different classes of objects as they are defined in the SDSS spectroscopic classification. We discuss three groups of classification problems: (i) the simultaneous classification of galaxies, quasars and stars; (ii) the separation of stars from quasars; (iii) the separation of galaxies with normal spectral energy distribution from those with peculiar spectra, such as starburst or star-forming galaxies and AGN. While confirming the difficulty of disentangling AGN from normal galaxies on a photometric basis only, MLPQNA proved to be quite effective in the three-class separation. In disentangling quasars from stars and galaxies, our method achieved an overall efficiency of 91.31 per cent and a QSO class purity of ˜95 per cent. The resulting catalogue of candidate quasars/AGNs consists of ˜3.6 million objects, of which about half a million are also flagged as robust candidates, and will be made available on CDS VizieR facility.

  12. Deep SDSS optical spectroscopy of distant halo stars I. Atmospheric parameters and stellar metallicity distribution

    CERN Document Server

    Prieto, C Allende; Schlesinger, K J; Lee, Y S; Morrison, H L; Schneider, D P; Beers, T C; Bizyaev, D; Ebelke, G; Malanushenko, E; Malanushenko, V; Oravetz, D; Pan, K; Simmons, A; Simmerer, J; Sobeck, J; Robin, A C

    2014-01-01

    We analyze a sample of tens of thousands of spectra of halo turnoff stars, obtained with the optical spectrographs of the Sloan Digital Sky Survey (SDSS), to characterize the stellar halo population "in situ" out to a distance of a few tens of kpc from the Sun. In this paper we describe the derivation of atmospheric parameters. We also derive the overall stellar metallicity distribution based on F-type stars observed as flux calibrators for the Baryonic Oscillations Spectroscopic Survey (BOSS). Our analysis is based on an automated method that determines the set of parameters of a model atmosphere that reproduces each observed spectrum best. We used an optimization algorithm and evaluate model fluxes by means of interpolation in a precomputed grid. In our analysis, we account for the spectrograph's varying resolution as a function of fiber and wavelength. Our results for early SDSS (pre-BOSS upgrade) data compare well with those from the SEGUE Stellar Parameter Pipeline (SSPP), except for stars with logg (cgs...

  13. Update on HI data collection from GBT, Parkes and Arecibo telescopes for the Cosmic Flows project

    CERN Document Server

    Courtois, Helene M

    2014-01-01

    Cosmic Flows is an international multi-element project with the goal to map motions of galaxies in the Local Universe. Kinematic information from observations in the radio HI line and photometry at optical or near-infrared bands are acquired to derive the large majority of distances that are obtained through the luminosity-linewidth or Tully-Fisher relation. This paper gathers additional observational radio data, frequently unpublished, retrieved from the archives of Green Bank, Parkes and Arecibo telescopes. Extracted HI profiles are consistently processed to produce linewidth measurements. Our current "All-Digital HI Catalog" contains a total of 20,343 HI spectra for 17,738 galaxies with 14,802 galaxies with accurate linewidth measurement useful for Tully-Fisher galaxy distances. This addition of 4,117 new measurements represents an augmentation of 34\\% compared to our last release.

  14. Optically-Selected BLR-less Active Galactic Nuclei from the SDSS Stripe82 Database I: The Sample

    CERN Document Server

    Zhang, Xue Guang

    2013-01-01

    This is the first paper in a dedicated series to study the properties of the optically selected BLR-less AGNs (Active Galactic Nuclei with no-hidden central broad emission line regions). We carried out a systematic search for the BLR-less AGNs through the Sloan Digital Sky Survey Legacy Survey (SDSS Stripe82 Database). Based on the spectral decomposition results for all the 136676 spectroscopic objects (galaxies and QSOs) with redshift less than 0.35 covered by the SDSS Stripe82 region, our spectroscopic sample for the BLR-less AGNs includes 22693 pure narrow line objects without broad emission lines but with apparent AGN continuum emission $R_{AGN}>0.3$ and apparent stellar lights $R_{ssp}>0.3$. Then, using the properties of the photometry magnitude RMS ($RMS$) and the Pearson's coefficients ($R_{1, 2}$) between two different SDSS band light curves: $RMS_k>3\\times RMS_{M_k}$ and $R_{1, 2}>\\sim0.8$, the final 281 pure narrow objects with true photometry variabilities are our selected reliable candidates for t...

  15. Seasonal variability and descent of mid-latitude sporadic E layers at Arecibo

    Directory of Open Access Journals (Sweden)

    N. Christakis

    2009-03-01

    Full Text Available Sporadic E layers (Es follow regular daily patterns in variability and altitude descent, which are determined primarily by the vertical tidal wind shears in the lower thermosphere. In the present study a large set of sporadic E layer incoherent scatter radar (ISR measurements are analyzed. These were made at Arecibo (Geog. Lat. ~18° N; Magnetic Dip ~50° over many years with ISR runs lasting from several hours to several days, covering evenly all seasons. A new methodology is applied, in which both weak and strong layers are clearly traced by using the vertical electron density gradient as a function of altitude and time. Taking a time base equal to the 24-h local day, statistics were obtained on the seasonal behavior of the diurnal and semidiurnal tidal variability and altitude descent patterns of sporadic E at Arecibo. The diurnal tide, most likely the S(1,1 tide with a vertical wavelength around 25 km, controls fully the formation and descent of the metallic Es layers at low altitudes below 110 km. At higher altitudes, there are two prevailing layers formed presumably by vertical wind shears associated mainly with semidiurnal tides. These include: 1 a daytime layer starting at ~130 km around midday and descending down to 105 km by local midnight, and 2 a less frequent and weaker nighttime layer which starts prior to midnight at ~130 km, descending downwards at somewhat faster rate to reach 110 km by sunrise. The diurnal and semidiurnal-like pattern prevails, with some differences, in all seasons. The differences in occurrence, strength and descending speeds between the daytime and nighttime upper layers are not well understood from the present data alone and require further study.

  16. Simultaneous measurements of HF-enhanced plasma waves and artificial field-aligned irregularities at Arecibo

    International Nuclear Information System (INIS)

    Two radar systems with beams intersecting in the HF-modified F region were used to simultaneously measure HF-enhanced plasma lines (HFPLs) and artificial geomagnetic field-aligned irregularities (AFAIs). The Arecibo 430-MHz radar was used for the HFPL observations, and a portable 49.92-MHz backscatter radar was deployed on the island of Guadeloupe to monitor the AFAIs. The experiment was desgined to examine the degree to which HF-induced plasma turbulence influences the development of AFAIs. When the HF beam is stepped up in power, sustained HFPLs and AFAIs are first observed at the same HF power level, indicating that ponderomotively driven instabilities may be involved in the early time development of AFAIs. As the HF power is increased, the HFPL backscatter power begins to saturate at ∼70 MW effective radiated power (ERP). However, the backscatter from AFAIs is linearly dependent on HF power, even at the highest (120 MW ERP) HF power levels available at Arecibo. This suggests that additional processes may contribute to the development of AFAIs. For example, ponderomotively driven instabilities may give rise to weak geomagnetic field-aligned irregularities that are subsequently driven unstable by processes excited near the upper hybrid resonance. It is also likely that AFAIs greatly impact the development of HF-induced plasma turbulence at late times (>1 s) following HF turn-on. Once the ionosphere is preconditioned by high-power HF modifications, AFAIs and HFPLs can be simultaneously sustained at a much lower HF power level than that needed to originally excite them. The nature of the preconditioning process is currently not well understood. New theoretical initiatives are clearly needed to guide future experimental activity in this area

  17. Very High Resolution Studies of Micrometeors Using the Arecibo 430 MHz Radar

    Science.gov (United States)

    Mathews, J. D.; Meisel, D. D.; Hunter, K. P.; Getman, V. S.; Zhou, Q.

    1997-03-01

    We present measured and inferred properties of a possible new class of "sporadic" micrometeors discovered during 18 January 1995 observations made using the very sensitive 430 MHz radar system located at Arecibo Observatory in Puerto Rico. Over 200 of these objects were observed in a 2-hr period near sunrise. The average speed was about 55 km/sec in a range of 45-63 km/sec. Approximately two-thirds of the observed trajectories were apparently nearly parallel with the vertical beam and occurred on the 93-102 km height interval. The observed occurrence rate of these meteor returns combined with the size the Arecibo beam points to a meteor flux corresponding—in the "classical" view—to ˜15th magnitude micrometeors. This information along with observed deceleration rates and radar scattering cross-sections of order 10 -8m 2, leads us to conclude that the majority of the meteors observed appear to be of order 1 μg in mass. The depth of atmospheric penetration and inferred perihelia, the majority of which lie mostly within the orbits of Mercury and Venus, point to compositions of dense refractory material. Retrograde orbits that lie well out of the plane of the ecliptic combined with the modeled effects of radiation pressure induced orbit decay suggest that these particles—with no obvious parent body—originated in the outer reaches of the solar system and that they may even be primordial in origin. It is suggested that most if not all of these particles are associated with the North Apex "source" of sporadic meteors reported by Jones and Brown (1993, Mon. Not. R. Astron. Soc.265, 524-532). Additionally, several possible radar scattering mechanisms are discussed, none of which seem completely satisfactory.

  18. Mapping Hydrogen in the Galaxy, Galactic Halo, and Local Group with ALFA: The GALFA-HI Survey Starting with TOGS

    CERN Document Server

    Gibson, S J; Heiles, C; Korpela, E J; Peek, J E G; Putman, M E; Stanimirović, S

    2008-01-01

    Radio observations of gas in the Milky Way and Local Group are vital for understanding how galaxies function as systems. The unique sensitivity of Arecibo's 305m dish, coupled with the 7-beam Arecibo L-Band Feed Array (ALFA), provides an unparalleled tool for investigating the full range of interstellar phenomena traced by the HI 21cm line. The GALFA (Galactic ALFA) HI Survey is mapping the entire Arecibo sky over a velocity range of -700 to +700 km/s with 0.2 km/s velocity channels and an angular resolution of 3.4 arcminutes. We present highlights from the TOGS (Turn on GALFA Survey) portion of GALFA-HI, which is covering thousands of square degrees in commensal drift scan observations with the ALFALFA and AGES extragalactic ALFA surveys. This work is supported in part by the National Astronomy and Ionosphere Center, operated by Cornell University under cooperative agreement with the National Science Foundation.

  19. Constraint on neutrino masses from SDSS-III/BOSS Ly$\\alpha$ forest and other cosmological probes

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Lesgourgues, Julien; Rossi, Graziano; Borde, Arnaud; Viel, Matteo; Aubourg, Eric; Kirkby, David; LeGoff, Jean-Marc; Rich, James; Roe, Natalie; Ross, Nicholas P; Schneider, Donald P; Weinberg, David

    2015-01-01

    We present constraints on the parameters of the $\\Lambda$CDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly$\\alpha$ forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS) by Palanque-Delabrouille et al. (2013), complemented by additional cosmological probes. The interpretation of the measured Ly$\\alpha$ spectrum is done using a second-order Taylor expansion of the simulated power spectrum. BOSS Ly$\\alpha$ data alone provide better bounds than previous Ly$\\alpha$ results, but are still poorly constraining, especially for the sum of neutrino masses $\\sum m_\

  20. Evidence for Primordial Clustering Around the QSO SDSS J1030+0524 at z=6.28

    OpenAIRE

    Stiavelli, M; Djorgovski, S. G.; Pavlovsky, C.; Scarlata, C.; Stern, D; Mahabal, A.; Thompson, D.; Dickinson, M.; Panagia, N.; Meylan, G

    2005-01-01

    We present tentative evidence for primordial clustering, manifested as an excess of color-selected objects in the field of the QSO SDSS J1030+0524 at redshift z=6.28. We have selected objects red in i_{775}-z_{850} on the basis of Hubble Space Telescope Advanced Camera for Surveys imaging of a field centered on the QSO. Compared to data at comparable depth obtained by the GOODS survey, we find an excess of objects with (i_{775}-z_{850}) \\geq 1.5 in the QSO field. The significance of the detec...

  1. Structural Analysis of the SDSS Cosmic Web I.Nonlinear Density Field Reconstructions

    CERN Document Server

    Platen, Erwin; Jones, Bernard J T; Vegter, Gert; Aragon-Calvo, Miguel A

    2011-01-01

    We investigate the ability of three reconstruction techniques to analyze and investigate weblike features and geometries in a discrete distribution of objects. The three methods are the linear Delaunay Tessellation Field Estimator (DTFE), its higher order equivalent Natural Neighbour Field Estimator (NNFE) and a version of Kriging interpolation adapted to the specific circumstances encountered in galaxy redshift surveys, the Natural Lognormal Kriging technique. DTFE and NNFE are based on the local geometry defined by the Voronoi and Delaunay tessellations of the galaxy distribution. The three reconstruction methods are analysed and compared using mock magnitude-limited and volume-limited SDSS redshift surveys, obtained on the basis of the Millennium simulation. We investigate error trends, biases and the topological structure of the resulting fields, concentrating on the void population identified by the Watershed Void Finder. Environmental effects are addressed by evaluating the density fields on a range of ...

  2. Automated physical classification in the SDSS DR10. A catalogue of candidate Quasars

    CERN Document Server

    Brescia, Massimo; Longo, Giuseppe

    2015-01-01

    We discuss whether modern machine learning methods can be used to characterize the physical nature of the large number of objects sampled by the modern multi-band digital surveys. In particular, we applied the MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) method to the optical data of the Sloan Digital Sky Survey - Data Release 10, investigating whether photometric data alone suffice to disentangle different classes of objects as they are defined in the SDSS spectroscopic classification. We discuss three groups of classification problems: (i) the simultaneous classification of galaxies, quasars and stars; (ii) the separation of stars from quasars; (iii) the separation of galaxies with normal spectral energy distribution from those with peculiar spectra, such as starburst or starforming galaxies and AGN. While confirming the difficulty of disentangling AGN from normal galaxies on a photometric basis only, MLPQNA proved to be quite effective in the three-class separation. In disentangling quasars ...

  3. Improved Spectrophotometric Calibration of the SDSS-III BOSS Quasar Sample

    CERN Document Server

    Margala, Daniel; Dawson, Kyle; Bailey, Stephen; Blanton, Michael; Schneider, Donald P

    2015-01-01

    We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) and describe the correction procedure we have developed and applied to this sample. Calibration errors are primarily due to atmospheric differential refraction and guiding offsets during each exposure. The corrections potentially reduce the systematics for any studies of BOSS quasars, including the measurement of baryon acoustic oscillations using the Lyman-$\\alpha$ forest. Our model suggests that, on average, the observed quasar flux in BOSS is overestimated by $\\sim 19\\%$ at 3600 \\AA\\ and underestimated by $\\sim 24\\%$ at 10,000 \\AA. Our corrections for the entire BOSS quasar sample are publicly available.

  4. Counts of low-Redshift SDSS quasar candidates

    International Nuclear Information System (INIS)

    We analyze the counts of low-redshift quasar candidates selected using nine-epoch SDSS imaging data. The co-added catalogs are more than 1 mag deeper than single-epoch SDSS data, and allow the selection of low-redshift quasar candidates using UV-excess and also variability techniques. The counts of selected candidates are robustly determined down to g = 21.5. This is about 2 magnitudes deeper than the position of a change in the slope of the counts reported by Boyle (and others) (1990, 2000) for a sample selected by UV-excess, and questioned by Hawkins and Veron (1995), who utilized a variability-selected sample. Using SDSS data, we confirm a change in the slope of the counts for both UV-excess and variability selected samples, providing strong support for the Boyle (and others) results

  5. Luminosity dependence of the quasar clustering from SDSS NBCKDE catalogue

    International Nuclear Information System (INIS)

    We study the clustering of quasars from the SDSS NBCKDE catalogue of photometrically selected quasar candidates (SDSS DR6). Dividing our sample with 0.8phot<2.2 onto three luminosity bins we have found no evidence for luminosity dependence of the quasar clustering. It is consistent with the models of the quasar formation, in which bring and faint quasars are assumed to be similar sources, hosted by dark matter halos of similar masses, but observed at different stages of their evolution

  6. The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo

    OpenAIRE

    Rodríguez, Silvio; Padilla, Nelson D.

    2013-01-01

    By modelling the axis ratio distribution of SDSS DR8 galaxies we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of shapes, while taking into account dust extinction. We measure the dust extinction of the full sample of spiral galaxies and find a smaller value than previous estimations, with an edge-on extinction of $E_0 = 0.284^{+0.015}_{-0.026}$ in the SDSS r band. We als...

  7. DIFFERENCE IMAGING OF LENSED QUASAR CANDIDATES IN THE SLOAN DIGITAL SKY SURVEY SUPERNOVA SURVEY REGION

    International Nuclear Information System (INIS)

    Difference imaging provides a new way to discover gravitationally lensed quasars because few nonlensed sources will show spatially extended, time variable flux. We test the method on the fields of lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and one serendipitously discovered lensed quasar. Starting from 20,536 sources, including 49 SDSS quasars, 32 candidate lenses/lensed images, and one known lensed quasar, we find that 174 sources including 35 SDSS quasars, 16 candidate lenses/lensed images, and the known lensed quasar are nonperiodic variable sources. We can measure the spatial structure of the variable flux for 119 of these variable sources and identify only eight as candidate extended variables, including the known lensed quasar. Only the known lensed quasar appears as a close pair of sources on the difference images. Inspection of the remaining seven suggests they are false positives, and only two were spectroscopically identified quasars. One of the lens candidates from the SQLS survives our cuts, but only as a single image instead of a pair. This indicates a false positive rate of order ∼1/4000 for the method, or given our effective survey area of order 0.82 deg.2, ∼5 per deg.2 in the SDSS Supernova Survey. The fraction of quasars not found to be variable and the false positive rate would both fall if we had analyzed the full, later data releases for the SDSS fields. While application of the method to the SDSS is limited by the resolution, depth, and sampling of the survey, several future surveys such as Pan-STARRS, LSST, and SNAP will significantly improve on these limitations.

  8. Difference Imaging of Lensed Quasar Candidates in the Sloan Digital Sky Survey Supernova Survey Region

    Science.gov (United States)

    Lacki, Brian C.; Kochanek, Christopher S.; Stanek, Krzysztof Z.; Inada, Naohisa; Oguri, Masamune

    2009-06-01

    Difference imaging provides a new way to discover gravitationally lensed quasars because few nonlensed sources will show spatially extended, time variable flux. We test the method on the fields of lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and one serendipitously discovered lensed quasar. Starting from 20,536 sources, including 49 SDSS quasars, 32 candidate lenses/lensed images, and one known lensed quasar, we find that 174 sources including 35 SDSS quasars, 16 candidate lenses/lensed images, and the known lensed quasar are nonperiodic variable sources. We can measure the spatial structure of the variable flux for 119 of these variable sources and identify only eight as candidate extended variables, including the known lensed quasar. Only the known lensed quasar appears as a close pair of sources on the difference images. Inspection of the remaining seven suggests they are false positives, and only two were spectroscopically identified quasars. One of the lens candidates from the SQLS survives our cuts, but only as a single image instead of a pair. This indicates a false positive rate of order ~1/4000 for the method, or given our effective survey area of order 0.82 deg2, ~5 per deg2 in the SDSS Supernova Survey. The fraction of quasars not found to be variable and the false positive rate would both fall if we had analyzed the full, later data releases for the SDSS fields. While application of the method to the SDSS is limited by the resolution, depth, and sampling of the survey, several future surveys such as Pan-STARRS, LSST, and SNAP will significantly improve on these limitations.

  9. The properties of Brightest Cluster Galaxies in the SDSS DR6 adaptive matched filter cluster catalogue

    CERN Document Server

    Pipino, A; Pierpaoli, E; MacKenzie, S M; Dong, F

    2010-01-01

    We study the properties of Brightest Cluster Galaxies (BCGs) drawn from a catalogue of more than 69000 clusters in the SDSS DR6 based on the adaptive matched filter technique (AMF, Szabo et al., 2010). Our sample consists of more than 14300 galaxies in the redshift range 0.1-0.3. We test the catalog by showing that it includes well-known BCGs which lie in the SDSS footprint. We characterize the BCGs in terms of r-band luminosities and optical colours as well as their trends with redshift. In particular, we define and study the fraction of blue BCGs, namely those that are likely to be missed by either colour-based cluster surveys and catalogues. Richer clusters tend to have brighter BCGs, however less dominant than in poorer systems. 4-9% of our BCGs are at least 0.3 mag bluer in the g-r colour than the red-sequence at their given redshift. Such a fraction decreases to 1-6% for clusters above a richness of 50, where 3% of the BCGs are 0.5 mag below the red-sequence. A preliminary morphological study suggests t...

  10. Statistical Study of 2XMMi-DR3/SDSS-DR8 Cross-correlation Sample

    CERN Document Server

    Yan-Xia, Zhang; Yong-Heng, Zhao; Xue-Bing, Wu; 10.1088/0004-6256/145/2/42

    2013-01-01

    Cross-correlating the XMM-Newton 2XMMi-DR3 catalog with the Sloan Digital Sky Survey (SDSS) Data Release 8, we obtain one of the largest X-ray/optical catalogs and explore the distribution of various classes of X-ray emitters in the multidimensional photometric parameter space. Quasars and galaxies occupy different zones while stars scatter in them. However, X-ray active stars have a certain distributing rule according to spectral types. The earlier the type of stars, the stronger X-ray emitting. X-ray active stars have a similar distribution to most of stars in the g-r versus r-i diagram. Based on the identified samples with SDSS spectral classification, a random forest algorithm for automatic classification is performed. The result shows that the classification accuracy of quasars and galaxies adds up to more than 93.0% while that of X-ray emitting stars only amounts to 45.3%. In other words, it is easy to separate quasars and galaxies, but it is difficult to discriminate X-ray active stars from quasars and...

  11. Herschel-ATLAS/GAMA: SDSS cross-correlation induced by weak lensing

    CERN Document Server

    González-Nuevo, J; Negrello, M; Danese, L; De Zotti, G; Amber, S; Baes, M; Bland-Hawthorn, J; Bourne, N; Brough, S; Bussmann, R S; Cai, Z -Y; Cooray, A; Dunne, L; Dye, S; Eales, S; Ibar, E; Ivison, R; Liske, J; Loveday, J; Maddox, S; Michałowski, M J; Schneider, M D; Scott, D; Smith, M W L; Valiante, E; Xia, J -Q

    2014-01-01

    We report a highly significant ($>10\\sigma$) spatial correlation between galaxies with $S_{350\\mu\\rm m}\\ge 30\\,$mJy detected in the equatorial fields of the \\textsl{Herschel} Astrophysical Terahertz Large Area Survey (H-ATLAS) with estimated redshifts $\\gtrsim 1.5$, and SDSS or GAMA galaxies at $0.2\\le z\\le 0.6$. The significance of the cross-correlation is much higher than those reported so far for samples with non-overlapping redshift distributions selected in other wavebands. Extensive, realistic simulations of clustered sub-mm galaxies amplified by foreground structures confirm that the cross-correlation is explained by weak gravitational lensing ($\\mu<2$). The simulations also show that the measured amplitude and range of angular scales of the signal are larger than can be accounted for by galaxy-galaxy weak lensing. However, for scales $\\lesssim 2\\,$arcmin, the signal can be reproduced if SDSS/GAMA galaxies act as signposts of galaxy groups/clusters with halo masses in the range ~$10^{13.2}$--$10^{14...

  12. Galaxy-galaxy weak lensing in SDSS: intrinsic alignments and shear calibration errors

    CERN Document Server

    Hirata, C M; Seljak, U; Guzik, J; Padmanabhan, N; Blake, C; Brinkmann, J; Budavari, T; Connolly, A; Csabai, I; Scranton, R; Szalay, A S; Hirata, Christopher M.; Mandelbaum, Rachel; Seljak, Uros; Guzik, Jacek; Padmanabhan, Nikhil; Blake, Cullen; Brinkmann, Jonathan; Budavari, Tamas; Connolly, Andrew; Csabai, Istvan; Scranton, Ryan; Szalay, Alexander S.

    2004-01-01

    Galaxy-galaxy lensing has emerged as a powerful probe of the dark matter haloes of galaxies, but is subject to contamination if intrinsically aligned satellites of the lens galaxy are used as part of the source sample. We present a measurement of this intrinsic shear using 200,747 lens galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic sample and a sample of satellites selected using photometric redshifts. The mean intrinsic shear at transverse separations of 30--446$h^{-1}$ kpc is constrained to be $-0.0062<\\Delta\\gamma<+0.0066$ (99.9 per cent confidence, including identified systematics), which limits contamination of the galaxy-galaxy lensing signal to at most $\\sim 15$ per cent on these scales. We present these limits as a function of transverse separation and lens luminosity. We furthermore investigate shear calibration biases in the SDSS and conclude that the shear amplitude is calibrated to better than 18 per cent. This includes noise-induced calibration biases in the ellipticity, wh...

  13. A Search for PNe in Nearby Galaxies with SDSS Imaging Data

    CERN Document Server

    Kniazev, A Yu; Zucker, D B; Bell, E F; Rix, H W; Martínez-Delgado, D; Harris, H C; Kniazev, Alexei Y.; Grebel, Eva K.; Zucker, Daniel B.; Bell, Eric F.; Rix, Hans-Walter; Martinez-Delgado, David; Harris, Hugh C.

    2005-01-01

    We present the latest results from our project to search for new planetary nebulae in nearby galaxies using Sloan Digital Sky Survey (SDSS) imaging data. Our method is based on photometric criteria and can be applied to galaxies where PNe appear as point sources. We applied these criteria to the whole area of M31 as scanned by SDSS, detecting 130 new PN candidates and 30 known PNe. All selected PNe candidates are located in the outer regions of M31. For 85 candidates follow-up spectroscopy was obtained with the 2.2m telescope at Calar Alto Observatory. The observations show that our method has a detection efficiency of about 82%. We discuss the 2D velocity field of the outer part of M31 based on our observed PN data. The PNe suggest an exponential disk scale length of 13 kpc along the minor axis. We discovered two PNe along the line of sight to Andromeda NE, a very low surface brightness giant stellar structure in the outer halo of M31. These two PNe are located at projected distances of ~48 kpc and ~41 kpc f...

  14. A Computer-generated Visual Morphology Catalog of ~3,000,000 SDSS Galaxies

    Science.gov (United States)

    Kuminski, Evan; Shamir, Lior

    2016-04-01

    We have applied computer analysis to classify the broad morphological types of ∼3 · 106 Sloan Digital Sky Survey (SDSS) galaxies. For each galaxy, the catalog provides the DR8 object ID, the R.A., the decl., and the certainty for the automatic classification as either spiral or elliptical. The certainty of the classification allows us to control the accuracy of a subset of galaxies by sacrificing some of the least certain classifications. The accuracy of the catalog was tested using galaxies that were classified by the manually annotated Galaxy Zoo catalog. The results show that the catalog contains ∼900,000 spiral galaxies and ∼600,000 elliptical galaxies with classification certainty that has a statistical agreement rate of ∼98% with the Galaxy Zoo debiased “superclean” data set. The catalog also shows that objects assigned by the SDSS pipeline with a relatively high redshift (z > 0.4) can have clear visual spiral morphology. The catalog can be downloaded at http://vfacstaff.ltu.edu/lshamir/data/morph_catalog. The image analysis software that was used to create the catalog is also publicly available.

  15. VizieR Online Data Catalog: SDSS bulge, disk and total stellar mass estimates (Mendel+, 2014)

    Science.gov (United States)

    Mendel, J. T.; Simard, L.; Palmer, M.; Ellison, S. L.; Patton, D. R.

    2014-01-01

    We present a catalog of bulge, disk, and total stellar mass estimates for ~660000 galaxies in the Legacy area of the Sloan Digital Sky Survey Data (SDSS) Release 7. These masses are based on a homogeneous catalog of g- and r-band photometry described by Simard et al. (2011, Cat. J/ApJS/196/11), which we extend here with bulge+disk and Sersic profile photometric decompositions in the SDSS u, i, and z bands. We discuss the methodology used to derive stellar masses from these data via fitting to broadband spectral energy distributions (SEDs), and show that the typical statistical uncertainty on total, bulge, and disk stellar mass is ~0.15 dex. Despite relatively small formal uncertainties, we argue that SED modeling assumptions, including the choice of synthesis model, extinction law, initial mass function, and details of stellar evolution likely contribute an additional 60% systematic uncertainty in any mass estimate based on broadband SED fitting. We discuss several approaches for identifying genuine bulge+disk systems based on both their statistical likelihood and an analysis of their one-dimensional surface-brightness profiles, and include these metrics in the catalogs. Estimates of the total, bulge and disk stellar masses for both normal and dust-free models and their uncertainties are made publicly available here. (4 data files).

  16. SDSS J085431.18+173730.5: The First Compact Elliptical Galaxy Hosting an Active Nucleus

    CERN Document Server

    Paudel, Sanjaya; Ree, Change Hee; Kim, Minjin

    2016-01-01

    We report the discovery of a rare compact early-type galaxy, SDSS J085431.18+173730.5 (hereafter cE\\_AGN). It has an half light radius of R$_{e}$ = 490 pc and a brightness of M$_{r}$ = $-$18.08 mag. Optical spectroscopy available from the Sloan Digital Sky Survey (SDSS) reveals the presence of prominent broad-line emissions with the H$\\alpha$ broad component width of FWHM=2400 km/s. The black hole (BH) mass, as estimated from the luminosity and width of the broad H$\\alpha$ emission, is 2.1$\\times$10$^{6}$ M$_{\\sun}$. With the help of surface photometry, we perform a detailed analysis of the structural properties. The observed light distribution is best modeled with a double S\\'ersic function. Fixing the outer component as an exponential disk, we find that the inner component has a S\\'ersic index of n = 1.4. Considering the inner component as bulge/spheroidal we find that cE\\_AGN remains consistent in both BH mass -- bulge mass relation and BH mass -- bulge S\\'ersic index relation. Given these observational pr...

  17. Radar investigations of near-Earth asteroids at Arecibo and Goldstone

    Science.gov (United States)

    Brozovic, M.; Nolan, M.; Benner, L.; Busch, M.; Howell, E.; Taylor, P.; Springmann, A.; Giorgini, J.; Margot, J.; Magri, C.; Sheppard, M.; Naidu, S.

    2014-07-01

    Radar observations are a powerful technique to study near-Earth asteroids (NEAs). The Arecibo and Goldstone planetary radars can provide delay-Doppler images that can directly resolve surface features such as concavities, hills, ridges, and boulders. Goldstone's 3.75-m resolution capability is invaluable when attempting to image NEAs with diameters smaller than 50 m. To date, over 430 near-Earth asteroids and 136 main-belt asteroids have been observed with radar. 80 % of the radar-detected NEAs have been observed within the last 10 years. The radar detection rate in the last three years has tripled relative to the average in the previous decade due to an increase in funding and greater scheduling flexibility. Currently, ˜400 observing hours per year at Goldstone and ˜600 observing hours per year at Arecibo are devoted to observing asteroids. We strive to observe all strong and moderately strong imaging targets, Yarkovsky drift candidates, NEOWISE targets, asteroids with very low perihelia that can be used to measure solar oblateness, and as many other detectable asteroids as resources allow. We also regularly attempt to observe any asteroid that is flagged by the Near-Earth Object Human Spaceflight Accessible Targets Study (NHATS) list (http://neo.jpl.nasa.gov/nhats/). To date, we have observed more than 60 NHATS objects at Arecibo and Goldstone. In the past three years, ˜1/3 of the detected asteroids were targets of opportunity (TOOs), some of which we observed within 24 h from when the discoveries were announced. Many TOOs are small, rapidly moving objects that are detectable by radar only within few lunar distances. Radar astrometry is particularly important for these asteroids because they are too faint to be followed for long with optical telescopes. A radar-range measurement often secures their orbit for decades or centuries, where otherwise the object would be lost and require rediscovery. In one of the extreme cases, two delay and two Doppler

  18. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    CERN Document Server

    Shi, Xiheng; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-01-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of H$\\beta$ shows a variation of more than 5$\\sigma$ at a high velocity portion ($>3000\\ \\mathrm{km\\ s}^{-1}$) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He I and optical Fe II absorptions ($\\lambda 4233$ from b$^4$P$_{5/2}$ level and $\\lambda 5169$ from a$^6$S$_{5/2}$) at the same velocity. These Fe II lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of $n(\\mathrm{H})\\approx 10^{9.1}\\ \\mathrm{cm}^{-3}$ and a column density of $N_{\\mathrm{col}}(\\mathrm{H})\\approx 10^{23}\\ \\mathrm{cm}^{-2}$ for ...

  19. Spatially Resolved Stellar Populations Of Nearby Post-Starburst Galaxies In SDSS-IV MaNGA

    Science.gov (United States)

    Liu, Charles; Betances, Ashley; Bonilla, Alaina Marie; Gonzalez, Andrea; Migliore, Christina; Goddard, Daniel; Masters, Karen; SDSS-IV MaNGA Team

    2016-01-01

    We have selected five galaxies in the Mapping Nearby Galaxies at APO (MaNGA) project of the latest generation of the Sloan Digital Sky Survey (SDSS-IV) identified as post-starburst (E+A) systems, in the transition between "blue cloud" and "red sequence" galaxies. We measure the equivalent widths of the Balmer series, D4000 break, and metal lines across each galaxy, and produce maps of the stellar age, stellar mass, and metallicities of each galaxy using FIREFLY, a full spectral analysis code. We have found that the measured properties of the galaxies overall generally matches well with single-aperture SDSS spectra from which the original post-starburst identifications were made. The variation in the spatial distributions of the stellar populations, in particular the A-stars, give us insight into the details of the transitional E+A quenching phase. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement No. SSP483 to the CUNY College of Staten Island.

  20. The new Arecibo Observatory Remote Optical Facility (AO-ROF) in Culebra Island, Puerto Rico: Current Status and Future Projects

    Science.gov (United States)

    Santos, P. T.

    2015-12-01

    The idea of establishing the Arecibo Observatory Remote Optical Facility (AO-ROF) in the island of Culebra is a solution to mitigate the ever cumulative quantity of cloud, fog, and rain that has distressed observations at the Arecibo Observatory (AO) during major optical campaigns and observations. Given Culebra Island's favorable geographical and climatological characteristics as its low elevation and geographic location, it appears to have more steady weather conditions than Arecibo, so therefore it provides more availability for optical observations. Placed on Culebra, optical instruments can observe the same thermospheric volume over AO sampled by the Incoherent Scatter Radar (ISR). This capability will become especially important during the High Frequency (HF) facility is on operation. Small and large scale irregularities created by that HF can be readily observed and tracked from the Culebra site, and simultaneous observations from AO of the same atmospheric volume will permit direct vector measurements of dynamical evolution of the irregularities. This work presents a discussion of the current status of AO-ROF facility, as well the future projects.

  1. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    Science.gov (United States)

    Shi, Xiheng; Zhou, Hongyan; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-03-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of Hβ shows a variation of more than 5σ at a high velocity portion (\\gt 3000 {km} {{{s}}}-1) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He i and optical Fe ii absorptions (λ4233 from b4P5/2 level and λ5169 from a6S5/2) at the same velocity. These Fe ii lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of n({{H}})≈ {10}9.1 {{cm}}-3 and a column density of {N}{col}({{H}})≈ {10}23 {{cm}}-2 for the BOSS data, but the model fails to predict the variations of ionic column densities between the SDSS and BOSS observations if changes in ionizing flux are assumed. We thus propose transverse motion of the absorbing gas being the cause of the observed broad Balmer absorption line variability. In fact, we find that the changes in covering factors of the absorber can well-reproduce all of the observed variations. The absorber is estimated ∼0.94 pc away from the central engine, which is where the outflow likely experiences deceleration due to the collision with the surrounding medium. This scheme is consistent with the argument that LoBAL QSOs may represent the transition from obscured star-forming galaxies to classic QSOs.

  2. The NASA High Resolution Microwave Survey

    Science.gov (United States)

    Tarter, J. C.; Gulkis, S.

    1993-05-01

    The NASA High Resolution Microwave Survey (HRMS) began a decade of planned observations to search for signals of extraterrestrial intelligent origin with inaugural ceremonies at two sites on October 12, 1992. At Goldstone, California the Sky Survey began executing precisely controlled scanning patterns on the celestial sphere using a new beam waveguide 34m antenna operating at a frequency near 8500 MHz (X-band). At Arecibo, Puerto Rico the Targeted Search began tracking GL615.1A, one of 24 solar-type stars selected for these inaugural observations, using the NAIC 300m radio telescope operating in a band of frequencies centered at 1406 MHz. Since the initiation of the search, the Sky Survey has completed X-band observations of several dozen sky-frames measuring 30(deg) times 1.5(deg) . In addition, observations of selected areas of the galactic plane have been observed in several frequency bands (1400 MHz and 1600 MHz) using a 26m antenna located near the 34m antenna. The Targeted Search has completed the first 200 hours of observations at Arecibo covering some 300 MHz of bandwidth. This paper summarizes the results of the observations to date, including a synopsis of the interference observed at the Goldstone and Arecibo sites, and a discussion of techniques that will be used to improve future observations. The HRMS program is managed by the Ames Research Center in collaboration with the Jet Propulsion Laboratory. The results presented in this paper represent the efforts of a team of scientists and engineers at these two institutions as well as the SETI Institute, Silicon Engines Inc., John C. Reykjalin Inc., Sverdrup Technology, Sterling Federal Systems, Cornell University, the Harvard-Smithsonian Center for Astrophysics, the American Astronomical Society, Arecibo Observatory, UC Santa Cruz, the University of Washington, UC Berkeley, California Institute of Technology, Georgia Institute of Technology, Innovative Systems, and the Space Telescope Science Institute.

  3. An Introduction to SDSS and its Database

    Science.gov (United States)

    Krzesinski, Jurek

    2015-12-01

    The Sloan Digital Sky Survey is the largest and most successful sky survey of the Northern and part of the Southern celestial hemispheres ever made. The survey was performed using a dedicated 2.5~m telescope, the state-of-the-art imaging camera and spectrographs. It resulted in five band photometry of more than 14,000 square degrees of the sky, as well as over 4,000,000 unique spectra of galaxies, quasars and stars. The data are publicly available in the form of images, optical spectra, infrared spectra, and catalog data. All data can be downloaded from several different online sources. In this review I will present the past and current status of the Sloan Digital Sky Survey and wills introduce two main database web sites: Science Archive Server and SkyServer.

  4. The Discovery of a Second Field Methane Brown Dwarf from Sloan Digital Sky Survey Commissioning Data

    CERN Document Server

    Tsvetanov, Z I

    2000-01-01

    We report the discovery of a second field methane brown dwarf from the commissioning data of the Sloan Digital Sky Survey (SDSS). The object, SDSS J134646.45-003150.4 (SDSS 1346-00), was selected because of its very red color and stellar appearance. Its spectrum between 0.8-2.5 mic is dominated by strong absorption bands of H_2O and CH_4 and closely mimics those of Gliese 229B and SDSS 162414.37+002915.6 (SDSS 1624+00), two other known methane brown dwarfs. SDSS 1346-00 is approximately 1.5 mag fainter than Gliese 229B, suggesting that it lies about 11 pc from the sun. The ratio of flux at 2.1 mic to that at 1.27 mic is larger for SDSS 1346-00 than for Gliese 229B and SDSS 1624+00, which suggests that SDSS 1346-00 has a slightly higher effective temperature than the others. Based on a search area of 130 sq. deg. and a detection limit of z* = 19.8, we estimate a space density of 0.05 pc^-3 for methane brown dwarfs with T_eff ~ 1000 K in the 40 pc^3 volume of our search. This estimate is based on small-sample s...

  5. XMM-{\\em Newton} Observations of Optically Selected SDSS Clusters

    CERN Document Server

    Plionis, M; Georgantopoulos, I; Georgakakis, A

    2004-01-01

    We explore the X-ray properties of a subset of the optically selected SDSS cluster sample of Goto et al. (2002), by analysing seven public XMM-{\\em Newton} pointings, with exposure times ranging from $\\sim$ 4 to 46 ksec. There are in total 17 SDSS clusters out of which only eight are detected at X-ray wavelengths with $\\rm f_{0.5-2keV}\\magcir 1.2 \\times 10^{-14}$ ergs cm$^{-2}$ s$^{-1}$. For the remaining 9 SDSS clusters we estimate their 3$\\sigma$ luminosity upper limits (corresponding to $L_x\\mincir 5\\times 10^{42}$ ergs/sec in the 0.5-2 keV band). This relatively low luminosity suggests that if real structures, these galaxy aggregations correspond to poor groups of galaxies. Using the SDSS photometric catalogue we also derive the cluster optical $r$-band luminosities. The resulting scaling relations ($L_{\\rm opt}-L_x$, $L_{\\rm opt}-T_x$) are consistent with those of other recent studies.

  6. The SDSS-based Polar Rings Catalogue: new confirmations

    CERN Document Server

    Moiseev, Alexei; Smirnova, Ksenia

    2014-01-01

    Using the long-slit spectroscopic and scanning Fabry-Perot interferometer observations at the SAO RAS 6-m telescope we have studied the gas and stars kinematics of galaxies among the SDSS-based Polar Rings Catalogue. The updated list of the confirmed candidates with gas chemical abundance measurements is presented.

  7. Bright X-ray galaxies in SDSS filaments

    OpenAIRE

    Tugay, A. V.

    2013-01-01

    Eighteen bright X-ray emitting galaxies were found in nearby filaments within SDSS region. Basic X-ray spectral parameters were estimated for these galaxies using power law model with photoelectric absorption. A close pair of X-ray galaxies was found.

  8. Results of optical monitoring of 5 SDSS double QSOs with the Nordic Optical Telescope

    CERN Document Server

    Paraficz, Danuta; Elíasdóttir, Árdís

    2009-01-01

    We present optical R-band light curves of five SDSS double QSOs (SDSS J0903+5028, SDSS J1001+5027, SDSS J1206+4332, SDSS J1353+1138, SDSS J1335+0118) obtained from monitoring at the Nordic Optical Telescope (NOT) between September 2005 and September 2007. We also present analytical and pixelated modeling of the observed systems. For SDSS J1206+4332, we measured the time delay to be 116 days, which, for a Singular Isothermal Ellipsoid model, corresponds to a Hubble constant of 73 km/s/Mpc. Simultaneous pixeleted modeling of five other systems for which a time delay has now been previously measured at the NOT leads to H_0 = 61.5 km/s/Mpc. Finally, by comparing lightcurves of the two images of each system, suitably shifted by the predicted or observed time-delays, we found no evidence for microlensing variability over the course of the monitoring period.

  9. The Sloan Nearby Cluster Weak Lensing Survey

    CERN Document Server

    Kubo, Jeffrey M; Hardin, Frances Mei; Kubik, Donna; Lawhorn, Kelsey; Lin, Huan; Nicklaus, Liana; Nelson, Dylan; Reis, Ribamar R R; Seo, Hee-Jong; Soares-Santos, Marcelle; Stebbins, Albert; Yunker, Tony

    2009-01-01

    We describe and present initial results of a weak lensing survey of nearby ($\\rm{z}\\lesssim0.1$) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of \\citet{miller05} and \\citet{berlind06}. We report a total of seven individual low redshift cluster weak lensing measurements which include: A2048, A1767, A2244, A1066, A2199, and two clusters specifically identified with the C4 algorithm. Our program of weak lensing of nearby galaxy clusters in the SDSS will eventually reach $\\sim 200$ clusters, making it the largest weak lensing survey of individual galaxy clusters to date.

  10. Mapping Hydrogen in the Galaxy, Galactic Halo, and Local Group with ALFA: The GALFA-H I Survey Starting with TOGS

    Science.gov (United States)

    Gibson, S. J.; Douglas, K. A.; Heiles, C.; Korpela, E. J.; Peek, J. E. G.; Putman, M. E.; Stanimirović, S.

    2008-08-01

    Radio observations of gas in the Milky Way and Local Group are vital for understanding how galaxies function as systems. The unique sensitivity of Arecibo's 305 m dish, coupled with the 7-beam Arecibo L-Band Feed Array (ALFA), provides an unparalleled tool for investigating the full range of interstellar phenomena traced by the H I 21 cm line. The GALFA (Galactic ALFA) H I Survey is mapping the entire Arecibo sky over a velocity range of -700 to +700 km s-1 with 0.2 km s-1 velocity channels and an angular resolution of 3.4'. We present highlights from the TOGS (Turn On GALFA Survey) portion of GALFA-H I, which is covering thousands of square degrees in commensal drift scan observations with the ALFALFA and AGES extragalactic ALFA surveys. This work is supported in part by the National Astronomy and Ionosphere Center, operated by Cornell University under cooperative agreement with the National Science Foundation.

  11. Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

    Directory of Open Access Journals (Sweden)

    D. Janches

    2004-01-01

    Full Text Available Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam and finally seen in the side lobe again. Using geometrical arguments to calculate the meteor velocity in the plane perpendicular to the beam axis, we find that most of the meteors are travelling within ~15° with respect to the beam axis, in excellent agreement with previous estimates. These results suggest that meteoroids entering the atmosphere at greater angles may deposit their meteoric material at higher altitudes explaining at some level the missing mass inconsistency raised by the comparisson of meteor fluxes derived from satellite and traditional meteor radar observations. They also may be the source of the observed high altitude ions and metalic layers observed by radars and lidars respectively.

  12. Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

    Science.gov (United States)

    Janches, D.; Nolan, M. C.; Sulzer, M.

    2004-04-01

    Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO) micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR) meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam and finally seen in the side lobe again. Using geometrical arguments to calculate the meteor velocity in the plane perpendicular to the beam axis, we find that most of the meteors are travelling within ~15° with respect to the beam axis, in excellent agreement with previous estimates. These results suggest that meteoroids entering the atmosphere at greater angles may deposit their meteoric material at higher altitudes explaining at some level the missing mass inconsistency raised by the comparisson of meteor fluxes derived from satellite and traditional meteor radar observations. They also may be the source of the observed high altitude ions and metalic layers observed by radars and lidars respectively.

  13. Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz dual-beam radar

    Directory of Open Access Journals (Sweden)

    D. Janches

    2004-01-01

    Full Text Available Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam and finally seen in the side lobe again. Using geometrical arguments to calculate the meteor velocity in the plane perpendicular to the beam axis, we find that most of the meteors are travelling within ~15° with respect to the beam axis, in excellent agreement with previous estimates. These results suggest that meteoroids entering the atmosphere at greater angles may deposit their meteoric material at higher altitudes explaining at some level the missing mass inconsistency raised by the comparisson of meteor fluxes derived from satellite and radar observations. They also may be the source of the observed high altitude ions and metallic layers observed by radars and lidars respectively.

  14. Arecibo Multi-Epoch HI Absorption Measurements Against Pulsars: Tiny-Scale Atomic Structure

    CERN Document Server

    Stanimirovic, S; Pei, Z; Tuttle, K; Green, J T

    2010-01-01

    We present results from multi-epoch neutral hydrogen (HI) absorption observations of six bright pulsars with the Arecibo telescope. Moving through the interstellar medium (ISM) with transverse velocities of 10--150 AU/yr, these pulsars have swept across 1--200 AU over the course of our experiment, allowing us to probe the existence and properties of the tiny scale atomic structure (TSAS) in the cold neutral medium (CNM). While most of the observed pulsars show no significant change in their HI absorption spectra, we have identified at least two clear TSAS-induced opacity variations in the direction of B1929+10. These observations require strong spatial inhomogeneities in either the TSAS clouds' physical properties themselves or else in the clouds' galactic distribution. While TSAS is occasionally detected on spatial scales down to 10 AU, it is too rare to be characterized by a spectrum of turbulent CNM fluctuations on scales of 10-1000 AU, as previously suggested by some work. In the direction of B1929+10, an...

  15. ARECIBO MULTI-EPOCH H I ABSORPTION MEASUREMENTS AGAINST PULSARS: TINY-SCALE ATOMIC STRUCTURE

    International Nuclear Information System (INIS)

    We present results from multi-epoch neutral hydrogen (H I) absorption observations of six bright pulsars with the Arecibo telescope. Moving through the interstellar medium (ISM) with transverse velocities of 10-150 AU yr-1, these pulsars have swept across 1-200 AU over the course of our experiment, allowing us to probe the existence and properties of the tiny-scale atomic structure (TSAS) in the cold neutral medium (CNM). While most of the observed pulsars show no significant change in their H I absorption spectra, we have identified at least two clear TSAS-induced opacity variations in the direction of B1929+10. These observations require strong spatial inhomogeneities in either the TSAS clouds' physical properties themselves or else in the clouds' galactic distribution. While TSAS is occasionally detected on spatial scales down to 10 AU, it is too rare to be characterized by a spectrum of turbulent CNM fluctuations on scales of 101-103 AU, as previously suggested by some work. In the direction of B1929+10, an apparent correlation between TSAS and interstellar clouds inside the warm Local Bubble (LB) indicates that TSAS may be tracing the fragmentation of the LB wall via hydrodynamic instabilities. While similar fragmentation events occur frequently throughout the ISM, the warm medium surrounding these cold cloudlets induces a natural selection effect wherein small TSAS clouds evaporate quickly and are rare, while large clouds survive longer and become a general property of the ISM.

  16. Cool White Dwarfs in the Sloan Digital Sky Survey

    CERN Document Server

    Kilic, M; Harris, H C; Liebert, J; Von Hippel, T; Williams, K A; Metcalfe, T S; Winget, D E; Levine, S E; Kilic, Mukremin; Munn, Jeffrey A.; Harris, Hugh C.; Liebert, James; Hippel, Ted von; Williams, Kurtis A.; Metcalfe, Travis S.; Levine, Stephen E.

    2005-01-01

    A reduced proper motion diagram utilizing Sloan Digital Sky Survey (SDSS) photometry and astrometry and USNO-B plate astrometry is used to separate cool white dwarf candidates from metal-weak, high-velocity main sequence Population II stars (subdwarfs) in the SDSS Data Release 2 imaging area. Follow-up spectroscopy using the Hobby-Eberly Telescope, the MMT, and the McDonald 2.7m Telescope is used to demonstrate that the white dwarf and subdwarf loci separate cleanly in the reduced proper motion diagram, and that the contamination by subdwarfs is small near the cool white dwarf locus. This enables large statistically complete samples of white dwarfs, particularly the poorly understood cool white dwarfs, to be created from the SDSS imaging survey, with important implications for white dwarf luminosity function studies. SDSS photometry for our sample of cool white dwarfs is compared to current white dwarf models.

  17. A topological analysis of large-scale structure, studied using the CMASS sample of SDSS-III

    International Nuclear Information System (INIS)

    We study the three-dimensional genus topology of large-scale structure using the northern region of the CMASS Data Release 10 (DR10) sample of the SDSS-III Baryon Oscillation Spectroscopic Survey. We select galaxies with redshift 0.452 < z < 0.625 and with a stellar mass M stellar > 1011.56 M ☉. We study the topology at two smoothing lengths: R G = 21 h –1 Mpc and R G = 34 h –1 Mpc. The genus topology studied at the R G = 21 h –1 Mpc scale results in the highest genus amplitude observed to date. The CMASS sample yields a genus curve that is characteristic of one produced by Gaussian random phase initial conditions. The data thus support the standard model of inflation where random quantum fluctuations in the early universe produced Gaussian random phase initial conditions. Modest deviations in the observed genus from random phase are as expected from shot noise effects and the nonlinear evolution of structure. We suggest the use of a fitting formula motivated by perturbation theory to characterize the shift and asymmetries in the observed genus curve with a single parameter. We construct 54 mock SDSS CMASS surveys along the past light cone from the Horizon Run 3 (HR3) N-body simulations, where gravitationally bound dark matter subhalos are identified as the sites of galaxy formation. We study the genus topology of the HR3 mock surveys with the same geometry and sampling density as the observational sample and find the observed genus topology to be consistent with ΛCDM as simulated by the HR3 mock samples. We conclude that the topology of the large-scale structure in the SDSS CMASS sample is consistent with cosmological models having primordial Gaussian density fluctuations growing in accordance with general relativity to form galaxies in massive dark matter halos.

  18. A topological analysis of large-scale structure, studied using the CMASS sample of SDSS-III

    Energy Technology Data Exchange (ETDEWEB)

    Parihar, Prachi; Gott, J. Richard III [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544-1001 (United States); Vogeley, Michael S. [Department of Physics, Drexel University, Philadelphia, PA 19104 (United States); Choi, Yun-Young [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Kim, Juhan [Center for Advanced Computation, Korea Institute for Advanced Study, Heogiro 85, Seoul 130-722 (Korea, Republic of); Kim, Sungsoo S. [School of Space Research, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Speare, Robert [New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi (United Arab Emirates); Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Brinkmann, J., E-mail: pparihar@caltech.edu, E-mail: yy.choi@khu.ac.kr [Apache Point Observatory, Sunspot, NM 88349 (United States)

    2014-12-01

    We study the three-dimensional genus topology of large-scale structure using the northern region of the CMASS Data Release 10 (DR10) sample of the SDSS-III Baryon Oscillation Spectroscopic Survey. We select galaxies with redshift 0.452 < z < 0.625 and with a stellar mass M {sub stellar} > 10{sup 11.56} M {sub ☉}. We study the topology at two smoothing lengths: R {sub G} = 21 h {sup –1} Mpc and R {sub G} = 34 h {sup –1} Mpc. The genus topology studied at the R {sub G} = 21 h {sup –1} Mpc scale results in the highest genus amplitude observed to date. The CMASS sample yields a genus curve that is characteristic of one produced by Gaussian random phase initial conditions. The data thus support the standard model of inflation where random quantum fluctuations in the early universe produced Gaussian random phase initial conditions. Modest deviations in the observed genus from random phase are as expected from shot noise effects and the nonlinear evolution of structure. We suggest the use of a fitting formula motivated by perturbation theory to characterize the shift and asymmetries in the observed genus curve with a single parameter. We construct 54 mock SDSS CMASS surveys along the past light cone from the Horizon Run 3 (HR3) N-body simulations, where gravitationally bound dark matter subhalos are identified as the sites of galaxy formation. We study the genus topology of the HR3 mock surveys with the same geometry and sampling density as the observational sample and find the observed genus topology to be consistent with ΛCDM as simulated by the HR3 mock samples. We conclude that the topology of the large-scale structure in the SDSS CMASS sample is consistent with cosmological models having primordial Gaussian density fluctuations growing in accordance with general relativity to form galaxies in massive dark matter halos.

  19. COLOR-DENSITY RELATION IN THE LOW Z SAMPLE OF THE SDSS DR10

    Directory of Open Access Journals (Sweden)

    Xin-Fa Deng

    2015-01-01

    Full Text Available El objetivo de este estudio es examinar la dependencia ambiental de los colores u - r, u - g, g - r, r - i e i - z en la muestra de baja z del Sloan Digital Sky Survey Data Release 10 (SDSS DR10. Para disminuir el efecto de selección radial, divido la muestra de baja z en submuestras agrupadas en intervalos de ∆z=0.01 y analizo la dependencia ambiental de los colores para estas submuestras en cada intervalo de corrimiento al rojo. Los resultados estadísticos indican que los cinco colores de la muestra de baja z están levemente correlacionados con las propiedades ambientales locales, lo cual coincide con lo encontrado para galaxias principales a z > 0.15 y para galaxias GMASS.

  20. Nature or nurture? Clues from the distribution of specific star formation rates in SDSS galaxies

    CERN Document Server

    Casado, Javier; Gavilán, Marta; Terlevich, Roberto; Terlevich, Elena; Hoyos, Carlos; Díaz, Ángeles I

    2015-01-01

    This work investigates the main mechanism(s) that regulate the specific star formation rate (SSFR) in nearby galaxies, cross-correlating two proxies of this quantity -- the equivalent width of the \\Ha\\ line and the $(u-r)$ colour -- with other physical properties (mass, metallicity, environment, morphology, and the presence of close companions) in a sample of $\\sim82500$ galaxies extracted from the Sloan Digital Sky Survey (SDSS). The existence of a relatively tight `ageing sequence' in the colour-equivalent width plane favours a scenario where the secular conversion of gas into stars (i.e. `nature') is the main physical driver of the instantaneous SSFR and the gradual transition from a `chemically primitive' (metal-poor and intensely star-forming) state to a `chemically evolved' (metal-rich and passively evolving) system. Nevertheless, environmental factors (i.e. `nurture') are also important. In the field, galaxies may be temporarily affected by discrete `quenching' and `rejuvenation' episodes, but such eve...

  1. Mean-flux Regulated PCA Continuum Fitting of SDSS Lyman-alpha Forest Spectra

    CERN Document Server

    Lee, Khee-Gan; Spergel, David N

    2011-01-01

    Continuum fitting is an important aspect of Lyman-alpha forest science, since errors in the estimated optical depths scale with the fractional continuum error. However, traditional methods of estimating continua in noisy and moderate-resolution spectra (S/N 5. The residual Fourier power in the continuum is decreased by a factor of a few in comparison with dividing by the mean continuum, enabling Lyman-alpha flux power spectrum measurements to be extended to ~2x larger scales. Using this new technique, we make available continuum fits for 12,069 z>2.3 Lyman-alpha forest spectra from SDSS DR7 for use by the community. This technique is also applicable to future releases of the ongoing BOSS survey, which is obtaining spectra for ~ 150,000 Lyman-alpha forest spectra at low signal-to-noise (S/N ~ 2).

  2. Self-similarity and universality of void density profiles in simulation and SDSS data

    CERN Document Server

    Nadathur, S; Diego, J M; Iliev, I T; Gottlöber, S; Watson, W A; Yepes, G

    2014-01-01

    The stacked density profile of cosmic voids in the galaxy distribution provides an important tool for the use of voids for precision cosmology. We study the density profiles of voids identified using the ZOBOV watershed transform algorithm in realistic mock luminous red galaxy (LRG) catalogues from the Jubilee simulation, as well as in void catalogues constructed from the SDSS LRG and Main Galaxy samples. We compare different methods for reconstructing density profiles scaled by the void radius and show that the most commonly used method based on counts in shells and simple averaging is statistically flawed as it underestimates the density in void interiors. We provide two alternative methods that do not suffer from this effect; one based on Voronoi tessellations is also easily able to account from artefacts due to finite survey boundaries and so is more suitable when comparing simulation data to observation. Using this method we show that voids in simulation are exactly self-similar, meaning that their avera...

  3. Mass Models and Environment of the New Quadruply Lensed Quasar SDSS J1330+1810

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Inada, Naohisa; Blackburne, Jeffrey A.; Shin, Min-Su; Kayo, Issha; Strauss, Michael A.; Schneider, Donald P.; York, Donald G.

    2008-09-09

    We present the discovery of a new quadruply lensed quasar. The lens system, SDSS J1330+1810 at z{sub s} = 1.393, was identified as a lens candidate from the spectroscopic sample of the Sloan Digital Sky Survey. Optical and near-infrared images clearly show four quasar images with a maximum image separation of 1.76 inch, as well as a bright lensing galaxy. We measure a redshift of the lensing galaxy of z{sub 1} = 0.373 from absorption features in the spectrum. We find a foreground group of galaxies at z = 0.31 centred {approx} 120 inch southwest of the lens system. Simple mass models fit the data quite well, including the flux ratios between images, although the lens galaxy appears to be {approx} 1 mag brighter than expected by the Faber-Jackson relation. Our mass modeling suggests that shear from nearby structure is affecting the lens potential.

  4. Detailed abundances in extremely metal poor dwarf stars extracted from SDSS

    CERN Document Server

    Sbordone, Luca; Caffau, Elisabetta; Ludwig, Hans-Gunther

    2012-01-01

    We report on the result of an ongoing campaign to determine chemical abundances in extremely metal poor (EMP) turn-off (TO) stars selected from the Sloan Digital Sky Survey (SDSS) low resolution spectra. This contribution focuses principally on the largest part of the sample (18 stars out of 29), observed with UVES@VLT and analyzed by means of the automatic abundance analysis code MyGIsFOS to derive atmosphere parameters and detailed compositions. The most significant findings include i) the detection of a C-rich, strongly Mg-enhanced star ([Mg/Fe]=1.45); ii) a group of Mn-rich stars ([Mn/Fe]>-0.4); iii) a group of Ni-rich stars ([Ni/Fe]>0.2). Li is measured in twelve stars, while for three upper limits are derived.

  5. The sloan digital sky survey-II supernova survey

    DEFF Research Database (Denmark)

    Frieman, Joshua A.; Bassett, Bruce; Becker, Andrew;

    2008-01-01

    The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5° wide...

  6. [Searching for WDMS Candidates In SDSS-DR10 With Automatic Method].

    Science.gov (United States)

    Jiang, Bin; Wang, Cheng-you; Wang, Wen-yu; Wang, Wei

    2015-05-01

    The Sloan Digital Sky Survey (SDSS) has released the latest data (DR10) which covers the first APOGEE spectra. The massive spectra can be used for large sample research inscluding the structure and evolution of the Galaxy and multi-wave-band identi cation. In addition, the spectra are also ideal for searching for rare and special objects like white dwarf main-sequence star (WDMS). WDMS consist of a white dwarf primary and a low-mass main-sequence (MS) companion which has positive significance to the study of evolution and parameter of close binaries. WDMS is generally discovered by repeated imaging of the same area of sky, measuring light curves for objects or through photometric selection with follow-up observations. These methods require significant manual processing time with low accuracy and the real-time processing requirements can not be satisfied. In this paper, an automatic and efficient method for searching for WDMS candidates is presented. The method Genetic Algorithm (GA) is applied in the newly released SDSS-DR10 spectra. A total number of 4 140 WDMS candidates are selected by the method and 24 of them are new discoveries which prove that our approach of finding special celestial bodies in massive spectra data is feasible. In addition, this method is also applicable to mining other special celestial objects in sky survey telescope data. We report the identfication of 24 new WDMS with spectra. A compendium of positions, mjd, plate and fiberid of these new discoveries is presented which enrich the spectral library and will be useful to the research of binary evolution models. PMID:26415473

  7. STATISTICAL STUDY OF 2XMMi-DR3/SDSS-DR8 CROSS-CORRELATION SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanxia; Zhou Xinlin; Zhao Yongheng [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, 100012 Beijing (China); Wu Xuebing, E-mail: zyx@bao.ac.cn [Department of Astronomy, Peking University, 100871 Beijing (China)

    2013-02-01

    Cross-correlating the XMM-Newton 2XMMi-DR3 catalog with the Sloan Digital Sky Survey (SDSS) Data Release 8, we obtain one of the largest X-ray/optical catalogs and explore the distribution of various classes of X-ray emitters in the multidimensional photometric parameter space. Quasars and galaxies occupy different zones while stars scatter in them. However, X-ray active stars have a certain distributing rule according to spectral types. The earlier the type of stars, the stronger its X-ray emitting. X-ray active stars have a similar distribution to most stars in the g - r versus r - i diagram. Based on the identified samples with SDSS spectral classification, a random forest algorithm for automatic classification is performed. The result shows that the classification accuracy of quasars and galaxies adds up to more than 93.0% while that of X-ray emitting stars only amounts to 45.3%. In other words, it is easy to separate quasars and galaxies, but it is difficult to discriminate X-ray active stars from quasars and galaxies. If we want to improve the accuracy of automatic classification, it is necessary to increase the number of X-ray emitting stars, since the majority of X-ray emitting sources are quasars and galaxies. The results obtained here will be used for the optical spectral survey performed by the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST, also named the Guo Shou Jing Telescope), which is a Chinese national scientific research facility operated by the National Astronomical Observatories, Chinese Academy of Sciences.

  8. Past and present cosmic structure in the SDSS DR7 main sample

    International Nuclear Information System (INIS)

    We present a chrono-cosmography project, aiming at the inference of the four dimensional formation history of the observed large scale structure from its origin to the present epoch. To do so, we perform a full-scale Bayesian analysis of the northern galactic cap of the Sloan Digital Sky Survey (SDSS) Data Release 7 main galaxy sample, relying on a fully probabilistic, physical model of the non-linearly evolved density field. Besides inferring initial conditions from observations, our methodology naturally and accurately reconstructs non-linear features at the present epoch, such as walls and filaments, corresponding to high-order correlation functions generated by late-time structure formation. Our inference framework self-consistently accounts for typical observational systematic and statistical uncertainties such as noise, survey geometry and selection effects. We further account for luminosity dependent galaxy biases and automatic noise calibration within a fully Bayesian approach. As a result, this analysis provides highly-detailed and accurate reconstructions of the present density field on scales larger than ∼ 3 Mpc/h, constrained by SDSS observations. This approach also leads to the first quantitative inference of plausible formation histories of the dynamic large scale structure underlying the observed galaxy distribution. The results described in this work constitute the first full Bayesian non-linear analysis of the cosmic large scale structure with the demonstrated capability of uncertainty quantification. Some of these results will be made publicly available along with this work. The level of detail of inferred results and the high degree of control on observational uncertainties pave the path towards high precision chrono-cosmography, the subject of simultaneously studying the dynamics and the morphology of the inhomogeneous Universe

  9. Why Are Hyperbolic Micrometeors No Longer Detected with the Arecibo UHF Radar ?

    Science.gov (United States)

    Meisel, D. D.; Bartlett, B. D.; Mathews, J. D.; Janches, D.; Briczinski, S.

    2004-05-01

    Micrometeor detections using the AO UHF radar have been carried out since 1997. During 1997-2000, hyperbolic (presumed extrasolar origin) orbits were obtained for about 3% of the some 30,000 detections (Meisel et al. 2003 on publicly available from the author CD-ROM and Meisel et al. Ap.J. 567, 323 2002a, Ap.J. 579,895 2002b). In one of those papers (2002a), it was predicted that Jupiter was (over the next 3 to 5 years) going to move into the predominant radiant direction of the extrasolar orbits, i.e. the local interstellar bubble. Thus it was expected that the number of extrasolar meteors would diminish. What was not expected was, however, that so far in 2001-2004 no hyperbolic orbits have been found among nearly 20,000 more orbits. At the size range of the detected micrometeors, perturbations by the major planets, solar photons as well as solar wind particle charging and magnetic field interactions must be taken into account. Thus the apparent Jovian perturbing forces (even on elliptical orbits) seems to exceed that provided by gravity alone and is likely to involve action by the extensive Jovian magnetosphere. The situation in the future promises to be even more confused because Saturn will be moving through the same radiant area even as Jupiter moves out. The micrometeor flux is continuing to be closely monitored from AO. This research is supported through NSF Planetary Astronomy and Aeronomy grants AST0205974, AST9801590, and NRA9612055007. Radar time is provided by NAIC, Arecibo Observatory operated for the National Science Foundation through a cooperative agreement with Cornell University.

  10. Quasar Variability Measurements With SDSS Repeated Imaging and POSS Data

    CERN Document Server

    Ivezic, Z; Juric, M; Anderson, S; Hall, P B; Richards, G T; Rockosi, C M; Vanden Berk, Daniel E; Turner, E L; Knapp, G R; Gunn, J E; Schlegel, D J; Strauss, M A; Schneider, D P

    2004-01-01

    We analyze the properties of quasar variability using repeated SDSS imaging data in five UV-to-far red photometric bands, accurate to 0.02 mag, for 13,000 spectroscopically confirmed quasars. The observed time lags span the range from 3 hours to over 3 years, and constrain the quasar variability for rest-frame time lags of up to two years, and at rest-frame wavelengths from 1000 Ang. to 6000 Ang. We demonstrate that 66,000 SDSS measurements of magnitude differences can be described within the measurement noise by a simple function of only three free parameters. The addition of POSS data constrains the long-term behavior of quasar variability and provides evidence for a turn-over in the structure function. This turn-over indicates that the characteristic time scale for optical variability of quasars is of the order 1 year.

  11. The relative growth of Optical and Radio Quasars in SDSS

    OpenAIRE

    Shankar, Francesco; Sivakoff, Gregory R.; Vestergaard, Marianne; Dai, Xinyu

    2009-01-01

    We cross-correlate the SDSS DR3 quasar sample with FIRST and the Vestergaard et al. black hole (BH) mass sample to compare the mean accretion histories of optical and radio quasars. We find significant statistical evidence that radio quasars have a higher mean Eddington ratio Lambda at z > 2 with respect to optical quasars, while the situation is clearly reverse at z 2 radio quasars happen to be less massive than optical quasars; however, as redshift decreases radio quasars appear...

  12. Hypercalibration: A Pan-STARRS1-based Recalibration of the Sloan Digital Sky Survey Photometry

    Science.gov (United States)

    Finkbeiner, Douglas P.; Schlafly, Edward F.; Schlegel, David J.; Padmanabhan, Nikhil; Jurić, Mario; Burgett, William S.; Chambers, Kenneth C.; Denneau, Larry; Draper, Peter W.; Flewelling, Heather; Hodapp, Klaus W.; Kaiser, Nick; Magnier, E. A.; Metcalfe, N.; Morgan, Jeffrey S.; Price, Paul A.; Stubbs, Christopher W.; Tonry, John L.

    2016-05-01

    We present a recalibration of the Sloan Digital Sky Survey (SDSS) photometry with new flat fields and zero points derived from Pan-STARRS1. Using point-spread function (PSF) photometry of 60 million stars with 16 < r < 20, we derive a model of amplifier gain and flat-field corrections with per-run rms residuals of 3 millimagnitudes (mmag) in griz bands and 15 mmag in u band. The new photometric zero points are adjusted to leave the median in the Galactic north unchanged for compatibility with previous SDSS work. We also identify transient non-photometric periods in SDSS (“contrails”) based on photometric deviations co-temporal in SDSS bands. The recalibrated stellar PSF photometry of SDSS and PS1 has an rms difference of {9, 7, 7, 8} mmag in griz, respectively, when averaged over 15‧ regions.

  13. Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. I. Crowded Field Photometry and Cluster Fiducial Sequences in ugriz

    CERN Document Server

    An, Deokkeun; Clem, James L; Yanny, Brian; Rockosi, Constance M; Morrison, Heather L; Harding, Paul; Gunn, James E; Prieto, Carlos Allende; Beers, Timothy C; Cudworth, Kyle M; Ivans, Inese I; Ivezic, Zeljko; Lee, Young Sun; Lupton, Robert H; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie; Watters, Shannon; York, Donald G

    2008-01-01

    We present photometry for globular and open cluster stars observed with the Sloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellar objects with r < 22.5 mag observed by SDSS, we need to understand the characteristics of stars in the SDSS ugriz filters. While star clusters provide important calibration samples for stellar colors, the regions close to globular clusters, where the fraction of field stars is smallest, are too crowded for the standard SDSS photometric pipeline to process. To complement the SDSS imaging survey, we reduce the SDSS imaging data for crowded cluster fields using the DAOPHOT/ALLFRAME suite of programs and present photometry for 17 globular clusters and 3 open clusters in a SDSS value-added catalog. Our photometry and cluster fiducial sequences are on the native SDSS 2.5-meter ugriz photometric system, and the fiducial sequences can be directly applied to the SDSS photometry without relying upon any transformations. Model photometry for red giant branch and main...

  14. A Systematic Search for Changing-Look Quasars in SDSS

    CERN Document Server

    MacLeod, Chelsea L; Lawrence, Andy; Goad, Mike; Horne, Keith; Burgett, William; Chambers, Ken C; Flewelling, Heather; Hodapp, Klaus; Kaiser, Nick; Magnier, Eugene; Wainscoat, Richard; Waters, Christopher

    2015-01-01

    We present a systematic search for changing-look quasars based on repeat photometry from SDSS and Pan-STARRS1, along with repeat spectra from SDSS and SDSS-III BOSS. Objects with large, $|\\Delta g|>1$~mag photometric variations in their light curves are selected as candidates to look for changes in broad emission line (BEL) features. Out of a sample of 1011 objects that satisfy our selection criteria and have more than one epoch of spectroscopy, we find 10 examples of quasars that have variable and/or "changing-look'' BEL features. Four of our objects have emerging BELs; five have disappearing BELs, and one object shows tentative evidence for having both emerging and disappearing BELs. With redshifts in the range 0.2012% of luminous quasars that vary by |\\Delta g|>1 mag display changing-look BEL features on rest-frame timescales of 8 to 10 years. We discuss the possibilities for the origin of such BEL changes, such as a change in obscuration or in the central engine.

  15. Tracing Sagittarius Structure with SDSS and SEGUE Imaging and Spectroscopy

    CERN Document Server

    Yanny, Brian; Johnson, Jennifer A; Lee, Young Sun; Beers, Timothy C; Bizyaev, Dmitry; Brewington, Howard; Fiorentin, Paola Re; Harding, Paul; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie

    2009-01-01

    We show that the Sagittarius dwarf tidal stream can be traced with very red K/M-giant stars selected from SDSS photometry. A subset of these stars are spectroscopically confirmed with SEGUE and SDSS spectra, and the distance scale of 2MASS and SDSS M giants is calibrated to the RR Lyrae distance scale. The absolute g band magnitude of the K/M-giant stars at the tip of the giant branch is M_g=-1.0. The line-of-sight velocities of the M giant and BHB stars that are spatially coincident with the Sgr dwarf tidal stream are consistent with those of previous authors, reinforcing the need for new models that can explain all of the Sgr tidal debris stream observations. We estimate stellar densities along the tidal tails that can be used to help constrain future models. The K/M-giant, BHB, and F-turnoff stars in the lower surface brightness tidal stream that is adjacent to the main leading Sgr dwarf tidal tail have velocities and metallicities that are similar to those of the stars in the leading tidal tail. The ratio...

  16. LOW LUMINOSITY AGN CANDIDATES IN SDSS

    OpenAIRE

    J. P. Torres-Papaqui; R. Coziol; J. M. Islas-Islas; Ortega-Minakata, R. A.; D. M. Neri-Larios

    2011-01-01

    En una muestra de 476931 galaxias con l neas de emisi n agostas del Sloan Digital Sky Survey Data Release 5, identificamos y estudiamos galaxias de las cuales algunas importantes l neas de emisi n usadas para determinar la naturaleza de su actividad ([OIII]h5007 A, H , o ambas) no est an presentes. Este fen meno afecta al 22% de las galaxias con l neas de emisi n y no esta relacionado con una baja raz n de se al a ruido. En el diagrama comparando el ancho equivalente EW([NII]h6584) con la raz...

  17. Radio-Selected Quasars in the Sloan Digital Sky Survey

    Science.gov (United States)

    McGreer, Ian D.; Helfand, David J.; White, Richard L.

    2009-12-01

    We have conducted a pilot survey for z > 3.5 quasars by combining the FIRST radio survey with the Sloan Digital Sky Survey (SDSS). While SDSS already targets FIRST sources for spectroscopy as quasar candidates, our survey includes fainter quasars and greatly improves the discovery rate by using strict astrometric criteria for matching the radio and optical positions. Our method allows for selection of high-redshift quasars with less color bias than with optical selection, as using radio selection essentially eliminates stellar contamination. We report the results of spectroscopy for 45 candidates, including 29 quasars in the range 0.37 3.5. We compare quasars selected using radio and optical criteria, and find that radio-selected quasars have a much higher fraction of moderately reddened objects. We derive a radio-loud quasar luminosity function at 3.5 4.0, and find that it is in good agreement with expectations from prior SDSS results.

  18. Two More Candidate AM Canum Venaticorum (AM CVn) Binaries from the Sloan Digital Sky Survey

    CERN Document Server

    Anderson, S F; Haggard, D; Prieto, J L; Knapp, G R; Sako, M; Halford, K B; Jha, S; Martin, B; Holtzman, J; Frieman, J A; Garnavich, P M; Hayward, S; Ivezic, Z; Mukadam, A S; Sesar, B; Szkody, P; Malanushenko, V; Richmond, M W; Schneider, D P; York, D G

    2008-01-01

    AM CVn systems are a select group of ultracompact binaries with the shortest orbital periods of any known binary subclass; mass-transfer is likely from a low-mass (partially-)degenerate secondary onto a white dwarf primary, driven by gravitational radiation. In the past few years, the Sloan Digital Sky Survey (SDSS) has provided five new AM CVns. Here we report on two further candidates selected from more recent SDSS data. SDSS J1208+3550 is similar to the earlier SDSS discoveries, recognized as an AM CVn via its distinctive spectrum which is dominated by helium emission. From the expanded SDSS Data Release 6 (DR6) spectroscopic area, we provide an updated surface density estimate for such AM CVns of order 10^{-3.1} to 10^{-2.5} per deg^2 for 15SDSS J2047+0008, that was discovered in the course of followup of SDSS-II supernova candidates. It shows nova-like outbursts in multi-epoch imaging data; in contrast to the other SDSS AM CVn discoveri...

  19. Toward understanding environmental effects in SDSS clusters

    Energy Technology Data Exchange (ETDEWEB)

    Einasto, Jaan; Tago, E.; Einasto, M.; Saar, E.; Suhhonenko, I.; /Tartu Observ.; Heinamaki, P.; /Tartu Observ. /Tuorla Observ.; Hutsi, G.; /Tartu Observ. /Garching, Max; Tucker, D.L.; /Fermilab

    2004-11-01

    We find clusters and superclusters of galaxies using the Data Release 1 of the Sloan Digital Sky Survey. We determine the luminosity function of clusters and find that clusters in a high-density environment have a luminosity a factor of {approx}5 higher than in a low-density environment. We also study clusters and superclusters in numerical simulations. Simulated clusters in a high-density environment are also more massive than those in a low-density environment. Comparison of the density distribution at various epochs in simulations shows that in large low-density regions (voids) dynamical evolution is very slow and stops at an early epoch. In contrast, in large regions of higher density (superclusters) dynamical evolution starts early and continues until the present; here particles cluster early, and by merging of smaller groups very rich systems of galaxies form.

  20. Astronomical surveys and big data

    Science.gov (United States)

    Mickaelian, Areg M.

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum, from γ -rays to radio waves, are reviewed, including such as Fermi-GLAST and INTEGRAL in γ -ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and POSS II-based catalogues (APM, MAPS, USNO, GSC) in the optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio range, and many others, as well as the most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS), and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era, with Astrophysical Virtual Observatories and Computational Astrophysics playing an important role in using and analyzing big data for new discoveries.

  1. Astronomical Surveys and Big Data

    CERN Document Server

    Mickaelian, A M

    2015-01-01

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum are reviewed, from Gamma-ray to radio, such as Fermi-GLAST and INTEGRAL in Gamma-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era. Astrophysical Virtual Observatories and Computational Astrophysics play a...

  2. Search for Hyper Infrared-Luminous Dust Obscured Galaxies selected with WISE and SDSS

    CERN Document Server

    Toba, Yoshiki

    2016-01-01

    We aim to search for hyperliminous infrared (IR) galaxies (HyLIRGs) with IR luminosity $L_{{\\rm IR}}$ $>$ 10$^{13}$ $L_{\\odot}$ by applying the selection method of Dust Obscured Galaxies (DOGs). They are spatially rare but could correspond to a maximum phase of cosmic star formation and/or active galactic nucleus (AGN) activity, hence they are a crucial population for understanding the star formation and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE), we performed the extensive HyLIRGs survey; we selected 5,311 IR-bright DOGs with $i$ -- [22] $>$ 7.0 and flux at 22 $\\mu$m $>$ 3.8 mJy in 14,555 deg$^2$, where $i$ and [22] are $i$-band and 22 $\\mu$m AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the SED fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically-...

  3. Spectral energy distributions of an AKARI-SDSS-GALEX sample of galaxies

    CERN Document Server

    Buat, V; Takeuchi, T T; Heinis, S; Yuan, F T; Burgarella, D; Noll, S; Iglesias-Paramo, J

    2011-01-01

    The nearby universe remains the best laboratory to understand physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys performed from the ultraviolet (UV) to the far-infrared (far-IR) gives us large datasets with a very large wavelength coverage to perform a reference study. We want to investigate dust attenuation characteristics as well as star formation rate (SFR) calibrations on a sample of nearby galaxies observed over 13 bands from 0.15 to 160 microns. A sample of 363 galaxies is built from the AKARI /FIS all sky survey cross-correlated with SDSS and GALEX surveys. Broad band spectral energy distributions are fitted with the CIGALE code optimized to analyze variations in dust attenuation curves and SFR measurements and based on an energetic budget between the stellar and dust emission. Our galaxy sample is primarily selected in far-IR and mostly constituted of massive, actively star forming galaxies. There is some evidence ...

  4. SLoWPoKES-II: 100,000 Wide Binaries Identified in SDSS without Proper Motions

    Science.gov (United States)

    Dhital, Saurav; West, Andrew A.; Stassun, Keivan G.; Schluns, Kyle J.; Massey, Angela P.

    2015-08-01

    We present the Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES)-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey (SDSS) by matching photometric distances. The candidate pairs are vetted by comparing the stellar information. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need for proper motions. Here, 105,537 visual binaries with angular separations of ˜1-20″ were identified, each with a probability of chance alignment of ≤5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems—in mass, mass ratios, binary separations, metallicity, and evolutionary states—that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supporting earlier findings. We suggest that wide binaries are composed of multiple populations, most likely representing different formation modes. There are 141 M7 or later wide binary candidates, representing a seven-fold increase over the number currently known. These binaries are too wide to have been formed via the ejection mechanism. Finally, we found that 6% of spectroscopically confirmed M dwarfs are not included in the SDSS STAR catalog; they are misclassified as extended sources due to the presence of a nearby or partially resolved companion. The SLoWPoKES-II catalog is publicly available to the entire community on the World Wide Web via the Filtergraph data visualization portal.

  5. PHOTOMETRIC REDSHIFT PROBABILITY DISTRIBUTIONS FOR GALAXIES IN THE SDSS DR8

    International Nuclear Information System (INIS)

    We present redshift probability distributions for galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 8 imaging data. We used the nearest-neighbor weighting algorithm to derive the ensemble redshift distribution N(z), and individual redshift probability distributions P(z) for galaxies with r < 21.8 and u < 29.0. As part of this technique, we calculated weights for a set of training galaxies with known redshifts such that their density distribution in five-dimensional color-magnitude space was proportional to that of the photometry-only sample, producing a nearly fair sample in that space. We estimated the ensemble N(z) of the photometric sample by constructing a weighted histogram of the training-set redshifts. We derived P(z)'s for individual objects by using training-set objects from the local color-magnitude space around each photometric object. Using the P(z) for each galaxy can reduce the statistical error in measurements that depend on the redshifts of individual galaxies. The spectroscopic training sample is substantially larger than that used for the DR7 release. The newly added PRIMUS catalog is now the most important training set used in this analysis by a wide margin. We expect the primary sources of error in the N(z) reconstruction to be sample variance and spectroscopic failures: The training sets are drawn from relatively small volumes of space, and some samples have large incompleteness. Using simulations we estimated the uncertainty in N(z) due to sample variance at a given redshift to be ∼10%-15%. The uncertainty on calculations incorporating N(z) or P(z) depends on how they are used; we discuss the case of weak lensing measurements. The P(z) catalog is publicly available from the SDSS Web site.

  6. Peering through the OH Forest: public release of sky-residual subtracted spectra for SDSS DR7

    CERN Document Server

    Wild, Vivienne

    2010-01-01

    The Sloan Digital Sky Survey (SDSS) automated spectroscopic reduction pipeline provides >1.5 million intermediate resolution, R~2000, moderate signal-to-noise ratio (SNR), SNR~15, astronomical spectra of unprecedented homogeneity that cover the wavelength range 3800-9200AA. However, there remain significant systematic residuals in many spectra due to the sub-optimal subtraction of the strong OH sky emission lines longward of 6700AA. The OH sky lines extend over almost half the wavelength range of the SDSS spectra, and the SNR over substantial wavelength regions in many spectra is reduced by more than a factor two over that expected from photon counting statistics. Following the OH line subtraction procedure presented in Wild & Hewett (2005), we make available to the community sky-residual subtracted spectra for the Sloan Digital Sky Survey Data Relase 7. Here we summarise briefly the method, including minor changes in the implementation of the procedure with respect to WH05. The spectra are suitable for m...

  7. Peering through the OH-forest: a new technique to remove residual sky features from SDSS spectra

    CERN Document Server

    Wild, V; Wild, Vivienne; Hewett, Paul C.

    2005-01-01

    The Sloan Digital Sky Survey (SDSS) currently provides by far the largest homogeneous sample of intermediate signal-to-noise ratio (S/N) optical spectra of galaxies and quasars. The fully automated SDSS spectroscopic reduction pipeline has provided spectra of unprecedented quality that cover the wavelength range 3800-9200A. However, in common with spectra from virtually all multi-object surveys employing fibres, there remain significant systematic residuals in many of the spectra due to the incomplete subtraction of the strong OH sky emission lines longward of 6700A. The S/N over substantial wavelength regions in many spectra is reduced by more than a factor of 2 over that expected from counting statistics. We present a method to automatically remove the sky residual signal, using a principal component analysis (PCA) which takes advantage of the correlation in the form of the sky subtraction residuals present in each spectrum. Application of the method results in spectra with essentially no evidence for degra...

  8. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki [Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Itoh, Ryosuke [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, Kobe, Hyogo 658-8501 (Japan); Saito, Yoshihiko; Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Stawarz, Łukasz [Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Gandhi, Poshak [Department of Physics, Durham University, Durham DH1-3LE (United Kingdom); Ali, Gamal; Essam, Ahmad; Hamed, Gamal [National Research Institute of Astronomy and Geophysics, Helwan, Cairo (Egypt); Aoki, Tsutomu [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, Kiso, Nagano 397-0101 (Japan); Contreras, Carlos; Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Iwata, Ikuru, E-mail: masaomi.tanaka@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); and others

    2014-10-01

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

  9. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    International Nuclear Information System (INIS)

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼107 M ☉ implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 102-3 × 103, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies

  10. The ALFA ZOA Deep Survey: First Results

    CERN Document Server

    McIntyre, Travis P; Minchin, Robert F; Momjian, Emmanuel; Butcher, Zhon

    2015-01-01

    The Arecibo L-Band Feed Array Zone of Avoidance (ALFA ZOA) Deep Survey is the deepest and most sensitive blind Hi survey undertaken in the ZOA. ALFA ZOA Deep will cover about 300 square degrees of sky behind the Galactic plane in both the inner (30 deg < l < 75 deg; b < |2 deg|) and outer (175 deg < l < 207 deg; -2 deg < b < +1 deg) Galaxy, using the Arecibo Radio Telescope. First results from the survey have found 61 galaxies within a 15 square degree area centered on l = 192 deg and b = -2 deg. The survey reached its expected sensitivity of rms = 1 mJy at 9 km/s channel resolution, and is shown to be complete above integrated flux, F_HI = 0.5 Jy km/s. The positional accuracy of the survey is 28 arcsec and detections are found out to a recessional velocity of nearly 19,000 km/s. The survey confirms the extent of the Orion and Abell 539 clusters behind the plane of the Milky Way and discovers expansive voids, at 10,000 km/s and 18,000 km/s. 26 detections (43%) have a counterpart in the li...

  11. Statistical and fragmentation properties of the micrometeoroid flux observed at Arecibo

    Science.gov (United States)

    Briczinski, S. J.; Mathews, J. D.; Meisel, D. D.

    2009-04-01

    The micrometeor observations performed using the 430 MHz Arecibo Observatory radar have proven to be crucial for the understanding of meteoric effects on the aeronomy of the upper atmosphere. Meteors observed during the February 2001, 2006, and 2007 campaigns have been analyzed with a fast Fourier transform periodic search algorithm that automatically and uniformly detects meteor events between altitudes of 80 and 142 km. We present a description of the new technique used to detect meteors as well as the meteoroid parameters: altitude profiles, radial speeds, and decelerations. We also note the expected correlation between the radar transmitted power and the observed meteor event rate. The large number of events has enabled us to statistically estimate the average mass density of the observed population indicating that our detected events are generally cometary (1 g/cm3) and not asteroidal (3 g/cm3) in origin. Additionally, many meteor events are observed in which the radar meteor disappears from one radar pulse to the next (i.e., in 1 ms). We interpret this as indicative of the catastrophic destruction of the meteoroid. Until destruction, these events appear to undergo only minor ablation of their volatile components over the observed trajectory. As with a major fraction of all events recorded, the meteoroids that disappear in a terminal event show linear decelerations before their abrupt disappearance. This apparently low ablative mass deposition process may play an important role in the composition (aeronomy) of the upper atmosphere, as it likely produces submicron-sized particles rather than the atom level products of ablation. First results on the altitude, speed, and mass distributions of terminal event meteoroids are given yielding some clues on the physics of the terminal event. Finally, the statistics of those events that yield no deceleration are compared statistically with those that exhibit deceleration with the conclusion that both groups are

  12. Initial altitude of the micrometeor phenomenon: Comparison between Arecibo radar observations and theory

    Science.gov (United States)

    Janches, Diego; Revelle, Douglas O.

    2005-08-01

    We present calculations of the altitude at which the micrometeor phenomenon begins, that is, the point where the interaction between micrometeoroids and the Earth's atmosphere becomes important. At these altitudes, physical processes such as light emission, heating, electron production, etc., begin to occur. The calculations are performed using four very different initial height models including (1) solving the full integration of the single-body meteor equations, (2) using a balance between the loss of momentum and the component of the acceleration due to gravity along the meteor trajectory, (3) using a solution that emanates from a "linearized" form of the meteor energy equation but without including either atmosphere or meteoroid radiation emission effects, and finally (4) utilizing a solution of the meteor energy equation that is specifically approximated for small particles. We compare our evaluated theoretical results with direct micrometeor observations detected using the 430 MHz Arecibo Observatory (AO) radar system. The goal of these calculations is to provide reliable initial conditions in order to completely model the AO micrometeor observations, most of which have nearly constant decelerations. The nature of this study, although performed with already existing theoretical formulations, is of unprecedented value because it is the first study where these models are directly compared against very highly resolved micrometeor velocity and altitude distributions that are derived directly from the radar observations. We found that the meteor energy equation approximated for small particles agrees very well with the radar observations, in particular for meteor melting temperatures of the order of 2100 K and entry angles lower than 30° with respect to the radar beam normal direction. Unfortunately, from this model the composition characteristics of the particles detected by the AO radar cannot conclusively be drawn. However, comparison with the calculation of

  13. The atmospheric fate of 0.5-100 micron dust observed as radar micrometeors at Arecibo Observatory.

    Science.gov (United States)

    Mathews, J. D.; Janches, D.; Meisel, D. D.; Zhou, Q.-H.

    Radar micrometeor observations at Arecibo Observatory yield instantaneous Doppler speed and deceleration measurements that, combined with appropriate model atmosphere results, yield the ballistic parameter for many events. Assuming 3 gm/cc mass density and spherical particles, the ballistic parameter is converted to particle mass and size range. The observed size range is 0.5-100 micron radius. These measurements additionally provide daily and seasonal event rates and allow whole-earth mass flux estimates over the observable particle size distribution (Mathews et al., The micrometeor mass flux into the upper atmosphere: Arecibo results and a comparison with prior estimates, Geophysical Research Letters 28, 1929-1932, 2001). Updated mass fluxes will be presented. Further, we present information about the processes whereby the dust particles slow and disperse into the upper atmosphere. We find no evidence of simple ablation over the altitude range that these particles are observed as radar meteors. We do however find that a significant fraction of these particles catastrophically disintegrate and are likely not deposited in atomic form but rather into nanometer-sized smoke particles.

  14. Radio and Meteor Science Outcomes From Comparisons of Meteor Radar Observations at AMISR Poker Flat, Sondrestrom, and Arecibo

    Science.gov (United States)

    Mathews, J. D.; Briczinski, S. J.; Meisel, D. D.; Heinselman, C. J.

    2008-06-01

    Radio science and meteor physics issues regarding meteor “head-echo” observations with high power, large aperture (HPLA) radars, include the frequency and latitude dependency of the observed meteor altitude, speed, and deceleration distributions. We address these issues via the first ever use and analysis of meteor observations from the Poker Flat AMISR (PFISR: 449.3 MHz), Sondrestrom (SRF: 1,290 MHz), and Arecibo (AO: 430 MHz) radars. The PFISR and SRF radars are located near the Arctic Circle while AO is in the tropics. The meteors observed at each radar were detected and analyzed using the same automated FFT periodic micrometeor searching algorithm. Meteor parameters (event altitude, velocity, and deceleration distributions) from all three facilities are compared revealing a clearly defined altitude “ceiling effect” in the 1,290 MHz results relative to the 430/449.3 MHz results. This effect is even more striking in that the Arecibo and PFISR distributions are similar even though the two radars are over 2,000 times different in sensitivity and at very different latitudes, thus providing the first statistical evidence that HPLA meteor radar observations are dominated by the incident wavelength, regardless of the other radar parameters. We also offer insights into the meteoroid fragmentation and “terminal” process.

  15. Sloan Digital Sky Survey Photometric Calibration Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Marriner, John; /Fermilab

    2012-06-29

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  16. Sloan Digital Sky Survey Photometric Calibration Revisited

    Science.gov (United States)

    Marriner, J.

    2016-05-01

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  17. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. OPTICAL DATA

    International Nuclear Information System (INIS)

    We present the optical data for 195 H I-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a new photometric pipeline optimized for large galaxies, thus correcting for SDSS's limited reliability for automatic photometry of angularly large or low surface brightness (LSB) galaxies. We outline the magnitude of the uncertainty in the SDSS catalog-level photometry and derive a quantitative method for correcting the over-sky subtraction in the SDSS photometric pipeline. The main thrust of this paper is to present the ES/SDSS sample and discuss the methods behind the improved photometry, which will be used in future scientific analysis. We present the overall optical properties of the sample and briefly compare to a volume-limited, optically selected sample. Compared to the optically selected SDSS sample (in the similar volume), H I-selected galaxies are bluer and more luminous (fewer dwarf ellipticals and more star formation). However, compared to typical SDSS galaxy studies, which have their own selection effect, our sample is bluer, fainter, and less massive.

  18. Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples

    CERN Document Server

    Betoule, M; Guy, J; Mosher, J; Hardin, D; Biswas, R; Astier, P; El-Hage, P; Konig, M; Kuhlmann, S; Marriner, J; Pain, R; Regnault, N; Balland, C; Bassett, B A; Brown, P J; Campbell, H; Carlberg, R G; Cellier-Holzem, F; Cinabro, D; Conley, A; D'Andrea, C B; DePoy, D L; Doi, M; Ellis, R S; Fabbro, S; Filippenko, A V; Foley, R J; Frieman, J A; Fouchez, D; Galbany, L; Goobar, A; Gupta, R R; Hill, G J; Hlozek, R; Hogan, C J; Hook, I M; Howell, D A; Jha, S W; Guillou, L Le; Leloudas, G; Lidman, C; Marshall, J L; Möller, A; Mourão, A M; Neveu, J; Nichol, R; Olmstead, M D; Palanque-Delabrouille, N; Perlmutter, S; Prieto, J L; Pritchet, C J; Richmond, M; Riess, A G; Ruhlmann-Kleider, V; Sako, M; Schahmaneche, K; Schneider, D P; Smith, M; Sollerman, J; Sullivan, M; Walton, N A; Wheeler, C J

    2014-01-01

    We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The data set includes several low-redshift samples (z<0.1), all 3 seasons from the SDSS-II (0.05 < z < 0.4), and 3 years from SNLS (0.2

  19. Photometric Redshift Estimation on SDSS Data Using Random Forests

    CERN Document Server

    Carliles, Samuel; Heinis, Sebastien; Priebe, Carey; Szalay, Alexander

    2007-01-01

    Given multiband photometric data from the SDSS DR6, we estimate galaxy redshifts. We employ a Random Forest trained on color features and spectroscopic redshifts from 80,000 randomly chosen primary galaxies yielding a mapping from color to redshift such that the difference between the estimate and the spectroscopic redshift is small. Our methodology results in tight RMS scatter in the estimates limited by photometric errors. Additionally, this approach yields an error distribution that is nearly Gaussian with parameter estimates giving reliable confidence intervals unique to each galaxy photometric redshift.

  20. The Demographics of galactic bulges in the SDSS database

    OpenAIRE

    Kim, Keunho; Oh, Sree; Jeong, Hyunjin; Aragon-Salamanca, Alfonso; Smith, Rory; Yi, Sukyoung K.

    2016-01-01

    We present a new database of our two-dimensional bulge-disk decompositions for 14,233 galaxies drawn from SDSS DR12 in order to examine the properties of bulges residing in the local universe ($0.005 < z < 0.05$). We performed decompositions in $g$ and $r$ bands by utilizing the {\\sc{galfit}} software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique, and hence we hereby provide full details of our method. The $g-r$ colors of b...

  1. AKARI NEAR-INFRARED SPECTROSCOPY OF SDSS-SELECTED BLUE EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    A near-infrared (NIR; 2.5-4.5 μm) spectroscopic survey of Sloan Digital Sky Survey (SDSS)-selected blue early-type galaxies (BEGs) has been conducted using the AKARI. The NIR spectra of 36 BEGs are secured, which are well balanced in their star formation (SF)/Seyfert/LINER-type composition. For high signal-to-noise ratio, we stack the BEG spectra in its entirety and in bins of several properties: color, specific star formation rate, and optically determined spectral type. We estimate the NIR continuum slope and the equivalent width of 3.29 μm polycyclic aromatic hydrocarbon (PAH) emission. In the comparison between the estimated NIR spectral features of the BEGs and those of model galaxies, the BEGs seem to be old-SSP(simple stellar population)-dominated metal-rich galaxies with moderate dust attenuation. The dust attenuation in the BEGs may originate from recent SF or active galactic nucleus (AGN) activity and the BEGs have a clear feature of PAH emission, evidence of current SF. BEGs show NIR features different from those of ULIRGs from which we do not find any clear relationship between BEGs and ULIRGs. We find that Seyfert BEGs have more active SF than LINER BEGs, in spite of the fact that Seyferts show stronger AGN activity than LINERs. One possible scenario satisfying both our results and the AGN feedback is that SF, Seyfert, and LINER BEGs form an evolutionary sequence: SF → Seyfert → LINER.

  2. AKARI Near-Infrared Spectroscopy of SDSS-Selected Blue Early-Type Galaxies

    CERN Document Server

    Lee, Joon Hyeop; Lee, Myung Gyoon; Lee, Jong Chul; Matsuhara, Hideo

    2010-01-01

    A near-infrared (NIR; 2.5 - 4.5 micron) spectroscopic survey of SDSS(Sloan Digital Sky Survey)-selected blue early-type galaxies (BEGs) has been conducted using the AKARI. The NIR spectra of 36 BEGs are secured, which are well balanced in their star-formation(SF)/Seyfert/LINER type composition. For high signal-to-noise ratio, we stack the BEG spectra all and in bins of several properties: color, specific star formation rate and optically-determined spectral type. We estimate the NIR continuum slope and the equivalent width of 3.29 micron PAH emission. In the comparison between the estimated NIR spectral features of the BEGs and those of model galaxies, the BEGs seem to be old-SSP(Simple Stellar Population)-dominated metal-rich galaxies with moderate dust attenuation. The dust attenuation in the BEGs may originate from recent star formation or AGN activity and the BEGs have a clear feature of PAH emission, the evidence of current SF. BEGs show NIR features different from those of ULIRGs, from which we do not f...

  3. Large-scale clustering of Lyman-alpha emission intensity from SDSS/BOSS

    CERN Document Server

    Croft, Rupert A C; Zheng, Zheng; Bolton, Adam; Dawson, Kyle S; Peterson, Jeffrey B; York, Donald G; Eisenstein, Daniel; Brinkmann, Jon; Brownstein, Joel; Delubac, Timothée; Font-Ribera, Andreu; Hamilton, Jean-Christophe; Lee, Khee-Gan; Myers, Adam; Palanque-Delabrouille, Nathalie; Pâris, Isabelle; Petitjean, Patrick; Pieri, Matthew M; Ross, Nicholas P; Rossi, Graziano; Schlegel, David J; Schneider, Donald P; Slosar, Anže; Vazquez, José; Viel, Matteo; Weinberg, David H; Yèche, Christophe

    2015-01-01

    (Abridged) We detect the large-scale structure of Lya emission in the Universe at redshifts z=2-3.5 by measuring the cross-correlation of Lya surface brightness with quasars in SDSS/BOSS. We use a million spectra targeting Luminous Red Galaxies at z, the amplitude of mass fluctuations, and the quasar and Lya emission bias factors. Using known values, we infer (b_alpha/3) = (3.9 +/- 0.9) x 10^-21 erg/s cm^-2 A^-1 arcsec^-2, where b_alpha is the Lya emission bias factor. If the dominant sources of Lya emission are star forming galaxies, we infer rho_SFR = (0.28 +/- 0.07) (3/b_alpha) /yr/Mpc^3 at z=2-3.5. For b_alpha=3, this value is a factor of 21-35 above previous estimates from individually detected Lya emitters, although consistent with the total rho_SFR derived from dust-corrected, continuum UV surveys. 97% of the Lya emission in the Universe at these redshifts is therefore undetected in previous surveys of Lya emitters. Our measurement is much greater than seen from stacking analyses of faint halos surroun...

  4. Mining the SDSS archive. I. Photometric redshifts in the nearby universe

    CERN Document Server

    Raffaele, D A; Giuseppe, L; Massimo, B; Maurizio, P; Elisabetta, D F; Roberto, T; Antonino, Staiano; Giuseppe, Longo; Massimo, Brescia; Maurizio, Paolillo; Elisabetta, De Filippis; Roberto, Tagliaferri

    2007-01-01

    We present a supervised neural network approach to the determination of photometric redshifts. The method was tuned to match the characteristics of the Sloan Digital Sky Survey and it exploits the spectroscopic redshifts provided by this unique survey. In order to train, validate and test the networks we used two galaxy samples drawn from the SDSS spectroscopic dataset: the general galaxy sample (GG) and the luminous red galaxies subsample (LRG). The method consists of a two steps approach. In the first step, objects are classified in nearby (z<0.25) and distant (0.25

  5. The large-scale 3-point correlation function of the SDSS BOSS DR12 CMASS galaxies

    CERN Document Server

    Slepian, Zachary; Beutler, Florian; Cuesta, Antonio J; Ge, Jian; Gil-Marín, Héctor; Ho, Shirley; Kitaura, Franciso-Shu; McBride, Cameron K; Nichol, Robert C; Percival, Will J; Rodríguez-Torres, Sergio; Ross, Ashley J; Scoccimarro, Román; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana

    2015-01-01

    We report a measurement of the large-scale 3-point correlation function of galaxies using the largest dataset for this purpose to date, 777, 202 Luminous Red Galaxies in the Sloan Digital Sky Survey Baryon Acoustic Oscillation Spectroscopic Survey (SDSS BOSS) DR12 CMASS sample. This work exploits the novel algorithm of Slepian & Eisenstein (2015b) to compute the multipole moments of the 3PCF in $\\mathcal{O}(N^2)$ time, with $N$ the number of galaxies. Leading-order perturbation theory models the data well in a compressed basis where one triangle side is integrated out. We also present an accurate and computationally efficient means of estimating the covariance matrix. With these techniques the redshift-space linear and non-linear bias are measured, with 2.6% precision on the former if $\\sigma_8$ is fixed. The data also indicates a $2.8\\sigma$ preference for the BAO, confirming the presence of BAO in the 3-point function.

  6. ULAS J234311.93-005034.0: A gravitational lens system selected from UKIDSS and SDSS

    CERN Document Server

    Jackson, Neal; Oguri, Masamune

    2008-01-01

    We report the discovery of a new gravitational lens system. This object, ULAS J234311.93-005034.0, is the first to be selected by using the new UKIRT Infrared Deep Sky Survey (UKIDSS), together with the Sloan Digital Sky Survey (SDSS). The ULAS J234311.93-005034.0 system contains a quasar at redshift 0.788 which is doubly imaged, with separation 1.4". The two quasar images have the same redshift and similar, though not identical, spectra. The lensing galaxy is detected by subtracting point-spread functions from R-band images taken with the Keck telescope. The lensing galaxy can also be detected by subtracting the spectra of the A and B images, since more of the galaxy light is likely to be present in the latter. No redshift is determined from the galaxy, although the shape of its spectrum suggests a redshift of about 0.3. The object's lens status is secure, due to the identification of two objects with the same redshift together with a lensing galaxy. Our imaging suggests that the lens is found in a cluster e...

  7. Arecibo and Goldstone Radar Observations of the First-Recognized Binary Near-Earth Asteroid: (385186) 1994 AW1

    Science.gov (United States)

    Richardson, James E.; Taylor, Patrick A.; Rivera-Valentin, Edgard G.; Rodriguez-Ford, Linda A.; Benner, Lance A. M.; Naidu, Shantanu P.; Giorgini, Jon D.; Busch, Michael W.; Ghigo, Frank d.; Kobelski, Adam; Warner, Brian D.; Springmann, Alessondra; Marshall, Sean E.; Steckloff, Jordan K.; Sharkey, Benjamin

    2015-11-01

    Near-Earth asteroid (385186) 1994 AW1 was discovered at Palomar Observatory on 11 January 1994. Subsequent observations of this Amor family, Sa-class asteroid also identified it as the first candidate binary NEA, as indicated by multiple periodicities and possible mutual eclipsing/occulting events in the object’s lightcurve. On 15 July 2015 this asteroid made its closest approach to Earth since its discovery, coming within 0.065 AU (25 lunar distances), and prompting an extended observation campaign using both the JPL-Goldstone and Arecibo Observatory planetary radars. Goldstone observations covered the 14-19 July period of closest approach (0.066-0.070 AU) while the object remained below Arecibo’s observing horizon, with Arecibo picking up the observations between 20-30 July, as the object moved from 0.075 to 0.126 AU distance. At Goldstone, we were able to observe this object with range resolutions of 150 m using a Goldstone (DSS-14) to Green Bank Telescope (GBT) bistatic configuration, while at Arecibo, we conducted monostatic observations of 1994 AW1 using the 2380 MHz (12.6 cm) radar at resolutions of 30 m and 75 m.As a result, and twenty years after its discovery, these observations have confirmed the binary nature of 1994 AW1, showing the primary body to be about 600 m in diameter, the secondary body to be about half the diameter of the primary, with the two orbiting a common center of mass at a distance of about 1.2 km apart. Delay-Doppler image comparisons of the primary over the course of six nights (at 30 m resolution) confirm a lightcurve-derived rotation period of 2.518 +/- 0.002 hr, as >90% longitude coverage was achieved, revealing a slightly elongated, irregular surface morphology. Delay-Doppler images of the secondary reveal an elongated, irregular body which appears to be tidally locked, with its long axis pointed towards the primary as it orbits with a period of about 22 hr (also consistent with the lightcurve analysis). These very early

  8. Physical and orbital properties of micrometeors observed using the 430 MHz Arecibo observatory radar

    Science.gov (United States)

    Janches, Diego

    Physical and orbital properties of 1200+ radar micrometeors are deduced from more than 8000+ event detections using the 430 MHz Arecibo radar in Puerto Rico. These results are very distinct from classical HF/VHF radar observations in that the head-echo (radar scattering from the region immediately surrounding the meteoroid) is always observed, leading uniquely to very accurate Doppler speed determinations. A multi-pulse technique has been developed that permits the direct measurement of Doppler velocities from the micrometeor leading-edge (or head-echo), and in some 26% of the sample, micrometeor deceleration is also accurately measured. The results from those showing decelerations are described in some detail. The average measured micrometeor velocity is around ˜50 km/sec unlike that obtained with classical low-power VHF radars which is nearly a factor of two lower. The observed micrometeor decelerations range from a few km/sec2 to ˜1000 km/sec2. The measurements of highly resolved meteor altitudes, velocities and decelerations are crucial for understanding a number of aeronomical and astronomical problems in meteor science. One important property, the particle meteor ballistic parameter (BP)---the ratio of the meteoroid mass to cross-sectional area---gives a physical characterization of the decelerating particles independent of any assumption about meteoroid shape and mass density. The BP calculation for these micrometeors results in a distribution that covers a wide range (10-4--10 -1gm/cm2). The sizes and masses that these results represent, when the meteoroid is assumed to be a sphere of density 3 gm/cm3, are radii ˜0.5 x 10-4--2 x 10-2 cm and masses of a fraction of a nanogram to 10 mugm. An original criterion to separate particles that are travelling down-the-beam from those with a more significant across-the-beam velocity component was developed. This criterion is based on the variation of the meteor BP during the time the particles are observed by the

  9. Arecibo and Goldstone radar evidence for boulders on near-Earth asteroids

    Science.gov (United States)

    Benner, L.; Nolan, M.; Brozovic, M.; Taylor, P.; Busch, M.; Howell, E.; Margot, J.; Giorgini, J.; Springmann, A.; Naidu, S.; Magri, C.; Shepard, M.

    2014-07-01

    Delay-Doppler radar observations of numerous near-Earth asteroids (NEAs) since 1999 have revealed many small groups of radar-bright pixels in some of the highest signal-to-noise ratio (SNR) images obtained at Arecibo and Goldstone. Many of the spots remain observable as the asteroids rotate through tens of degrees. The bright pixels are not receiver noise, self noise, or artifacts, but are real features. Clusters of bright pixels appear primarily in high-resolution radar images with resolutions of 4-19 m/pixel and usually span a few rows and columns or less, indicating that these are surface features a few tens of meters in extent or smaller. Many clusters appear near the trailing edges of the images and are adjacent to and up range from radar shadows, implying the presence of small-scale topography. To date, small groups of bright pixels have been seen on at least ten NEAs observed at high resolution, such as (in chronological order of radar detection) (101955) Bennu, (33342) 1998 WT_{24}, (100085) 1992 UY_{4}, (374851) 2006 VV_{2}, (341843) 2008 EV_{5}, (136849) 1998 CS_{1}, (308635) 2005 YU_{55}, (214869) 2007 PA_{8}, (4179) Toutatis, and 2014 BR_{57}. Of these objects, Toutatis is the largest, with a long axis of 4.6 km, and 2004 BR_{57} is the smallest, with a diameter of about 80 m. These objects also span a considerable dynamic range of shapes, spin states, and spectral classes. What causes the radar-bright pixels? Radar albedo correlates positively with increasing near-surface density, so relatively bright echoes can result from scattering off surface and near-surface features with higher densities than their surroundings. Bright echoes can also be generated by specular reflections from relatively flat surfaces oriented nearly perpendicular to the radar line-of-sight. Many of these features are located near the radar terminator where the radar line-of-sight is at grazing incidence angles, which tends to highlight small-scale topography. We suggest that a

  10. The matter distribution in the local universe as derived from galaxy groups in SDSS DR12 and 2MRS

    CERN Document Server

    Saulder, Christoph; Mieske, Steffen; Zeilinger, Werner W

    2015-01-01

    Context. Friends-of-friends algorithms are a common tool to detect galaxy groups and clusters in large survey data. For them to be as precise as possible, they have to be carefully calibrated using mock-catalogues. Aims. To create an accurate and robust description of the matter distribution in the local universe using the most up-to-date available data. This will provide input for a specific cosmological test planned as follow-up to this work, and will be useful for general extra- galactic and cosmological research. Methods. We create a set of galaxy group catalogues based on the 2MRS and SDSS DR12 catalogues using a friends-of-friends based group finder algorithm. The algorithm is carefully calibrated and optimised on a new set of wide-angle mock catalogues from the Millennium simulation, such as to provide accurate total mass estimates of the galaxy groups taking into account the relevant observational biases in 2MRS and SDSS. Results. We provide four different catalogues: 1) a 2MRS based group catalogue; ...

  11. High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical Compositions

    CERN Document Server

    Aoki, Wako; Lee, Young Sun; Honda, Satoshi; Ito, Hiroko; Takada-Hidai, Masahide; Frebel, Anna; Suda, Takuma; Fujimoto, Masatuki Y; Carollo, Daniela; Sivarani, Thirupathi

    2012-01-01

    Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metal-poor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and its first stellar extension, the Sloan Extension for Galactic Understanding and Exploration (SEGUE). High-resolution spectra with moderate signal-to-noise (S/N) ratios were obtained with the High Dispersion Spectrograph of the Subaru Telescope. Most of the sample (approximately 80%) are main-sequence turn-off stars, including dwarfs and subgiants. Four cool main-sequence stars, the most metal-deficient such stars known, are included in the remaining sample. Good agreement is found between effective temperatures estimated by the SEGUE stellar parameter pipeline, based on the SDSS/SEGUE medium-resolution spectra, and those estimated from the broadband $(V-K)_0$ and $(g-r)_0$ colors. Our abundance measurements reveal that 70 stars in our sample have [Fe/H] $ +0.7$) among the 25 giants in our sample is as high as 36%, while only a lowe...

  12. GENUS STATISTICS USING THE DELAUNAY TESSELLATION FIELD ESTIMATION METHOD. I. TESTS WITH THE MILLENNIUM SIMULATION AND THE SDSS DR7

    International Nuclear Information System (INIS)

    We study the topology of cosmic large-scale structure through the genus statistics, using galaxy catalogs generated from the Millennium Simulation and observational data from the latest Sloan Digital Sky Survey Data Release (SDSS DR7). We introduce a new method for constructing galaxy density fields and for measuring the genus statistics of its isodensity surfaces. It is based on a Delaunay tessellation field estimation (DTFE) technique that allows the definition of a piece-wise continuous density field and the exact computation of the topology of its polygonal isodensity contours, without introducing any free numerical parameter. Besides this new approach, we also employ the traditional approaches of smoothing the galaxy distribution with a Gaussian of fixed width, or by adaptively smoothing with a kernel that encloses a constant number of neighboring galaxies. Our results show that the Delaunay-based method extracts the largest amount of topological information. Unlike the traditional approach for genus statistics, it is able to discriminate between the different theoretical galaxy catalogs analyzed here, both in real space and in redshift space, even though they are based on the same underlying simulation model. In particular, the DTFE approach detects with high confidence a discrepancy of one of the semi-analytic models studied here compared with the SDSS data, while the other models are found to be consistent.

  13. Box/Peanut and Bar structures in edge-on and face-on SDSS nearby galaxies I. Catalogue

    CERN Document Server

    Yoshino, Akira

    2014-01-01

    We investigate Box/Peanut and bar structures in image data of edge-on and face-on nearby galaxies taken from SDSS (Sloan Digital Sky Survey) to present catalogues containing the surface brightness parameters and the morphology classification. About 1700 edge-on galaxies and 2600 face-on galaxies are selected from SDSS DR7 in g, r and i-band. The images of each galaxy are fitted with the model of 2-dimensional surface brightness of S\\'{e}rsic bulge and exponential disk. After removing some irregular data, Box/Peanut, bar and other structures are easily distinguished by eye using residual (observed minus model) images. We find 292 Box/Peanut structures in the 1329 edge-on samples and 630 bar structures in 1890 face-on samples in i-band, after removing some irregular data. Then the fraction of Box/Peanut galaxies is about 22 percent against the edge-on samples, and that of bar is about 33 percent (about 50 percent if 629 elliptical galaxies are removed) against the face-on samples. Furthermore the strengths of t...

  14. Galaxies in filaments have more satellites: the influence of the cosmic web on the satellite luminosity function in the SDSS

    CERN Document Server

    Guo, Quan; Libeskind, Noam I

    2014-01-01

    We investigate if the satellite luminosity function (LFs) of primary galaxies identified in the Sloan Digital Sky Survey (SDSS DR8) depends on whether the host galaxy is in a filament or not. Isolated primary galaxies are identified in the SDSS spectroscopic sample while potential satellites are searched for in the much deeper photometric sample. Filaments are constructed from the galaxy distribution by the "Bisous" process. Isolated primary galaxies are divided into two subsamples: those in filaments and those not in filaments. We examine the stacked mean LF of each sample and found that, in the mean, the satellite LFs of primary galaxies (extending to at least 4 magnitude fainter than the primary galaxies) in filaments is significantly higher than those of primary galaxies not in filaments. The filamentary environment can increases the abundance of the brightest satellites ($M_\\mathrm{sat.} < M_\\mathrm{prim.}+ 2.0$), by a factor of $\\sim 2$ compared with non-filament galaxies. This result is independent ...

  15. A Dusty Mg~II absorber Associated with the Quasar SDSS J003545.13+011441.2

    CERN Document Server

    Jiang, P; Prochaska, J X; Kulkarni, V P; Lu, H L; Zhou, H Y; 10.1088/0004-637X/720/1/328

    2010-01-01

    We report on a dusty Mg~II absorber associated with the quasar SDSSJ003545.13+011441.2 (hereafter J0035+0114) at $z$=1.5501, which is the strongest one among the three Mg~II absorbers along the sight line of quasar. The two low redshift intervening absorbers are at $z$=0.7436, 0.5436, respectively. Based on the photometric and spectroscopic data of Sloan Digital Sky Survey (hereafter SDSS), we infer the rest frame color excess E(\\bv) due to the associated dust is more than 0.07 by assuming a Small Magellanic Cloud (hereafter SMC) type extinction curve. Our follow-up moderate resolution spectroscopic observation at the 10-m Keck telescope with the ESI spectrometer enable us to reliably identify most of the important metal elements, such as Zn, Fe, Mn, Mg, Al, Si, Cr, and Ni in the associated system. We measure the column density of each species and detect significant dust depletion. In addition, we develop a simulation technique to gauge the significance of 2175-{\\AA} dust absorption bump on the SDSS quasar sp...

  16. Isolated Main Galaxy Pairs from the SDSS Data Release 4

    Institute of Scientific and Technical Information of China (English)

    Xin-Fa Deng; Yi-Qing Chen; Ping Wu; Cheng-Hong Luo; Ji-Zhou He

    2006-01-01

    From the Main galaxy data of the SDSS Data Release 4 (SDSS4), we have identified close galaxy pairs at neighbourhood radius R = 100 kpc by three-dimensional cluster analysis. Using the criterion that an "isolated galaxy pair" must be separated from its "nearest neighbor" by more than 500 kpc, we constructed an isolated galaxy pair sample of 1158 pairs.We also constructed a random pair sample by randomly selecting 1158 galaxy pairs from the Main galaxy sample, which has the same redshift distribution as the isolated galaxy pair sample, and in which the two components of any pair have the same redshifts. Comparative studies of luminosity and size between the members of the galaxy pairs are performed. We find and further confirm there is no tendency for paired galaxies to have similar luminosities or sizes. From the isolated pair sample we also selected a subsample with the magnitude limit of the primary raised by 2 magnitudes, so as to include pairs in which the secondary is 2 magnitudes fainter than the primary. This subsample contains 82 pairs. A random pair sample is similarly constructed.

  17. The Slogan Great Wall from the SDSS Data Release 4

    International Nuclear Information System (INIS)

    Using the MAIN galaxy data from the SDSS Data Release 4 (SDSS4), we further study the Sloan Great Wall by three-dimensional cluster analysis. Because the basic properties of Main galaxies change with redshift, we select 50942 Main galaxies having the same redshift region (0.07 ≤ z ≤ 0.09) as the Sloan Great Wall from the Main galaxy sample, and construct our SubMain sample. From the SubMain sample, 2013 isolated galaxies are identified at dimensionless radius r = 1.4. We perform the comparative studies of galaxy properties among the Sloan Great Wall, isolated galaxies and the SubMain sample in different redshift bins. It turns out that the statistical properties of luminosities and sizes of galaxies for the Sloan Great Wall, isolated galaxies and the SubMain sample are almost the same, the proportion of early-type isolated galaxies is relatively low. We also d that mean color of member galaxies of the Sloan Great Wall is redder than that of isolated galaxies. These results indicate that some properties of galaxies may be closely correlated with the environment or clustering. (author)

  18. Outflows and complex stellar kinematics in SDSS star forming galaxies

    CERN Document Server

    Cicone, Claudia; Marconi, Alessandro

    2016-01-01

    We investigate the properties of star formation-driven outflows by using a large spectroscopic sample of ~160,000 local "normal" star forming galaxies, drawn from the SDSS, spanning a wide range of star formation rates and stellar masses. The galaxy sample is divided into a fine grid of bins in the M_*-SFR parameter space, for each of which we produce a composite spectrum by stacking together the SDSS spectra of the galaxies contained in that bin. We exploit the high signal-to-noise of the stacked spectra to study the emergence of faint features of optical emission lines that may trace galactic outflows and would otherwise be too faint to detect in individual galaxy spectra. We adopt a novel approach that relies on the comparison between the line-of-sight velocity distribution (LoSVD) of the ionised gas (as traced by the [OIII]5007 and Halpha+[NII]6548,6583 emission lines) and the LoSVD of the stars, which are used as a reference tracing virial motions. Significant deviations of the gas kinematics from the st...

  19. The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo

    CERN Document Server

    Rodríguez, Silvio

    2013-01-01

    By modelling the axis ratio distribution of SDSS DR8 galaxies we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of shapes, while taking into account dust extinction. We measure the dust extinction of the full sample of spiral galaxies and find a smaller value than previous estimations, with an edge-on extinction of $E_0 = 0.284^{+0.015}_{-0.026}$ in the SDSS r band. We also find that the distribution of minor to major axis ratio has a mean value of $ 0.267 \\pm 0.009 $, slightly larger than previous estimates mainly due to the lower extinction used; the same affects the circularity of galactic discs, which are found to be less round in shape than in previous studies, with a mean ellipticity of $0.215 \\pm 0.013$. For elliptical galaxies, we find that the minor to major axis ratio, with a mean value of $0.584 \\pm 0.006$, is larger than previous estimations due to the removal of spiral interlo...

  20. Beyond the fibre: Resolved properties of SDSS galaxies

    CERN Document Server

    Gerssen, J; Christensen, L

    2011-01-01

    We have used the VIMOS integral field spectrograph to map the emission line properties in a sample of 24 star forming galaxies selected from the SDSS database. In this data paper we present and describe the sample, and explore some basic properties of SDSS galaxies with resolved emission line fields. We fit the Halpha+[NII] emission lines in each spectrum to derive maps of continuum, Halpha flux, velocity and velocity dispersion. The Halpha, Hbeta, [NII] and [OIII] emission lines are also fit in summed spectra for circular annuli of increasing radius. A simple mass model is used to estimate dynamical mass within 10 kpc, which compared to estimates of stellar mass shows that between 10 and 100% of total mass is in stars. We present plots showing the radial behaviour of EW[Halpha], u-i colour and emission line ratios. Although EW[Halpha] and u-i colour trace current or recent star formation, the radial profiles are often quite different. Whilst line ratios do vary with annular radius, radial gradients in galaxi...