WorldWideScience

Sample records for absorption selected galaxies

  1. The X-ray spectra of optically selected Seyfert 2 galaxies. Are there any Sy2 galaxies with no absorption?

    Pappa, A; Stewart, G C; Zezas, A L

    2001-01-01

    We present an X-ray spectral analysis of a sample of 8 bona-fide Seyfert 2 galaxies, selected on the basis of their high $[OIII]\\lambda5007$ flux, from the Ho et al. (1997) spectroscopic sample of nearby galaxies. We find that, in general, the X-ray spectra of our Seyfert 2 galaxies are complex, with some our objects having spectra different from the 'typical' spectrum of X-ray selected Seyfert 2 galaxies. Two (NGC3147 and NGC4698) show no evidence for intrinsic absorption. We suggest this is due to the fact that when the torus suppresses the intrinsic medium and hard energy flux, underlying emission from the host galaxy, originating in circumnuclear starbursts, and scattering from warm absorbers contributes in these energy bands more significantly. Our asca data alone cannot discriminate whether low absorption objects are Compton-thick AGN with a strong scattered component or lack an obscuring torus. The most striking example of our low absorption Seyfert 2 is NGC4698. Its spectrum could be explained by eith...

  2. Lyman-alpha absorption around nearby galaxies

    Bowen, D V; Blades, J C; Bowen, David V.; Pettini, Max

    2002-01-01

    We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption lines in the outer regions of eight nearby galaxies using background QSOs and AGN as probes. Lya lines are detected within a few hundred km/s of the systemic velocity of the galaxy in all cases. We conclude that a background line-of-sight which passes within 26-200 h-1 kpc of a foreground galaxy is likely to intercept low column density neutral hydrogen with log N(HI) >~ 13.0. The ubiquity of detections implies a covering factor of ~ 100% for low N(HI) gas around galaxies within 200 h-1 kpc. We discuss the difficulty in trying to associate individual absorption components with the selected galaxies and their neighbors, but show that by degrading our STIS data to lower resolutions, we are able to reproduce the anti-correlation of Lya equivalent width and impact parameter found at higher redshift. We also show that the equivalent width and column density of Lya complexes (when individual components are summed over ~ 1000 km/s) correlate wel...

  3. AGN Absorption Linked to Host Galaxies

    Juneau, Stéphanie

    2013-01-01

    Multiwavelength identification of AGN is crucial not only to obtain a more complete census, but also to learn about the physical state of the nuclear activity (obscuration, efficiency, etc.). A panchromatic strategy plays an especially important role when the host galaxies are star-forming. Selecting far-Infrared galaxies at 0.3absorption and the specific star formation rate (sSFR) of the host galaxies, indicating a physical link between X-ray absorption and either the gas fraction or the gas geometry in the hosts. These findings have implications for our current understanding of both the AGN unification model and the nature of the black hole-galaxy connection. These proceedi...

  4. Galaxies in the Early Universe characterized in absorption and emission

    Krogager, Jens-Kristian

    2016-01-01

    Understanding how galaxies evolved from the early Universe through cosmic time is a fundamental part of modern astrophysics. In order to study this evolution it is important to sample the galaxies at various times in a consistent way through time. In regular luminosity selected samples, our analyses are biased towards the brightest galaxies at all times (as these are easier to observe and identify). A complementary method relies on the absorption imprint from neutral gas in galaxies, the so-called damped Ly-alpha absorbers (DLAs) seen towards distant bright objects. This thesis seeks to understand how the absorption selected galaxies relate to the emission selected galaxies by identifying the faint glow from the absorbing galaxies at redshift z~2. In the last Chapter, a study of the more evolved, massive galaxies is presented. These galaxies are observed to be a factor of 2 to 6 times smaller than local galaxies of similar masses. A new spectroscopically selected sample is presented and the increased precisio...

  5. Intermediate-redshift galaxy halos - Results from QSO absorption lines

    For a sample of Mg II-selected QSO absorption-line systems for which the absorbing galaxies have been successfully identified, the rest-frame equivalent widths of the Mg II 2796-A absorption lines are examined as a function of the known impact parameters between the background QSOs and the absorbing galaxies. There appears to exist a relationship between the equivalent widths and the impact parameters, in the sense that larger equivalent widths occur at smaller impact parameters. No trend of the doublet ratio is found with impact parameter, and neither the equivalent widths nor the doublet ratios are correlated with the absolute luminosities or redshifts of the absorbing galaxies. These results apparently indicate that the main factor that determines the equivalent width of a particular absorption system is the impact parameter between the background QSO and the absorbing galaxy. 32 refs

  6. Intermediate-redshift galaxy halos - Results from QSO absorption lines

    Lanzetta, K.M.; Bowen, D. (Cambridge Univ. (England) Royal Greenwich Observatory, Cambridge (England))

    1990-07-01

    For a sample of Mg II-selected QSO absorption-line systems for which the absorbing galaxies have been successfully identified, the rest-frame equivalent widths of the Mg II 2796-A absorption lines are examined as a function of the known impact parameters between the background QSOs and the absorbing galaxies. There appears to exist a relationship between the equivalent widths and the impact parameters, in the sense that larger equivalent widths occur at smaller impact parameters. No trend of the doublet ratio is found with impact parameter, and neither the equivalent widths nor the doublet ratios are correlated with the absolute luminosities or redshifts of the absorbing galaxies. These results apparently indicate that the main factor that determines the equivalent width of a particular absorption system is the impact parameter between the background QSO and the absorbing galaxy. 32 refs.

  7. Absorption of selected radionuclides

    In October 1978, the Institut fuer Energie- und Umweltforschung Heidelberg e.V. published a contribution to part 26 of the model study of radio-ecology at Biblis under the title 'Estimation of the absorption of radionuclides from the gastrointestinal tract in the blood'. Using the example of this contribution, a critical analysis is made to show how a selection of the information contained in various scientific publications and other items of literature can give uncritical readers the impression that all statements made are scientifically well founded. (orig./HP)

  8. The Connection Between Galaxies and Intergalactic Absorption Lines at Redshift 2

    Adelberger, K L; Steidel, C C; Pettini, M; Erb, D K; Reddy, N A

    2005-01-01

    Absorption-line spectroscopy of 23 background QSOs and numerous background galaxies has let us measure the spatial distribution of metals and neutral hydrogen around 1044 UV-selected galaxies at redshifts 1.8260 km/s) and produces very strong absorption lines (N_CIV >> 10^14 cm^-2) in the spectra of background objects. Absorption with an average column density of N_CIV ~ 10^14 cm^-2 extends to 80 kpc, a radius large enough to imply that most strong intergalactic CIV absorption is associated with star-forming galaxies like those in our sample. We find that the galaxy-CIV cross-correlation length increases with CIV column density and is similar to the galaxy-galaxy length (r_0 ~ 4 h^-1 Mpc) for N_CIV > 10^12.5 cm^-2. Distortions in the redshift-space galaxy-CIV correlation function on small scales may imply that some of the CIV systems have large peculiar velocities. Four of the five detected OVI absorption systems in our sample lie within 400 proper kpc of a known galaxy. Strong Lyman-a absorption is produced ...

  9. Galaxy selection and the surface brightness distribution

    McGaugh, S S; Schombert, J M

    1995-01-01

    Optical surveys for galaxies are biased against the inclusion of low surface brightness (LSB) galaxies. Disney (1976) suggested that the constancy of disk central surface brightness noticed by Freeman (1970) was not a physical result, but instead was an artifact of sample selection. Since LSB galaxies do exist, the pertinent and still controversial issue is if these newly discovered galaxies constitute a significant percentage of the general galaxy population. In this paper, we address this issue by determining the space density of galaxies as a function of disk central surface brightness. Using the physically reasonable assumption (which is motivated by the data) that central surface brightness is independent of disk scale length, we arrive at a distribution which is roughly flat (\\ie approximately equal numbers of galaxies at each surface brightness) faintwards of the Freeman (1970) value. Brightwards of this, we find a sharp decline in the distribution which is analogous to the turn down in the luminosity ...

  10. HI absorption and the ISM around radio galaxies

    Morganti, R; Tadhunter, C N; Wills, K A; Tzioumis, A K; Reynolds, J

    2000-01-01

    We present a study, done with the Australian LBA, of HI absorption for two compact radio galaxies (PKS 1549-79 and PKS 1814-63). In both the radio galaxies, the HI appears to give us information about the environment in which the radio sources are embedded, the effect that the ISM can have on the observed characteristics and the possible presence of interaction between the ISM and the radio plasma.

  11. The earliest galaxies seen in 21 cm line absorption

    Xu, Yidong; Chen, Xuelei

    2010-01-01

    We investigate the 21 cm absorption lines produced by non-linear structures during the early stage of reionization, i.e. the starless minihalos and the dwarf galaxies. After a detailed modelling of their properties, with particular attention to the coupling physics, we determine their 21 cm absorption line profiles. The infalling gas velocity around minihalos/dwarf galaxies strongly affects the line shape, and with the low spin temperatures outside the virial radii of the systems, gives rise to horn-like line profiles. The optical depth of a dwarf galaxy is reduced for lines of sight penetrating through its HII region, and especially, a large HII region created by a dwarf galaxy with higher stellar mass and/or a top-heavy initial mass function results in an optical depth trough rather than an absorption line. We compute synthetic spectra of 21 cm forest for both high redshift quasars and radio afterglows of gamma ray bursts (GRBs). Even with the planned SKA, radio afterglows of most if not all GRBs would stil...

  12. Complex Investigation of SBS Galaxies in Seven Selected Fields

    Hakopian, S A

    2014-01-01

    The main criterium for the selection of active objects in the First Byurakan Survey was the presence of uv-excess on low-dispersion spectra registered on photographic plates obtained with the 1m Shmidt type Byurakan telescope. Using the presence of emission lines as the second criterium became possible during the Second Byurakan Survey due to its improved technique. Through this criterium a majority of objects, extended by morphology, were selected into the separate "sample of galaxies". Certainly, there were cases of untrue selection, particularly, on faint magnitudes, when absorption lines were taken for emission ones and so on. Study of SBS galaxies, including evaluation of an effectivity of selection criteria, was undertaken by means of complex investigation of their very representative part, pooled in our basic sample. The completion of the follow-up slit spectroscopy of these about 500 objects formed the main stage of implementation of this program. Also, the scheme was developed to provide homogeneous ...

  13. The Gaseous Extent of Galaxies and the Origin of \\lya Absorption Systems at z < 1

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies in fields of HST spectroscopic target QSOs. The goal of the program is to investigate how the properties of \\lya absorption systems observed in the spectra of background QSOs vary with the properties of intervening galaxies. We found that \\lya absorption equivalent width depends strongly on galaxy impact parameter and galaxy B-band luminosity, and that the gaseous extent of individual galaxies scales wi...

  14. A hot gaseous galaxy halo candidate with Mg X absorption

    Qu, Zhijie

    2016-01-01

    The hot gas in galaxy halos may account for a significant fraction of missing baryons in galaxies, and some of these gases can be traced by high ionization absorption systems in QSO UV spectra. Using high S/N ratio $ HST$/COS spectra, we discovered a high ionization state system at $z=1.1912$ in the sightline toward \\object{LBQS 1435-0134}, and two-components absorption lines are matched for Mg X, Ne VIII, Ne VI, O VI, Ne V, O V, Ne IV, O IV, N IV, O III, and H I. Mg X, detected for the first time ($5.8 \\sigma$), is a particularly direct tracer of hot galactic halos, as its peak ion fraction occurs near $10^{6.1}\\rm~ K$, about the temperature of a virialized hot galaxy halo of mass $\\sim 0.5 M^*$. With Mg X and NeVIII, a photoionization model cannot reproduce the observed column densities with path lengths of galaxy halos. For collisional ionization models, one or two temperature models do not produce acceptable fits, but a three temperature model or a power law model can produce the observed results. In the ...

  15. Long-Duration Gamma-Ray Burst Host Galaxies in Emission and Absorption

    Perley, Daniel A.; Niino, Yuu; Tanvir, Nial R.; Vergani, Susanna D.; Fynbo, Johan P. U.

    2016-03-01

    The galaxy population hosting long-duration GRBs provides a means to constrain the progenitor and an opportunity to use these violent explosions to characterize the nature of the high-redshift universe. Studies of GRB host galaxies in emission reveal a population of star-forming galaxies with great diversity, spanning a wide range of masses, metallicities, and redshifts. However, as a population GRB hosts are significantly less massive and poorer in metals than the hosts of other core-collapse transients, suggesting that GRB production is only efficient at metallicities significantly below Solar. GRBs may also prefer compact galaxies, and dense and/or central regions of galaxies, more than other types of core-collapse explosion. Meanwhile, studies of hosts in absorption against the luminous GRB optical afterglow provide a unique means of unveiling properties of the ISM in even the faintest and most distant galaxies; these observations are helping to constrain the chemical evolution of galaxies and the properties of interstellar dust out to very high redshifts. New ground- and space-based instrumentation, and the accumulation of larger and more carefully-selected samples, are continually enhancing our view of the GRB host population.

  16. Detectability of cold streams into high-z galaxies by absorption lines

    Goerdt, Tobias; Sternberg, Amiel; Gnat, Orly; Ceverino, Daniel

    2012-01-01

    Cold gas streaming along the dark-matter filaments of the cosmic web is predicted to be the major source of fuel for disc buildup, violent disk instability and star formation in massive galaxies at high redshift. We investigate to what extent such cold gas is detectable in the extended circum-galactic environment of galaxies via Ly alpha absorption and selected low ionisation metal absorption lines. We model the expected absorption signatures using high resolution zoom-in AMR cosmological simulations. In the postprocessing, we distinguish between self-shielded gas and unshielded gas. In the self-shielded gas, which is optically thick to Lyman continuum radiation, we assume pure collisional ionisation for species with an ionisation potential greater than 13.6 eV. In the optically thin, unshielded gas these species are also photoionised by the meta-galactic radiation. In addition to absorption of radiation from background quasars, we compute the absorption line profiles of radiation emitted by the galaxy at the...

  17. The Gaseous Extent of Galaxies and The Origin of QSO Absorption Line Systems

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.; Fernández-Soto, A.

    1998-01-01

    We present results of an ongoing program to study the gaseous extent of galaxies and the origin of QSO absorption line systems. For \\lya absorption systems, we find that absorption equivalent width depends strongly on galaxy impact parameter and galaxy $B$-band luminosity, and that the gaseous extent of individual galaxies scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.40\\pm0.09}$. Applying the results to galaxies in the Hubble Deep Field to calculate the predicted number density ...

  18. Associated 21-cm absorption towards the cores of radio galaxies

    Chandola, Yogesh; Saikia, D J

    2012-01-01

    We present the results of Giant Metrewave Radio Telescope (GMRT) observations to detect H{\\sc i} in absorption towards the cores of a sample of radio galaxies. From observations of a sample of 16 sources, we detect H{\\sc i} in absorption towards the core of only one source, the FR\\,II radio galaxy 3C\\,452 which has been reported earlier by Gupta & Saikia (2006a). In this paper we present the results for the remaining sources which have been observed to a similar optical depth as for a comparison sample of compact steep-spectrum (CSS) and giga-hertz peaked spectrum (GPS) sources. We also compile available information on H{\\sc i} absorption towards the cores of extended radio sources observed with angular resolutions of a few arcsec or better. The fraction of extended sources with detection of H{\\sc i} absorption towards their cores is significantly smaller (7/47) than the fraction of H{\\sc i} detection towards CSS and GPS objects (28/49). For the cores of extended sources, there is no evidence of a signifi...

  19. A Simple Model for the Absorption of Starlight by Dust in Galaxies

    Charlot, S

    2000-01-01

    We present a new model to compute the effects of dust on the integratedspectral properties of galaxies, based on an idealized prescription of the mainfeatures of the interstellar medium (ISM). The model includes the ionization ofHII regions in the interiors of the dense clouds in which stars form and theinfluence of the finite lifetime of these clouds on the absorption ofradiation. We compute the production of emission lines and the absorption ofcontinuum radiation in the HII regions and the subsequent transfer of line andcontinuum radiation in the surrounding HI regions and the ambient ISM. Thisenables us to interpret simultaneously all the observations of a homogeneoussample of nearby UV-selected starburst galaxies, including the ratio of far-IRto UV luminosities, the ratio of Halpha to Hbeta luminosities, the Halphaequivalent width, and the UV spectral slope. We show that the finite lifetimeof stellar birth clouds is a key ingredient to resolve an apparent discrepancybetween the attenuation of line and con...

  20. Selective coherent perfect absorption in metamaterials

    We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency

  1. Selective gas absorption by ionic liquids

    Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes;

    2010-01-01

    Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

  2. Properties of damped Ly α absorption systems and star-forming galaxies in semi-analytic models at z = 2

    Berry, Michael; Somerville, Rachel S.; Gawiser, Eric; Maller, Ariyeh H.; Popping, Gergö; Trager, Scott C.

    2016-05-01

    We investigate predictions from semi-analytic cosmological models of galaxy formation for the properties of star-forming galaxies (SFGs) and damped Ly α absorption systems (DLAS), and the relationship between these two populations. Our models reproduce fairly well the observed distributions of redshift, stellar mass, star formation rate (SFR), and dust extinction for z ˜ 2 SFGs. We predict that DLA hosts span a broad range of properties, with broad and relatively flat distributions of stellar and halo mass, SFR, and luminosity. The photometric colours of DLA host galaxies trace the colours of galaxies with similar luminosities, but the majority are much fainter than the limits of most existing surveys of SFGs. Generally, DLA host galaxies and SFGs at z = 2 follow similar trends between stellar mass, DLA cross-section, cold gas fraction, SFR, metallicity, and dust extinction as the global population of galaxies with the same stellar mass. Since DLAS select galaxies with larger cold gas masses, they tend to have larger cold gas fractions, lower metallicities, higher SFRs, and less dust extinction than galaxies at the same stellar mass. Our models reproduce the observed relations between impact parameter, column density, and metallicity, suggesting that the sizes of the gas discs giving rise to DLAS in our models are roughly correct. We find that molecular fractions and SFRs are in general significantly lower at the location of the DLA line of sight than the galaxy-averaged value.

  3. 5 CM OH absorption toward the megamaser galaxy IC 4553

    Henkel, C.; Guesten, R.; Batrla, W.

    1986-11-01

    Absorption in the 2Π3/2 J = 5/2 main line of OH at 6035 MHz, 120K above the ground state, is reported from the OH megamaser galaxy IC 4553 (Arp 220). An upper limit is given for Mrk 231. For IC 4553, the authors derive an OH rotation temperature Trot ≡ 45K between the 2Π3/2 J = 5/2 and 3/2 ground levels, that is ≡30% below the dust temperature. Potential pumping mechanisms for the inversion of the ground state doublet are discussed and it is argued that the most likely OH excitation scenario involves pumping by FIR photons (79, 119 μm) and centimeter wave photons (5, 6 cm).

  4. HI emission and absorption in nearby, gas-rich galaxies II. -- sample completion and detection of intervening absorption in NGC 5156

    Reeves, S N; Allison, J R; Koribalski, B S; Curran, S J; Pracy, M B; Phillips, C J; Bignall, H E; Reynolds, C

    2016-01-01

    We present the results of a survey for intervening 21cm HI absorption in a sample of 10 nearby, gas-rich galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This follows the six HIPASS galaxies searched in previous work and completes our full sample. In this paper we searched for absorption along 17 sightlines with impact parameters between 6 and 46 kpc, making one new detection. We also obtained simultaneous HI emission-line data, allowing us to directly relate the absorption-line detection rate to the HI distribution. From this we find the majority of the non-detections in the current sample are because sightline does not intersect the HI disc of the galaxy at sufficiently high column density, but that source structure is also an important factor. The detected absorption-line arises in the galaxy NGC 5156 ($z = 0.01$) at an impact parameter of 19 kpc. The line is deep and narrow with an integrated optical depth of 0.82 km s$^{-1}$. High resolution Australia Telescope Compact Array (ATCA) images at...

  5. The 8 Coincidences of Galaxy Photometry - Selection Effects

    Disney, M. J.; Phillipps, S.

    When the photometric properties of significant numbers of galaxies are compared, eight remarkable coincidences turn up. No convincing explanation for these have appeared so far. However, it may be that they can all be explained through a single powerful selection effect which brings into prominence only galaxies of certain favourable surface brightnesses. If that is the case, then our current understanding of galaxy populations is a delusion, and there must be many more galaxies about than we presently assume.

  6. Galaxy populations in galaxy clusters selected by the Sunyaev-Zeldovich Effect

    Zenteno, Alfredo

    2014-01-01

    We present a study of the galaxy populations in massive galaxy clusters selected by their Sunyaev–Zel’dovich Effect (SZE) signatures. Selection via the SZE is approximately mass- limited where the mass limit varies only slightly with redshift, making it an ideal selection method for studying the evolution of the galaxy content of clusters. We begin by introducing the SZE, the South Pole Telescope (SPT), and the larger research project in which this Thesis is embedded. We then present the core...

  7. A GBT Survey for HI 21 cm Absorption in the Disks and Halos of Low-Redshift Galaxies

    Borthakur, Sanchayeeta; Yun, Min S; Bowen, David V; Meiring, Joseph D; York, Donald G; Momjian, Emmanuel

    2010-01-01

    We present an HI 21 cm absorption survey with the Green Bank Telescope (GBT) of galaxy-quasar pairs selected by combining data from the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. Our sample consists of 23 sightlines through 15 low-redshift foreground galaxy - background quasar pairs with impact parameters ranging from 1.7 kpc up to 86.7 kpc. We also present follow-up Very Large Array (VLA) imaging of the foreground galaxy UGC 7408. We detected one absorber in the GBT survey from the foreground dwarf galaxy at an impact parameter of 1.7 kpc and another possible absorber in the VLA imaging of the nearby dwarf galaxy, UGC 7408. Both of the absorbers are narrow (FWHM of 3.6 and 4.8 km/s), have sub Damped Lyman alpha column densities, and are most likely originating from the disk gas of the foreground galaxies. We also detected HI emission from three galaxies including UGC 7408. Although our sample contains both blue and red galaxies, the two HI abso...

  8. The Gaseous Extent of Galaxies and The Origin of QSO Absorption Line Systems

    Chen, H W; Webb, J K; Barcons, X; Fernández-Soto, A

    1998-01-01

    We present results of an ongoing program to study the gaseous extent of galaxies and the origin of QSO absorption line systems. For \\lya absorption systems, we find that absorption equivalent width depends strongly on galaxy impact parameter and galaxy $B$-band luminosity, and that the gaseous extent of individual galaxies scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.40\\pm0.09}$. Applying the results to galaxies in the Hubble Deep Field to calculate the predicted number density of \\lya absorption lines as a function of redshift and comparing it with observations, we find that at least 50% and perhaps as much as 100% of \\lya absorption systems with $W\\apg0.32$ Å can be explained by the extended gaseous envelops of normal galaxies. The anti-correlation analysis has also been performed on \\civ absorption line systems, and the results show that the ionized gas cross section scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.76\\pm0.26}$.

  9. The radial and azimuthal profiles of Mg II absorption around 0.5 < z < 0.9 zCOSMOS galaxies of different colors masses and environments

    Bordoloi, R; Knobel, C; Bolzonella, M; Kampczyk, P; Carollo, C M; Iovino, A; Zucca, E; Contini, T; Kneib, J -P; Fevre, O Le; Mainieri, V; Renzini, A; Scodeggio, M; Zamorani, G; Balestra, I; Bardelli, S; Bongiorno, A; Caputi, K; Cucciati, O; de la Torre, S; de Ravel, L; Garilli, B; Kovac, K; Lamareille, F; Borgne, J -F Le; Brun, V Le; Maier, C; Mignoli, M; Pello, R; Peng, Y; Montero, E Perez; Presotto, V; Scarlata, C; Silverman, J; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Barnes, L; Cappi, A; Cimatti, A; Coppa, G; Diener, C; Franzetti, P; Koekemoer, A; Lopez-Sanjuan, C; McCracken, H J; Moresco, M; Nair, P; Oesch, P; Pozzetti, L; Welikala, N

    2011-01-01

    We map the radial and azimuthal distribution of Mg II gas within 200 kpc (physical) of 4000 galaxies at redshifts 0.5 1. We investigate the variation of Mg II rest frame equivalent width as a function of the radial impact parameter for different subsets of foreground galaxies selected in terms of their rest-frame colors and masses. Blue galaxies have a significantly higher average Mg II equivalent width at close galactocentric radii as compared to the red galaxies. Amongst the blue galaxies, there is a correlation between Mg II equivalent width and galactic stellar mass of the host galaxy. We also find that the distribution of Mg II absorption around group galaxies is more extended than that for non-group galaxies, and that groups as a whole have more extended radial profiles than individual galaxies. Interestingly, these effects can be satisfactorily modeled by a simple superposition of the absorption profiles of individual member galaxies, assuming that these are the same as those of non-group galaxies, su...

  10. Reionization and high-redshift galaxies: the view from quasar absorption lines

    Becker, George D; Lidz, Adam

    2015-01-01

    Determining when and how the first galaxies reionized the intergalactic medium (IGM) promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review we examine the multiple ways in which absorption lines trace the connection between galaxies and the IGM near the reionization epoch. We first describe how the Ly$\\alpha$ forest is used to determine the intensity of the ionizing ultraviolet background and the global ionizing emissivity budget. Critically, these measurements reflect the escaping ionizing radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionization-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over $z \\sim 6$ to 5, although changes in ionizati...

  11. A Note on the Total Absorption Cross-section of Galaxies

    Cirkovic, M M; Ilic, D; Petrovic, J

    1997-01-01

    In this work we shall sketch a further piece of evidence for the plausibility of hypothesis of galactic origin of Ly-$\\alpha$ forest absorption systems. Two basic premises of our discussion are (1) HDF redshift surface densities in the redshift interval 0absorption cross-section corresponding to radius of 160$h^{-1}$ kpc for $L^*$ galaxies. Low-redshift analysis also showed covering factor nearing unity, which will be used and discussed in further considerations. Semantic problems concerned with the interpretation of galaxy absorption cross-section are discussed in some details, and importance of distinction between size of the absorbers and absorption coherence length is emphasized. It is shown that HDF data predict huge number of absorption systems, in fact much larger than observed, which shows frequently quoted argument that number of galaxies is insufficient to account for all absorption lines to be wrong. Road...

  12. The Gaseous Extent of Galaxies and the Origin of \\lya Absorption Systems. III. Hubble Space Telescope Imaging of \\lya-Absorbing Galaxies at z < 1

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding \\lya absorption systems and 24 do not produce corresponding \\lya absorption lines to within sensitive upper limits. Considering only galaxy and absorber pairs that are likely to be physically associated and exc...

  13. Long-Duration Gamma-Ray Burst Host Galaxies in Emission and Absorption

    Perley, Daniel A; Tanvir, Nial R; Vergani, Susanna D; Fynbo, Johan P U

    2016-01-01

    The galaxy population hosting long-duration GRBs provides a means to constrain the progenitor and an opportunity to use these violent explosions to characterize the nature of the high-redshift universe. Studies of GRB host galaxies in emission reveal a population of star-forming galaxies with great diversity, spanning a wide range of masses, metallicities, and redshifts. However, as a population GRB hosts are significantly less massive and poorer in metals than the hosts of other core-collapse transients, suggesting that GRB production is only efficient at metallicities significantly below Solar. GRBs may also prefer compact galaxies, and dense and/or central regions of galaxies, more than other types of core-collapse explosion. Meanwhile, studies of hosts in absorption against the luminous GRB optical afterglow provide a unique means of unveiling properties of the ISM in even the faintest and most distant galaxies; these observations are helping to constrain the chemical evolution of galaxies and the propert...

  14. Damped Lyman-$\\alpha$ Absorption Associated with an Early-Type Galaxy at Redshift z = 0.16377

    Lanzetta, K M; Altan, H; Barcons, X; Chen, H W; Fernández-Soto, A; Meyer, D; Ortiz-Gill, A; Savaglio, S; Webb, J; Yahata, N; Lanzetta, Kenneth M.; Wolfe, Arthur M.; Altan, Hakan; Barcons, Xavier; Chen, Hsiao-Wen; Fernandez-Soto, Alberto; Meyer, David; Ortiz-Gil, Amelia; Savaglio, Sandra; Webb, John; Yahata, Noriaki

    1997-01-01

    We report new HST and ground-based observations of a damped Lyman-alpha absorption system toward the QSO 0850+4400. The redshift of the absorption system is z = 0.163770 and the neutral hydrogen column density of the absorption system is log N = 19.81 cm**-2. The absorption system is by far the lowest redshift confirmed damped Lyman-alpha absorption system yet identified, which provides an unprecedented opportunity to examine the nature, impact geometry, and kinematics of the absorbing galaxy in great detail. The observations indicate that the absorption system is remarkable in three respects: First, the absorption system is characterized by weak metal absorption lines and a low metal abundance, possibly less than 4% of the solar metal abundance. This cannot be explained as a consequence of dust, because the neutral hydrogen column density of the absorption system is far too low for obscuration by dust to introduce any significant selection effects. Second, the absorption system is associated with a moderate-...

  15. Magellan LDSS3 emission confirmation of galaxies hosting metal-rich Lyman α absorption systems

    Straka, Lorrie A.; Johnson, Sean; York, Donald G.; Bowen, David V.; Florian, Michael; Kulkarni, Varsha P.; Lundgren, Britt; Péroux, Celine

    2016-06-01

    Using the Low Dispersion Survey Spectrograph 3 at the Magellan II Clay Telescope, we target candidate absorption host galaxies detected in deep optical imaging (reaching limiting apparent magnitudes of 23.0-26.5 in g, r, i, and z filters) in the fields of three QSOs, each of which shows the presence of high metallicity, high N_{H I} absorption systems in their spectra (Q0826-2230: zabs = 0.9110, Q1323-0021: zabs = 0.7160, Q1436-0051: zabs = 0.7377, 0.9281). We confirm three host galaxies at redshifts 0.7387, 0.7401, and 0.9286 for two of the Lyman α absorption systems (one with two galaxies interacting). For these systems, we are able to determine the star formation rates (SFRs); impact parameters (from previous imaging detections); the velocity shift between the absorption and emission redshifts; and, for one system, also the emission metallicity. Based on previous photometry, we find these galaxies have L > L*. The [O II] SFRs for these galaxies are in the range 11-25 M⊙ yr-1 (uncorrected for dust), while the impact parameters lie in the range 35-54 kpc. Despite the fact that we have confirmed galaxies at 50 kpc from the QSO, no gradient in metallicity is indicated between the absorption metallicity along the QSO line of sight and the emission line metallicity in the galaxies. We confirm the anticorrelation between impact parameter and N_{H I} from the literature. We also report the emission redshift of five other galaxies: three at zem > zQSO, and two (L < L*) at zem < zQSO not corresponding to any known absorption systems.

  16. The Detection of Lyman-alpha Absorption from Nine Nearby Galaxies

    Bowen, D V; Blades, J C; Bowen, David V.; Pettini, Max

    2001-01-01

    We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption in the outer regions of nine nearby (cz<6000 km/s) galaxies using background QSOs and AGN as probes. The foreground galaxies are intercepted between 26 and 199 h-1 kpc from their centers, and in all cases we detect Lya within +/-500 km/s of the galaxies' systemic velocities. The intervening galaxies have a wide range of luminosities, from M_B = -17.1 to -20.0, and reside in various environments: half the galaxies are relatively isolated, the remainder form parts of groups or clusters of varying richness. The equivalent widths of the Lya lines range from 0.08 - 0.68 A and, with the notable exception of absorption from one pair, crudely correlate with sightline separation in a way consistent with previously published data, though the column densities derived from the lines do not. The lack of correlation between line strength and galaxy luminosity or, in particular, the environment of the galaxy, suggests that the absorption is not relat...

  17. The Gaseous Extent of Galaxies and the Origin of $Ly\\alpha$ Absorption Systems at z < 1

    Chen, H W; Webb, J K; Barcons, X

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies in fields of HST spectroscopic target QSOs. The goal of the program is to investigate how the properties of \\lya absorption systems observed in the spectra of background QSOs vary with the properties of intervening galaxies. We found that \\lya absorption equivalent width depends strongly on galaxy impact parameter and galaxy B-band luminosity, and that the gaseous extent of individual galaxies scales with galaxy B-band luminosity by $r\\propto L_B^{0.35\\pm0.10}$.

  18. Optimized wavelength selection for molecular absorption thermometry.

    An, Xinliang; Caswell, Andrew W; Lipor, John J; Sanders, Scott T

    2015-04-01

    A differential evolution (DE) algorithm is applied to a recently developed spectroscopic objective function to select wavelengths that optimize the temperature precision of water absorption thermometry. DE reliably finds optima even when many-wavelength sets are chosen from large populations of wavelengths (here 120 000 wavelengths from a spectrum with 0.002 cm(-1) resolution calculated by 16 856 transitions). Here, we study sets of fixed wavelengths in the 7280-7520 cm(-1) range. When optimizing the thermometer for performance within a narrow temperature range, the results confirm that the best temperature precision is obtained if all the available measurement time is split judiciously between the two most temperature-sensitive wavelengths. In the wide temperature range case (thermometer must perform throughout 280-2800 K), we find (1) the best four-wavelength set outperforms the best two-wavelength set by an average factor of 2, and (2) a complete spectrum (all 120 000 wavelengths from 16 856 transitions) is 4.3 times worse than the best two-wavelength set. Key implications for sensor designers include: (1) from the perspective of spectroscopic temperature sensitivity, it is usually sufficient to monitor two or three wavelengths, depending on the sensor's anticipated operating temperature range; and (2) although there is a temperature precision penalty to monitoring a complete spectrum, that penalty may be small enough, particularly at elevated pressure, to justify the complete-spectrum approach in many applications. PMID:25909716

  19. Infrared color selection of massive galaxies at z > 3

    Wang, T; Schreiber, C; Pannella, M; Shu, X; Willner, S P; Ashby, M L N; Huang, J -S; Fontana, A; Dekel, A; Daddi, E; Ferguson, H C; Dunlop, J; Ciesla, L; Koekemoer, A M; Giavalisco, M; Boutsia, K; Finkelstein, S; Juneau, S; Barro, G; Koo, D C; Michałowski, M J; Orellana, G; Lu, Y; Castellano, M; Bourne, N; Buitrago, F; Santini, P; Faber, S M; Hathi, N; Lucas, R A; Pérez-González, P G

    2016-01-01

    We introduce a new color-selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H_{160} and IRAC 4.5um bands, specifically H - [4.5] > 2.25 mag. These galaxies, dubbed "HIEROs", include two major populations that can be separated with an additional J - H color. The populations are massive and dusty star-forming galaxies at z > 3 (JH-blue) and extremely dusty galaxies at z 3) HIEROs, which have a median photometric redshift z ~4.4 and stellar massM_{*}~10^{10.6} Msun, and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs) reaches ~240 Msun yr^{-1} leading to a specific SFR, sSFR ~4.2 Gyr^{-1}, suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z=0 to z=2. With a median half-light radius of 2 kpc, including ~20% as compact as quiescent galaxies at similar redshifts, JH-blue HIEROs r...

  20. A correlation between the HI 21-cm absorption strength and impact parameter in external galaxies

    Curran, S J; Allison, J R; Sadler, E M

    2016-01-01

    By combining the data from surveys for HI 21-cm absorption at various impact parameters in near-by galaxies, we report an anti-correlation between the 21-cm absorption strength (velocity integrated optical depth) and the impact parameter. Also, by combining the 21-cm absorption strength with that of the emission, giving the neutral hydrogen column density, we find no evidence that the spin temperature of the gas (degenerate with the covering factor) varies significantly across the disk. This is consistent with the uniformity of spin temperature measured across the Galactic disk. Furthermore, comparison with the Galactic distribution suggests that intervening 21-cm absorption preferentially arises in disks of high inclinations (near face-on). We also investigate the hypothesis that 21-cm absorption is favourably detected towards compact radio sources. Although there is insufficient data to determine whether there is a higher detection rate towards quasar, rather than radio galaxy, sight-lines, the 21-cm detect...

  1. Building an unbiased sample of quiescent galaxies up to z=2.5 based on the Mg(UV) absorption index

    Domínguez Sánchez, H.; Eliche-Moral, M. Carmen; Pérez-González, P. G.; Esquej, P.; Alcalde-Pampliega, B.; SHARDS Team

    2015-05-01

    Samples of ``red & dead" galaxies selected through traditional color-based techniques usually suffer from contamination by strongly dust obscured sources. We are using GTC/OSIRIS data from the SHARDS project on the GOODSN field to define unbiased samples of really quiescent massive galaxies at different redshifts up to z=2.5. By measuring the Mg(UV) absorption index in the pseudo-spectra of these galaxies, we intend to determine the redshift evolution of the characteristic age of their stellar populations to shed some light into their assembly epoch.

  2. Outer Disk Star Formation in HI selected Galaxies

    Meurer, Gerhardt

    2016-01-01

    The HI in galaxies often extends past their conventionally defined optical extent. I report results from our team which has been probing low intensity star formation in outer disks using imaging in H-alpha and ultraviolet. Using a sample of hundreds of HI selected galaxies, we confirm that outer disk HII regions and extended UV disks are common. Hence outer disks are not dormant but are dimly forming stars. Although the ultraviolet light in galaxies is more centrally concentrated than the HI, the UV/HI ratio (the Star Formation Efficiency) is nearly constant, with a slight dependency on surface brightness. This result is well accounted for in a model where disks maintain a constant stability parameter Q. This model also accounts for how the ISM and star formation are distributed in the bright parts of galaxies, and how HI appears to trace the distribution of dark matter in galaxy outskirts.

  3. Selection effects in the bivariate brightness distribution for spiral galaxies

    The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

  4. The SAMI Galaxy Survey: instrument specification and target selection

    Bryant, J J; Robotham, A S G; Croom, S M; Driver, S P; Drinkwater, M J; Lorente, N P F; Cortese, L; Scott, N; Colless, M; Schaefer, A; Taylor, E N; Konstantopoulos, I S; Allen, J T; Baldry, I; Barnes, L; Bauer, A E; Bland-Hawthorn, J; Bloom, J V; Brooks, A M; Brough, S; Cecil, G; Couch, W; Croton, D; Davies, R; Ellis, S; Fogarty, L M R; Foster, C; Glazebrook, K; Goodwin, M; Green, A; Gunawardhana, M L; Hampton, E; Ho, I -T; Hopkins, A M; Kewley, L; Lawrence, J S; Leon-Saval, S G; Leslie, S; Lewis, G; Liske, J; Lopez-Sanchez, A R; Mahajan, S; Medling, A M; Metcalfe, N; Meyer, M; Mould, J; Obreschkow, D; O'Toole, S; Pracy, M; Richards, S N; Shanks, T; Sharp, R; Sweet, S M; Thomas, A D; Tonini, C; Walcher, C J

    2014-01-01

    The SAMI Galaxy Survey will observe 3400 galaxies with the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) on the Anglo-Australian Telescope (AAT) in a 3-year survey which began in 2013. We present the throughput of the SAMI system, the science basis and specifications for the target selection, the survey observation plan and the combined properties of the selected galaxies. The survey includes four volume limited galaxy samples based on cuts in a proxy for stellar mass, along with low-stellar mass dwarf galaxies all selected from the Galaxy And Mass Assembly (GAMA) survey. The GAMA regions were selected because of the vast array of ancillary data available, including ultraviolet through to radio bands. These fields are on the celestial equator at 9, 12, and 14.5 hours, and cover a total of 144 square degrees (in GAMA-I). Higher density environments are also included with the addition of eight clusters. The clusters have spectroscopy from 2dFGRS and SDSS and photometry in regions covered by the Slo...

  5. Neutral hydrogen absorption by galaxies and implications for the soft X-ray background

    Results are presented from a search for neutral hydrogen absorption in the 21-cm spectra of 59 radio continuum sources in the proximity of spiral and lenticular galaxies using the Arecibo radio telescope. Five galaxies showed possible but uncertain absorption. For the 54 other sources, the column density of the neutral hydrogen in the intervening material is well below 2 x 10 to the 19th/cu cm or the spin temperature is at least one order of magnitude above the microwave background temperature. For these cases, subthermal effects are not hiding appreciable amounts of neutral hydrogen. 47 refs

  6. Photometric redshifts and selection of high redshift galaxies in the NTT and Hubble Deep Fields

    Fontana, A; Poli, F; Giallongo, E; Arnouts, S; Cristiani, S; Moorwood, A F M; Saracco, P

    2000-01-01

    We present and compare in this paper new photometric redshift catalogs of the galaxies in three public fields: the NTT Deep Field, the HDF-N and the HDF-S. Photometric redshifts have been obtained for thewhole sample, by adopting a $\\chi^2$ minimization technique on a spectral library drawn from the Bruzual and Charlot synthesis models, with the addition of dust and intergalactic absorption. The accuracy, determined from 125 galaxies with known spectroscopic redshifts, is $\\sigma_z\\sim 0.08 (0.3)$ in the redshift intervals $z=0-1.5 (1.5-3.5)$. The global redshift distribution of I-selected galaxies shows a distinct peak at intermediate redshifts, z~0.6 at I_{AB}5 candidates in the HDF filter set and that the 4 brightest candidates at $z>5$ in the HDF-S are indeed most likely M stars. (ABRIDGED)

  7. SUBMILLIMETER FOLLOW-UP OF WISE-SELECTED HYPERLUMINOUS GALAXIES

    We have used the Caltech Submillimeter Observatory (CSO) to follow-up a sample of Wide-field Infrared Survey Explorer (WISE) selected, hyperluminous galaxies, the so-called W1W2-dropout galaxies. This is a rare (∼1000 all-sky) population of galaxies at high redshift (peaks at z = 2-3), which are faint or undetected by WISE at 3.4 and 4.6 μm, yet are clearly detected at 12 and 22 μm. The optical spectra of most of these galaxies show significant active galactic nucleus activity. We observed 14 high-redshift (z > 1.7) W1W2-dropout galaxies with SHARC-II at 350-850 μm, with nine detections, and observed 18 with Bolocam at 1.1 mm, with five detections. Warm Spitzer follow-up of 25 targets at 3.6 and 4.5 μm, as well as optical spectra of 12 targets, are also presented in the paper. Combining WISE data with observations from warm Spitzer and CSO, we constructed their mid-IR to millimeter spectral energy distributions (SEDs). These SEDs have a consistent shape, showing significantly higher mid-IR to submillimeter ratios than other galaxy templates, suggesting a hotter dust temperature. We estimate their dust temperatures to be 60-120 K using a single-temperature model. Their infrared luminosities are well over 1013 L☉. These SEDs are not well fitted with existing galaxy templates, suggesting they are a new population with very high luminosity and hot dust. They are likely among the most luminous galaxies in the universe. We argue that they are extreme cases of luminous, hot dust-obscured galaxies (DOGs), possibly representing a short evolutionary phase during galaxy merging and evolution. A better understanding of their long-wavelength properties needs ALMA as well as Herschel data.

  8. Submillimeter Follow-Up of WISE-Selected Hyperluminous Galaxies

    Wu, Jingwen; Tsai, Chao-Wei; Sayers, Jack; Benford, Dominic; Bridge, Carrie; Blain, Andrew; Eisenhardt, Peter R.; Stern, Daniel; Petty, Sara; Assef, Roberto; Bussmann, Shane; Comerford, Julia M.; Cutri, Roc; Evans, Neal J., II; Griffith, Roger; Jarrett, Thomas; Lake, Sean; Lonsdale, Carol; Rho, Jeonghee; Stanford, S. Adam; Weiner, Benjamin; Wright, Edward L.; Yan, Lin

    2012-01-01

    We have used the Caltech Submillimeter Observatory (CSO) to follow-up a sample of Wide-field Infrared Survey Explorer (WISE) selected, hyperluminous galaxies, the so-called W1W2-dropout galaxies. This is a rare (approx.1000 all-sky) population of galaxies at high redshift (peaks at z = 2-3), which are faint or undetected by WISE at 3.4 and 4.6 microns, yet are clearly detected at 12 and 22 microns. The optical spectra of most of these galaxies show significant active galactic nucleus activity. We observed 14 high-redshift (z > 1.7) W1W2-dropout galaxies with SHARC-II at 350-850 microns, with nine detections, and observed 18 with Bolocam at 1.1 mm, with five detections. Warm Spitzer follow-up of 25 targets at 3.6 and 4.5 microns, as well as optical spectra of 12 targets, are also presented in the paper. Combining WISE data with observations from warm Spitzer and CSO, we constructed their mid-IR to millimeter spectral energy distributions (SEDs). These SEDs have a consistent shape, showing significantly higher mid-IR to submillimeter ratios than other galaxy templates, suggesting a hotter dust temperature.We estimate their dust temperatures to be 60 C120 K using a single-temperature model. Their infrared luminosities are well over 10(exp 13) Stellar Luminosity. These SEDs are not well fitted with existing galaxy templates, suggesting they are a new population with very high luminosity and hot dust. They are likely among the most luminous galaxies in the universe.We argue that they are extreme cases of luminous, hot dust-obscured galaxies (DOGs), possibly representing a short evolutionary phase during galaxy merging and evolution. A better understanding of their long-wavelength properties needs ALMA as well as Herschel data.

  9. A GREEN BANK TELESCOPE SURVEY FOR H I 21 cm ABSORPTION IN THE DISKS AND HALOS OF LOW-REDSHIFT GALAXIES

    We present an H I 21 cm absorption survey with the Green Bank Telescope (GBT) of galaxy-quasar pairs selected by combining galaxy data from the Sloan Digital Sky Survey (SDSS) and radio sources from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. Our sample consists of 23 sight lines through 15 low-redshift foreground galaxy-background quasar pairs with impact parameters ranging from 1.7 kpc up to 86.7 kpc. We detected one absorber in the GBT survey from the foreground dwarf galaxy, GQ1042+0747, at an impact parameter of 1.7 kpc and another possible absorber in our follow-up Very Large Array (VLA) imaging of the nearby foreground galaxy UGC 7408. The line widths of both absorbers are narrow (FWHM of 3.6 and 4.8km s-1). The absorbers have sub-damped Lyα column densities, and most likely originate in the disk gas of the foreground galaxies. We also detected H I emission from three foreground galaxies including UGC 7408. Although our sample contains both blue and red galaxies, the two H I absorbers as well as the H I emissions are associated with blue galaxies. We discuss the physical conditions in the 21 cm absorbers and some drawbacks of the large GBT beam for this type of survey.

  10. Distribution of Cold ($\\lesssim 300$K) Atomic Gas in Galaxies: Results from the GBT HI Absorption Survey Probing the Inner Halos ($\\rho<20$kpc) of Low-z Galaxies

    Borthakur, Sanchayeeta

    2016-01-01

    We present the Green Bank Telescope absorption survey of cold atomic hydrogen ($\\lesssim 300$K) in the inner halo of low-redshift galaxies. The survey aims to characterize the cold gas distribution and to address where condensation - the process where ionized gas accreted by galaxies condenses into cold gas within the disks of galaxies - occurs. Our sample consists of 16 galaxy-quasar pairs with impact parameters of $\\le$ 20kpc. We detected an HI absorber associated with J0958+3222 (NGC 3067) and HI emission from six galaxies. We also found two \\ion{Ca}{2} absorption system in the archival SDSS data associated with galaxies J0958+3222 and J1228+3706, although the sample was not selected based on the presence of metals in absorption. Our detection rate of HI absorbers with optical depths of $\\ge 0.06$ is $\\sim$7\\%. We also find that cold HI phase ($\\lesssim$300K) is 44($\\pm$18)\\% of the total atomic gas in the sightline probing J0958+3222. We find no correlation between the peak optical depth and impact parame...

  11. MAPPING DUST THROUGH EMISSION AND ABSORPTION IN NEARBY GALAXIES

    Kreckel, Kathryn; Groves, Brent; Schinnerer, Eva; Meidt, Sharon E.; Tabatabaei, Fatemeh S. [Max Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Johnson, Benjamin D. [Institut d' Astrophysique de Paris, UMR 7095, 98 bis Bvd Arago, F-75014 Paris (France); Aniano, Gonzalo [Institut d' Astrophysique Spatiale (IAS), Batiment 121, Universite Paris-Sud 11 and CNRS (UMR 8617), F-91405 Orsay (France); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Croxall, Kevin V. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Draine, Bruce T. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001 (United States); Gordon, Karl D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Crocker, Alison F.; Smith, J. D. T. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Hunt, Leslie K. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Kennicutt, Robert C., E-mail: kreckel@mpia.de [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-07-01

    Dust has long been identified as a barrier to measuring inherent galaxy properties. However, the link between dust and attenuation is not straightforward and depends on both the amount of dust and its distribution. Herschel imaging of nearby galaxies undertaken as part of the KINGFISH project allows us to map the dust as seen in emission with unprecedented sensitivity and {approx}1 kpc resolution. We present here new optical integral field unit spectroscopy for eight of these galaxies that provides complementary 100-200 pc scale maps of the dust attenuation through observation of the reddening in both the Balmer decrement and the stellar continuum. The stellar continuum reddening, which is systematically less than that observed in the Balmer decrement, shows no clear correlation with the dust, suggesting that the distribution of stellar reddening acts as a poor tracer of the overall dust content. The brightest H II regions are observed to be preferentially located in dusty regions, and we do find a correlation between the Balmer line reddening and the dust mass surface density for which we provide an empirical relation. Some of the high-inclination systems in our sample exhibit high extinction, but we also find evidence that unresolved variations in the dust distribution on scales smaller than 500 pc may contribute to the scatter in this relation. We caution against the use of integrated A{sub V} measures to infer global dust properties.

  12. Using 21cm Absorption in Small Impact Parameter Galaxy-QSO Pairs to Probe Low-Redshift Damped and Sub-Damped Lyman $\\alpha$ System

    Borthakur, Sanchayeeta; Yun, Min S; Momjian, Emmanuel; Meiring, Joseph D; Bowen, David V; York, Donald G

    2009-01-01

    To search for low-redshift damped Lyman $\\alpha$ (DLA) and sub-DLA quasar absorbers, we have conducted a 21cm absorption survey of radio-loud quasars at small impact parameters to foreground galaxies selected from the Sloan Digital Sky Survey (SDSS). Here we present the first results from this survey based on observations of SDSS J104257.58+074850.5 ($z_{QSO}$ = 2.66521), a quasar at an angular separation from a foreground galaxy ($z_{gal}$ = 0.03321) of 2.5" (1.7 kpc in projection). The foreground galaxy is a low-luminosity spiral with on-going star formation (0.004 M$_{\\odot}$ yr$^{-1}$ kpc$^{-2}$) and a metallicity of $-0.27 \\pm 0.05$ dex. We detect 21cm absorption from the galaxy with the Green Bank Telescope (GBT), the Very Large Array (VLA), and the Very Long Baseline Array (VLBA). Only two components separated by approximately 6 km/s are detected; the absorption appears to be quiescent disk gas corotating with the galaxy. The width of the main absorption line indicates that the gas is cold, $T_{k} <...

  13. The chemical evolution of galaxies causing damped Ly$\\alpha$ absorption

    Lindner, Ulrich; Alvensleben, Uta Fritze - v.; Fricke, Klaus J.

    1997-01-01

    We have compiled all available data on chemical abundances in damped Lyman alpha absorption systems for comparison with results from our combined chemical and spectrophotometric galaxy evolution models. Preliminary results from chemically consistent calculations are in agreement with observations of damped Ly$\\alpha$ systems.

  14. Magellan LDSS3 emission confirmation of galaxies hosting metal-rich Lyman-alpha absorption systems

    Straka, Lorrie A; York, Donald G; Bowen, David V; Florian, Michael; Kulkarni, Varsha P; Lundgren, Britt; Peroux, Celine

    2015-01-01

    Using the Low Dispersion Survey Spectrograph 3 at the Magellan II Clay Telescope in Chile, we target candidate absorption host galaxies detected in deep optical imaging (reaching limiting apparent magnitudes of 23.0-26.5 in g; r; i; and z filters) in the fields of three QSOs, each of which shows the presence of high metallicity, strong NHI absorption systems in their spectra (Q0826-2230: zabs=0.9110, Q1323-0021: zabs = 0.7160, Q1436-0051: zabs = 0.7377; 0.9281). We confirm host galaxies at redshifts 0.7387, 0.7401, and 0.9286 for two out of four of the Ly-alpha absorption systems. For these systems, we are able to determine the SFRs; impact parameters (known from previous imaging detections); the velocity shift between the absorption and emission redshifts; and, for one system, also the emission metallicity. Based on previous photometry, we find these galaxies have L>L*. The SFRs for these galaxies, based on [O II] emission, are in the range 11-25 M_sol/yr (uncorrected for dust), while the impact parameters l...

  15. Reionisation and High-Redshift Galaxies: The View from Quasar Absorption Lines

    Becker, George D.; Bolton, James S.; Lidz, Adam

    2015-12-01

    Determining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review, we examine the multiple ways in which absorption lines trace the connection between galaxies and the intergalactic medium near the reionisation epoch. We first describe how the Ly α forest is used to determine the intensity of the ionising ultraviolet background and the global ionising emissivity budget. Critically, these measurements reflect the escaping ionising radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionisation-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over z ~ 6 to 5, although changes in ionisation will also affect the evolution of metal line properties. A substantial fraction of metal absorbers at these redshifts may trace relatively low-mass galaxies. Finally, we review constraints from the Ly α forest and quasar near zones on the timing of reionisation. Along with other probes of the high-redshift Universe, absorption line data are consistent with a relatively late end to reionisation (5.5 ≲ z ≲ 7); however, the constraints are still fairly week. Significant progress is expected to come through improved analysis techniques, increases in the number of known high-redshift quasars from optical and infrared sky surveys, large gains in sensitivity from next-generation observing facilities, and synergies with other probes of the reionisation era.

  16. First Connection between Cold Gas in Emission and Absorption: CO Emission from a Galaxy-Quasar Pair

    Neeleman, M; Zwaan, M A; Kanekar, N; Christensen, L; Dessauges-Zavadsky, M; Fynbo, J P U; van Kampen, E; Møller, P; Zafar, T

    2016-01-01

    We present the first detection of molecular emission from a galaxy selected to be near a projected background quasar using the Atacama Large Millimeter/submillimeter Array (ALMA). The ALMA detection of CO(1$-$0) emission from the $z=0.101$ galaxy toward quasar PKS 0439-433 is coincident with its stellar disk and yields a molecular gas mass of $M_{\\rm mol} \\approx 4.2 \\times 10^9 M_\\odot$ (for a Galactic CO-to-H$_2$ conversion factor), larger than the upper limit on its atomic gas mass. We resolve the CO velocity field, obtaining a rotational velocity of $134 \\pm 11$ km s$^{-1}$, and a resultant dynamical mass of $\\geq 4 \\times 10^{10} M_\\odot$. Despite its high metallicity and large molecular mass, the $z=0.101$ galaxy has a low star formation rate, implying a large gas consumption timescale, larger than that typical of late-type galaxies. Most of the molecular gas is hence likely to be in a diffuse extended phase, rather than in dense molecular clouds. By combining the results of emission and absorption stud...

  17. Selecting background galaxies in weak-lensing analysis of galaxy clusters

    Formicola, I; Meneghetti, M; Mazzotta, P; Grado, A; Giocoli, C

    2016-01-01

    In this paper, we present a new method to select the faint, background galaxies used to derive the mass of galaxy clusters by weak lensing. The method is based on the simultaneous analysis of the shear signal, that should be consistent with zero for the foreground, unlensed galaxies, and of the colors of the galaxies: photometric data from the COSMic evOlution Survey are used to train the color selection. In order to validate this methodology, we test it against a set of state-of-the-art image simulations of mock galaxy clusters in different redshift [$0.23-0.45$] and mass [$0.5-1.55\\times10^{15}M_\\odot$] ranges, mimicking medium-deep multicolor imaging observations (e.g. SUBARU, LBT). The performance of our method in terms of contamination by unlensed sources is comparable to a selection based on photometric redshifts, which however requires a good spectral coverage and is thus much more observationally demanding. The application of our method to simulations gives an average ratio between estimated and true ...

  18. Selecting background galaxies in weak-lensing analysis of galaxy clusters

    Formicola, I.; Radovich, M.; Meneghetti, M.; Mazzotta, P.; Grado, A.; Giocoli, C.

    2016-05-01

    In this paper, we present a new method to select the faint, background galaxies used to derive the mass of galaxy clusters by weak lensing. The method is based on the simultaneous analysis of the shear signal, that should be consistent with zero for the foreground, unlensed galaxies, and of the colours of the galaxies: photometric data from the COSMic evOlution Survey are used to train the colour selection. In order to validate this methodology, we test it against a set of state-of-the-art image simulations of mock galaxy clusters in different redshift [0.23-0.45] and mass [0.5-1.55 × 1015 M⊙] ranges, mimicking medium-deep multicolour imaging observations [e.g. Subaru, Large Binocular Telescope]. The performance of our method in terms of contamination by unlensed sources is comparable to a selection based on photometric redshifts, which however requires a good spectral coverage and is thus much more observationally demanding. The application of our method to simulations gives an average ratio between estimated and true masses of ˜0.98 ± 0.09. As a further test, we finally apply our method to real data, and compare our results with other weak-lensing mass estimates in the literature: for this purpose, we choose the cluster Abell 2219 (z = 0.228), for which multiband (BVRi) data are publicly available.

  19. Spatial density fluctuations and selection effects in galaxy redshift surveys

    Labini, Francesco Sylos; Baryshev, Yurij V

    2014-01-01

    One of the main problems of observational cosmology is to determine the range in which a reliable measurement of galaxy correlations is possible. This corresponds to determine the shape of the correlation function, its possible evolution with redshift and the size and amplitude of large scale structures. Different selection effects, inevitably entering in any observation, introduce important constraints in the measurement of correlations. In the context of galaxy redshift surveys selection effects can be caused by observational techniques and strategies and by implicit assumptions used in the data analysis. Generally all these effects are taken into account by using pair-counting algorithms to measure two-point correlations. We review these methods stressing that they are based on the a-priori assumption that galaxy distribution is spatially homogeneous inside a given sample. We show that, when this assumption is not satisfied by the data, results of the correlation analysis are affected by finite size effect...

  20. The optical redshift survey sample selection and the galaxy distribution

    Santiago, B X; Lahav, O; Davis, M; Dressler, A; Huchra, J P

    1994-01-01

    This is the first in a series of papers describing the {\\it Optical Redshift Survey} (ORS), a redshift survey of optically selected galaxies covering 98\\% of the sky above |b| = 20^\\circ (8.09 ster). The survey is drawn from the UGC, ESO, and ESGC galaxy catalogues, and contains two sub-samples, one complete to a B magnitude of 14.5, the other complete to a B major axis diameter of 1.9^\\prime. The entire sample consists of 8457 objects, of which redshifts are now available for 8286; 171 objects remain without measured redshifts. The ORS provides the most detailed and homogeneous sampling of the large-scale galaxy distribution to date in these areas. The density field of bright optical galaxies is well-defined to 8000 \\kms, and is dominated by the Virgo, Telescopium-Pavo-Indus, Hydra-Centaurus, Pisces-Perseus, and Coma-A1367 Superclusters. The dense sampling provided by ORS allows a detailed analysis of the galaxy density field, and will be used to test its dependence on morphology and other galaxy parameters.

  1. Dynamics and Metallicity of Far-IR Selected Galaxies

    Williams, R J; Santini, P; Marconi, A; Cresci, G; Mannucci, F; Lutz, D

    2014-01-01

    We present near-IR integral field spectroscopy of 10 Herschel selected galaxies at z~1.5. From detailed mapping of the H$\\alpha$ and [NII] emission lines we trace the dynamics, SFRs, metallicities and also investigate gas fractions for these galaxies. For a few galaxies the distribution of star formation traced by H$\\alpha$ only traces a small fraction of the stellar disc, suggesting that in these cases the H$\\alpha$ is tracing recent minor merging events with a massive galaxy. The restframe UV continuum emission often has a completely different distribution to H$\\alpha$, which warns about the use of UV-SED based star formation tracers in these systems. For a few galaxies the SFR(FIR) is much higher than SFR(H$\\alpha$-extinction corrected) suggesting that in these cases optical nebular emission associated with the bulk of star formation is completely undetected. Our analysis of galaxy dynamics shows that minor dynamical disruptions (e.g. minor merging) are generally not enough to cause a deviation from the es...

  2. The gaseous extent of galaxies and the origin of Lyman alpha absorption systems; 4, Lyman$\\alpha$ absorbers arising in a galaxy group

    Ortiz-Gill, A; Webb, J K; Barcons, X; Fernández-Soto, A

    1999-01-01

    We present new GHRS observations of Lyman alpha absorption lines associated with a group of galaxies towards the QSO 1545+2101. We have identified eight distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645 and velocity dispersion 239 km/s. The identification of discrete absorption systems indicates that they arise in clouds of neutral hydrogen rather than in a diffuse intragroup medium. Our analysis suggests that the Lyman alpha absorption lines are associated with individual galaxies in the group, although a one-to-one relationship between absorbers and galaxies is difficult to establish in such a dense environment.

  3. The Gaseous Extent of Galaxies and the Origin of Ly$\\alpha$ Absorption Systems; 3, Hubble Space Telescope Imaging of Ly$\\alpha$-Absorbing Galaxies at z < 1

    Chen, H W; Webb, J K; Barcons, X

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding \\lya absorption systems and 24 do not produce corresponding \\lya absorption lines to within sensitive upper limits. Considering only galaxy and absorber pairs that are likely to be physically associated and excluding galaxy and absorber pairs within 3000 \\kms of the background QSOs leaves 26 galaxy and absorber pairs and seven galaxies that do not produce corresponding \\lya absorption lines to within sensitive upper limits. Redshifts of the galaxy and absorber pairs range from 0.0750 to 0.8912 with a median of 0.3718, and impact parameter separations of the galaxy and absorber pairs range from 12.4 to $157.4 h^{-1}$ kpc with a median of $62.4 h^{-1}$ kpc. The primary result of the analysis is that the amount of gas encountered ...

  4. Are Dusty Galaxies Blue? Insights on UV Attenuation from Dust-Selected Galaxies

    Casey, C M; Sanders, D B; Lee, N; Cooray, A; Finkelstein, S L; Capak, P; Conley, A; De Zotti, G; Farrah, D; Fu, H; Floc'h, E Le; Ilbert, O; Ivison, R J; Takeuchi, T T

    2014-01-01

    Galaxies' rest-frame ultraviolet (UV) properties are often used to directly infer the degree to which dust obscuration affects the measurement of star formation rates. While much recent work has focused on calibrating dust attenuation in galaxies selected at rest-frame ultraviolet wavelengths, locally and at high-$z$, here we investigate attenuation in dusty, star-forming galaxies (DSFGs) selected at far-infrared wavelengths. By combining multiwavelength coverage across 0.15--500\\,$\\mu$m in the COSMOS field, in particular making use of {\\it Herschel} imaging, and a rich dataset on local galaxies, we find a empirical variation in the relationship between rest-frame UV slope ($\\beta$) and ratio of infrared-to-ultraviolet emission ($L_{\\rm IR}/L_{\\rm UV}\\equiv\\,IRX$) as a function of infrared luminosity, or total star formation rate, SFR. Both locally and at high-$z$, galaxies above SFR$\\gt$50\\,M$_\\odot$\\,yr$^{-1}$ deviate from the nominal $IRX-\\beta$ relation towards bluer colors by a factor proportional to the...

  5. A Detailed Analysis of the Multi-Velocity Components of strong HI-selected absorbers in the Halos of z~0.5 Galaxies

    Vanderhoof, Brittany; Ribaudo, Joseph; Lehner, Nicolas; Howk, J. Christopher

    2016-01-01

    One driving force of galaxy evolution is the presence and circulation of material throughout the extended gaseous environment of a galaxy, the circumgalactic material (CGM). In the Milky Way, high-velocity clouds (HVC) are well studied systems that trace outflows, inflows, and recycled material throughout the CGM. We examine archival QSO spectra from HST/COS in an effort to similarly identify absorption systems with high-velocity absorption relative to the rest-frame of a strong HI-selected absorber in order to dissect the various components and their origins in the halos of z~0.5 galaxies.

  6. Spatial density fluctuations and selection effects in galaxy redshift surveys

    One of the main problems of observational cosmology is to determine the range in which a reliable measurement of galaxy correlations is possible. This corresponds to determining the shape of the correlation function, its possible evolution with redshift and the size and amplitude of large scale structures. Different selection effects, inevitably entering in any observation, introduce important constraints in the measurement of correlations. In the context of galaxy redshift surveys selection effects can be caused by observational techniques and strategies and by implicit assumptions used in the data analysis. Generally all these effects are taken into account by using pair-counting algorithms to measure two-point correlations. We review these methods stressing that they are based on the a-priori assumption that galaxy distribution is spatially homogeneous inside a given sample. We show that, when this assumption is not satisfied by the data, results of the correlation analysis are affected by finite size effects. In order to quantify these effects, we introduce a new method based on the computation of the gradient of galaxy counts along tiny cylinders. We show, by using artificial homogeneous and inhomogeneous point distributions, that this method identifies redshift dependent selection effects and disentangles them from the presence of large scale density fluctuations. We then apply this new method to several redshift catalogs and we find evidence that galaxy distribution, in those samples where selection effects are small enough, is characterized by power-law correlations with exponent γ=0.9 up to 20 Mpc/h followed by a change of slope that, in the range 20–100 Mpc/h, corresponds to a power-law exponent γ=0.25. Whether a crossover to spatial uniformity occurs at ∼ 100 Mpc/h or larger scales cannot be clarified by the present data

  7. Line Transfer through Clumpy, Large-Scale Outflows: Lyman Alpha Absorption and Halos around Starforming Galaxies

    Dijkstra, Mark

    2012-01-01

    We present constrained radiative transfer calculations of Lyman Alpha (Lya) photons propagating through clumpy, dusty, large scale outflows, and explore whether we can quantitatively explain the Lya halos that have been observed around Lyman Break Galaxies. We construct phenomenological models of large-scale outflows which consist of cold clumps that are in pressure equilibrium with a constant-velocity hot wind. First we consider models in which the cold clumps are distributed symmetrically around the galaxy, and in which the clumps undergo a continuous acceleration in its 'circumgalactic' medium (CGM). We constrain the properties of the cold clumps (radius, velocity, HI column density, & number density) by matching the observed Lya absorption strength of the CGM in the spectra of background galaxies. We then insert a Lya source in the center of this clumpy outflow, which consists of 1e5-1e6 clumps, and compute observable properties of the scattered Lya photons. In these models, the scattered radiation fo...

  8. Tuning target selection algorithms to improve galaxy redshift estimates

    Hoyle, Ben; Rau, Markus Michael; Seitz, Stella; Weller, Jochen

    2015-01-01

    We showcase machine learning (ML) inspired target selection algorithms to determine which of all potential targets should be selected first for spectroscopic follow up. Efficient target selection can improve the ML redshift uncertainties as calculated on an independent sample, while requiring less targets to be observed. We compare the ML targeting algorithms with the Sloan Digital Sky Survey (SDSS) target order, and with a random targeting algorithm. The ML inspired algorithms are constructed iteratively by estimating which of the remaining target galaxies will be most difficult for the machine learning methods to accurately estimate redshifts using the previously observed data. This is performed by predicting the expected redshift error and redshift offset (or bias) of all of the remaining target galaxies. We find that the predicted values of bias and error are accurate to better than 10-30% of the true values, even with only limited training sample sizes. We construct a hypothetical follow-up survey and fi...

  9. On the Anomalous Silicate Absorption Feature of the Prototypical Seyfert 2 Galaxy NGC 1068

    Koehler, Melanie; Li, Aigen

    2012-01-01

    The first detection of the silicate absorption feature in AGNs was made at 9.7 micrometer for the prototypical Seyfert 2 galaxy NGC 1068 over 30 years ago, indicating the presence of a large column of silicate dust in the line-of-sight to the nucleus. It is now well recognized that type 2 AGNs exhibit prominent silicate absorption bands, while the silicate bands of type 1 AGNs appear in emission. More recently, using the Mid-Infrared Interferometric Instrument on the Very Large Telescope Inte...

  10. A correlation between the H I 21-cm absorption strength and impact parameter in external galaxies

    Curran, S. J.; Reeves, S. N.; Allison, J. R.; Sadler, E. M.

    2016-07-01

    By combining the data from surveys for H I 21-cm absorption at various impact parameters in near-by galaxies, we report an anti-correlation between the 21-cm absorption strength (velocity integrated optical depth) and the impact parameter. Also, by combining the 21-cm absorption strength with that of the emission, giving the neutral hydrogen column density, N_{H I}, we find no evidence that the spin temperature of the gas (degenerate with the covering factor) varies significantly across the disc. This is consistent with the uniformity of spin temperature measured across the Galactic disc. Furthermore, comparison with the Galactic N_{H I} distribution suggests that intervening 21-cm absorption preferentially arises in discs of high inclinations (near face-on). We also investigate the hypothesis that 21-cm absorption is favourably detected towards compact radio sources. Although there is insufficient data to determine whether there is a higher detection rate towards quasar, rather than radio galaxy, sight-lines, the 21-cm detections intervene objects with a mean turnover frequency of turnover frequency is anti-correlated with radio source size, this does indicate a preferential bias for detection towards compact background radio sources.

  11. A correlation between the H I 21-cm absorption strength and impact parameter in external galaxies

    Curran, S. J.; Reeves, S. N.; Allison, J. R.; Sadler, E. M.

    2016-04-01

    By combining the data from surveys for H I 21-cm absorption at various impact parameters in near-by galaxies, we report an anti-correlation between the 21-cm absorption strength (velocity integrated optical depth) and the impact parameter. Also, by combining the 21-cm absorption strength with that of the emission, giving the neutral hydrogen column density, N_{H I}, we find no evidence that the spin temperature of the gas (degenerate with the covering factor) varies significantly across the disk. This is consistent with the uniformity of spin temperature measured across the Galactic disk. Furthermore, comparison with the Galactic N_{H I} distribution suggests that intervening 21-cm absorption preferentially arises in disks of high inclinations (near face-on). We also investigate the hypothesis that 21-cm absorption is favourably detected towards compact radio sources. Although there is insufficient data to determine whether there is a higher detection rate towards quasar, rather than radio galaxy, sight-lines, the 21-cm detections intervene objects with a mean turnover frequency of ≈ 5× 108 Hz, compared to ≈ 1× 108 Hz for the non-detections. Since the turnover frequency is anti-correlated with radio source size, this does indicate a preferential bias for detection towards compact background radio sources.

  12. The influence of radio-galaxy activity on X-ray absorption lines from the intracluster medium

    Koeckert, F; Koeckert, Franziska; Reynolds, Christopher S.

    2006-01-01

    We present an investigation of the X-ray absorption features predicted by hydrodynamic simulations of radio galaxies interacting with the intracluster medium (ICM) of their host galaxy clusters. We show how these absorption lines can be used as a new diagnostic for the radio-galaxy/ICM interactions. Such interactions have been observed in numerous systems by ROSAT, CHANDRA and XMM-NEWTON, and understanding them has implications for AGN feedback and galaxy formation. Starting from the hydrodynamic simulations of Reynolds, Heinz & Begelman (2002), we calculate the properties of the highly ionized iron and oxygen lines (seen in absorption against the central active galactic nucleus; AGN), predicting line shapes, equivalent widths, column densities and velocity shifts. The main effect of the jet on the absorption lines is a reduction of the line strength from that of the quiescent ICM and the introduction of some velocity structure in the line profile. We investigate whether these features are detectable with...

  13. A search for HI absorption in nearby radio galaxies using HIPASS

    Allison, J R; Meekin, A M

    2014-01-01

    Using archival data from the HI Parkes All Sky Survey (HIPASS) we have searched for 21 cm-line absorption in 204 nearby radio and star-forming galaxies with continuum flux densities greater than $S_{1.4} \\approx 250$ mJy within the redshift range $0 < cz < 12\\,000$ km s$^{-1}$. By applying a detection method based on Bayesian model comparison, we successfully detect and model absorption against the radio-loud nuclei of four galaxies, of which the Seyfert 2 galaxy 2MASX J130804201-2422581 was previously unknown. All four detections were achieved against compact radio sources, which include three active galactic nuclei (AGNs) and a nuclear starburst, exhibiting high dust and molecular gas content. Our results are consistent with the detection rate achieved by the recent ALFALFA HI absorption pilot survey by Darling et al. and we predict that the full ALFALFA survey should yield more than 3-4 times as many detections as we have achieved here. Furthermore, we predict that future all-sky surveys on the SKA p...

  14. The gaseous extent of galaxies and the origin of Lyman alpha absorption systems. IV: Lyman alpha absorbers arising in a galaxy group

    Ortiz-Gil, A.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.; Fernandez-Soto, A.

    1999-01-01

    We present new GHRS observations of Lyman alpha absorption lines associated with a group of galaxies towards the QSO 1545+2101. We have identified eight distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645 and velocity dispersion 239 km/s. The identification of discrete absorption systems indicates that they aris...

  15. CLASH: Extreme Emission Line Galaxies and Their Implication on Selection of High-Redshift Galaxies

    Huang, Xingxing; Wang, Junxian; Ford, Holland; Lemze, Doron; Moustakas, John; Shu, Xinwen; Van der Wel, Arjen; Zitrin, Adi; Frye, Brenda L; Postman, Marc; Bartelmann, Matthias; Benitez, Narciso; Bradley, Larry; Broadhurst, Tom; Coe, Dan; Donahue, Megan; Infante, Leopoldo; Kelson, Daniel; Koekemoer, Anton; Lahav, Ofer; Medezinski, Elinor; Moustakas, Leonidas; Rosati, Piero; Seitz, Stella; Umetsu, Keiichi

    2014-01-01

    We utilize the CLASH (Cluster Lensing And Supernova survey with Hubble) observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y105) and F125W (J125), as the flux of the central bands could be enhanced by the presence of [O III] 4959, 5007 at redshift of about 0.93-1.14 and 1.57-1.79, respectively. The multi-band observations help to constrain the equivalent widths of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] 4959,5007 equivalent width of about 3737 angstrom. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high equivalent width can be only found in such faint galaxies. These EELGs can mimic the dropout feature similar to that of high redshift galaxies and contaminate the color-color selection of high redshift galaxies when the S/N ratio is limited ...

  16. The Origin of C IV Absorption Systems at Redshifts z<1---Discovery of Extended C IV Envelopes Around Galaxies

    Chen, H W; Webb, J K; Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Webb, John K.

    2001-01-01

    (Abridged) We report the discovery of extended CIV gaseous envelopes around galaxies of a wide range of luminosity and morphological type. First, we show that CIV absorption systems are strongly clustered around galaxies on velocity scales of v < 250 km/s and impact parameter scales of rho < 100 h^{-1} kpc but not on larger velocity or impact parameter scales. Next, adopting measurements of galaxy properties presented in previous papers, we examine how properties of the CIV absorption systems depend on properties of the galaxies. On the basis of 14 galaxy and absorber pairs and 36 galaxies that do not produce corresponding CIV absorption lines to within sensitive upper limits, we find that: (1) Galaxies of a range of morphological type and luminosity appear to possess extended CIV gaseous envelopes of radius R ~ 100 h^{-1} kpc, with abrupt boundaries between the CIV absorbing and non-absorbing regions. (2) The extent of CIV-absorbing gas around galaxies scales with galaxy B-band luminosity as R \\propto ...

  17. A Groundbased Imaging Study of Galaxies Causing DLA, subDLA, and LLS Absorption in Quasar Spectra

    Rao, Sandhya M; Turnshek, David A; Monier, Eric M; Nestor, Daniel B; Quider, Anna M

    2011-01-01

    We present results from a search for galaxies that give rise to damped Lyman alpha (DLA), subDLA, and Lyman limit system (LLS) absorption at redshifts 0.1 ~= 0.3 A) whose HI column densities were determined by measuring the Ly-alpha line in HST UV spectra. Photometric redshifts, galaxy colors, and proximity to the quasar sightline, in decreasing order of importance, were used to identify galaxies responsible for the absorption. Our sample includes 80 absorption systems for which the absorbing galaxies have been identified, of which 54 are presented here for the first time. The main results of this study are: (i) the surface density of galaxies falls off exponentially with increasing impact parameter, b, from the quasar sightline relative to a constant background of galaxies, with an e-folding length of ~46 kpc. Galaxies with b >~ 100 kpc calculated at the absorption redshift are statistically consistent with being unrelated to the absorption system. (ii) log N(HI) is inversely correlated with b at the 3.0 sig...

  18. Nature of H-alpha selected galaxies at z>2. II. Clumpy galaxies and compact star-forming galaxies

    Tadaki, Ken-ichi; Tanaka, Ichi; Hayashi, Masao; Koyama, Yusei; Shimakawa, Rhythm

    2013-01-01

    We present the morphological properties of 109 H\\alpha-selected galaxies at z>2 in SXDF-UDS-CANDELS field. With high-resolution optical/near-infrared images obtained by Hubble Space Telescope, we identify giant clumps within the H\\alpha emitters (HAEs). We find that at least 41% of our sample show clumpy structures in the underlying disks. The color gradient of clumps is commonly seen in the sense that the clumps near the galactic center tend to be redder than those in the outer regions. The mid-infrared detection in galaxies with red clumps and the spatial distribution of H\\alpha emission suggest that dusty star-formation activity is probably occurring in the nuclear red clumps. A gas supply to a bulge component through the clump migration is one of the most potent physical processes to produce such dusty star-forming clumps and form massive bulges in local early-type galaxies. They would become large quiescent galaxies at later times just by consumption or blowout of remaining gas. Also, while most of the H...

  19. Complex Investigation of SBS Galaxies in Seven Selected Fields

    Hakopian, Susanna

    2014-07-01

    It is known that the main criterion for the selection of active objects in the First Byurakan, otherwise Markarian survey was the presence of signs of UV-excess in their low-dispersion spectra. Using the presence of emission lines as the second criteria became real during the Second Byurakan survey because of its improved technique. Extended (not stellated) objects, selected with the use of this criterion, made the main part of the separate sample of SBS galaxies. Originally, this sample included 1286 objects, selected in 65 fields of the survey (16 square degree each), to which, with the help of other sources than the survey, there were later added some objects. We studied a subsample of SBS galaxies in seven selected fields (the deepest according to the V/Vmax criterion), including about the third of the whole sample. The first, already completed phase of this program was started with carrying out a follow-up slit spectroscopy of all, about 500 objects, based on observations with long-slit spectrographs with 6m telescope of SAO Russia and 2.6.m telescope of Byurakan. As a result redshifts were determined, as well as spectral classification was made for all of objects, using the scheme adapted to the spectral material. Besides other, obtained data allowed us to estimate the efficiency of used criteria for the selection of galaxies of different classes of starformation and nuclear activity along the full scale of the apparent magnitudes, including close to the limit values (18.5 VAGR, correspondently. Processing of the data obtained for more than twenty objects are at different stages (see arXiv:1403.0127 for extended version).

  20. The VIMOS Ultra-Deep Survey (VUDS): IGM transmission towards galaxies with 2.5selection of high redshift galaxies

    Thomas, R; Cassata, V Le Brun P; Garilli, B; Lemaux, B C; Maccagni, D; Pentericci, L; Tasca, L A M; Zamorani, G; Zucca, E; Amorin, R; Bardelli, S; Cassarà, L; Castellano, M; Cimatti, A; Cucciati, O; Durkalec, A; Fontana, A; Giavalisco, M; Grazian, A; Hathi, N P; Ilbert, O; Paltani, S; Ribeiro, B; Schaerer, D; Scodeggio, M; Sommariva, V; Talia, M; Tresse, L; Vanzella, E; Vergani, D; Capak, P; Charlot, S; Contini, T; Cuby, J G; de la Torre, S; Dunlop, J; Fotopoulou, S; Koekemoer, A; López-Sanjuan, C; Mellier, Y; Pforr, J; Salvato, M; Scoville, N; Taniguchi, Y; Wang, P W

    2014-01-01

    (arXiv abridged abstract) The observed UV rest-frame spectra of distant galaxies are the result of their intrinsic emission combined with absorption along the line of sight produced by the inter-galactic medium (IGM). Here we analyse the evolution of the mean IGM transmission Tr(Ly_alpha) and its dispersion along the line of sight for 2127 galaxies with 2.5= 4 compared to results from QSOs, but a degeneracy between dust extinction and IGM prevents to draw firm conclusions if the internal dust extinction for star-forming galaxies at z>4 takes a mean value significantly in excess of E(B-V)>0.15. Most importantly, we find a large dispersion of IGM transmission along the lines of sight towards distant galaxies with 68% of the distribution within 10 to 17% of the median value in delta z=0.5 bins, similar to what is found on the LOS towards QSOs. We demonstrate the importance of taking into account this large range of IGM transmission when selecting high redshift galaxies based on their colour properties (e.g. LBG ...

  1. Tuning target selection algorithms to improve galaxy redshift estimates

    Hoyle, Ben; Paech, Kerstin; Rau, Markus Michael; Seitz, Stella; Weller, Jochen

    2016-06-01

    We showcase machine learning (ML) inspired target selection algorithms to determine which of all potential targets should be selected first for spectroscopic follow-up. Efficient target selection can improve the ML redshift uncertainties as calculated on an independent sample, while requiring less targets to be observed. We compare seven different ML targeting algorithms with the Sloan Digital Sky Survey (SDSS) target order, and with a random targeting algorithm. The ML inspired algorithms are constructed iteratively by estimating which of the remaining target galaxies will be most difficult for the ML methods to accurately estimate redshifts using the previously observed data. This is performed by predicting the expected redshift error and redshift offset (or bias) of all of the remaining target galaxies. We find that the predicted values of bias and error are accurate to better than 10-30 per cent of the true values, even with only limited training sample sizes. We construct a hypothetical follow-up survey and find that some of the ML targeting algorithms are able to obtain the same redshift predictive power with 2-3 times less observing time, as compared to that of the SDSS, or random, target selection algorithms. The reduction in the required follow-up resources could allow for a change to the follow-up strategy, for example by obtaining deeper spectroscopy, which could improve ML redshift estimates for deeper test data.

  2. An HST/COS legacy survey of intervening Si III absorption in the extended gaseous halos of low-redshift galaxies

    Richter, P.; Wakker, B. P.; Fechner, C.; Herenz, P.; Tepper-García, T.; Fox, A. J.

    2016-05-01

    Aims: Doubly ionized silicon (Si iii) is a powerful tracer of diffuse ionized gas inside and outside of galaxies. It can be observed in the local Universe in ultraviolet (UV) absorption against bright extragalactic background sources. We here present an extensive study of intervening Si iii-selected absorbers and study the properties of the warm circumgalactic medium (CGM) around low-redshift (z ≤ 0.1) galaxies. Methods: We analyzed the UV absorption spectra of 303 extragalactic background sources, as obtained with the Cosmic Origins Spectrograph (COS) on-board the Hubble Space Telescope (HST). We developed a geometrical model for the absorption-cross section of the CGM around the local galaxy population and compared the observed Si iii absorption statistics with predictions provided by the model. We also compared redshifts and positions of the absorbers with those of ~64 000 galaxies using archival galaxy-survey data to investigate the relation between intervening Si iii absorbers and the CGM. Results: Along a total redshift path of Δz ≈ 24, we identify 69 intervening Si iii systems that all show associated absorption from other low and high ions (e.g., H i, Si ii, Si iv, C ii, C iv). We derive a bias-corrected number density of dN/dz(Si iii)= 2.5 ± 0.4 for absorbers with column densities log N(Si iii) > 12.2, which is ~3 times the number density of strong Mg ii systems at z = 0. This number density matches the expected cross section of a Si iii absorbing CGM around the local galaxy population with a mean covering fraction of ⟨ fc ⟩ = 0.69. For the majority (~60 percent) of the absorbers, we identify possible host galaxies within 300 km s-1 of the absorbers and derive impact parameters ρ operated by the Space Telescope Science Institute (STScI) for the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5D26555.Full Tables A.1 and A.2, and the reduced spectra (FITS files) are only available at the CDS via anonymous ftp to

  3. Radio Continuum Evidence for Outflow and Absorption in the Seyfert 1 Galaxy Markarian 231

    Ulvestad, J S; Carilli, C L

    1999-01-01

    The VLBA and the VLA have been used to image the continuum radio emission from Mrk 231, a Seyfert 1 galaxy and the brightest infrared galaxy in the local universe. The smallest scales reveal a double source less than 2 pc in extent. The components of this central source have minimum brightness temperatures of 10^9 to 10^{10} K, spectral turnovers between 2 and 10 GHz, and appear to define the galaxy nucleus plus the inner regions of a jet. The components may be free-free absorbed or synchtrotron self-absorbed. On larger scales, the images confirm a previously known north-south triple source extending 40 pc and elongated perpendicular to a 350-pc starburst disk. Both lobes show evidence for free-free absorption near 2 GHz, probably due to ionized gas with a density of 1-2 X 10^3 cm^{-3} in the innermost parts of the starburst disk. The absorbing gas may be ionized by the active nucleus or by local regions of enhanced star formation. The elongation of the 40-pc triple differs by 65 deg from that of the 2-pc sou...

  4. On the Anomalous Silicate Absorption Feature of the Prototypical Seyfert 2 Galaxy NGC 1068

    Koehler, Melanie

    2012-01-01

    The first detection of the silicate absorption feature in AGNs was made at 9.7 micrometer for the prototypical Seyfert 2 galaxy NGC 1068 over 30 years ago, indicating the presence of a large column of silicate dust in the line-of-sight to the nucleus. It is now well recognized that type 2 AGNs exhibit prominent silicate absorption bands, while the silicate bands of type 1 AGNs appear in emission. More recently, using the Mid-Infrared Interferometric Instrument on the Very Large Telescope Interferometer, Jaffe et al. (2004) by the first time spatially resolved the parsec-sized dust torus around NGC 1068 and found that the 10 micrometer silicate absorption feature of the innermost hot component exhibits an anomalous profile differing from that of the interstellar medium and that of common olivine-type silicate dust. While they ascribed the anomalous absorption profile to gehlenite (Ca_2Al_2SiO_7, a calcium aluminum silicate species), we propose a physical dust model and argue that, although the presence of gehl...

  5. THE STELLAR INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES FROM ABSORPTION LINE SPECTROSCOPY. II. RESULTS

    The spectral absorption lines in early-type galaxies contain a wealth of information regarding the detailed abundance pattern, star formation history, and stellar initial mass function (IMF) of the underlying stellar population. Using our new population synthesis model that accounts for the effect of variable abundance ratios of 11 elements, we analyze very high quality absorption line spectra of 38 early-type galaxies and the nuclear bulge of M31. These data extend to 1 μm and they therefore include the IMF-sensitive spectral features Na I, Ca II, and FeH at 0.82 μm, 0.86 μm, and 0.99 μm, respectively. The models fit the data well, with typical rms residuals ∼stars, are derived for individual galaxies. We find that the IMF becomes increasingly bottom-heavy with increasing velocity dispersion and [Mg/Fe]. At the lowest dispersions and [Mg/Fe] values the derived IMF is consistent with the Milky Way (MW) IMF, while at the highest dispersions and [Mg/Fe] values the derived IMF contains more low-mass stars (is more bottom-heavy) than even a Salpeter IMF. Our best-fit (M/L)stars values do not exceed dynamically based M/L values. We also apply our models to stacked spectra of four metal-rich globular clusters in M31 and find an (M/L)stars that implies fewer low-mass stars than a MW IMF, again agreeing with dynamical constraints. We discuss other possible explanations for the observed trends and conclude that variation in the IMF is the simplest and most plausible.

  6. Star formation rates in isolated galaxies selected from the Two-Micron All-Sky Survey

    Melnyk, O; Karachentsev, I

    2015-01-01

    We have considered the star formation properties of 1616 isolated galaxies from the 2MASS XSC selected sample (2MIG) with the FUV GALEX magnitudes. This sample was then compared with corresponding properties of isolated galaxies from the Local Orphan Galaxies catalogue (LOG) and paired galaxies. We found that different selection algorithms define different populations of isolated galaxies. The population of the LOG catalogue, selected from non-clustered galaxies in the Local Supercluster volume, mostly consists of low-mass spiral and late type galaxies. The SSFR upper limit in isolated and paired galaxies does not exceed the value of ~dex(-9.4). This is probably common for galaxies of differing activity and environment (at least at z11.5 have higher (S)SFR than isolated galaxies. Our results suggest that the environment helps to trigger the star formation in the highest mass galaxies. We found that the fraction of AGN in the paired sample is only a little higher than in our isolated galaxy sample. We assume t...

  7. Spectropolarimetry of Radio-Selected Broad Absorption Line Quasars

    DiPompeo, M. A.; Brotherton, M. S.; Becker, R. H.; Tran, H. D.; Gregg, M. D.; White, R L; Laurent-Muehleisen, S. A.

    2010-01-01

    We report spectropolarimetry of 30 radio-selected broad absorption line (BAL) quasars with the Keck Observatory, 25 from the sample of Becker et al. (2000). Both high and low-ionization BAL quasars are represented, with redshifts ranging from 0.5 to 2.5. The spectropolarimetric properties of radio-selected BAL quasars are very similar to those of radio-quiet BAL quasars: a sizeable fraction (20%) show large continuum polarization (2-10%) usually rising toward short wavelengths, emission lines...

  8. Low X-Ray Luminosity Galaxy Clusters: Main goals, sample selection, photometric and spectroscopic observations

    Castellón, J L Nilo; Lambas, D García; Valotto, Carlos; Mill, A L O'; Cuevas, H; Carrasco, E R; Ramírez, A; Astudillo, J M; Ramos, F; Jaque, M; Ulloa, N; Órdenes, Y

    2016-01-01

    We present the study of nineteen low X-ray luminosity galaxy clusters (L$_X \\sim$ 0.5--45 $\\times$ $10^{43}$ erg s$^{-1}$), selected from the ROSAT Position Sensitive Proportional Counters (PSPC) Pointed Observations (Vikhlinin et al. 1998) and the revised version of Mullis et al. (2003) in the redshift range of 0.16 to 0.7. This is the introductory paper of a series presenting the sample selection, photometric and spectroscopic observations and data reduction. Photometric data in different passbands were taken for eight galaxy clusters at Las Campanas Observatory; three clusters at Cerro Tololo Interamerican Observatory; and eight clusters at the Gemini Observatory. Spectroscopic data were collected for only four galaxy clusters using Gemini telescopes. With the photometry, the galaxies were defined based on the star-galaxy separation taking into account photometric parameters. For each galaxy cluster, the catalogues contain the PSF and aperture magnitudes of galaxies within the 90\\% completeness limit. They...

  9. STACKED REST-FRAME ULTRAVIOLET SPECTRA OF Lyα-EMITTING AND CONTINUUM-SELECTED GALAXIES AT 2 < z < 3.5

    We present properties of individual and composite rest-UV spectra of continuum- and narrowband-selected star-forming galaxies (SFGs) at a redshift of 2 Lyα > 20 Å, the canonical limit to be classified as an Lyα-emitting galaxy. We divide our data set into subsamples based on properties that we are able to measure for each individual galaxy: Lyα equivalent width, rest-frame UV colors, and redshift. Among our subsample of galaxies with R Lyα > 20 Å have bluer UV continua, weaker low-ionization interstellar absorption lines, weaker C IV absorption, and stronger Si II* nebular emission than those with WLyα –1 between Lyα emission and low-ionization absorption, which does not vary substantially among any of our subsamples. We find that the interstellar component, as opposed to the stellar component, dominates the high-ionization absorption line profiles. We find that the low- and high-ionization Si ionization states have similar kinematic properties, yet the low-ionization absorption is correlated with Lyα emission and the high-ionization absorption is not. These trends are consistent with outflowing neutral gas being in the form of neutral clouds embedded in ionized gas as previously suggested by Steidel et al. Moreover, our galaxies with bluer UV colors have stronger Lyα emission, weaker low-ionization absorption, and more prominent nebular emission line profiles. From a redshift of 2.7 Lyα Lyα > 20 Å exhibit weaker Lyα emission at lower redshifts, although we caution that this could be caused by spectroscopic confirmation of low Lyα equivalent width galaxies being harder at z ∼ 3 than z ∼ 2.

  10. A comparative study of intervening and associated HI 21-cm absorption profiles in redshifted galaxies

    Curran, S J; Divoli, A; Allison, J R

    2016-01-01

    The star-forming reservoir in the distant Universe can be detected through HI 21-cm absorption arising from either cool gas associated with a radio source or from within a galaxy intervening the sight-line to the continuum source. In order to test whether the nature of the absorber can be predicted from the profile shape, we have compiled and analysed all of the known redshifted (z > 0.1) HI 21-cm absorption profiles. Although between individual spectra there is too much variation to assign a typical spectral profile, we confirm that associated absorption profiles are on average, wider than their intervening counterparts. It is widely hypothesised that this is due to high velocity nuclear gas feeding the central engine, absent in the more quiescent intervening absorbers. Modelling the column density distribution of the mean associated and intervening spectra, we confirm that the additional low optical depth, wide dispersion component, typical of associated absorbers, arises from gas within the inner parsec. W...

  11. Quasar Absorption Lines in the Far Ultraviolet: An Untapped Gold Mine for Galaxy Evolution Studies

    Tripp, Todd

    2013-01-01

    This white paper emphasizes the potential of QSO absorption lines in the rest-frame far/extreme UV at rest-frame wavelengths from ~500 to 2000 A. In this wavelength range, species such as Ne VIII, Na IX, and Mg X can be detected, providing diagnostics of gas with temperatures >> 10^{6} K, as well as banks of adjacent ions such as O I, O II, O III, O IV, O V, and O VI (and similarly N I - N V; S II - S VI; Ne II - Ne VIII, etc.), which constrain physical conditions with unprecedented precision. A UV spectrograph with good sensitivity down to observed wavelengths of 1000 A can detect these new probes in absorption systems with redshift z(abs) > 0.3, and at these redshifts, the detailed relationships between the absorbers and nearby galaxies and large-scale environment can be studied from the ground. By observing QSOs at z = 1.0 - 1.5, HST has started to exploit extreme-UV QSO absorption lines, but HST can only reach a small number of these targets. A future, more sensitive UV spectrograph could open up this new...

  12. The Properties of Intergalactic CIV Absorption II: Which Systems Are Associated With Galaxy Outflows?

    Songaila, A

    2005-01-01

    Using the extremely high S/N quasar absorption-line sample described in the first paper of the series, we investigate which intergalactic CIV absorption line systems could be directly associated with galactic outflows at z = 2 - 3.5 from an analysis of the velocity widths of the CIV absorption line systems. Only about half the systems with a peak tau(CIV) above 0.4 in the 1548 Angstrom line (roughly a column density of CIV above about 2 x 10^13 cm^-2) have velocity widths large enough to originate in this way, and very few of the weaker systems do. The median velocity full width at a tenth max is found to be 50 km/s for systems with peak tau(CIV) in the range 0.1--0.4 and 160 km/s for systems with a peak tau(CIV) in the range 0.4--3. We show that this critical value of tau(CIV) also separates systems that could be ionized by galaxy-like spectra from those in which the ionization is clearly AGN-dominated. Together the results are consistent with a picture in which almost all the lower column density, and at le...

  13. Higher prevalence of X-ray selected AGN in intermediate-age galaxies up to z ~ 1

    Hernán-Caballero, Antonio; Alonso-Herrero, A.; Pérez-González, P. G.; Barro, Guillermo; Aird, James; Ferreras, Ignacio; Cava, A; Esquej, P.; Gallego, Jesús; Nandra, K.; Rodríguez Zaurín, Javier

    2014-01-01

    We analyse the stellar populations in the host galaxies of 53 X-ray selected optically dull active galactic nuclei (AGN) at 0.34 < z < 1.07 with ultradeep (mAB = 26.5, 3σ) optical mediumband (R ~ 50) photometry from the Survey for High-z Absorption Red and Dead Sources (SHARDS). The spectral resolution of SHARDS allows us to consistently measure the strength of the 4000Å break, Dn(4000), a reliable age indicator for stellar populations.We confirm that most X-ray selected moderate-luminosity A...

  14. Galaxies in the Early Universe

    Krogager, Jens-Kristian

    analyses are biased towards the brightest galaxies at all times (as these are easier to observe and identify). A complementary method relies on the absorption imprint from neutral gas in galaxies, the so-called damped Ly absorbers (DLAs) seen towards distant bright objects. This thesis seeks to understand...... how the absorption selected galaxies relate to the emission selected galaxies by identifying the faint glow from the absorbing galaxies at redshift z 2. In Chapters 2 and 3, the emission properties of DLAs are studied in detail using state-of-the-art instrumentation. The specific DLA studied in...... Chapter 3 is found to be a young, star-forming galaxy with evidence for strong outflows of gas. This suggests that the more evolved and metal-rich DLAs overlap with the faint end of the luminosity selected galaxies in terms of mass, metallicity, star formation rate, and age. DLAs are generally observed to...

  15. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. II. THE COLORS OF GAS-RICH GALAXIES

    We utilize color information for an H I-selected sample of 195 galaxies to explore the star formation histories and physical conditions that produce the observed colors. We show that the H I selection creates a significant offset toward bluer colors that can be explained by enhanced recent bursts of star formation. There is also no obvious color bimodality, because the H I selection restricts the sample to bluer, actively star-forming systems, diminishing the importance of the red sequence. Rising star formation rates are still required to explain the colors of galaxies bluer than g - r< 0.3. We also demonstrate that the colors of the bluest galaxies in our sample are dominated by emission lines and that stellar population synthesis models alone (without emission lines) are not adequate for reproducing many of the galaxy colors. These emission lines produce large changes in the r - i colors but leave the g - r color largely unchanged. In addition, we find an increase in the dispersion of galaxy colors at low masses that may be the result of a change in the star formation process in low-mass galaxies.

  16. Clean process for the treatment of volatile organic compounds by selective absorption; Procede propre de traitement de COV par absorption selective

    Hadjoudj, R.; Monnier, H.; Lapicque, F.; Roizard, C. [Ecole Nationale Superieure des Industries Chimiques, Lab. des Sciences du Genie Chimique-Groupe ENSIC, 54 - Nancy (France)

    2001-07-01

    This study concerns the development of a selective absorption process for the processing of chlorinated and oxygenated volatile organic compounds (VOCs). One or several solvents will be selected according to their capacity of absorption, to their selectiveness with respect to the other compounds present in the gaseous effluent, to their capacity to be regenerated, and to their low volatility and toxicity. (J.S.)

  17. UV Absorption Lines as Metallicity Estimator and the Metal Content of Star-forming Galaxies at z=5

    Faisst, Andreas; Capak, Peter L.; Davidson, Iary; Kakazu, Yuko; Salvato, Mara; Laigle, Clotilde; Onodera, Masato; Masters, Daniel; COSMOS Team

    2016-01-01

    Probing the metal content of high redshift galaxies is essential to study their formation and evolution in the early universe. However, the spectral features used to measure the metallicity are shifted out of the wavelength range of current spectrographs at high-z and therefore alternative methods must be used.We measure the relation between four prominent UV absorption complexes and metallicity for more than 50 local galaxies and, by using a sample of more than 20 galaxies at z ~ 2 - 3, verify that this relation holds up to z ˜ 3. We then apply this method to a sample of ˜ 220 galaxies at 3.5 build up of stellar mass within a short time of several 100 Myr can explain a shallow MZ relation at z ˜ 5. Furthermore, we find a weak anti-correlation between star-formation rates and UV absorption strength (i.e., metallicity), indicative of these galaxies being fueled by the inflow of pristine (metal-poor) gas. The galaxy sample presented in this work is unique to further test these scenarios using ALMA and the upcoming James Webb Space Telescope.

  18. Made-to-measure galaxy modelling utilising absorption line strength data

    Long, Richard

    2016-01-01

    We enhance the Syer & Tremaine made-to-measure (M2M) particle method of stellar dynamical modelling to model simultaneously both kinematic data and absorption line strength data thus creating a `chemo-M2M' modelling scheme. We apply the enhanced method to four galaxies (NGC 1248, NGC 3838, NGC 4452, NGC 4551) observed using the SAURON integral-field spectrograph as part of the ATLAS3D programme. We are able to reproduce successfully the 2D line strength data achieving mean chi^2 per bin values of ~1 with >95\\% of particles having converged weights. Because M2M uses a 3D particle system, we are also able to examine the underlying 3D line strength distributions. The extent to which these distributions are plausible representations of real galaxies requires further consideration. Overall we consider the modelling exercise to be a promising first step in developing a `chemo-M2M' modelling system and in understanding some of the issues to be addressed. Whilst the made-to-measure techniques developed have been ...

  19. On the relation of optical obscuration and X-ray absorption in Seyfert galaxies

    Burtscher, L; Gracia-Carpio, J; Koss, M J; Lin, M -Y; Lutz, D; Nandra, P; Netzer, H; de Xivry, G Orban; Ricci, C; Rosario, D J; Veilleux, S; Contursi, A; Genzel, R; Schnorr-Mueller, A; Sternberg, A; Sturm, E; Tacconi, L J

    2016-01-01

    The optical classification of a Seyfert galaxy and whether it is considered X-ray absorbed are often used interchangeably. But there are many borderline cases and also numerous examples where the optical and X-ray classifications appear to be in conflict. In this article we re-visit the relation between optical obscuration and X-ray absorption in AGNs. We make use of our "dust color" method (Burtscher et al. 2015) to derive the optical obscuration A_V and consistently estimated X-ray absorbing columns using 0.3--150 keV spectral energy distributions. We also take into account the variable nature of the neutral gas column N_H and derive the Seyfert sub-classes of all our objects in a consistent way. We show in a sample of 25 local, hard-X-ray detected Seyfert galaxies (log L_X / (erg/s) ~ 41.5 - 43.5) that there can actually be a good agreement between optical and X-ray classification. If Seyfert types 1.8 and 1.9 are considered unobscured, the threshold between X-ray unabsorbed and absorbed should be chosen a...

  20. On the nature of the first galaxies selected at 350 microns

    Khan, Sophia A; Willner, S P; Pearson, Chris P; Ashby, M L N; Benford, Dominic J; Clements, David L; Dye, Simon; Farrah, Duncan; Fazio, G G; Huang, J -S; Lebouteiller, V; Floc'h, Emeric Le; Mainetti, Gabriele; Moseley, S Harvey; Negrello, Mattia; Serjeant, Stephen; Shafer, Richard A; Staguhn, Johannes; Sumner, Timothy J; Vaccari, Mattia

    2009-01-01

    [abridged] We present constraints on the nature of the first galaxies selected at 350 microns. The sample includes galaxies discovered in the deepest blank-field survey at 350 microns (in the Bootes Deep Field) and also later serendipitous detections in the Lockman Hole. Spectral energy distribution templates are fit to identified counterparts, and the sample is found to comprise IR-luminous galaxies at 1selected galaxy provides an additional confirmation, showing prominent dust grain features typically associated with star-forming galaxies. Compared to submillimeter galaxies selected at 850 and 1100 microns, galaxies selected at 350 microns have a similar range of far-infrared color temperatures. However, no 350-micron-selected sources are reliably detected at 850 or 1100 microns. Galaxies in our sample with redshifts 1galaxies at hig...

  1. KECK DEEP FIELDS. IV. LUMINOSITY-DEPENDENT CLUSTERING AND GALAXY DOWNSIZING IN UV-SELECTED GALAXIES AT z = 4, 3, AND 2

    We investigate the luminosity-dependent clustering of rest-frame UV-selected galaxies at z ∼ 4, 3, 2.2, and 1.7 in the Keck Deep Fields, which are complete to R = 27 and cover 169 arcmin2. We find that at z ∼ 4 and 3, UV-bright galaxies cluster more strongly than UV-faint ones, but at z ∼ 2.2 and 1.7, the UV-bright galaxies are no longer the most strongly clustered. We derive mass estimates for objects in our sample by comparing our measurements to the predicted clustering of dark matter halos in the Millennium Simulation. From these estimates, we infer relationships between halo mass and star formation rate (SFR), and find that the most massive dark matter halos in our sample host galaxies with high SFRs (M1700 50 Msun yr-1) at z ∼ 3 and 4, moderate SFRs (-20 1700 sun yr-1) at z ∼ 2.2, and lower SFRs (-19 1700 sun yr-1) at z ∼ 1.7. We believe our measurements may provide a new line of evidence for galaxy downsizing by extending that concept from stellar to halo mass. We also find that the objects with blue UV colors in our sample are much more strongly clustered than those with red UV colors, and we propose that this may be due to the presence of the 2175 A dust absorption bump in more massive halos, which contain the older stellar populations and dust needed to produce the feature. The relatively small area covered by the survey means that the absolute values of the correlation lengths and halo masses we derive are heavily dependent on the 'integral constraint' correction, but the uniformly deep coverage across a large-redshift interval allows us to detect several important trends that are independent of this correction.

  2. Rest-UV Absorption Lines as Metallicity Estimator: the Metal Content of Star-Forming Galaxies at z~5

    Faisst, A L; Davidzon, I; Salvato, M; Laigle, C; Ilbert, O; Onodera, M; Hasinger, G; Kakazu, Y; Masters, D; Mobasher, B; Sanders, D; Silverman, J D; Yan, L; Scoville, N Z

    2015-01-01

    We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z~3. We then apply this relation to a sample of 224 galaxies at 3.5 = 4.8) in COSMOS, for which unique UV spectra from DEIMOS and accurate stellar masses from SPLASH are available. The average galaxy population at z~5 and log(M/Msun) > 9 is characterized by 0.3-0.4 dex (in units of 12+log(O/H)) lower metallicities than at z~2, but comparable to z~3.5. We find galaxies with weak/no Ly-alpha emission to have metallicities comparable to z~2 galaxies and therefore may represent an evolved sub-population of z~5 galaxies. We find a correlation between metallicity and dust in good agreement with local galaxies and an inverse trend between metallicity and star-formation rate (SFR) consistent with observations at z~2. The relation between stellar mass and metallicity (MZ relation) is similar to z~3.5, however, there are indications of it being slightly shallower, in particular ...

  3. The MOSDEF survey: AGN multi-wavelength identification, selection biases and host galaxy properties

    Azadi, Mojegan; Aird, James; Reddy, Naveen; Shapley, Alice; Freeman, William R; Kriek, Mariska; Leung, Gene C K; Mobasher, Bahram; Price, Sedona H; Sanders, Ryan L; Shivaei, Irene; Siana, Brian

    2016-01-01

    We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on the identification, selection biases and host galaxy properties of 55 X-ray, IR and optically-selected active galactic nuclei (AGN) at $1.4 < z < 3.8$. We obtain rest-frame optical spectra of galaxies and AGN and use the BPT diagram to identify optical AGN. We examine the uniqueness and overlap of the AGN identified at different wavelengths. There is a strong bias against identifying AGN at any wavelength in low mass galaxies, and an additional bias against identifying IR AGN in the most massive galaxies. AGN host galaxies span a wide range of star formation rate (SFR), similar to inactive galaxies once stellar mass selection effects are accounted for. However, we generally identify IR AGN in less dusty galaxies with relatively higher SFR and optical AGN in dusty galaxies with relatively lower SFR. X-ray AGN selection does not display a bias with host galaxy SFR. These results are consistent with those from larger studies at low...

  4. Resonance scattering, absorption and off-centre abundance peaks in clusters of galaxies

    Sanders, J S

    2006-01-01

    A possible explanation for the central abundance dips found from spatially-resolved X-ray spectroscopy of several groups and clusters of galaxies is resonance scattering. A number of the prominent iron emission lines are resonance lines. We construct a unique spectral model which takes account of resonance scattering for several thousand resonance lines, projection effects, photoelectric absorption, and allows direct spectral fitting. We apply our model to Chandra observations of two clusters with pronounced central abundance dips, Centaurus and Abell 2199. The results show that the effect of resonance scattering on emission from the centre of the cluster can be as much as 30 per cent for the Fe-K resonance lines, and 10 per cent for several Fe-L lines, if turbulence is low. The change to the metallicities obtained by fitting low resolution CCD spectra is at most 10 per cent. Accounting for resonance scattering does not remove the central dip. Allowing for internal absorption within the Centaurus significantl...

  5. Absorption variability as a probe of the multiphase interstellar media surrounding active galaxies

    Macquart, Jean-Pierre

    2016-01-01

    We examine a model for the variable free-free and neutral hydrogen absorption inferred towards the cores of some compact radio galaxies in which a spatially fluctuating medium drifts in front of the source. We relate the absorption-induced intensity fluctuations to the statistics of the underlying opacity fluctuations. We investigate models in which the absorbing medium consists of either discrete clouds or a power-law spectrum of opacity fluctuations. We examine the variability characteristics of a medium comprised of Gaussian-shaped clouds in which the neutral and ionized matter are co-located, and in which the clouds comprise spherical constant-density neutral cores enveloped by ionized sheaths. The cross-power spectrum indicates the spatial relationship between neutral and ionized matter, and distinguishes the two models, with power in the Gaussian model declining as a featureless power-law, but that in the ionized sheath model oscillating between positive and negative values. We show how comparison of th...

  6. Molecular Hydrogen Absorption from the Halo of a z~0.4 Galaxy

    Muzahid, Sowgat; Charlton, Jane C; Churchill, Christopher W

    2016-01-01

    Lyman- and Werner-band absorption of molecular hydrogen (H2) is detected in ~50% of low redshift (z10^14.4 cm^-2. However the true origin(s) of the H2 bearing gas remain elusive. Here we report a new detection of an H2 absorber at z = 0.4298 in the HST/COS spectra of quasar PKS~2128--123. The total N(HI) of 10^{19.50\\pm0.15} cm^-2 classifies the absorber as a sub-DLA. H2 absorption is detected up to the J=3 rotational level with a total log N(H2)=16.36\\pm0.08 corresponding to a molecular fraction of log f(H2)=-2.84\\pm0.17. The excitation temperature of T_ex = 206\\pm6K indicates the presence of cold gas. Using detailed ionization modelling we obtain a near-solar metallicity (i.e., [O/H]= -0.26\\pm0.19) and a dust-to-gas ratio of log \\kappa ~ -0.45 for the H2 absorbing gas. The host-galaxy of the sub-DLA is detected at an impact parameter of \\rho ~ 48 kpc with an inclination angle of i~48 degree and an azimuthal angle of \\Phi ~ 15 degree with respect to the QSO sightline. We show that co-rotating gas in an exten...

  7. Optical Properties of Radio-Selected Narrow Line Seyfert 1 Galaxies

    Whalen, J; Laurent-Muehleisen, S A; Moran, E C; Becker, R H

    2006-01-05

    We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density limit {approx} 1 mJy) in the VLA FIRST Survey. We run Spearman rank correlation tests on several sets of parameters and conclude that, except for their radio properties, radio-selected NLS1 galaxies do not exhibit significant differences from traditional NLS1 galaxies. Our results are also in agreement with previous studies suggesting that NLS1 galaxies have small black hole masses that are accreting very close to the Eddington rate. We have found 16 new radio-loud NLS1 galaxies, which increases the number of known radio-loud NLS1 galaxies by a factor of {approx} 5.

  8. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    Perley, D. A.; Krühler, T.; Schulze, S.; De Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R; Fong, W.; Fynbo, J. P. U.; J. Gorosabel; Greiner, J.; Jakobsson, P.

    2015-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy obs...

  9. HI Selected Galaxies in the Sloan Digital Sky Survey II: The Colors of Gas-Rich Galaxies

    West, Andrew A; Dalcanton, Julianne J; Disney, Mike J; Rockosi, Constance R; Ivezic, Zeljko

    2009-01-01

    We utilize color information for an HI-selected sample of 195 galaxies to explore the star formation histories and physical conditions that produce the observed colors. We show that the HI selection creates a significant offset towards bluer colors that can be explained by enhanced recent bursts of star formation. There is also no obvious color bimodality, because the HI selection restricts the sample to bluer, actively star forming systems, diminishing the importance of the red sequence. Rising star formation rates are still required to explain the colors of galaxies bluer than g-r < 0.3. We also demonstrate that the colors of the bluest galaxies in our sample are dominated by emission lines and that stellar population synthesis models alone (without emission lines) are not adequate for reproducing many of the galaxy colors. These emission lines produce large changes in the r-i colors but leave the g-r color largely unchanged. In addition, we find an increase in the dispersion of galaxy colors at low mass...

  10. Rest-UV Absorption Lines as Metallicity Estimator: The Metal Content of Star-forming Galaxies at z ~ 5

    Faisst, A. L.; Capak, P. L.; Davidzon, I.; Salvato, M.; Laigle, C.; Ilbert, O.; Onodera, M.; Hasinger, G.; Kakazu, Y.; Masters, D.; McCracken, H. J.; Mobasher, B.; Sanders, D.; Silverman, J. D.; Yan, L.; Scoville, N. Z.

    2016-05-01

    We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z˜ 3. We then apply this relation to a sample of 224 galaxies at 3.5\\lt z\\lt 6.0 ( =4.8) in the Cosmic Evolution Survey (COSMOS), for which unique UV spectra from the Deep Imaging Multi-object Spectrograph (DEIMOS) and accurate stellar masses from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) are available. The average galaxy population at z˜ 5 and {log}(M/{M}⊙ )\\gt 9 is characterized by 0.3-0.4 dex (in units of 12+{log}({{O/H}})) lower metallicities than at z ˜ 2, but comparable to z˜ 3.5. We find galaxies with weak or no Lyα emission to have metallicities comparable to z ˜ 2 galaxies and therefore may represent an evolved subpopulation of z˜ 5 galaxies. We find a correlation between metallicity and dust in good agreement with local galaxies and an inverse trend between metallicity and star-formation rate consistent with observations at z ˜ 2. The relation between stellar mass and metallicity (MZ relation) is similar to z˜ 3.5, but there are indications of it being slightly shallower, in particular for the young, Lyα-emitting galaxies. We show that, within a “bathtub” approach, a shallower MZ relation is expected in the case of a fast (exponential) build-up of stellar mass with an e-folding time of 100-200 Myr. Because of this fast evolution, the process of dust production and metal enrichment as a function of mass could be more stochastic in the first billion years of galaxy formation compared to later times.

  11. Selective Absorption Mechanism for the Maintenance of Blocking

    Yamazaki, Akira; Itoh, Hisanori

    2010-05-01

    Atmospheric blocking is one of the most influential phenomena in global atmospheric environments. The understanding of its dynamical processes is important to clarify weather extremes and the stratosphere-troposphere coupling and to extend forecast periods. In the dynamics of blocking, especially, its maintenance mechanism has been a stimulating topic for many meteorologists. About the maintenance mechanism of blocking, Shutts (1983) evaluated the effect of synoptic eddies in his numerical model and proposed the Eddy Straining Mechanism (hereafter, referred to as ESM). Using simple numerical models, he demonstrated that synoptic eddies strained in the north-south direction by blocking provide negative/positive vorticity to a blocking high/low and this vorticity forcing, i.e., the second-order flow maintains the blocking dipole structure against dissipation. Some pieces of evidence, however have shown that the ESM does not work well in several real cases of the block maintenance. For example, Arai and Mukougawa (2002) performed a similar experiment to Shutts (1983) and indicated the strong sensitivity of the ESM against a small meridional shift of the stormtrack (strictly speaking, wavemaker), or a small change of the size of high-frequency eddies. This is a very adverse constraint in the real atmosphere because the relative positions of blocking to the stormtrack tend to fluctuate from case to case so that they do not necessarily exist in the same latitude band. Thus, we propose a more realistic mechanism of the block maintenance named as the Selective Absorption Mechanism (hereafter referred to as SAM), in which a blocking anticyclone selectively and exclusively absorbs synoptic anticyclones. This mechanism is essentially the same mechanism as the Fujiwhara effect, which qualitatively explains that binary eddies with the same polarity merge and eddies with the opposite polarity separate. In this study, we verify the effectiveness of the SAM by observational

  12. Broadband Reflectionless Metasheets: Frequency-Selective Transmission and Perfect Absorption

    Asadchy, V. S.; Faniayeu, I. A.; Ra'di, Y.; Khakhomov, S. A.; Semchenko, I. V.; Tretyakov, S. A.

    2015-07-01

    Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin resonant absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper, we explore possibilities to realize a thin absorbing layer that produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a thin resonant absorber, invisible in reflection in a very wide frequency range, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cell, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit cell but compensating the field coupling at the macroscopic level. We prove that the concept and the proposed realization approach also can be used to create nonreflecting layers for full control of transmitted fields. Our results can have a broad range of potential applications over the entire electromagnetic spectrum including, for example, perfect ultracompact wave filters and selective multifrequency sensors.

  13. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes

    Friese, Daniel Henrik; Bast, Radovan; Ruud, Kenneth

    2015-01-01

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon abs...

  14. Neutral Hydrogen Absorption and Emission in the Quasar/Galaxy Pair 3C275.1/\\NGC4651

    Schneider, Stephen E.; Corbelli, Edvige

    1993-01-01

    3C275.1 and \\NGC4651 make a particularly interesting quasar/galaxy pairing because of the alignment of such a strong radio emitter behind the outer H\\I disk of a relatively undisturbed spiral galaxy. This provides an opportunity to study the spin-temperature characteristics of atomic hydrogen at low column densities, in an apparently star-free environment. We previously reported a tentative detection of absorption against the quasar based on VLA C--array observations; we have now made more se...

  15. The Clustering Characteristics of HI-Selected Galaxies from the 40% ALFALFA Survey

    Martin, Ann M; Haynes, Martha P; Guzzo, Luigi

    2012-01-01

    The 40% Arecibo Legacy Fast ALFA (ALFALFA) survey catalog (\\alpha.40) of approximately 10,150 HI-selected galaxies is used to analyze the clustering properties of gas-rich galaxies. By employing the Landy-Szalay estimator and a full covariance analysis for the two-point galaxy-galaxy correlation function, we obtain the real-space correlation function and model it as a power law, \\xi(r) = (r/r_0)^(-\\gamma), on scales less than 10 h^{-1} Mpc. As the largest sample of blindly HI-selected galaxies to date, \\alpha.40 provides detailed understanding of the clustering of this population. We find \\gamma = 1.51 +/- 0.09 and r_0 = 3.3 +0.3, -0.2 h^{-1} Mpc, reinforcing the understanding that gas-rich galaxies represent the most weakly clustered galaxy population known; we also observe a departure from a pure power law shape at intermediate scales, as predicted in \\Lambda CDM halo occupation distribution models. Furthermore, we measure the bias parameter for the \\alpha.40 galaxy sample and find that HI galaxies are seve...

  16. The SAURON project - XVII. Stellar population analysis of the absorption line strength maps of 48 early-type galaxies

    Kuntschner, Harald; Bacon, Roland; Cappellari, Michele; Davies, Roger L; de Zeeuw, P Tim; Falcón-Barroso, Jesús; Krajnović, Davor; McDermid, Richard M; Peletier, Reynier F; Sarzi, Marc; Shapiro, Kristen L; Bosch, Remco C E van den; van de Ven, Glenn

    2010-01-01

    (Abridged) We present a stellar population analysis of the absorption line strength maps for 48 early-type galaxies from the SAURON sample. Using the line strength index maps of Hbeta, Fe5015, and Mgb, measured in the Lick/IDS system and spatially binned to a constant signal-to-noise, together with predictions from up-to-date stellar population models, we estimate the simple stellar population-equivalent (SSP-equivalent) age, metallicity and abundance ratio [alpha/Fe] over a two-dimensional field extending up to approximately one effective radius. We find a large range of SSP-equivalent ages in our sample, of which ~40% of the galaxies show signs of a contribution from a young stellar population. The most extreme cases of post-starburst galaxies, with SSP-equivalent ages of =10 Gyr) stellar populations.

  17. Galaxy density profiles and shapes -- II. selection biases in strong lensing surveys

    Mandelbaum, Rachel; Keeton, Charles R

    2008-01-01

    [Abridged] Many current and future astronomical surveys will rely on samples of strong gravitational lens systems to draw conclusions about galaxy mass distributions. We use a new strong lensing pipeline (presented in Paper I of this series) to explore selection biases that may cause the population of strong lensing systems to differ from the general galaxy population. Our focus is on point-source lensing by early-type galaxies with two mass components (stellar and dark matter) that have a variety of density profiles and shapes motivated by observational and theoretical studies of galaxy properties. We seek not only to quantify but also to understand the physics behind selection biases related to: galaxy mass, orientation and shape; dark matter profile parameters such as inner slope and concentration; and adiabatic contraction. We study how all of these properties affect the lensing Einstein radius, total cross-section, quad/double ratio, and image separation distribution. We find significant (factors of seve...

  18. Using 21-cm absorption surveys to measure the average HI spin temperature in distant galaxies

    Allison, J R; Duchesne, S W; Curran, S J

    2016-01-01

    We present a statistical method for measuring the average HI spin temperature in distant galaxies using the expected detection yields from future wide-field 21-cm absorption surveys. As a demonstrative case study we consider a simulated survey with the Australian Square Kilometre Array Pathfinder for intervening HI absorbers at intermediate cosmological redshifts between $z = 0.4$ and 1. If such a survey yielded $\\sim 1000$ absorbers we would infer a harmonic-mean spin temperature of $\\overline{T}_\\mathrm{spin} \\sim 100$K for the population of Damped Lyman-$\\alpha$ absorbers at these redshifts, indicating that more than $50$ percent of the neutral gas in these systems is in a cold neutral medium (CNM). Conversely, a lower yield of only 100 detections would imply $\\overline{T}_\\mathrm{spin} \\sim 1000$K and a correspondingly lower CNM fraction. We propose that this method can be used to provide independent verification of the spin temperature evolution reported in recent 21-cm surveys of known DLAs at high reds...

  19. Is there a connection between Broad Absorption Line Quasars and Narrow Line Seyfert 1 galaxies?

    Grupe, Dirk

    2014-01-01

    We consider whether Broad Absorption Line Quasars (BAL QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt & Gallagher (2000) and Boroson (2002). For this purpose we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/Ledd, although BAL QSOs have slightly lower L/Ledd. BAL QSOs and NLS1s in general have high FeII/H$\\beta$ and low [OIII]/H$\\beta$ ratios following the classic 'Boroson \\& Green' eigenvector 1 relation. We also found that the mass accretion rates $\\dot{M}$ of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 \\msun/year. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M-$\\sigma$ plot, we find that BAL QSOs contain fu...

  20. Is there a connection between broad absorption line quasars and narrow-line Seyfert 1 galaxies?

    Grupe, Dirk [Space Science Center, Morehead State University, 235 Martindale Dr., Morehead, KY 40351 (United States); Nousek, John A., E-mail: d.grupe@moreheadstate.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt and Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/L{sub Edd}, although BAL QSOs have slightly lower L/L{sub Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson and Green” eigenvector 1 relation. We also found that the mass accretion rates M-dot of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 M{sub ⊙} yr{sup −1}. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M−σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/L{sub Edd}, and eigenvector 2 to black hole mass.

  1. SHARDS: stellar populations and star formation histories of a mass-selected sample of 0.65galaxies

    Hernán-Caballero, Antonio; Alonso-Herrero, A.; Pérez-González, P. G.; Cava, A; Gallego, Jesús

    2013-01-01

    We report on results from the analysis of a stellar mass-selected (log (M-*/M-circle dot) >= 9.0) sample of 1644 galaxies at 0.65 < z < 1.1 with ultradeep (m(AB) < 26.5) optical medium-band (R similar to 50) photometry from the Survey for High-z Absorption Red and Dead Sources (SHARDS). The spectral resolution of SHARDS allows us to consistently measure the strength of the 4000 A spectral break [D-n(4000), an excellent age indicator for the stellar populations of quiescent galaxies] for all g...

  2. A Study of Selection Methods for H alpha Emitting Galaxies at z~1.3 for the Subaru/FMOS Galaxy Redshift Survey for Cosmology (FastSound)

    Tonegawa, Motonari; Totani, Tomonori; Akiyama, Masayuki; Dalton, Gavin; Glazebrook, Karl; Iwamuro, Fumihide; Sumiyoshi, Masanao; Tamura, Naoyuki; Yabe, Kiyoto; Coupon, Jean; Goto, Tomotsugu; Spitler, Lee R.

    2013-01-01

    The efficient selection of high-redshift emission galaxies is important for future large galaxy redshift surveys for cosmology. Here we describe the target selection methods for the FastSound project, a redshift survey for H alpha emitting galaxies at z=1.2-1.5 using Subaru/FMOS to measure the linear growth rate f\\sigma 8 via Redshift Space Distortion (RSD) and constrain the theory of gravity. To select ~400 target galaxies in the 0.2 deg^2 FMOS field-of-view from photometric data of CFHTLS-W...

  3. Low X-Ray Luminosity Galaxy Clusters: Main Goals, Sample Selection, Photometric and Spectroscopic Observations

    Nilo Castellón, José Luis; Alonso, M. Victoria; García Lambas, Diego; Valotto, Carlos; O’ Mill, Ana Laura; Cuevas, Héctor; Carrasco, Eleazar R.; Ramírez, Amelia; Astudillo, José M.; Ramos, Felipe; Jaque Arancibia, Marcelo; Ulloa, Natalie; Órdenes, Yasna

    2016-06-01

    We present our study of 19 low X-ray luminosity galaxy clusters (L{}X ∼ 0.5–45 × 1043 erg s‑1), selected from the ROSAT Position Sensitive Proportional Counters Pointed Observations and the revised version of Mullis et al. in the redshift range of 0.16–0.7. This is the introductory paper of a series presenting the sample selection, photometric and spectroscopic observations, and data reduction. Photometric data in different passbands were taken for eight galaxy clusters at Las Campanas Observatory; three clusters at Cerro Tololo Interamerican Observatory; and eight clusters at the Gemini Observatory. Spectroscopic data were collected for only four galaxy clusters using Gemini telescopes. Using the photometry, the galaxies were defined based on the star-galaxy separation taking into account photometric parameters. For each galaxy cluster, the catalogs contain the point-spread function and aperture magnitudes of galaxies within the 90% completeness limit. They are used together with structural parameters to study the galaxy morphology and to estimate photometric redshifts. With the spectroscopy, the derived galaxy velocity dispersion of our clusters ranged from 507 km s‑1 for [VMF98]022 to 775 km s‑1 for [VMF98]097 with signs of substructure. Cluster membership has been extensively discussed taking into account spectroscopic and photometric redshift estimates. In this sense, members are the galaxies within a projected radius of 0.75 Mpc from the X-ray emission peak and with clustercentric velocities smaller than the cluster velocity dispersion or 6000 km s‑1, respectively. These results will be used in forthcoming papers to study, among the main topics, the red cluster sequence, blue cloud and green populations, the galaxy luminosity function, and cluster dynamics.

  4. Host Galaxy Properties of the Swift BAT Ultra Hard X-Ray Selected AGN

    Koss, Michael; Mushotzky, Richard; Veilleux, Sylvain; Winter, Lisa M.; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) AGN with host galaxy optical data to date, with 185 nearby (zBAT) sample. The BAT AGN host galaxies have intermediate optical colors (u -- r and g -- r) that are bluer than a comparison sample of inactive galaxies and optically selected AGN from the Sloan Digital Sky Survey (SDSS) which are chosen to have the same stellar mass. Based on morphological classifications from the RC3 and the Galaxy Zoo, the bluer colors of BAT AGN are mainly due to a higher fraction of mergers and massive spirals than in the comparison samples. BAT AGN in massive galaxies (log Stellar Mass >10.5) have a 5 to 10 times higher rate of spiral morphologies than in SDSS AGN or inactive galaxies. We also see enhanced far-IR emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGN are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGN have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] Lambda 5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGN in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as whole. In agreement with the Unified Model of AGN, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGN suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  5. Sulfur K-edge absorption spectroscopy on selected biological systems

    Sulfur is an essential element in organisms. In this thesis investigations of sulfur compounds in selected biological systems by XANES (X-ray Absorption Near Edge Structure) spectroscopy are reported. XANES spectroscopy at the sulfur K-edge provides an excellent tool to gain information about the local environments of sulfur atoms in intact biological samples - no extraction processes are required. Spatially resolved measurements using a Kirkpatrick-Baez mirror focusing system were carried out to investigate the infection of wheat leaves by rust fungi. The results give information about changes in the sulfur metabolism of the host induced by the parasite and about the extension of the infection into visibly uninfected plant tissue. Furthermore, XANES spectra of microbial mats from sulfidic caves were measured. These mats are dominated by microbial groups involved in cycling sulfur. Additionally, the influence of sulfate deprivation and H2S exposure on sulfur compounds in onion was investigated. To gain an insight into the thermal degradation of organic material the influence of roasting of sulfur compounds in coffee beans was studied. (orig.)

  6. Guided-wave approaches to spectrally selective energy absorption

    Stegeman, G. I.; Burke, J. J.

    1987-01-01

    Results of experiments designed to demonstrate spectrally selective absorption in dielectric waveguides on semiconductor substrates are reported. These experiments were conducted with three waveguides formed by sputtering films of PSK2 glass onto silicon-oxide layers grown on silicon substrates. The three waveguide samples were studied at 633 and 532 nm. The samples differed only in the thickness of the silicon-oxide layer, specifically 256 nm, 506 nm, and 740 nm. Agreement between theoretical predictions and measurements of propagation constants (mode angles) of the six or seven modes supported by these samples was excellent. However, the loss measurements were inconclusive because of high scattering losses in the structures fabricated (in excess of 10 dB/cm). Theoretical calculations indicated that the power distribution among all the modes supported by these structures will reach its steady state value after a propagation length of only 1 mm. Accordingly, the measured loss rates were found to be almost independent of which mode was initially excited. The excellent agreement between theory and experiment leads to the conclusion that low loss waveguides confirm the predicted loss rates.

  7. Formaldehyde in Absorption: Tracing Molecular Gas in Early-Type Galaxies

    Dollhopf, Niklaus M.; Donovan Meyer, Jennifer

    2016-01-01

    Early-Type Galaxies (ETGs) have been long-classified as the red, ellipsoidal branch of the classic Hubble tuning fork diagram of galactic structure. In part with this classification, ETGs are thought to be molecular and atomic gas-poor with little to no recent star formation. However, recent efforts have questioned this ingrained classification. Most notably, the ATLAS3D survey of 260 ETGs within ~40 Mpc found 22% contain CO, a common tracer for molecular gas. The presence of cold molecular gas also implies the possibility for current star formation within these galaxies. Simulations do not accurately predict the recent observations and further studies are necessary to understand the mechanisms of ETGs.CO traces molecular gas starting at densities of ~102 cm-3, which makes it a good tracer of bulk molecular gas, but does little to constrain the possible locations of star formation within the cores of dense molecular gas clouds. Formaldehyde (H2CO) traces molecular gas on the order of ~104 cm-3, providing a further constraint on the location of star-forming gas, while being simple enough to possibly be abundant in gas-poor ETGs. In cold molecular clouds at or above ~104 cm-3 densities, the structure of formaldehyde enables a phenomenon in which rotational transitions have excitation temperatures driven below the temperature of the cosmic microwave background (CMB), ~2.7 K. Because the CMB radiates isotropically, formaldehyde can be observed in absorption, independent of distance, as a tracer of moderately-dense molecular clouds and star formation.This novel observation technique of formaldehyde was incorporated for observations of twelve CO-detected ETGs from the ATLAS3D sample, including NGC 4710 and PGC 8815, to investigate the presence of cold molecular gas, and possible star formation, in ETGs. We present images from the Very Large Array, used in its C-array configuration, of the J = 11,0 - 11,1 transition of formaldehyde towards these sources. We report our

  8. A Bayesian Method For Finding Galaxies That Cause Quasar Absorption Lines

    Shoemaker, Emileigh Suzanne; Laubner, David Andrew; Scott, Jennifer E.

    2016-01-01

    We present a study of candidate absorber-galaxy pairs for 39 low redshift quasar sightlines (0.06 Digital Sky Survey (SDSS). We downloaded the COS linelists for these quasar spectra from MAST and queried the SDSS DR12 database for photometric data on all galaxies within 1 Mpc of each of these quasar lines of sight. We calculated photometric redshifts for all the SDSS galaxies using the Bayesian Photometric Redshift code. We used all these absorber and galaxy data as input into an absorber-galaxy matching code which also employs a Bayesian scheme, along with known statistics of the intergalactic medium and circumgalactic media of galaxies, for finding the most probable galaxy match for each absorber. We compare our candidate absorber-galaxy matches to existing studies in the literature and explore trends in the absorber and galaxy properties among the matched and non-matched populations. This method of matching absorbers and galaxies can be used to find targets for follow up spectroscopic studies.

  9. CALIFA: a diameter-selected sample for an integral field spectroscopy galaxy survey

    Walcher, C J; Bekeraité, S; Husemann, B; Iglesias-Páramo, J; Backsmann, N; Ballesteros, J Barrera; Catalán-Torrecilla, C; Cortijo, C; del Olmo, A; Lorenzo, B Garcia; Falcón-Barroso, J; Jilkova, L; Kalinova, V; Mast, D; Marino, R A; Méndez-Abreu, J; Pasquali, A; Sánchez, S F; Trager, S; Zibetti, S; Aguerri, J A L; Alves, J; Bland-Hawthorn, J; Boselli, A; Morales, A Castillo; Fernandes, R Cid; Flores, H; Galbany, L; Gallazzi, A; García-Benito, R; de Paz, A Gil; González-Delgado, R M; Jahnke, K; Jungwiert, B; Kehrig, C; Lyubenova, M; Perez, I Márquez; Masegosa, J; Ibero, A Monreal; Pérez, E; Quirrenbach, A; Rosales-Ortega, F F; Roth, M M; Sanchez-Blazquez, P; Spekkens, K; Tundo, E; van de Ven, G; Verheijen, M A W; Vilchez, J V; Ziegler, B

    2014-01-01

    We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area Survey (CALIFA), a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45" and 79.2" and with a redshift 0.005 Mr > -23.1 and over a stellar mass range between 10^9.7 and 10^11.4Msun. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of Mr = -19 (or stellar masses < 10^9.7Msun) is there a prevalence of galaxies with larger isophotal sizes, especially of nearly edge-on late-type galaxies, but such galaxies form < 10% of the full sample. We estimate volume-corrected distribution functions in luminosities and sizes and show that these ...

  10. Radial Trends in IMF-sensitive Absorption Features in Two Early-type Galaxies: Evidence for Abundance-driven Gradients

    McConnell, Nicholas J.; Lu, Jessica R.; Mann, Andrew W.

    2016-04-01

    Samples of early-type galaxies show a correlation between stellar velocity dispersion and the stellar initial mass function (IMF) as inferred from gravity-sensitive absorption lines in the galaxies’ central regions. To search for spatial variations in the IMF, we have observed two early-type galaxies with Keck/LRIS and measured radial gradients in the strengths of absorption features from 4000–5500 Å and 8000–10000 Å. We present spatially resolved measurements of the dwarf-sensitive spectral indices {Na} {{I}} (8190 Å) and Wing-Ford {{FeH}} (9915 Å), as well as indices for species of H, C2, CN, Mg, Ca, {{TiO}}, and Fe. Our measurements show a metallicity gradient in both objects, and Mg/Fe consistent with a shallow gradient in α-enhancement, matching widely observed trends for massive early-type galaxies. The {Na} {{I}} index and the CN1 index at 4160 Å exhibit significantly steeper gradients, with a break at r∼ 0.1 {r}{{eff}} (r∼ 300 pc). Inside this radius, {Na} {{I}} strength increases sharply toward the galaxy center, consistent with a rapid central rise in [Na/Fe]. In contrast, the ratio of the {{FeH}} to Fe index strength decreases toward the galaxy center. This behavior cannot be reproduced by a steepening IMF inside of 0.1 {r}{{eff}} if the IMF is a single power law. While gradients in the mass function above ∼ 0.4 {M}ȯ may occur, exceptional care is required to disentangle these IMF variations from the extreme variations in individual element abundances near the galaxies’ centers.

  11. Ca II and Na I absorption in the QSO S4 0248 + 430 due to an intervening galaxy

    Observations of the QSO S4 0248 + 430 and a nearby anonymous galaxy are presented. Two absorption components are found in both Ca II H and K and Na I D1 and D2 at z(a) = 0.0515, 0.0523. Column densities of log N(Ca II) = 13.29, 13.50, and log N(Na I) = 13.79, 14.18 are found for z(a) = 0.0515, 0.0523 absorption systems, respectively. The column density ratios imply considerable calcium depletion and disk-type absorbing gas. At least one and possibly both absorption components are produced by high-velocity gas. A broadband image of the field shows an asymmetrical armlike feature or possible tidal tail covering and extending past the position of the QSO. The presence of this extended feature and the apparent difference between the absorption velocities and galaxy rotation velocity suggest that the absorbing gas is not ordinary disk gas, but rather is a result of tidal disruption. 24 refs

  12. Mapping kiloparsec-scale structures in the extended HI disc of the galaxy UGC 00439 by HI 21-cm absorption

    Dutta, Rajeshwari; Srianand, Raghunathan; O'Meara, John

    2016-01-01

    We study the properties of HI gas in the outer regions (~2r_25) of a spiral galaxy, UGC 00439 (z = 0.01769), using HI 21-cm absorption towards different components of an extended background radio source, J0041$-$0043 (z = 1.679). The radio source exhibits a compact core coincident with the optical quasar and two lobes separated by ~7 kpc, all at an impact parameter ~25 kpc. The HI 21-cm absorption detected towards the southern lobe is found to extend over ~2 kpc^2. The absorbing gas shows sub-kpc-scale structures with the line-of-sight velocities dominated by turbulent motions. Much larger optical depth variations over 4-7 kpc-scale are revealed by the non-detection of HI 21-cm absorption towards the radio core and the northern lobe, and the detection of NaI and CaII absorption towards the quasar. This could reflect a patchy distribution of cold gas in the extended HI disc. We also detect HI 21-cm emission from UGC 00439 and two other galaxies within ~150 kpc to it, that probably form an interacting group. Ho...

  13. Selections from 2015: Discovery of Diffuse Galaxies in the Coma Cluster

    Kohler, Susanna

    2015-12-01

    Editors Note:In these last two weeks of 2015, well be looking at a few selections from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume after the AAS winter meeting.Forty-Seven Milky Way-Sized, Extremely Diffuse Galaxies in the Coma ClusterPublished January 2015Main takeaway:Using the Dragonfly Telephoto Array, a team led by Pieter van Dokkum (Yale University) discovered 47 ultra-diffuse galaxies in the Coma galaxy cluster. These galaxies are very large, with half-light (effective) radii of 1.54.6 kpc, similar to that of the Milky Ways disk. But their stellar masses are a factor of 1000 lower than the Milky Ways, and theyre accordingly much dimmer.Plot of the effective radius versus the central surface brightness for the ultra-diffuse Coma cluster galaxies (red markers). These galaxies are similar in size to the Milky Ways disk (blue), but significantly dimmer. [Van Dokkum et al. 2015]Why its interesting:These galaxies make up an odd population. Why are their stellar masses so low? The authors posit that these objects may be failed galaxies that lost their gas after having formed their first generation of stars. Adding to the intrigue, the authors find that in order for these galaxies to hold themselves together at their current distance from the cluster core, they must have a whopping dark-matter fraction of 98%.About the discovery:These ultra-diffuse galaxies were actually discovered entirely by accident. Van Dokkum and collaborators observed the Coma cluster in a project to measure properties of the intra-cluster light and look for streams and tidal features. Surprisingly, their images revealed these faint, uncataloged galaxies.CitationPieter G. van Dokkum et al 2015 ApJ 798 L45. doi:10.1088/2041-8205/798/2/L45

  14. Halpha3: an Halpha imaging survey of HI selected galaxies from ALFALFA. II. The star formation properties of galaxies in the Virgo cluster and surroundings

    Gavazzi, Giuseppe; Fossati, Matteo; Galardo, Vincenzo; Grossetti, Francesco; Boselli, Alessandro; Giovanelli, Riccardo; Haynes, Martha P

    2013-01-01

    We present the analysis of Halpha3, an Halpha imaging survey of 409 galaxies selected from the HI Arecibo ALFALFA Survey in the Local Supercluster, including the Virgo cluster. We explore the relations between the stellar mass, the HI mass and the current, massive SFR of nearby galaxies in the Virgo cluster and we compare them with those of isolated galaxies in the Local Supercluster, disentangling the role of the environment in shaping the star formation properties of galaxies at the present cosmological epoch. We investigate the relationships between atomic neutral gas and newly formed stars in different environments, across many morphological types, and over a wide range of stellar masses adopting an updated calibration of the HI deficiency parameter. Studying the mean properties of late-type galaxies in the Local Supercluster, we find that galaxies in increasing local galaxy density conditions (or decreasing projected angular separation from M87) show a significant decrease in the HI content and in the me...

  15. Ultra-Flat Galaxies Selected from RFGC Catalog. I. The Sample Properties

    Karachentseva, V E; Karachentsev, I D; Makarov, D I; Melnik, O V

    2016-01-01

    We used the Revised Flat Galaxy Catalog (RFGC) to create a sample of ultra-flat galaxies (UFG) covering the whole northern and southern sky apart from the Milky Way zone. It contains 817 spiral galaxies seen edge-on, selected into the UFG sample according to their apparent axial ratios $(a/b)_B\\geq10.0$ and $(a/b)_R\\geq8.53$ in the blue and red bands, respectively. Within this basic sample we fixed an exemplary sample of 441 UFG galaxies having the radial velocities of $V_{LG} 10^{\\circ}$ and the blue angular diameter of $a_B > 1.0^{\\prime}$. According to the Schmidt test the exemplary sample of 441 galaxies is characterized by about (80--90)% completeness, what is quite enough to study different properties of the ultra-flat galaxies. We found that more than 3/4 of UFGs have the morphological types within the narrow range of $T= 7\\pm1$, i.e. the thinnest stellar disks occur among the Scd, Sd, and Sdm types. The average surface brightness of UFG galaxies tends to diminish towards the flattest bulge-less galaxi...

  16. Associated HI Absorption in the = 3.4 Radio Galaxy B2 0902 + 343 Observed with the GMRT

    Poonam Chandra; Govind Swarup; Vasant K. Kulkarni; Nimisha G. Kantharia

    2004-03-01

    We have made observations of the associated HI absorption of a high redshift radio galaxy 0902+34 at = 3.395 with the Giant Meterwave Radio Telescope in the 323+1 MHz band. We find a narrow absorption line with a flux density of 11.5 mJy at a redshift of 3.397 consistent with that observed by Uson et al. (1991), Briggs et al. (1993) and de Bruyn (1996). A weak broad absorption feature reported by de Bruyn (1996) has not been detected in our observations. We also place an upper limit of 4 mJy (2) on emission line strength at the position where Uson et al. (1991) claimed to have found a narrow emission line.

  17. Selection and Physical Properties of High-redshift Galaxies

    Fang, G. W.

    2014-09-01

    Extremely Red Objects (EROs) and BzKs continue to attract considerable interest. It has been suggested that they may be the direct progenitors of present-day massive E/S0 galaxies, and can provide crucial constraints on the current galaxy formation and evolution models. Therefore, the key question is to measure the relative fraction of OGs (old galaxies) and DGs (young, and dusty starburst galaxies) in the sample of EROs. Many groups have been currently investigating the fractions of these two ERO populations using a variety of observational approaches, but the fraction of OGs and DGs from different surveys is different. In the meantime, a number of observations suggest that the epoch of z˜2 also plays an important role in galaxy formation and evolution for various reasons: the cosmic star formation rate density (SFRD) begins to drop at z˜2 from a flat plateau at higher redshifts; the morphological type mix of field galaxies changes remarkably at z˜2; the number density of QSOs has a peak at z˜2; and about 50% to 70% of the stellar mass assembly of galaxies took place in the redshift range 1research progresses of EROs at z˜1, BzKs at z˜2, and ULIRGs at z˜2, respectively. In Chapter 2 we present a quantitative study of the classification of EROs in the UDF and COSMOS field. Our sample includes 5264 (COSMOS, K_{Vega} ≤19.2) and 24 EROs (UDF, K_{Vega}≤22.0) with (i-K)_{AB}≥2.45. Using the fitting method of spectral energy distribution (SED), [3.6]-[8.0] color, and the nonparametric measures of galaxy morphology, we classify EROs into two classes: DGs and OGs. We find that the fraction of OGs and DGs in our sample (COSMOS) is similar, about 52% of them are DGs, and the other 48% are OGs. For 24 EROs in the UDF, 16 fall into DGs, while 8 are OGs. To reduce the redundancy of these three different classification methods, we perform a principal component analysis on the measurements of EROs, and find that the nonparametric measures and SEDs are efficient in

  18. Companions around the nearest luminous galaxies: segregation and selection effects

    Karachentsev, I D

    2015-01-01

    Using the "Updated Nearby Galaxy Catalog", we consider different properties of companion galaxies around luminous hosts in the Local Volume. The data on stellar masses, linear diameters,surface brightnesses, HI-richness, specific star formation rate (sSFR), and morphological types are discussed for members of the nearest groups, including the Milky Way and M 31 groups, as a function of their separation from the hosts. Companion galaxies in groups tend to have lower stellar masses, smaller linear diameters and fainter mean surface brightnesses as the distance to their host decreases. The hydrogen-to-stellar mass ratio of the companions increases with their linear projected separation from the dominant luminous galaxy. This tendency is more expressed around the bulge-dominated hosts. While linear separation of the companions decreases, their mean sSFR becomes lower, accompanied with the increasing sSFR scatter. Typical linear projected separation of dSphs around the bulge-dominated hosts, 350 kpc, is substantia...

  19. The colour selection of distant galaxies in the UKIDSS Ultra-Deep Survey Early Data Release

    Lane, K P; Foucaud, S; Simpson, C; Smail, Ian; McLure, R J; Conselice, C J; Cirasuolo, M; Page, M J; Dunlop, J S; Hirst, P; Watson, M G; Sekiguchi, K

    2007-01-01

    We investigate colour selection techniques for high redshift galaxies in the UKIDSS Ultra Deep Survey Early Data Release (UDS EDR). Combined with very deep Subaru optical photometry, the depth (K_AB = 22.5) and area (0.62 deg^2) of the UDS EDR allows us to investigate optical/near-IR selection using a large sample of over 30,000 objects. By using the B-z, z-K colour-colour diagram (the BzK technique) we identify over 7500 candidate galaxies at z > 1.4, which can be further separated into passive and starforming systems (pBzK and sBzK respectively). Our unique sample allows us to identify a new feature not previously seen in BzK diagrams, consistent with the passively evolving track of early type galaxies at z 1 galaxies over a narrow redshift range.

  20. Galaxies Associated with z~4 Damped Lya Systems: I. Imaging and Photometric Selection

    Prochaska, Jason X.; Gawiser, Eric; Wolfe, Arthur M.; Quirrenbach, Andreas; Lanzetta, Kenneth M.; Chen, Hsiao-Wen; Cooke, Jeff; Yahata, Noriaki

    2002-01-01

    This paper describes the acquisition and analysis of imaging data for the identification of galaxies associated with z~4 damped Lya systems. We present deep BRI images of three fields known to contain four z~4 damped systems. We discuss the reduction and calibration of the data, detail the color criteria used to identify z~4 galaxies, and present a photometric redshift analysis to complement the color selection. We have found no galaxy candidates closer to the QSO than 7'' which could be resp...

  1. LoCuSS: Exploring the selection of faint blue background galaxies for cluster weak-lensing

    Ziparo, Felicia; Okabe, Nobuhiro; Haines, Chris P; Pereira, Maria J; Egami, Eiichi

    2015-01-01

    Cosmological constraints from galaxy clusters rely on accurate measurements of the mass and internal structure of clusters. An important source of systematic uncertainty in cluster mass and structure measurements is the secure selection of background galaxies that are gravitationally lensed by clusters. This issue has been shown to be particular severe for faint blue galaxies. We therefore explore the selection of faint blue background galaxies, by reference to photometric redshift catalogs derived from the COSMOS survey and our own observations of massive galaxy clusters at z~0.2. We show that methods relying on photometric redshifts of galaxies in/behind clusters based on observations through five filters, and on deep 30-band COSMOS photometric redshifts are both inadequate to identify safely faint blue background galaxies. This is due to the small number of filters used by the former, and absence of massive galaxy clusters at redshifts of interest in the latter. We therefore develop a pragmatic method to c...

  2. Ion competition effects on the selective absorption of radionuclides by komatsuna (Brassica rapa var. perviridis)

    The selective absorption coefficient, which is a parameter of an uptake model of radionuclides by plants, was determined for various radionuclides by a multitracer technique. Komatsuna, Brassica rapa var. perviridis, was hydroponically cultivated in a nutrient solution containing a multitracer for 1 day. Nutrient concentration dependence of the selective absorption coefficient of various elements from Be to Re was obtained separately for leaves and roots. The selective absorption coefficients of these elements were, in general, found to decrease with an increase in the concentration of nutrient solutions. Regression equations of the power function for the selective absorption coefficients and the concentration of nutrient solutions were obtained for the leaves and roots. The effects of photon flux and growth stage of plants on the selective absorption coefficients were also studied. It was found that the photon flux influenced the accumulation of radionuclides in the roots but had no significant effect on the selective absorption coefficients for the leaves in 1-day cultivation with the multitracer. The selective absorption coefficients of Mn and Zn in the leaves of the plants at the development stage were higher than those at the maturation stage. For the other elements, no significant effects of the growth stage on the selective absorption coefficients were observed. (author)

  3. GALEX-SELECTED LYMAN BREAK GALAXIES AT z {approx} 2: COMPARISON WITH OTHER POPULATIONS

    Haberzettl, L.; Williger, G. [Department of Physics and Astronomy, University of Louisville, Louisville KY 20492 (United States); Lehnert, M. D. [GEPI, Observatoire de Paris, UMR 8111 du CNRS, 5 Place Jules Janssen, 92195 Meudon (France); Nesvadba, N. [Institut d' Astrophysique Spatiale, CNRS, Universite Paris-Sud, Bat. 120-121, 91405 Orsay (France); Davies, L. [Department of Physics, H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2012-01-20

    We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 {<=} z {<=} 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and find the NUV data to provide greater efficiency for selecting star-forming galaxies. We estimate LBG candidate ages, masses, star formation rates, and extinction from fitting PEGASE synthesis evolution models. We find that about 20% of our LBG candidates are comparable to infrared-luminous LBGs or submillimeter galaxies which are thought to be precursors of massive elliptical galaxies today. Overall, we can show that although BM/BX and BzK methods do identify star-forming galaxies at z {approx} 2, the sample they provide biases against those star-forming galaxies which are more massive and contain sizeable red stellar populations. A true Lyman break criterion at z {approx} 2 is therefore more directly comparable to the populations found at z {approx} 3, which does contain a red fraction.

  4. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. OPTICAL DATA

    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.

  5. Selective loss of metals from low-mass galaxies

    The fate of metals produced by type II supernovae occurring at time intervals of order 1 Myr in a low-mass gas-rich disk galaxy have been studied via a numerical model. Two-dimensional hydrodynamic simulations were made for a typical stellar OB association located near the center of a model disk galaxy with a mass of 1.4 x 10 to the 9th solar mass. Consistent with earlier studies, multiple SN led first to the production of a supershell and later to a galactic chimney which channels SN debris out from the disk. Chimney development is aided by the low metallicity (Z = 0.1 solar Z) of the model, which depresses cooling rates. 25 refs

  6. On the Nature of the First Galaxies Selected at 350 Micrometers

    Khan, Sophia A.; Chanial, Pierre F.; Willner, S. P.; Pearson, Chris P.; Ashby, M. L. N.; Benford, Dominic J.; Clements, David L.; Dye, Simon; Farrah, Duncan; Fazio, G. G.; Huang, J. S.; Lebouteiller, V.; Le Floc'H, Emeric; Mainetti, Gabriele; Harvey Moseley, S.; Negrello, Mattia; Serjeant, Stephen; Shafer, Richard A.; Staguhn, Johannes; Sumner, Timothy J.; Vaccari, Mattia

    2009-01-01

    We present constraints on the nature of the first galaxies selected at 350 micrometers. The sample includes galaxies discovered in the deepest blank-field survey at 350 micrometers (in the Bo6tes Deep Field) and also later serendipitous detections in the Lockman Hole. In determining multiwavelength identifications, the 350 lam position and map resolution of the second generation Submillimeter High Angular Resolution Camera are critical, especially in the cases where multiple radio sources exist and the 24 micrometer counterparts are unresolved. Spectral energy distribution templates are fitted to identified counterparts, and the sample is found to comprise IR-luminous galaxies at 1 nature of the dominant source of the 350 micrometers background-star-forming galaxies in the epoch of peak star formation in the universe-could be more effectively probed using ground-based instruments with their angular resolution and sensitivity offering significant advantages over space-based imaging. Key words: galaxies: high-redshift galaxies: starburst infrared: galaxies submillimeter

  7. HOST GALAXY PROPERTIES OF THE SWIFT BAT ULTRA HARD X-RAY SELECTED ACTIVE GALACTIC NUCLEUS

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) active galactic nucleus (AGN) with host galaxy optical data to date, with 185 nearby (z * >10.5) have a 5-10 times higher rate of spiral morphologies than in SDSS AGNs or inactive galaxies. We also see enhanced far-infrared emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGNs are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGNs have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] λ5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGNs in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as a whole. In agreement with the unified model of AGNs, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGNs suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  8. Ultra-Flat Galaxies Selected from RFGC Catalog. II. Orbital Estimates of Halo Masses

    Karachentsev, I D; Kudrya, Yu N

    2016-01-01

    We used the Revised Flat Galaxy Catalog (RFGC) to select 817 ultra-flat (UF) edge-on disk galaxies with blue and red apparent axial ratios of $(a/b)_B > 10.0$ and $(a/b)_R > 8.5$. The sample covering the whole sky, except the Milky Way zone, contains 490 UF galaxies with measured radial velocities. Our inspection of the neighboring galaxies around them revealed only 30 companions with radial velocity difference of $\\mid\\Delta V\\mid<500$ km s$^{-1}$ inside the projected separation of $R_p < 250$ kpc. Wherein, the wider area around the UF galaxy within $R_p < 750$ kpc contains no other neighbors brighter than the UF galaxy itself in the same velocity span. The resulting sample galaxies mostly belong to the morphological types Sc, Scd, Sd. They have a moderate rotation velocity curve amplitude of about $120$ km s$^{-1}$ and a moderate K-band luminosity of about $10^{10}L_{\\odot}$. The median difference of radial velocities of their companions is $87$ km s$^{-1}$, yielding the median orbital mass estimat...

  9. Optically Selected Compact Stellar Regions and Tidal Dwarf Galaxies in (Ultra)-Luminous Infrared Galaxies

    Miralles-Caballero, Daniel

    2012-01-01

    This thesis work is devoted to the analysis of compact star forming regions (knots) in a representative sample of 32 (U)LIRGs. The project is based mainly on optical high angular resolution images taken with the ACS and WFPC2 cameras on board the HST telescope, data from a high spatial resolution simulation of a major galaxy encounter, and with the combination of optical integral field spectroscopy (IFS) taken with the INTEGRAL (WHT) and VIMOS (VLT) instruments. A few thousand knots -a factor of more than one order of magnitude higher than in previous studies- are identified and their photometric properties are characterized as a function of the infrared luminosity of the system and of the interaction phase. These properties are compared with those of compact objects identified in simulations of galaxy encounters. Finally, and with the additional use of IFS data, we search for suitable candidates to tidal dwarf galaxies, setting up constraints on the formation of these objects for the (U)LIRG class. Knots in ...

  10. The hydrogen-poor superluminous supernova iPTF 13ajg and its host galaxy in absorption and emission

    Vreeswijk, Paul M.; Gal-Yam, Avishay; De Cia, Annalisa; Rubin, Adam; Yaron, Ofer; Tal, David; Ofek, Eran O. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001 (Israel); Savaglio, Sandra [Max Planck Institute for Extraterrestrial Physics, D-85748 Garching bei München (Germany); Quimby, Robert M. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8583 (Japan); Sullivan, Mark [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Cenko, S. Bradley; Filippenko, Alexei V.; Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Perley, Daniel A.; Cao, Yi [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos [Department of Astronomy, The Oskar Klein Center, Stockholm University, AlbaNova 10691 Stockholm (Sweden); Arcavi, Iair [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Kasliwal, Mansi M., E-mail: paul.vreeswijk@weizmann.ac.il [The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); and others

    2014-12-10

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z = 0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M {sub u,} {sub AB} = –22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2 × 10{sup 44} erg s{sup –1}, while the estimated total radiated energy is 1.3 × 10{sup 51} erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the Very Large Telescope. From Voigt profile fitting, we derive the column densities log N(Mg I) =11.94 ± 0.06, log N(Mg II) =14.7 ± 0.3, and log N(Fe II) =14.25 ± 0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs) whose progenitors are also thought to be massive stars. This suggests that the environments of hydrogen-poor SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. The neutral gas responsible for the absorption in iPTF 13ajg exhibits a single narrow component with a low velocity width, ΔV = 76 km s{sup –1}, indicating a low-mass host galaxy. No host galaxy emission lines are detected, leading to an upper limit on the unobscured star formation rate (SFR) of SFR{sub [O} {sub II]}<0.07M{sub ⊙}yr{sup −1}. Late-time imaging shows the iPTF 13ajg host galaxy to be faint, with g {sub AB} ≈ 27.0 and R {sub AB} ≥ 26.0 mag, corresponding to M {sub B,} {sub Vega} ≳ –17.7 mag.

  11. THE STAR FORMATION HISTORY OF MASS-SELECTED GALAXIES IN THE COSMOS FIELD

    We explore the redshift evolution of the specific star formation rate (SSFR) for galaxies of different stellar mass by drawing on a deep 3.6 μm selected sample of >105 galaxies in the 2 deg2 COSMOS field. The average star formation rate (SFR) for subsets of these galaxies is estimated with stacked 1.4 GHz radio continuum emission. We separately consider the total sample and a subset of galaxies that shows evidence for substantive recent star formation in the rest-frame optical spectral energy distributions. At redshifts 0.2 n, where n ∼ 4.3 for all galaxies and n ∼ 3.5 for star-forming (SF) sources. The decrease appears to have started at z>2, at least for high-mass (M* ∼> 4 x 1010 Msun) systems where our conclusions are most robust. Our data show that there is a tight correlation with power-law dependence, SSFR ∝ M*β, between SSFR and stellar mass at all epochs. The relation tends to flatten below M* ∼ 1010 Msun if quiescent galaxies are included; if they are excluded from the analysis a shallow index βSFG ∼ -0.4 fits the correlation. On average, higher mass objects always have lower SSFRs, also among SF galaxies. At z>1.5 there is tentative evidence for an upper threshold in SSFR that an average galaxy cannot exceed, possibly due to gravitationally limited molecular gas accretion. It is suggested by a flattening of the SSFR-M* relation (also for SF sources), but affects massive (>1010 Msun) galaxies only at the highest redshifts. Since z = 1.5 there thus is no direct evidence that galaxies of higher mass experience a more rapid waning of their SSFR than lower mass SF systems. In this sense, the data rule out any strong downsizingin the SSFR. We combine our results with recent measurements of the galaxy (stellar) mass function in order to determine the characteristic mass of an SF galaxy: we find that since z ∼ 3 the majority of all new stars were always formed in galaxies of M* = 1010.6±0.4 Msun. In this sense, too, there is no downsizing

  12. The assembly histories of quiescent galaxies since z = 0.7 from absorption line spectroscopy

    We present results from modeling the optical spectra of a large sample of quiescent galaxies between 0.1 < z < 0.7 from the Sloan Digital Sky Survey (SDSS) and the AGN and Galaxy Evolution Survey (AGES). We examine how the stellar ages and abundance patterns of galaxies evolve over time as a function of stellar mass from 109.6-1011.8 M ☉. Galaxy spectra are stacked in bins of mass and redshift and modeled over a wavelength range from 4000 Å to 5500 Å. Full spectrum stellar population synthesis modeling provides estimates of the age and the abundances of the elements Fe, Mg, C, N, and Ca. We find negligible evolution in elemental abundances at fixed stellar mass over roughly 7 Gyr of cosmic time. In addition, the increase in stellar ages with time for massive galaxies is consistent with passive evolution since z = 0.7. Taken together, these results favor a scenario in which the inner ∼0.3-3 R e of massive quiescent galaxies have been passively evolving over the last half of cosmic time. Interestingly, the derived stellar ages are considerably younger than the age of the universe at all epochs, consistent with an equivalent single-burst star formation epoch of z ≲ 1.5. These young stellar population ages coupled with the existence of massive quiescent galaxies at z > 1 indicate the inhomogeneous nature of the z ≲ 0.7 quiescent population. The data also permit the addition of newly quenched galaxies at masses below ∼1010.5 M ☉ at z < 0.7. Additionally, we analyze very deep Keck DEIMOS spectra of the two brightest quiescent galaxies in a cluster at z = 0.83. There is tentative evidence that these galaxies are older than their counterparts in low-density environments. In the Appendix, we demonstrate that our full spectrum modeling technique allows for accurate and reliable modeling of galaxy spectra to low S/N (∼20 Å–1) and/or low spectral resolution (R ∼ 500).

  13. The Effect of Surface Brightness Dimming in the Selection of High-z Galaxies

    Calvi, Valentina; Bradley, Larry; Pizzella, Alessandro; Kim, Soyoung

    2014-01-01

    Cosmological surface brightness dimming of the form $(1+z)^{-4}$ affects all sources. The strong dependence of surface brightness dimming on redshift z suggests the presence of a selection bias when searching for high-redshift galaxies, i.e. we tend to detect only those galaxies with a high surface brightness (SB). However, unresolved knots of emission are not affected by SB dimming, thus providing a way to test the clumpiness of high-z galaxies. Our strategy relies on the comparison of the total flux detected for the same source in surveys characterized by different depth. For all galaxies, deeper images permit the better investigation of low-SB features. Cosmological SB dimming makes these low-SB features hard to detect when going to higher and higher redshifts. We used the GOODS and HUDF Hubble Space Telescope legacy datasets to study the effect of SB dimming on low-SB features of high-redshift galaxies and compare it to the prediction for smooth sources. We selected a sample of Lyman-break galaxies at z~4...

  14. Galaxies Associated with z~4 Damped Lya Systems I. Imaging and Photometric Selection

    Prochaska, J X; Wolfe, A M; Quirrenbach, Andreas G; Lanzetta, K M; Chen, H W; Cooke, J; Yahata, N; Prochaska, Jason X.; Gawiser, Eric; Wolfe, Arthur M.; Quirrenbach, Andreas; Lanzetta, Kenneth M.; Chen, Hsiao-Wen; Cooke, Jeff; Yahata, Noriaki

    2002-01-01

    This paper describes the acquisition and analysis of imaging data for the identification of galaxies associated with z~4 damped Lya systems. We present deep BRI images of three fields known to contain four z~4 damped systems. We discuss the reduction and calibration of the data, detail the color criteria used to identify z~4 galaxies, and present a photometric redshift analysis to complement the color selection. We have found no galaxy candidates closer to the QSO than 7'' which could be responsible for the damped Lya systems. Assuming that at least one of the galaxies is not directly beneath the QSO, we set an upper limit on this damped Lya system of L < L*/4. Finally, we have established a web site to release these imaging data to the public.

  15. Damped Lyman-alpha absorption from a nearby Low Surface Brightness galaxy

    Bowen, D V

    2001-01-01

    Ground-based & HST images of the nearby galaxy SBS 1543+593 (z=0.009) show it to be a Low Surface Brightness (LSB) galaxy with a central surface brightness of mu_B(0)=23.2 mag/arcsec-2 and scale length 0.9 h-1 kpc, values typical for the local LSB galaxy population. The galaxy lies directly in front of the QSO HS 1543+5921 (z=0.807); an HST STIS spectrum of the quasar reveals a damped Lyman-alpha (DLA) line at the redshift of the interloper with an HI column density of log N(HI) = 20.35, as well as several low-ionization metal lines with strengths similar to those found in the Milky Way interstellar medium. Our data show that LSB galaxies are certainly able to produce the DLA lines seen at higher redshift, and fuels the speculation that LSB galaxies are a major contributor to that population of absorbers.

  16. High redshift galaxies in the ALHAMBRA survey: I. selection method and number counts based on redshift PDFs

    Viironen, K; López-Sanjuan, C; Varela, J; Chaves-Montero, J; Cristóbal-Hornillos, D; Molino, A; Fernández-Soto, A; Ascaso, B; Cenarro, A J; Cerviño, M; Cepa, J; Ederoclite, A; Márquez, I; Masegosa, J; Moles, M; Oteo, I; Pović, M; Aguerri, J A L; Alfaro, E; Aparicio-Villegas, T; Benítez, N; Broadhurst, T; Cabrera-Caño, J; Castander, J F; Del Olmo, A; Delgado, R M González; Husillos, C; Infante, L; Martínez, V J; Perea, J; Prada, F; Quintana, J M

    2015-01-01

    Context. Most observational results on the high redshift restframe UV-bright galaxies are based on samples pinpointed using the so called dropout technique or Ly-alpha selection. However, the availability of multifilter data allows now replacing the dropout selections by direct methods based on photometric redshifts. In this paper we present the methodology to select and study the population of high redshift galaxies in the ALHAMBRA survey data. Aims. Our aim is to develop a less biased methodology than the traditional dropout technique to study the high redshift galaxies in ALHAMBRA and other multifilter data. Thanks to the wide area ALHAMBRA covers, we especially aim at contributing in the study of the brightest, less frequent, high redshift galaxies. Methods. The methodology is based on redshift probability distribution functions (zPDFs). It is shown how a clean galaxy sample can be obtained by selecting the galaxies with high integrated probability of being within a given redshift interval. However, reach...

  17. THE MASS-DEPENDENT CLUSTERING HISTORY OF K-SELECTED GALAXIES AT z < 4 IN THE SXDS/UDS FIELD

    We investigate mass-dependent galaxy evolution based on a large sample of (more than 50,000) K-band selected galaxies in a multi-wavelength catalog of the Subaru/XMM-Newton Deep Survey and the UKIRT Infrared Deep Sky Survey/Ultra Deep Survey. We employ optical to near-infrared photometry to determine photometric redshifts of these galaxies. Then, we estimate the stellar mass of our sample galaxies using a standard fitting procedure as we used for estimation of the photometric redshift. From the sample galaxies, we obtain the stellar mass function of galaxies and the cosmic stellar mass density up to z ∼ 4. Our results are consistent with previous studies and we find a considerable number of low-mass galaxies (M* ∼ 1010.5) at the redshift range 3 14 Msun) to low (1013 Msun) with decreasing redshift at around z ∼ 2. We also find some high-mass density regions of massive galaxies at 1.4 ≤ z < 2.5 in our sample. These concentrations of massive galaxies may be candidate progenitors of the present-day clusters of galaxies. At this redshift range, massive star-forming galaxies are the dominant population making up the structures and the passively evolving galaxies show stronger clustering and they may have formed earlier than those star-forming galaxies.

  18. Soft Gamma-ray selected radio galaxies: favouring giant size discovery

    Bassani, L; Molina, M; Malizia, A; Dallacasa, D; Panessa, F; Bazzano, A; Ubertini, P

    2016-01-01

    Using the recent INTEGRAL/IBIS and Swift/BAT surveys we have extracted a sample of 64 confirmed plus 3 candidate radio galaxies selected in the soft gamma-ray band. The sample covers all optical classes and is dominated by objects showing a FR II radio morphology; a large fraction (70%) of the sample is made of radiative mode or High Excitation Radio Galaxies (HERG). We have measured the source size on NVSS, FIRST and SUMSS images and have compared our findings with data in the literature obtaining a good match. We surprisingly found that the soft gamma-ray selection favours the detection of large size radio galaxies: 60% of objects in the sample have size greater than 0.4 Mpc while around 22% reach dimension above 0.7 Mpc at which point they are classified as Giant Radio Galaxies or GRGs, the largest and most energetic single entities in the Universe. Their fraction among soft gamma ray selected radio galaxies is significantly larger than typically found in radio surveys, where only a few percent of objects ...

  19. Broadband reflectionless metasheets: Frequency-selective transmission and perfect absorption

    Asadchy, V S; Ra'di, Y; Khakhomov, S A; Semchenko, I V; Tretyakov, S A

    2015-01-01

    Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper we explore possibilities to realize a thin absorbing layer which produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a wide-band-matched thin resonant absorber, invisible in reflection, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cells, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit ...

  20. Spectroscopic confirmation of hydrogen alpha-selected satellite galaxies

    Ivory, Clare F

    2010-01-01

    We present a spectroscopic test confirming the potential of narrow-band optical imaging as a method for detecting star-forming satellites around nearby galaxies. To date the efficiency of such methods, and particularly the fraction of false detections resulting from its use, has not been tested. In this paper we use optical spectroscopy to verify the nature of objects that are apparently emission-line satellites, taken from imaging presented elsewhere. Observations of 12 probable satellites around 11 host galaxies are presented and used to compare the recession velocities of the host and satellite. This test confirms, in all cases, that there is genuine line emission, that the detected line is hydrogen alpha, and that the satellites have similar recession velocities to their hosts with a maximum difference of ~ 250 km/s, consistent with their being gravitationally bound companions. We conclude that the spectroscopy has confirmed that narrow-band imaging through H alpha filters is a reliable method for detecti...

  1. Neutral gas in Lyman-alpha emitting galaxies Haro 11 and ESO 338-IG04 measured through sodium absorption

    Sandberg, A; Hayes, M; Fathi, K; Schaerer, D; Mas-Hesse, J M; Rivera-Thorsen, T

    2013-01-01

    Context. The Lyman alpha emission line of galaxies is an important tool for finding galaxies at high redshift, and thus probe the structure of the early universe. However, the resonance nature of the line and its sensitivity to dust and neutral gas is still not fully understood. Aims. We present measurements of the velocity, covering fraction and optical depth of neutral gas in front of two well known local blue compact galaxies that show Lyman alpha in emission: ESO 338-IG 04 and Haro 11. We thus test observationally the hypothesis that Lyman alpha can escape through neutral gas by being Doppler shifted out of resonance. Methods. We present integral field spectroscopy from the GIRAFFE/Argus spectrograph at VLT/FLAMES in Paranal, Chile. The excellent wavelength resolution allows us to accurately measure the velocity of the ionized and neutral gas through the H-alpha emission and Na D absorption, which traces the ionized medium and cold interstellar gas, respectively. We also present independent measurements w...

  2. 21 cm absorption by compact hydrogen discs around black holes in radio-loud nuclei of galaxies

    The clumpy maser discs observed in some galactic nuclei mark the outskirts of the accretion disc that fuels the central black hole and provide a potential site of nuclear star formation. Unfortunately, most of the gas in maser discs is currently not being probed; large maser gains favor paths that are characterized by a small velocity gradient and require rare edge-on orientations of the disc. Here we propose a method for mapping the atomic hydrogen distribution in nuclear discs through its 21 cm absorption against the radio continuum glow around the central black hole. In NGC 4258, the 21 cm optical depth may approach unity for high angular resolution (VLBI) imaging of coherent clumps which are dominated by thermal broadening and have the column density inferred from x-ray absorption data, ∼1023 cm−2. Spreading the 21 cm absorption over the full rotation velocity width of the material in front of the narrow radio jets gives a mean optical depth of ∼0.1. Spectroscopic searches for the 21 cm absorption feature in other galaxies can be used to identify the large population of inclined gaseous discs which are not masing in our direction. Follow-up imaging of 21 cm silhouettes of accelerating clumps within these discs can in turn be used to measure cosmological distances

  3. High Frequency Cluster Radio Galaxies: Luminosity Functions and Implications for SZE Selected Cluster Samples

    Gupta, N; Mohr, J J; Benson, B A; Bocquet, S; Carlstrom, J E; Capasso, R; Chiu, I; Crawford, T M; de Haan, T; Dietrich, J P; Gangkofner, C; Holzapfel, W L; McDonald, M; Rapetti, D; Reichardt, C L

    2016-01-01

    We study the overdensity of point sources in the direction of X-ray-selected galaxy clusters from the Meta-Catalog of X-ray detected Clusters of galaxies (MCXC; $\\langle z \\rangle = 0.14$) at South Pole Telescope (SPT) and Sydney University Molonglo Sky Survey (SUMSS) frequencies. Flux densities at 95, 150 and 220 GHz are extracted from the 2500 deg$^2$ SPT-SZ survey maps at the locations of SUMSS sources, producing a multi-frequency catalog of radio galaxies. In the direction of massive galaxy clusters, the radio galaxy flux densities at 95 and 150 GHz are biased low by the cluster Sunyaev-Zel'dovich Effect (SZE) signal, which is negative at these frequencies. We employ a cluster SZE model to remove the expected flux bias and then study these corrected source catalogs. We find that the high frequency radio galaxies are centrally concentrated within the clusters and that their luminosity functions (LFs) exhibit amplitudes that are characteristically an order of magnitude lower than the cluster LF at 843 MHz. ...

  4. A uniformly selected catalogue of distant galaxy clusters

    We present a new catalogue of faint southern galaxy clusters identified from examination of high-contrast film derivatives of a set of 55 prime focus AAT photographic plates taken in one or both of two pass-bands (J ''indent to'' bJ and F ''indent to'' rF). Visual scans of these films have been compared with machine measurements of the original plates and the results demonstrate that the films offer ready access to the positions (but not photometry) of large numbers of faint objects to limiting magnitudes of bJ ≅ 24.4 ± 0.3 and rF ≅ 22.9 ± 0.2. Our cluster candidates are chosen according to their contrast, σcl, above the fluctuations in the field counts as determined locally on the same film. A total of 112 candidate clusters are tabulated down to a contrast level of σcl = 2.0. (author)

  5. Cosmology and Astrophysics from Relaxed Galaxy Clusters I: Sample Selection

    Mantz, Adam B; Morris, R Glenn; Schmidt, Robert W; von der Linden, Anja; Urban, Ondrej

    2015-01-01

    This is the first in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Here we present a new, automated method for identifying relaxed clusters based on their morphologies in X-ray imaging data. While broadly similar to others in the literature, the morphological quantities that we measure are specifically designed to provide a fair basis for comparison across a range of data quality and cluster redshifts, to be robust against missing data due to point-source masks and gaps between detectors, and to avoid strong assumptions about the cosmological background and cluster masses. Based on three morphological indicators - Symmetry, Peakiness and Alignment - we develop the SPA criterion for relaxation. This analysis was applied to a large sample of cluster observations from the Chandra and ROSAT archives. Of the 361 clusters which received the SPA treatment, 57 (16 per cent) were subsequently found to be relaxed according to our criterion. We compare our me...

  6. Clustering of the AKARI NEP Deep Field 24 $\\mu$m selected galaxies

    Solarz, A; Takeuchi, T T; Małek, K; Matsuhara, H; White, G J; Pȩpiak, A; Goto, T; Wada, T; Oyabu, S; Takagi, T; Ohyama, Y; Pearson, C P; Hanami, H; Ishigaki, T; Malkan, M

    2015-01-01

    We present a method of selection of 24~$\\mu$m galaxies from the AKARI North Ecliptic Pole (NEP) Deep Field down to $150 \\mbox{ }\\mu$Jy and measurements of their two-point correlation function. We aim to associate various 24 $\\mu$m selected galaxy populations with present day galaxies and to investigate the impact of their environment on the direction of their subsequent evolution. We discuss using of Support Vector Machines (SVM) algorithm applied to infrared photometric data to perform star-galaxy separation, in which we achieve an accuracy higher than 80\\%. The photometric redshift information, obtained through the CIGALE code, is used to explore the redshift dependence of the correlation function parameter ($r_{0}$) as well as the linear bias evolution. This parameter relates galaxy distribution to the one of the underlying dark matter. We connect the investigated sources to their potential local descendants through a simplified model of the clustering evolution without interactions. We observe two differe...

  7. The Tully-Fisher Relation and Its Residuals for a Broadly Selected Sample of Galaxies

    Pizagno, J; Weinberg, D H; Rix, H W; Pogge, R W; Grebel, E K; Harbeck, D; Blanton, M; Brinkmann, J; Gunn, J E; Pizagno, James; Prada, Francisco; Weinberg, David H.; Rix, Hans-Walter; Pogge, Richard W.; Grebel, Eva K.; Harbeck, Daniel; Blanton, Michael; Gunn, James E.

    2006-01-01

    We measure the relation between galaxy luminosity and disk circular velocity (the Tully-Fisher [TF] relation), in the g, r, i, and z-bands, for a broadly selected sample of galaxies from the Sloan Digital Sky Survey, with the goal of providing well defined observational constraints for theoretical models of galaxy formation. The input sample of 234 galaxies has a roughly flat distribution of absolute magnitudes in the range -18.5 > Mr > -22, and our only morphological selection is an axis-ratio cut b/a < 0.6 to allow accurate inclination corrections. Long-slit spectroscopy yields usable H-alpha rotation curves for 170 galaxies. Observational errors, including distance errors due to peculiar velocities, are small compared to the intrinsic scatter of the TF relation. The slope of the forward TF relation steepens from -5.4 +/- 0.2 mag/log(km/s) in the g-band to -6.4 +/- 0.2 mag/log(km/s) in the z-band. The intrinsic scatter is approximately 0.4 mag in all bands. The scatter is not dominated by rare outliers o...

  8. Higher prevalence of X-ray selected AGN in intermediate age galaxies up to z~1

    Hernán-Caballero, Antonio; Pérez-González, Pablo G; Barro, Guillermo; Aird, James; Ferreras, Ignacio; Cava, Antonio; Cardiel, Nicolás; Esquej, Pilar; Gallego, Jesús; Nandra, Kirpal; Rodríguez-Zaurín, Javier

    2014-01-01

    We analyse the stellar populations in the host galaxies of 53 X-ray selected optically dull active galactic nuclei (AGN) at 0.3410^10.5 M_sun) and that the observed fraction of galaxies hosting an AGN increases with the stellar mass. A careful selection of random control samples of inactive galaxies allows us to remove the stellar mass and redshift dependencies of the AGN fraction to explore trends with several stellar age indicators. We find no significant differences in the distribution of the rest-frame U-V colour for AGN hosts and inactive galaxies, in agreement with previous results. However, we find significantly shallower 4000 AA breaks in AGN hosts, indicative of younger stellar populations. With the help of a model-independent determination of the extinction, we obtain extinction-corrected U-V colours and light-weighted average stellar ages. We find that AGN hosts have younger stellar populations and higher extinction compared to inactive galaxies with the same stellar mass and at the same redshift. ...

  9. High redshift evolution of optically and IR-selected galaxies a comparison with CDM scenarios

    Fontana, A; D'Odorico, S; Giallongo, E; Poli, F; Cristiani, S; Moorwood, A F M; Saracco, P

    1999-01-01

    A combination of ground-based (NTT and VLT) and HST (HDF-N and HDF-S) public imaging surveys have been used to collect a sample of 1712 I-selected and 319 $K\\leq 21$ galaxies. Photometric redshifts have been obtained for all these galaxies. The results have been compared with the prediction of an analytic rendition of the current CDM hierarchical models for galaxy formation. We focus in particular on two observed quantities: the galaxy redshift distribution at K2. This result strongly supports hierarchical scenarios where present-day massive galaxies are the result of merging processes. The observed UV luminosity density in the I-selected sample is confined within a factor of 4 over the whole range 03. CDM models in $\\Lambda$-dominated universe are in better agreement at 3

  10. Selective absorption of carbon nanotube thin films for solar energy applications

    Abendroth, Thomas; Althues, Holger; Mäder, Gerrit; Kaskel, Stefan; Beyer, Eckhard

    2015-01-01

    A new spectrally selective coating based on carbon nanotubes (CNTs) for solar thermal applications is demonstrated. For optimized coatings solar absorptance coefficients α>0.92 and thermal emittance coefficients ε

  11. HI Selected Galaxies in the Sloan Digital Sky Survey I: Optical Data

    West, Andrew A; Dalcanton, Julianne J; Disney, Mike J; Rockosi, Constance M; Ivezic, Zeljko; Bentz, Misty C; Brinkmann, J

    2009-01-01

    We present the optical data for 195 HI-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), HI-selected galaxies are bluer and more lumi...

  12. Extending ALFALFA: Reducing L-Band Wide Observations of Optically Selected Galaxies

    Smith, Evan; O'Donoghue, Aileen A.; Haynes, Martha P.; Koopmann, Rebecca A.; Undergraduate ALFALFA Team

    2016-01-01

    Observations of galaxies in the Virgo Cluster were completed at the Arecibo Observatory in the spring and summer of 2015. 161 targets were observed, selected by photometry criteria such as magnitude and shape from the Sloan Digital Sky Survey. The targets, some too dim to be detected by Arecibo's ALFA drift scanner, were observed with the L-Band Wide detector. Once reductions in an IDL environment were done, these data were matched to the targets from the Sloan Digital Sky Survey and the GALEX/MAST catalog. 115 of the 161 targets observed had positive detections, a 71% success rate. Comparing the galaxies that were detected against the galaxies that were not detected (by the L-Band Wide receiver) will allow us to refine our method of using photometric data to select HI-rich galaxies in the 2000 km/s to 9000 km/s range to refine our selection for the Arecibo Pisces-Perseus Supercluster Survey (APPSS), which uses the same method of target selection.

  13. Deep absorption line studies of quiescent galaxies at z similar z ~ 2

    Toft, Sune; Gallazzi, Anna Rita; Zirm, Andrew Wasmuth; Wold, Margrethe; Zibetti, Stefano; Grillo, Claudio; Man, A.

    2012-01-01

    We present dynamical and structural scaling relations of quiescent galaxies at z = 2, including the dynamical-mass-size relation and the first constraints on the fundamental plane (FP). The backbone of the analysis is a new, very deep Very Large Telescope/X-shooter spectrum of a massive, compact...

  14. ALMA redshifts of millimeter-selected galaxies from the SPT survey: The redshift distribution of dusty star-forming galaxies

    Weiss, A; Marrone, D P; Vieira, J D; Aguirre, J E; Aird, K A; Aravena, M; Ashby, M L N; Bayliss, M; Benson, B A; Bethermin, M; Biggs, A D; Bleem, L E; Bock, J J; Bothwell, M; Bradford, C M; Brodwin, M; Carlstrom, J E; Chang, C L; Chapman, S C; Crawford, T M; Crites, A T; de Haan, T; Dobbs, M A; Downes, T P; Fassnacht, C D; George, E M; Gladders, M D; Gonzalez, A H; Greve, T R; Halverson, N W; Hezaveh, Y D; High, F W; Holder, G P; Holzapfel, W L; Hoover, S; Hrubes, J D; Husband, K; Keisler, R; Lee, A T; Leitch, E M; Lueker, M; Luong-Van, D; Malkan, M; McIntyre, V; McMahon, J J; Mehl, J; Menten, K M; Meyer, S S; Murphy, E J; Padin, S; Plagge, T; Reichardt, C L; Rest, A; Rosenman, M; Ruel, J; Ruhl, J E; Schaffer, K K; Shirokoff, E; Spilker, J S; Stalder, B; Staniszewski, Z; Stark, A A; Story, K; Vanderlinde, K; Welikala, N; Williamson, R

    2013-01-01

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have conducted a blind redshift survey in the 3 mm atmospheric transmission window for 26 strongly lensd dusty star-forming galaxies (DSFGs) selected with the South Pole Telescope (SPT). The sources were selected to have S_1.4mm>20 mJy and a dust-like spectrum and, to remove low-z sources, not have bright radio (S_843MHz=3.5. This finding is in contrast to the redshift distribution of radio-identified DSFGs, which have a significantly lower mean redshift of =2.3 and for which only 10-15% of the population is expected to be at z>3. We discuss the effect of gravitational lensing on the redshift distribution and compare our measured redshift distribution to that of models in the literature.

  15. A ground-based imaging study of galaxies causing damped Lyman α (DLA), sub-DLA and Lyman limit system absorption in quasar spectra

    Rao, Sandhya M.; Belfort-Mihalyi, Michèle; Turnshek, David A.; Monier, Eric M.; Nestor, Daniel B.; Quider, Anna

    2011-09-01

    We present results from a search for galaxies that give rise to damped Lyman α (DLA), sub-DLA and Lyman limit system (LLS) absorption at redshifts 0.1 ≲z≲ 1 in the spectra of background quasars. The sample was formed from a larger sample of strong Mg II absorbers (Wλ27960≥ 0.3 Å) whose H I column densities were determined by measuring the Lyα line in Hubble Space Telescope ultraviolet spectra. Photometric redshifts, galaxy colours and proximity to the quasar sightline, in decreasing order of importance, were used to identify galaxies responsible for the absorption. Our sample includes 80 absorption systems for which the absorbing galaxies have been identified, of which 54 are presented here for the first time. In some cases a reasonable identification for the absorbing galaxy could not be made. The main results of this study are (i) the surface density of galaxies falls off exponentially with increasing impact parameter, b, from the quasar sightline relative to a constant background of galaxies, with an e-folding length of ≈46 kpc. Galaxies with b≳ 100 kpc calculated at the absorption redshift are statistically consistent with being unrelated to the absorption system, and are either background or foreground galaxies. (ii) ? is inversely correlated with b at the 3.0σ level of significance. DLA galaxies are found systematically closer to the quasar sightline, by a factor of 2, than are galaxies which give rise to sub-DLAs or LLSs. The median impact parameter is 17.4 kpc for the DLA galaxy sample, 33.3 kpc for the sub-DLA sample and 36.4 kpc for the LLS sample. We also find that the decline in ? with b can be roughly described by an exponential with an e-folding length of 12 kpc that occurs at ?. (iii) Absorber galaxy luminosity relative to L*, L/L*, is not significantly correlated with Wλ27960, ? or b. (iv) DLA, sub-DLA and LLS galaxies comprise a mix of spectral types, but are inferred to be predominantly late-type galaxies based on their spectral

  16. The Spatial Distribution of Satellite Galaxies Selected from Redshift Space

    Agustsson, Ingolfur

    2015-01-01

    We investigate the spatial distribution of satellite galaxies that were obtained from a mock redshift survey of the first Millennium Run simulation. The satellites were identified using typical redshift space criteria and, hence, the sample includes both genuine satellites and a large number of interlopers. As expected from previous work, the 3D locations of the satellites are well-fitted by a combination of a Navarro, Frenk & White (NFW) density profile and a power law. At fixed stellar mass, the NFW scale parameter, r_s, for the satellite distribution of red hosts exceeds that for the satellite distribution of blue hosts. In both cases the dependence of r_s on host stellar mass is well-fitted by a power law. For the satellites of red hosts, r_s^{red} \\propto (M_\\ast / M_sun)^{0.71 \\pm 0.05} while for the satellites of blue hosts, r_s^{blue} \\propto (M_\\ast / M_sun)^{0.48 \\pm 0.07}. For hosts with stellar masses greater than 4.0E+10 M_sun, the satellite distribution around blue hosts is much more concent...

  17. The Properties of Intergalactic CIV Absorption II: Which Systems Are Associated With Galaxy Outflows?

    Songaila, Antoinette

    2005-01-01

    Using the extremely high S/N quasar absorption-line sample described in the first paper of the series, we investigate which intergalactic CIV absorption line systems could be directly associated with galactic outflows at z = 2 - 3.5 from an analysis of the velocity widths of the CIV absorption line systems. Only about half the systems with a peak tau(CIV) above 0.4 in the 1548 Angstrom line (roughly a column density of CIV above about 2 x 10^13 cm^-2) have velocity widths large enough to orig...

  18. Spitzer Imaging of Strongly-Lensed Herschel-Selected Dusty Star Forming Galaxies

    Ma, Brian; Nayyeri, J A Calanog H; Timmons, N; Casey, C; Baes, M; Chapman, S; Dannerbauer, H; Da Cunha, E L; De Zotti, G; Dunne, L; Farrah, D; Fu, Hai; Gonzalez-Nuevo, J; Magdis, G; Michalowski, M J; Oteo, I; Riechers, D A; Scott, D; Smith, M W L; Wang, L; Wardlow, J; Vaccari, M; Viaene, S; Vieira, J D; Vaccari, M

    2015-01-01

    We present the rest-frame optical spectral energy distribution and stellar masses of six Herschel- selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5um. Due to the spatial resolution of the IRAC observations at the level of 2 arcseconds, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measu...

  19. Multi-wavelength seds of Herschel-selected galaxies in the cosmos field

    We combine Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver maps of the full 2 deg2 Cosmic Evolution Survey (COSMOS) field with existing multi-wavelength data to obtain template and model-independent optical-to-far-infrared spectral energy distributions (SEDs) for 4218 Herschel-selected sources with log(L IR/L ☉) = 9.4-13.6 and z = 0.02-3.54. Median SEDs are created by binning the optical to far-infrared (FIR) bands available in COSMOS as a function of infrared luminosity. Herschel probes rest-frame wavelengths where the bulk of the infrared radiation is emitted, allowing us to more accurately determine fundamental dust properties of our sample of infrared luminous galaxies. We find that the SED peak wavelength (λpeak) decreases and the dust mass (M dust) increases with increasing total infrared luminosity (L IR). In the lowest infrared luminosity galaxies (log(L IR/L ☉) = 10.0-11.5), we see evidence of polycyclic aromatic hydrocarbon (PAH) features (λ ∼ 7-9 μm), while in the highest infrared luminosity galaxies (L IR > 1012 L ☉) we see an increasing contribution of hot dust and/or power-law emission, consistent with the presence of heating from an active galactic nucleus (AGN). We study the relationship between stellar mass and star formation rate of our sample of infrared luminous galaxies and find no evidence that Herschel-selected galaxies follow the SFR/M * 'main sequence' as previously determined from studies of optically selected, star-forming galaxies. Finally, we compare the mid-infrared to FIR properties of our infrared luminous galaxies using the previously defined diagnostic, IR8 ≡ L IR/L 8, and find that galaxies with L IR ≳ 1011.3 L ☉ tend to systematically lie above (× 3-5) the IR8 'infrared main sequence', suggesting either suppressed PAH emission or an increasing contribution from AGN heating.

  20. SDSS-IV MaNGA: Faint quenched galaxies I- Sample selection and evidence for environmental quenching

    Penny, Samantha J; Weijmans, Anne-Marie; Westfall, Kyle B; Bershady, Matthew A; Bundy, Kevin; Drory, Niv; Falcón-Barroso, Jesús; Law, David; Nichol, Robert C; Thomas, Daniel; Bizyaev, Dmitry; Brownstein, Joel R; Freischlad, Gordon; Gaulme, Patrick; Grabowski, Katie; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Roman-Lopes, Alexandre; Pan, Kaike; Simmons, Audrey; Wake, David A

    2016-01-01

    Using kinematic maps from the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we reveal that the majority of low-mass quenched galaxies exhibit coherent rotation in their stellar kinematics. Our sample includes all 39 quenched low-mass galaxies observed in the first year of MaNGA. The galaxies are selected with $M_{r} > -19.1$, stellar masses $10^{9}$ M$_{\\odot} 1.9$. They lie on the size-magnitude and $\\sigma$-luminosity relations for previously studied dwarf galaxies. Just six ($15\\pm5.7$ per cent) are found to have rotation speeds $v_{e,rot} 5\\times10^{10}$ M$_{\\odot}$), supporting the hypothesis that galaxy-galaxy or galaxy-group interactions quench star formation in low-mass galaxies. The local bright galaxy density for our sample is $\\rho_{proj} = 8.2\\pm2.0$ Mpc$^{-2}$, compared to $\\rho_{proj} = 2.1\\pm0.4$ Mpc$^{-2}$ for a star forming comparison sample, confirming that the quenched low mass galaxies are preferentially found in higher density environ...

  1. SDSS-IV MaNGA: Faint quenched galaxies I- Sample selection and evidence for environmental quenching

    Penny, Samantha J.; Masters, Karen L.; Weijmans, Anne-Marie; Westfall, Kyle B.; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Falcón-Barroso, Jesús; Law, David; Nichol, Robert C.; Thomas, Daniel; Bizyaev, Dmitry; Brownstein, Joel R.; Freischlad, Gordon; Gaulme, Patrick; Grabowski, Katie; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Roman-Lopes, Alexandre; Pan, Kaike; Simmons, Audrey; Wake, David A.

    2016-08-01

    Using kinematic maps from the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we reveal that the majority of low-mass quenched galaxies exhibit coherent rotation in their stellar kinematics. Our sample includes all 39 quenched low-mass galaxies observed in the first year of MaNGA. The galaxies are selected with Mr > -19.1, stellar masses 109 M⊙ 1.9. They lie on the size-magnitude and σ-luminosity relations for previously studied dwarf galaxies. Just six (15 ± 5.7 per cent) are found to have rotation speeds ve, rot 5 × 1010 M⊙), supporting the hypothesis that galaxy-galaxy or galaxy-group interactions quench star formation in low-mass galaxies. The local bright galaxy density for our sample is ρproj = 8.2 ± 2.0 Mpc-2, compared to ρproj = 2.1 ± 0.4 Mpc-2 for a star forming comparison sample, confirming that the quenched low mass galaxies are preferentially found in higher density environments.

  2. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey. I. Sample Selection and Redshift Distribution

    Perley, D. A.; Krühler, T.; Schulze, S.; de Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R.; Fong, W.; Fynbo, J. P. U.; Gorosabel, J.; Greiner, J.; Jakobsson, P.; Kim, S.; Laskar, T.; Levan, A. J.; Michałowski, M. J.; Milvang-Jensen, B.; Tanvir, N. R.; Thöne, C. C.; Wiersema, K.

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey (“SHOALS”), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly deep, multicolor optical/near-IR photometry, plus spectroscopy of events without preexisting redshifts. Our optimized selection cuts combined with host galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust obscured, and at most 2% originate from z\\gt 5.5. Using this sample, we estimate the redshift-dependent GRB rate density, showing it to peak at z∼ 2.5 and fall by at least an order of magnitude toward low (z = 0) redshift, while declining more gradually toward high (z∼ 7) redshift. This behavior is consistent with a progenitor whose formation efficiency varies modestly over cosmic history. Our survey will permit the most detailed examination to date of the connection between the GRB host population and general star-forming galaxies, directly measure evolution in the host population over cosmic time and discern its causes, and provide new constraints on the fraction of cosmic star formation occurring in undetectable galaxies at all redshifts.

  3. Spatially extended absorption around the z=2.63 radio galaxy MRC 2025-218: outflow or infall?

    Humphrey, A; Sánchez, S F; Alighieri, S di Serego; De Breuck, C; Binette, L; Tadhunter, C; Vernet, J; Fosbury, R; Stasielak, J

    2008-01-01

    We present an investigation into the absorber in front of the z=2.63 radio galaxy MRC 2025-218, using integral field spectroscopy obtained at the Very Large Telescope, and long slit spectroscopy obtained at the Keck II telescope. The properties of MRC 2025-218 are particularly conducive to study the nature of the absorbing gas, i.e., this galaxy shows bright and spatially extended Ly-alpha emission, along with bright continuum emission from the active nucleus. Ly-alpha absorption is detected across ~40x30 kpc^2, has a covering factor of ~1, and shows remarkably little variation in its properties across its entire spatial extent. This absorber is kinematically detached from the extended emission line region (EELR). Its properties suggest that the absorber is outside of the EELR. We derive lower limits to the HI, HII and H column densities for this absorber of 3x10^16, 7x10^17 and 2x10^18 cm^-2, respectively. Moreover, the relatively bright emission from the active nucleus has allowed us to measure a number of ...

  4. MULTI-WAVELENGTH STUDIES OF SPECTACULAR RAM PRESSURE STRIPPING OF A GALAXY: DISCOVERY OF AN X-RAY ABSORPTION FEATURE

    We report the detection of an X-ray absorption feature near the galaxy M86 in the Virgo cluster. The absorber has a column density of 2-3 × 1020 cm–2, and its position coincides with the peak of an intracluster H I cloud which was removed from the galaxy NGC 4388 presumably by ram pressure. These results indicate that the H I cloud is located in front of M86 along the line-of-sight, and suggest that the stripping was primarily created by an interaction between NGC 4388 and the hot plasmas of the Virgo cluster, not the M86 halo. By calculating an X-ray temperature map, we further detected an X-ray counterpart of the H I cloud up to ≈3' south of M86. It has a temperature of 0.89 keV and a mass of ∼4.5 × 108 M ☉, exceeding the estimated H I gas mass. The high hot-to-cold gas ratio in the cloud indicates a significant evaporation of the H I gas, probably by thermal conduction from the hotter cluster plasma with a sub-Spitzer rate

  5. Parsec-scale HI absorption structure in a low-redshift galaxy seen against a Compact Symmetric Object

    Biggs, A D; Hatziminaoglou, E; Péroux, C; Liske, J

    2016-01-01

    We present global VLBI observations of the 21-cm transition of atomic hydrogen seen in absorption against the radio source J0855+5751. The foreground absorber (SDSS~J085519.05+575140.7) is a dwarf galaxy at $z$ = 0.026. As the background source is heavily resolved by VLBI, the data allow us to map the properties of the foreground HI gas with a spatial resolution of 2pc. The absorbing gas corresponds to a single coherent structure with an extent $>$35pc, but we also detect significant and coherent variations, including a change in the HI optical depth by a factor of five across a distance of $\\leq$6pc. The large size of the structure provides support for the Heiles & Troland model of the ISM, as well as its applicability to external galaxies. The large variations in HI optical depth also suggest that caution should be applied when interpreting $T_S$ measurements from radio-detected DLAs. In addition, the distorted appearance of the background radio source is indicative of a strong jet-cloud interaction in ...

  6. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    Perley, D A; Schulze, S; Postigo, A de Ugarte; Hjorth, J; Berger, E; Cenko, S B; Chary, R; Cucchiara, A; Ellis, R; Fong, W; Fynbo, J P U; Gorosabel, J; Greiner, J; Jakobsson, P; Laskar, T; Levan, A J; Michałowski, M J; Milvang-Jensen, B; Tanvir, N R; Thöne, C C; Wiersema, K

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host-galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly-deep, multi-color optical/NIR photometry, plus spectroscopy of events without pre-existing redshifts. Our optimized selection cuts combined with host-galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust-obscured, and at most 2% originate from z>5.5. Using this sample we estimate the redshift-depen...

  7. The star formation history of mass-selected galaxies from the VIDEO survey

    Zwart, Jonathan T. L.; Jarvis, Matt J.; Deane, Roger P.; Bonfield, David G.; Knowles, Kenda; Madhanpall, Nikhita; Rahmani, Hadi; Smith, Daniel J. B.

    2014-04-01

    We measure star formation rates (SFRs) and specific SFRs (SSFRs) of Ks -selected galaxies from the VISTA Deep Extragalactic Observations survey by stacking 1.4 GHz Very Large Array data. We split the sample, which spans 0 galaxies based on their spectral energy distributions. We find that SSFR falls with stellar mass, in agreement with the `downsizing' paradigm. We consider the dependence of the SSFR-mass slope on redshift: for our full and elliptical samples the slope flattens, but for the irregular and starburst samples the slope is independent of redshift. The rate of SSFR evolution reduces slightly with stellar mass for ellipticals, but irregulars and starbursts co-evolve across stellar masses. Our results for SSFR as a function of stellar mass and redshift are in agreement with those derived from other radio-stacking measurements of mass-selected passive and star-forming galaxies, but inconsistent with those generated from semi-analytic models, which tend to underestimate SFRs and SSFRs. There is a need for deeper high-resolution radio surveys such as those from telescopes like the next-generation MeerKAT in order to probe lower masses at earlier times and to permit direct detections, i.e. to study individual galaxies in detail.

  8. The XMM spectral catalog of SDSS optically selected Seyfert 2 galaxies

    Koulouridis, E; Loukaidou, G; Corral, A; Akylas, A; Koutoulidis, L; Jiménez-Andrade, E F; Tavares, J León; Ranalli, P

    2016-01-01

    We present an X-ray spectroscopic study of optically selected (SDSS) Seyfert 2 (Sy2) galaxies. The goal is to study the obscuration of Sy2 galaxies beyond the local universe, using good quality X-ray spectra in combination with high S/N optical spectra for their robust classification. We analyze all available XMM-Newton archival observations of narrow emission line galaxies that meet the above criteria in the redshift range 0.05select narrow line AGN using the SDSS optical spectra and the BPT classification diagram. We further model and remove the stellar continuum, and we analyze the residual emission line spectrum to exclude any possible intermediate-type Seyferts. Our final catalog comprises 31 Sy2 galaxies with median redshift z~0.1. X-ray spectroscopy is performed using the available X-ray spectra from the 3XMM and the XMMFITCAT catalogs. Implementing various indicators of obscuration, we find seven (~23%) Compton-thick AGN. The X-ray spectroscopic Compton-thick classification...

  9. The evolution of Balmer jump selected galaxies in the ALHAMBRA survey

    Iribarren, P Troncoso; Padilla, N; Lacerna, I; Garcia, S; Orsi, A; Arancibia, A Muñoz; Moustakas, J; Cristóbal-Hornillos, J; Moles, M; Fernández-Soto, A; Martínez, V J; Cerviño, M; Alfaro, E J; Ascaso, B; Arnalte-Mur, P; Nieves-Seoane, L; Benítez, N

    2016-01-01

    We present a new color-selection technique, based on the Bruzual & Charlot models convolved with the bands of the ALHAMBRA survey, and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 < z < 1.5. These galaxies are dubbed Balmer jump Galaxies BJGs. We apply the iSEDfit Bayesian approach to fit each detailed SED and determine star-formation rate (SFR), stellar mass, age and absolute magnitudes. The mass of the haloes where these samples reside are found via a clustering analysis. Five volume-limited BJG sub-samples with different mean redshifts are found to reside in haloes of median masses $\\sim 10^{12.5 \\pm 0.2} M_\\odot$ slightly increasing toward z=0.5. This increment is similar to numerical simulations results which suggests that we are tracing the evolution of an evolving population of haloes as they grow to reach a mass of $\\sim 10^{12.7 \\pm 0.1} M_\\odot$ at z=0.5. The likely progenitors of our samples at z$\\sim$3 are Lyman Break Galaxies, whic...

  10. Highly selective population of two excited states in nonresonant two-photon absorption

    Zhang Hui; Zhang Shi-An; Sun Zhen-Rong

    2011-01-01

    A nonresonant two-photon absorption process can be manipulated by tailoring the ultra-short laser pulse.In this paper,we theoretically demonstrate a highly selective population of two excited states in the nonresonant two-photon absorption process by rationally designing a spectral phase distribution.Our results show that one excited state is maximally populated while the other state population is widely tunable from zero to the maximum value.We believe that the theoretical results may play an important role in the selective population of a more complex nonlinear process comprising nonresonant two-photon absorption,such as resonance-mediated(2+1)-three-photon absorption and (2+1)-resonant multiphoton ionization.

  11. Photometric redshifts and clustering of emission line galaxies selected jointly by DES and eBOSS

    Jouvel, S.; et al.

    2015-09-23

    We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71\\% and 68\\% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a mean redshift of 0.8 and 0.87, with 15 and 13\\% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6galaxy bias averaged on scales of 1 and 10~Mpc/h of 1.72 \\pm 0.1 for the bright sample and of 1.78 \\pm 0.12 for the faint sample. The error on the galaxy bias have been obtained propagating the errors in the correlation function to the fitted parameters. This redshift evolution for the galaxy bias is in agreement with theoretical expectations for a galaxy population with MB-5\\log h < -21.0. We note that biasing is derived from the galaxy clustering relative to a model for the mass fluctuations. We investigate the quality of the DES photometric redshifts and find that the outlier fraction can be reduced using a comparison between template fitting and neural network, or using a random forest algorithm.

  12. The hydrogen-poor superluminous supernova iPTF13ajg and its host galaxy in absorption and emission

    Vreeswijk, Paul M; Gal-Yam, Avishay; De Cia, Annalisa; Quimby, Robert M; Sullivan, Mark; Cenko, S Bradley; Perley, Daniel A; Filippenko, Alexei V; Clubb, Kelsey I; Taddia, Francesco; Sollerman, Jesper; Leloudas, Giorgos; Arcavi, Iair; Rubin, Adam; Kasliwal, Mansi M; Cao, Yi; Yaron, Ofer; Tal, David; Ofek, Eran O; Capone, John; Kutyrev, Alexander S; Toy, Vicki; Nugent, Peter E; Laher, Russ; Surace, Jason; Kulkarni, Shrinivas R

    2014-01-01

    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory: iPTF13ajg. At a redshift of z=0.7403, derived from narrow absorption lines, iPTF13ajg peaked at an absolute magnitude M(u,AB)=-22.5, one of the most luminous supernovae to date. The uBgRiz light curves, obtained with the P48, P60, NOT, DCT, and Keck telescopes, and the nine-epoch spectral sequence secured with the Keck and the VLT (covering 3 rest-frame months), are tied together photometrically to provide an estimate of the flux evolution as a function of time and wavelength. The observed bolometric peak luminosity of iPTF13ajg is 3.2x10^44 erg/s, while the estimated total radiated energy is 1.3x10^51 erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the VLT. From Voigt-profile fitting, we derive the column densities log N(Mg I)=11.94+-0.06, log ...

  13. The Gaseous Extent of Galaxies and the Origin of Lya Absorption Systems. V. Optical and Near-Infrared Photometry of Lya-absorbing Galaxies at z < 1

    Chen, H W; Webb, J K; Barcons, X; Chen, Hsiao-Wen; Lanzetta, Kenneth M; Webb, John K.

    2001-01-01

    (Abridged) We present results of a program to obtain and analyze HST WFPC2 images and ground-based images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We confirm and improve the results presented by Lanzetta et al. (1995) and Chen et al. (1998) that (1) extended gaseous envelopes are a common and generic feature of galaxies of a wide range of luminosity and morphological type, (2) the extent of tenuous gas (N(H I) > 10^{14} cm^{-2} around galaxies scales with galaxy B-band luminosity as r\\propto L_B^{0.39+/-0.09}, and (3) galaxy interactions do not play an important role in distributing tenuous gas around galaxies in most cases. We further demonstrate that (4) the gaseous extent of galaxies scales with galaxy K-band luminosity as r\\propto L_K^{0.28+/-0.08}, and (5) tenuous gas around typical L_* galaxies is likely to be distributed in spherical halos of radius ~ 180 h^{-1} kpc of covering factor of nearly unity. Because galaxies of...

  14. A Census of Optical and Near-Infrared Selected Star-Forming and Passively Evolving Galaxies at Redshift Z~2

    Reddy, N A; Steidel, C C; Shapley, A E; Adelberger, K L; Pettini, M; Reddy, Naveen A.; Erb, Dawn K.; Steidel, Charles C.; Shapley, Alice E.; Adelberger, Kurt L.; Pettini, Max

    2005-01-01

    Using the extensive multi-wavelength data in the GOODS-North field, we construct and draw comparisons between samples of optical and near-IR selected star-forming and passively evolving galaxies at redshifts 1.42.3 galaxies (Distant Red Galaxies; DRGs) are very similar as a function of K, with K~120 Msun/yr, a factor of two to three higher than those with K>20.5. The absence of X-ray emission from the reddest DRGs and BzK galaxies with z-K>3 indicates they must have declining star formation histories to explain their red colors and low SFRs. While the M/L ratio of passively-evolving galaxies may be larger on average, the Spitzer/IRAC data indicate that their inferred stellar masses do not exceed the range spanned by optically selected galaxies, suggesting that the disparity in current SFR may not indicate a fundamental difference between optical and near-IR selected massive galaxies (M* > 10^11 Msun). We consider the contribution of UGR, BzK, DRG, and submillimeter galaxies (SMGs) to the SFRD at z~2, taking i...

  15. Orientation Bias of Optically Selected Galaxy Clusters and Its Impact on Stacked Weak Lensing Analyses

    Dietrich, Jörg P; Song, Jeeseon; McKay, Christopher P Davis Timothy A; Baruah, Leon; Becker, Matthew; Benoist, Christophe; Busha, Michael; da Costa, Luiz A N; Hao, Jiangang; Maia, Marcio A G; Miller, Christopher J; Ogando, Ricardo; Romer, A Kathy; Rozo, Eduardo; Rykoff, Eli; Wechsler, Risa

    2014-01-01

    Weak-lensing measurements of the averaged shear profiles of galaxy clusters binned by some proxy for cluster mass are commonly converted to cluster mass estimates under the assumption that these cluster stacks have spherical symmetry. In this paper we test whether this assumption holds for optically selected clusters binned by estimated optical richness. Using mock catalogues created from N-body simulations populated realistically with galaxies, we ran a suite of optical cluster finders and estimated their optical richness. We binned galaxy clusters by true cluster mass and estimated optical richness and measure the ellipticity of these stacks. We find that the processes of optical cluster selection and richness estimation are biased, leading to stacked structures that are elongated along the line-of-sight. We show that weak-lensing alone cannot measure the size of this orientation bias. Weak lensing masses of stacked optically selected clusters are overestimated by up to 3-6 per cent when clusters can be uni...

  16. The AzTEC/SMA Interferometric Imaging Survey of Submillimeter-Selected High-Redshift Galaxies

    Younger, J D; Huang, J -S; Yun, M S; Wilson, G W; Ashby, M L N; Gurwell, M A; Peck, A B; Petitpas, G R; Wilner, D J; Hughes, D H; Aretxaga, I; Kim, S; Scott, K S; Austermann, J; Perera, T; Lowenthal, J D

    2009-01-01

    We present results from a continuing interferometric survey of high-redshift submillimeter galaxies with the Submillimeter Array, including high-resolution (beam size ~2 arcsec) imaging of eight additional AzTEC 1.1mm selected sources in the COSMOS Field, for which we obtain six reliable (peak S/N>5 or peak S/N>4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N>4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric followup. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology - including the nature of submillimeter galaxies with multiple radio counterparts and constraints on the physical scale of the far infrared - of the sample, and (3) find additional evidence for a population of extremely luminous, radio-dim submillimeter galaxies that peaks at higher redshift than previous, radio-selected samples. I...

  17. Scaling Properties of a Complete X-ray Selected Galaxy Group Sample

    Lovisari, Lorenzo; Schellenberger, Gerrit

    2014-01-01

    Upcoming X-ray surveys like eROSITA require precise calibration between X-ray observables and mass down to the low mass regime to set tight constraints on the fundamental cosmological parameters. Since an individual mass measurement is only possible for a relatively small number of objects it is crucial to have robust and well understood scaling relations that relate the total mass to easily observable quantities. The main goal of this work is to constrain the galaxy group scaling relations corrected for selection effects, and to quantify the influence of non-gravitational physics at the low-mass regime. We analyzed XMM-Newton observations for a complete sample of galaxy groups selected from the ROSAT All-Sky Survey and we compared the derived scaling properties with a galaxy cluster sample. To investigate the role played by the different non-gravitational processes we then compared the observational data with the predictions of hydrodynamical simulations. After applying the correction for selection effects (...

  18. Halpha3: Halpha imaging survey of HI selected galaxies from ALFALFA

    Gavazzi, Giuseppe; Galardo, Vincenzo; Grossetti, Francesco; Boselli, Alessandro; Giovanelli, Riccardo; Haynes, Martha P; Fabello, Silvia

    2012-01-01

    We present Halpha3 (acronym for Halpha-alpha-alpha), an Halpha narrow-band imaging survey of ~400 galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Local Supercluster, including the Virgo cluster. By using hydrogen recombination lines as a tracer of recent star formation, we aim to investigate the relationships between atomic neutral gas and newly formed stars in different environments (cluster and field), morphological types (spirals and dwarfs), and over a wide range of stellar masses (~10^7.5-10^11.5 Msun). We image in Halpha+[NII] all the galaxies that contain more than 10^7 Msun of neutral atomic hydrogen in the sky region 11^h < R.A. <16^h 4^o < Dec. <16^o; 350< cz <2000 km/s using the San Pedro Martir 2m telescope. This survey provides a complete census of the star formation in HI rich galaxies of the local universe. We present the properties of the galaxy sample, together with Halpha fluxes and equivalent widths. We find an excellent agreement between the...

  19. Host Galaxy Properties of the Swift BAT Ultra Hard X-ray Selected AGN

    Koss, Michael; Veilleux, Sylvain; Winter, Lisa M; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) AGN with host galaxy optical data to date, with 185 nearby (z10.5) have a 5 to 10 times higher rate of spiral morphologies than in SDSS AGN or inactive galaxies. We also see enhanced far-IR emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGN are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line BAT AGN have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III]. There is also a correlation between the stellar mass and X-ray emission. The BAT AGN in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as whole. In agreement with the Unified Model of AGN, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of ...

  20. Clustering properties of $g$-selected galaxies at $z\\sim0.8$

    Favole, Ginevra; Prada, Francisco; Yepes, Gustavo; Jullo, Eric; Niemiec, Anna; Kneib, Jean-Paul; Rodríguez-Torres, Sergio A; Klypin, Anatoly; Skibba, Ramin A; McBride, Cameron K; Eisenstein, Daniel J; Schlegel, David J; Nuza, Sebastián E; Chuang, Chia-Hsun; Delubac, Timothée; Yèche, Christophe; Schneider, Donald P

    2015-01-01

    Current and future large redshift surveys, as the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) or the Dark Energy Spectroscopic Instrument (DESI), will use Emission-Line Galaxies (ELG) to probe cosmological models by mapping the large-scale structure of the Universe in the redshift range $0.6 < z < 1.7$. With current data, we explore the halo-galaxy connection by measuring three clustering properties of $g$-selected ELGs as matter tracers in the redshift range $0.6 < z < 1$: (i) the redshift-space two-point correlation function using spectroscopic redshifts from the BOSS ELG sample and VIPERS; (ii) the angular two-point correlation function on the footprint of the CFHT-LS; (iii) the galaxy-galaxy lensing signal around the ELGs using the CFHTLenS. We interpret these observations by mapping them onto the latest high-resolution MultiDark Planck N-body simulation, using a novel (Sub)Halo-Abundance Matching technique that accounts for the ELG incompletene...

  1. The theory of QSO absorption line systems and their relationship to the galaxies

    Charlton, Jane

    1993-01-01

    The fundamental goal of this effort is to paint a picture of what the Ly-alpha forest clouds are and how they are distributed in space. Progress during the first phase of this program involved development of the 'Cheshire Cat Model' of Ly-alpha clouds in which systems over a large range of column densities are produced by disks with somewhat smaller column densities than those of normal galaxies. A prediction of the slab model of Ly-alpha clouds was confirmed by a new observational result, and the comparison of models to the new data allowed an estimate of the pressure of the intergalactic medium. This result should be forthcoming in pre-print form within the next month. The various results will now be described in more detail.

  2. Determining Type Ia Supernovae Host galaxy extinction probabilities and a statistical approach to estimating the absorption-to-reddening ratio $R_V$

    Cikota, Aleksandar; Marleau, Francine

    2016-01-01

    We investigate limits on the extinction values of Type Ia supernovae to statistically determine the most probable color excess, E(B-V), with galactocentric distance, and use these statistics to determine the absorption-to-reddening ratio, $R_V$, for dust in the host galaxies. We determined pixel-based dust mass surface density maps for 59 galaxies from the Key Insight on Nearby Galaxies: a Far-Infrared Survey with \\textit{Herschel} (KINGFISH, Kennicutt et al. (2011)). We use Type Ia supernova spectral templates (Hsiao et al. 2007) to develop a Monte Carlo simulation of color excess E(B-V) with $R_V$ = 3.1 and investigate the color excess probabilities E(B-V) with projected radial galaxy center distance. Additionally, we tested our model using observed spectra of SN 1989B, SN 2002bo and SN 2006X, which occurred in three KINGFISH galaxies. Finally, we determined the most probable reddening for Sa-Sap, Sab-Sbp, Sbc-Scp, Scd-Sdm, S0 and Irregular galaxy classes as a function of $R/R_{25}$. We find that the larges...

  3. Search for Hyper Infrared-Luminous Dust Obscured Galaxies selected with WISE and SDSS

    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-...

  4. The star-formation history of mass-selected galaxies from the VIDEO survey

    Zwart, Jonathan T L; Deane, Roger P; Bonfield, David G; Knowles, Kenda; Madhanpall, Nikhita; Rahmani, Hadi; Smith, Daniel J B

    2014-01-01

    We measure star-formation rates (SFRs) and specific SFRs (SSFRs) of Ks-selected galaxies from the VIDEO survey by stacking 1.4-GHz Very Large Array data. We split the sample, which spans 0 < z < 3 and stellar masses 10**8.0 < Mstellar/Msol < 10**11.5, into elliptical, irregular or starburst galaxies based on their spectral-energy distributions. We find that SSFR falls with stellar mass, in agreement with the `downsizing' paradigm. We consider the dependence of the SSFR-mass slope on redshift: for our full and elliptical samples the slope flattens, but for the irregular and starburst samples the slope is independent of redshift. The rate of SSFR evolution reduces slightly with stellar mass for ellipticals, but irregulars and starbursts co-evolve across stellar masses. Our results for SSFR as a function of stellar mass and redshift are in agreement with those derived from other radio-stacking measurements of mass-selected passive and star-forming galaxies, but inconsistent with those generated from ...

  5. Damped Lyman-alpha absorption by disk galaxies with large redshifts. III. Intermediate-resolution spectroscopy

    New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due to damped Ly-alpha absorption. A standard curve-of-growth analysis on five of the damped systems is performed, and relevant properties are tabulated and discussed. Six of the seven damped Ly-alpha systems have H I column densities of 2 x 10 to the 20th/sq cm or larger, while the remaining system has an H I column density of about 10 to the 20th/sq cm. It is suggested that damped Ly-alpha systems arise when a sight line intercepts a high-redshift protogalaxy disk containing a quiescent cloud component characterized by high column density and low effective velocity dispersion. At the same time, the sight line usually intercepts a broader turbulent component, which is identified as the halo, characterized by much lower column density and higher effective velocity dispersion. 42 refs

  6. Damped Lyman-alpha absorption by disk galaxies with large redshifts. III. Intermediate-resolution spectroscopy

    Turnshek, D.A.; Wolfe, A.M.; Lanzetta, K.M.; Briggs, F.H.; Cohen, R.D. (Space Telescope Science Institute, Baltimore, MD (USA); Multiple Mirror Telescope Observatory, Tucson, AZ (USA); Pittsburgh Univ., PA (USA); California Univ., La Jolla (USA))

    1989-09-01

    New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due to damped Ly-alpha absorption. A standard curve-of-growth analysis on five of the damped systems is performed, and relevant properties are tabulated and discussed. Six of the seven damped Ly-alpha systems have H I column densities of 2 x 10 to the 20th/sq cm or larger, while the remaining system has an H I column density of about 10 to the 20th/sq cm. It is suggested that damped Ly-alpha systems arise when a sight line intercepts a high-redshift protogalaxy disk containing a quiescent cloud component characterized by high column density and low effective velocity dispersion. At the same time, the sight line usually intercepts a broader turbulent component, which is identified as the halo, characterized by much lower column density and higher effective velocity dispersion. 42 refs.

  7. Search for Hyperluminous Infrared Dust-obscured Galaxies Selected with WISE and SDSS

    Toba, Y.; Nagao, T.

    2016-03-01

    We aim to search for hyperluminous infrared (IR) galaxies (HyLIRGs) with IR luminosity {L}{{IR}} > 1013 L⊙ 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 (SF) and/or active galactic nucleus (AGN) activity hence, they are a crucial population for understanding the SF and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE), we performed the extensive HyLIRGs survey; we selected 5311 IR-bright DOGs with i - [22] > 7.0 and flux at 22 μm > 3.8 mJy in 14,555 deg2, where i and [22] are i-band and 22 μm AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the spectral energy distribution fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically confirmed DOGs. We found that (i) i - [22] color of IR-bright DOGs correlates with the total IR luminosity and (ii) the surface number density of HyLIRGs is >0.17 deg-2. A large fraction (˜73%) of IR-bright DOGs with i - [22] > 7.5 show {L}{{IR}} > 1013 L⊙, and the DOG criterion we adopted could be independently effective against the “W1W2-dropout method,” based on four WISE bands, for searching hyperluminous IR populations of galaxies.

  8. GOODS-HERSCHEL MEASUREMENTS OF THE DUST ATTENUATION OF TYPICAL STAR-FORMING GALAXIES AT HIGH REDSHIFT: OBSERVATIONS OF ULTRAVIOLET-SELECTED GALAXIES AT z ∼ 2

    We take advantage of the sensitivity and resolution of the Herschel Space Observatory at 100 and 160 μm to directly image the thermal dust emission and investigate the infrared luminosities (LIR) and dust obscuration of typical star-forming (L*) galaxies at high redshift. Our sample consists of 146 UV-selected galaxies with spectroscopic redshifts 1.5 ≤ zspec UV ∼> 1010 L☉ at z ∼ 2 are luminous infrared galaxies with a median LIR = (2.2 ± 0.3) × 1011 L☉. Their median ratio of LIR to rest-frame 8 μm luminosity (L8) is LIR/L8 = 8.9 ± 1.3 and is ≈80% larger than that found for most star-forming galaxies at z ∼IR/L8 ratio may be tied to the trend of larger infrared luminosity surface density for z ∼> 2 galaxies relative to those at lower redshift. Typical galaxies at 1.5 ≤ z IR/LUV = 7.1 ± 1.1, which corresponds to a dust correction factor, required to recover the bolometric star formation rate (SFR) from the unobscured UV SFR, of 5.2 ± 0.6. This result is similar to that inferred from previous investigations of the UV, Hα, 24 μm, radio, and X-ray properties of the same galaxies studied here. Stacking in bins of UV slope (β) implies that L* galaxies with redder spectral slopes are also dustier and that the correlation between β and dustiness is similar to that found for local starburst galaxies. Hence, the rest-frame ≅ 30 and 50 μm fluxes validate on average the use of the local UV attenuation curve to recover the dust attenuation of typical star-forming galaxies at high redshift. In the simplest interpretation, the agreement between the local and high-redshift UV attenuation curves suggests a similarity in the dust production and stellar and dust geometries of starburst galaxies over the last 10 billion years.

  9. Relativistic Iron K Emission and Absorption in the Seyfert 1.9 Galaxy MCG-05-23-16

    Braito, V.; Reeves, J. N.; Dewangan, G. C.; George, I.; Griffiths, R.; Markowitz, A.; Nandra, K.; Porquet, D.; Ptak, A.; Turner, T. J.; Yaqoob, T.; Weaver, K.

    2007-01-01

    We present the results of the simultaneous deep XMM-Newton and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a relativistically broadened iron Kalpha line. We detected a narrow sporadic absorption line at 7.7 keV which appears to be variable on a time-scale of 20 ksec. If associated with FeXXVI this absorption is indicative of a possible variable high ionization, high velocity outflow. The time averaged spectral analysis shows that the iron K-shell complex is best modeled with an unresolved narrow emission component (FWHM less than 5000 kilometers per second, EW approx. 60 eV) plus a broad component. This latter component has FWHM approx. 44000 kilometers per second, an EW approx. 50 eV and its profile is well described with an emission line originating from the accretion disk viewed with an inclination angle approx. 40 deg. and with the emission arising from within a few tens of gravitational radii of the central black hole. The time-resolved spectral analysis of the XMM-Newton EPIC-pn spectrum shows that both the narrow and broad components of the Fe K emission line appear to be constant within the errors. The analysis of the XMM-Newton/RGS spectrum reveals that the soft X-ray emission of MCG-5-23-16 is likely dominated by several emission lines superimposed on an unabsorbed scattered power-law continuum. The lack of strong Fe L shell emission together with the detection of a strong forbidden line in the O VII triplet supports a scenario where the soft X ray emission lines are produced in a plasma photoionized by the nuclear emission.

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

    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...

  11. Photometric Selection of a Luminous Red Galaxy Catalog with $z\\geq0.55$

    Núñez, Carolina; Ho, Shirley

    2016-01-01

    We present the development of a photometrically selected Luminous Red Galaxy (LRG) catalog at redshift $z\\geq 0.55$. LRG candidates are selected using infrared/optical color-color cuts, optimized using ROC curve analysis, with optical data from Sloan Digital Sky Survey (SDSS) and infrared data from "unWISE" forced photometry derived from the Wide-field Infrared Survey Explorer (WISE). The catalog contains 16,191,145 objects, selected over the full SDSS DR10 footprint. The redshift distribution of the resulting catalogs is estimated using spectroscopic redshifts from the DEEP2 Galaxy Redshift Survey and photometric redshifts from COSMOS. Restframe $U-B$ colors from DEEP2 are used to estimate LRG selection efficiency. In DEEP2, the resulting catalog has average redshift $z=0.65$, with standard deviation $\\sigma = 2.0$, and average restframe $U-B=1.0$, with $\\sigma=0.27$. In COSMOS, the resulting catalog has average redshift $z=0.60$, with standard deviation $\\sigma = 1.8$. We allow for 35% contamination from bl...

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

    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.

  13. Relativistic Iron K Emission and absorption in the Seyfert 1.9 galaxy MCG-5-23-16

    Braito, V; Dewangan, G C; George, I; Griffiths, R E; Markowitz, A; Nandra, K; Porquet, D; Ptak, A; Turner, T J; Yaqoob, T; Weaver, K

    2007-01-01

    We present the results of the simultaneous deep XMM and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a relativistically broadened iron K-alpha line. The time averaged spectral analysis shows that the iron K-shell complex is best modeled with an unresolved narrow emission component (FWHM < 5000 km/s, EW ~ 60 eV) plus a broad component. This latter component has FWHM ~ 44000 km/s and EW ~ 50 eV. Its profile is well described by an emission line originating from an accretion disk viewed with an inclination angle ~ 40^\\circ and with the emission arising from within a few tens of gravitational radii of the central black hole. The time-resolved spectral analysis of the XMM EPIC-pn spectrum shows that both the narrow and broad components of the Fe K emission line appear to be constant in time within the errors. We detected a narrow sporadic absorption line at 7.7 keV which appears to be variable on a time-scale of 20 ksec. If associa...

  14. Enhanced Microwave Absorption Properties of Carbon Black/Silicone Rubber Coating by Frequency-Selective Surface

    Yang, Zhaoning; Luo, Fa; Gao, Lu; Qing, Yuchang; Zhou, Wancheng; Zhu, Dongmei

    2016-06-01

    A square frequency-selective surface (FSS) design has been employed to improve the microwave absorption properties of carbon black/silicone rubber (CBSR) composite coating. The FSS is placed on the surface of the CBSR coating. The effects of FSS design parameters on the microwave absorption properties of the CBSR coating have been investigated, including the size and period of the FSS design, and the thickness and permittivity of the coating. Simulation results indicate that the absorption peak for the CBSR coating alone is related to its thickness and electromagnetic parameters, while the combination of the CBSR coating with a FSS can exhibit a new absorption peak in the reflection curve; the frequency of the new absorption peak is determined by the resonance of the square FSS design and tightly depends on the size of the squares, with larger squares in the FSS design leading to a lower frequency of the new absorption peak. The enhancement of the absorption performance depends on achievement of a new absorption peak using a suitable␣size and period of the FSS design. In addition, the FSS design has a stable␣frequency response for both transverse electromagnetic (TE) and transverse magnetic (TM) polarizations as the incident angle varies from 0° to 40°. The optimized results indicate that the bandwidth with reflection loss below -5 dB can encompass the whole frequency range from 8 GHz to 18 GHz for thickness of the CBSR coating of only 1.8 mm. The simulation results are confirmed by experiments.

  15. AKARI NEAR-INFRARED SPECTROSCOPY OF SDSS-SELECTED BLUE EARLY-TYPE GALAXIES

    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.

  16. AKARI Near-Infrared Spectroscopy of SDSS-Selected Blue Early-Type Galaxies

    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...

  17. Properties of Radio-Selected Broad Absorption-Line Quasars from the FIRST Survey

    Becker, R. H.; White, R L; Gregg, M. D.; Brotherton, M. S.; Laurent-Meuleisen, S. A.; Arav, N.

    2000-01-01

    In a spectroscopic follow-up to the VLA FIRST survey, the FIRST Bright Quasar Survey (FBQS) has found 29 radio-selected broad absorption line (BAL) quasars. This sample provides the first opportunity to study the properties of radio-selected BAL quasars. Contrary to most previous studies, we establish that a significant population of radio-loud BAL quasars exists. Radio-selected BAL quasars display compact radio morphologies and possess both steep and flat radio spectra. Quasars with low-ioni...

  18. HOST GALAXIES, CLUSTERING, EDDINGTON RATIOS, AND EVOLUTION OF RADIO, X-RAY, AND INFRARED-SELECTED AGNs

    We explore the connection between different classes of active galactic nuclei (AGNs) and the evolution of their host galaxies, by deriving host galaxy properties, clustering, and Eddington ratios of AGNs selected in the radio, X-ray, and infrared (IR) wavebands. We study a sample of 585 AGNs at 0.25 -1 Mpc, and derive typical dark matter halo masses. We find that: (1) radio AGNs are mainly found in luminous red sequence galaxies, are strongly clustered (with M halo ∼ 3 x 1013 h -1 M sun), and have very low Eddington ratios λ ∼-3; (2) X-ray-selected AGNs are preferentially found in galaxies that lie in the 'green valley' of color-magnitude space and are clustered similar to the typical AGES galaxies (M halo ∼ 1013 h -1 M sun), with 10-3 ∼halo ∼12 h -1 M sun), and have λ>10-2. We interpret these results in terms of a simple model of AGN and galaxy evolution, whereby a 'quasar' phase and the growth of the stellar bulge occurs when a galaxy's dark matter halo reaches a critical mass between ∼1012 and 1013 M sun. After this event, star formation ceases and AGN accretion shifts from radiatively efficient (optical- and IR-bright) to radiatively inefficient (optically faint, radio-bright) modes.

  19. AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies

    We use deep and wide near infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra Space Telescope imaging to investigate the nature of galaxies that are red in NIR colors. We locate these 'distant red galaxies' (DRGs) through the color cut (J - K)vega > 2.3 over 0.7 deg2, where we find 1010 DRG candidates down to Ks = 20.5. We combine 95 high quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J - K)vega > 2.3 galaxies with Ks 9 - 1012 M· , but with most z > 2 systems massive with M* > 1011 M·. HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact (57%), and the remainder edge-on spirals (7%), and peculiar galaxies (29%). The DRGs at z < 1.4 with high quality spectroscopic redshifts are generally compact, with small half-light radii, and span a range in rest-frame optical properties. The spectral energy distributions for these objects differ from higher redshift DRGs: they are bluer by one magnitude in observed (I - J) color. A pure IR color selection of high redshift populations is not sufficient to identify unique populations, and other colors, or spectroscopic redshifts are needed to produce homogeneous samples

  20. Clustering properties of galaxies selected in stellar mass: Breaking down the link between luminous and dark matter in massive galaxies from z=0 to z=2

    Foucaud, S; Hartley, W G; Lane, K P; Bamford, S P; Almaini, O; Bundy, K

    2010-01-01

    We present a study on the clustering of a stellar mass selected sample of 18,482 galaxies with stellar masses M*>10^10M(sun) at redshifts 0.410^13M(sun) we find that this ratio is <0.02, m uch lower than the universal baryonic mass fraction. We show that the remaining baryonic mass is included partially in stars within satellite galaxies in these haloes, and as diffuse hot and warm gas. We also find that, at a fixed stellar mass, the stellar-to-total-mass ratio increases at lower redshifts. This suggests that galaxies at a fixed stellar mass form later in lower mass dark matter haloes, and earlier in massive haloes. We interpret this as a "halo downsizing" effect, however some of this evolution could be attributed to halo assembly bias.

  1. Halpha3: an Halpha imaging survey of HI selected galaxies from ALFALFA. IV. The structure of galaxies in the Local and Coma Superclusters

    Fossati, Matteo; Savorgnan, Giulia; Fumagalli, Michele; Boselli, Alessandro; Gutierrez, Leonel; Toledo, Hector Hernandez; Giovanelli, Riccardo; Haynes, Martha P

    2013-01-01

    We present the analysis of the galaxy structural parameters from Halpha3, an Halpha narrow-band imaging follow-up survey of ~800 galaxies selected from the HI ALFALFA Survey in the Local and Coma Superclusters. Taking advantage of Halpha3 which provides the complete census of the recent star-forming, HI-rich galaxies in the local universe, we aim to investigate the structural parameters of both the young (1 Gyr) stellar populations. By comparing the sizes of these stellar components we investigated the spatial scale on which galaxies are growing at the present cosmological epoch and the role of the environment in quenching the star-formation activity. We computed the concentration, asymmetry, and clumpiness structural parameters. To quantify the sizes we computed half-light radii and a new parameter dubbed EW/r. The concentration index computed in the r band depends on the stellar mass and on the Hubble type, these variables being related since most massive galaxies are bulge dominated thus most concentrated....

  2. First results from the VIRIAL survey: the stellar content of $UVJ$-selected quiescent galaxies at $1.5 < z < 2$ from KMOS

    Mendel, J Trevor; Bender, Ralf; Beifiori, Alessandra; Chan, Jeffrey; Fossati, Matteo; Wilman, David J; Bandara, Kaushala; Brammer, Gabriel B; Schreiber, Natascha M Förster; Galametz, Audrey; Kulkarni, Sandesh; Momcheva, Ivelina G; Nelson, Erica J; van Dokkum, Pieter G; Whitaker, Katherine E; Wuyts, Stijn

    2015-01-01

    We investigate the stellar populations of 25 massive, galaxies ($\\log[M_\\ast/M_\\odot] \\geq 10.9$) at $1.5 < z < 2$ using data obtained with the K-band Multi-Object Spectrograph (KMOS) on the ESO VLT. Targets were selected to be quiescent based on their broadband colors and redshifts using data from the 3D-HST grism survey. The mean redshift of our sample is $\\bar{z} = 1.75$, where KMOS YJ-band data probe age- and metallicity-sensitive absorption features in the rest-frame optical, including the $G$ band, Fe I, and high-order Balmer lines. Fitting simple stellar population models to a stack of our KMOS spectra, we derive a mean age of $1.03^{+0.13}_{-0.08}$ Gyr. We confirm previous results suggesting a correlation between color and age for quiescent galaxies, finding mean ages of $1.22^{+0.56}_{-0.19}$ Gyr and $0.85^{+0.08}_{-0.05}$ Gyr for the reddest and bluest galaxies in our sample. Combining our KMOS measurements with those obtained from previous studies at $0.2 < z < 2$ we find evidence for a...

  3. The Gaseous Extent of Galaxies and the Origin of Lya Absorption Systems. V. Optical and Near-Infrared Photometry of Lya-absorbing Galaxies at z < 1

    Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Webb, John K.; Barcons, Xavier

    2001-01-01

    (Abridged) We present results of a program to obtain and analyze HST WFPC2 images and ground-based images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We confirm and improve the results presented by Lanzetta et al. (1995) and Chen et al. (1998) that (1) extended gaseous envelopes are a common and generic feature of galaxies of a wide range of luminosity and morphological type, (2) the extent of tenuous gas (N(H I) ...

  4. Minor vs Major Mergers: The Stellar Mass Growth of Massive Galaxies from z=3 using Number Density Selection Techniques

    Ownsworth, Jamie R; Mortlock, Alice; Hartley, William G; Almaini, Omar; Duncan, Ken; Mundy, Carl J

    2014-01-01

    We present a study on the stellar mass growth of the progenitors of local massive galaxies with a variety of number density selections with $n\\le1\\times10^{-4}\\,\\rm{Mpc^{-3}}$ (corresponding to $M_*=10^{11.24}\\rm{M_{\\odot}}$ at z=0.3) in the redshift range $0.3select the progenitors of massive galaxies using a constant number density selection, and one which is adjusted to account for major mergers. We find that the progenitors of massive galaxies grow by a factor of four in total stellar mass over this redshift range. On average the stellar mass added via the processes of star formation, major and minor mergers account for $24\\pm8\\%$, $17\\pm15\\%$ and $34\\pm14\\%$, respectively, of the total galaxy stellar mass at $z=0.3$. Therefore $51\\pm20\\%$ of the total stellar mass in massive galaxies at $z=0.3$ is created externally to their z=3 progenitors. We explore the implication of these results on the cold gas accretion rate and size evolution of the progenitors of most massive galaxies over the ...

  5. Material selection for elastic energy absorption in origami-inspired compliant corrugations

    Elastic absorption of kinetic energy and distribution of impact forces are required in many applications. Recent attention to the potential for using origami in engineering may provide new methods for energy absorption and force distribution. A three-stage strategy is presented for selecting materials for such origami-inspired designs that can deform to achieve a desired motion without yielding, absorb elastic strain energy, and be lightweight or cost effective. Two material indices are derived to meet these requirements based on compliant mechanism theory. Finite element analysis is used to investigate the effects of the material stiffness in the Miura-ori tessellation on its energy absorption and force distribution characteristics compared with a triangular wave corrugation. An example is presented of how the method can be used to select a material for a general energy absorption application of the Miura-ori. Whereas the focus of this study is the Miura-ori tessellation, the methods developed can be applied to other tessellated patterns used in energy absorbing or force distribution applications. (paper)

  6. Organic-inorganic hybrid gels for the selective absorption of oils from water.

    Ozan Aydin, Gulsah; Bulbul Sonmez, Hayal

    2016-06-01

    Organic-inorganic hybrid gels were synthesized by the condensation of a linear aliphatic diol (1,8-octanediol) and altering the chain length of the alkyltriethoxysilanes (from ethyltriethoxysilane to hexadecyltrimethoxysilane) through a bulk polymerization process without using any initiator, activator, catalyst, or solvent for the selective removal of oils from water. Fourier transform infrared spectroscopy (FTIR) and solid-state (13)C and (29)Si cross-polarization magic-angle spinning nuclear magnetic resonance (CPMAS NMR) were used for the structural analysis of hybrid gels. Thermal properties of the hybrid gels were determined by thermogravimetric analysis (TGA). Oil absorbency of organic-inorganic hybrid gels was determined by oil absorption tests. The results showed that hybrid gels have high and fast absorption capacities and excellent reusability. Good selectivity, high thermal stability, low density, and excellent recyclability for the oil removal give the material potential applications. PMID:26939691

  7. Detection of HI 21 cm-line absorption in the Warm Neutral Medium and in the Outer Arm of the Galaxy

    Dwarakanath, K S; Goss, W M

    2001-01-01

    Using the Westerbork Synthesis Radio Telescope, we have detected HI 21 cm-line absorption in the Warm Neutral Medium of the Galaxy toward the extragalactic source 3C147. This absorption, at an LSR velocity of -29+/-4 km/s with a full width at half maximum of 53+/-6 km/s, is associated with the Perseus Arm of the Galaxy. The observed optical depth is (1.9+/-0.2)*10**(-3). The estimated spin temperature of the gas is 3600+/-360 K. The volume density is 0.4 per cc assuming pressure equilibrium. Toward two other sources, 3C273 and 3C295, no wide HI 21 cm-line absorption was detected. The highest of the 3sigma lower limits on the spin temperature of the Warm Neutral Medium is 2600 K. In addition, we have also detected HI 21 cm-line absorption from high velocity clouds in the Outer Arm toward 3C147 and 3C380 at LSR velocities of -117.3, -124.5 and -113.7 km/s respectively. We find two distinct temperature components in the high velocity clouds with spin temperatures of greater than 1000 K and less than 200 K, respe...

  8. Photometric Selection of Emission Line Galaxies, Clustering Analysis and a Search for the ISW effect

    Bielby, Rich; Sawangwit, U; Croom, S M; Ross, Nicholas P; Wake, D A

    2009-01-01

    We investigate the use of simple colour cuts applied to the SDSS optical imaging to perform photometric selections of emission line galaxies out to z<1. From colour-cuts using the SDSS g, r and i bands, we obtain mean photometric redshifts of z=0.32+-0.08, z=0.44+-0.12 and z=0.65+-0.21. We further calibrate our high redshift selection using spectroscopic observations with the AAOmega spectrograph on the 4m Anglo-Australian Telescope (AAT), observing ~50-200 galaxy candidates in 4 separate fields. With just 1-hour of integration time and with seeing of ~1.6", we successfully determined redshifts for ~65% of the targeted candidates. We calculate the angular correlation functions of the samples and find correlation lengths of r0=2.64 h-1 Mpc, r0=3.62 h-1 Mpc and r0=5.88 h-1 Mpc for the low, mid and high redshift samples respectively. Comparing these results with predicted dark matter clustering, we estimate the bias parameter for each sample to be b=0.70, b=0.92 and b=1.46. We calculate the 2-point redshift-s...

  9. The Evolution of the Field and Cluster Morphology-Density Relation for Mass-Selected Samples of Galaxies

    Van der Wel, A; Franx, M; Illingworth, G D; Postman, M P; Kelson, D D; Labbé, I; Blakeslee, J P; Ford, H C

    2007-01-01

    The Sloan Digital Sky Survey (SDSS) and photometric/spectroscopic surveys in the GOODS-South field (the Chandra Deep Field-South, CDFS) are used to construct volume-limited, stellar mass-selected samples of galaxies at redshifts 02.5. The fraction of E+S0 galaxies is 43+/-3%$ at z~0.03 and 48+/-7% at z~0.8, i.e., it has not changed significantly since z~0.8. When combined with recent results for cluster galaxies in the same redshift range, we find that the morphology-density relation for galaxies more massive than 0.5M* has remained constant since at least z~0.8. This implies that galaxies evolve in mass, morphology and density such that the morphology-density relation does not change. In particular, the decline of star formation activity and the accompanying increase in the stellar mass density of red galaxies since z~1 must happen without large changes in the early-type galaxy fraction in a given environment.

  10. Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

    Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Gandhi, P.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Madsen, K. K.; Ptak, A. F.; Rigby, Jane Rebecca; Risaliti, G.; Saz, C.; Stern, D.; Veilleux, S.; Walton, D. J.; Wik, D. R.; Zhang, W. W.

    2014-01-01

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin N(sub H) approx. 1.2(sup +0.3) sub-0.3) x 10(exp 23) / sq cm) column. The intrinsic X-ray luminosity L(sub 0.5-30 Kev) approx. 1.0 x 10(exp 43) erg /s) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is approx. 0.03% compared to the typical values of 2-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope alpha(sub 0X) approx. -1.7. It is a local example of a low-ionization broad absorption line (LoBAL) quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  11. The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Near-Infrared Imaging and the Selection of Distant Galaxies

    Quadri, R; van Dokkum, P; Gawiser, E; Franx, M; Lira, P; Rudnick, G; Urry, C M; Maza, J; Kriek, M; Barrientos, L F; Blanc, G; Castander, F J; Christlein, D; Coppi, P S; Hall, P B; Herrera, D; Infante, L; Taylor, E N; Treister, E; Willis, J P; Quadri, Ryan; Marchesini, Danilo; Dokkum, Pieter van; Gawiser, Eric; Franx, Marijn; Lira, Paulina; Rudnick, Gregory; Maza, Jose; Kriek, Mariska; Blanc, Guillermo; Castander, Francisco J.; Christlein, Daniel; Coppi, Paolo S.; Hall, Patrick B.; Herrera, David; Infante, Leopoldo; Taylor, Edward N.; Treister, Ezequiel; Willis, Jon P.

    2006-01-01

    We present deep near-infrared JHK imaging of four 10'x10' fields. The observations were carried out as part of the Multiwavelength Survey by Yale-Chile (MUSYC) with ISPI on the CTIO 4m telescope. The typical point source limiting depths are J~22.5, H~21.5, and K~21 (5sigma; Vega). The effective seeing in the final images is ~1.0". We combine these data with MUSYC UBVRIz imaging to create K-selected catalogs that are unique for their uniform size, depth, filter coverage, and image quality. We investigate the rest-frame optical colors and photometric redshifts of galaxies that are selected using common color selection techniques, including distant red galaxies (DRGs), star-forming and passive BzKs, and the rest-frame UV-selected BM, BX, and Lyman break galaxies (LBGs). These techniques are effective at isolating large samples of high redshift galaxies, but none provide complete or uniform samples across the targeted redshift ranges. The DRG and BM/BX/LBG criteria identify populations of red and blue galaxies, r...

  12. A Photometrically and Spectroscopically Confirmed Population of Passive Spiral Galaxies

    Fraser-McKelvie, Amelia; Pimbblet, Kevin A; Dolley, Tim; Crossett, Jacob P; Bonne, Nicolas J

    2016-01-01

    We have identified a population of passive spiral galaxies from photometry and integral field spectroscopy. We selected z<0.035 spiral galaxies that have WISE colours consistent with little mid-infrared emission from warm dust. Matched aperture photometry of 51 spiral galaxies in ultraviolet, optical and mid-infrared show these galaxies have colours consistent with passive galaxies. Six galaxies form a spectroscopic pilot study and were observed using the Wide-Field Spectrograph (WiFeS) to check for signs of nebular emission from star formation. We see no evidence of substantial nebular emission found in previous red spiral samples. These six galaxies possess absorption-line spectra with 4000\\AA\\ breaks consistent with an average luminosity-weighted age of 2.3 Gyr. Our photometric and IFU spectroscopic observations confirm the existence of a population of local passive spiral galaxies, implying that transformation into early-type morphologies is not required for the quenching of star formation.

  13. Mapping kiloparsec-scale structures in the extended H I disc of the galaxy UGC 000439 by H I 21-cm absorption

    Dutta, R.; Gupta, N.; Srianand, R.; O'Meara, J. M.

    2016-03-01

    We study the properties of H I gas in the outer regions (˜2r25) of a spiral galaxy, UGC 00439 (z = 0.017 69), using H I 21-cm absorption towards different components of an extended background radio source, J0041-0043 (z = 1.679). The radio source exhibits a compact core coincident with the optical quasar and two lobes separated by ˜7 kpc, all at an impact parameter ˜25 kpc. The H I 21-cm absorption detected towards the southern lobe is found to extend over ˜2 kpc2. The absorbing gas shows sub-kpc-scale structures with the line-of-sight velocities dominated by turbulent motions. Much larger optical depth variations over 4-7 kpc scale are revealed by the non-detection of H I 21-cm absorption towards the radio core and the northern lobe, and the detection of Na I and Ca II absorption towards the quasar. This could reflect a patchy distribution of cold gas in the extended H I disc. We also detect H I 21-cm emission from UGC 00439 and two other galaxies within ˜150 kpc to it, that probably form an interacting group. However, no H I 21-cm emission from the absorbing gas is detected. Assuming a linear extent of ˜4 kpc, as required to cover both the core and the southern lobe, we constrain the spin temperature ≲ 300 K for the absorbing gas. The kinematics of the gas and the lack of signatures of any ongoing in situ star formation are consistent with the absorbing gas being at the kinematical minor axis and corotating with the galaxy. Deeper H I 21-cm observations would help to map in greater detail both the large- and small-scale structures in the H I gas associated with UGC 00439.

  14. Disrupted Stars in Unusual Galaxies

    Kohler, Susanna

    2016-03-01

    Tidal disruption events (TDEs) occur when a star passes a little too close to a supermassive black hole at the center of a galaxy. Tidal forces from the black hole cause the passing star to be torn apart, resulting in a brief flare of radiation as the stars material accretes onto the black hole. A recent study asks the following question: do TDEs occur most frequently in an unusual type of galaxy?A Trend in DisruptionsSo far, we have data from eight candidate TDEs that peaked in optical and ultraviolet wavelengths. The spectra from these observations have shown an intriguing trend: many of these TDEs host galaxies exhibit weak line emission (indicating little or no current star-formation activity), and yet they show strong Balmer absorption lines (indicating star formation activity occurred within the last Gyr). These quiescent, Balmer-strong galaxies likely underwent a period of intense star formation that recently ended.To determine if TDEs are overrepresented in such galaxies, a team of scientists led by Decker French (Steward Observatory, University of Arizona) has quantified the fraction of galaxies in the Sloan Digital Sky Survey (SDSS) that exhibit similar properties to those of TDE hosts.Quantifying OverrepresentationSpectral characteristics of SDSS galaxies (gray) and TDE candidate host galaxies (colored points): line emission vs. Balmer absorption. The lower right-hand box identifies thequiescent, Balmer-strong galaxies which contain most TDE events, yet are uncommon among the galaxy sample as a whole. Click for a better look! [French et al. 2016]French and collaborators compare the optical spectra of the TDE host galaxies to those of nearly 600,000 SDSS galaxies, using two different cutoffs for the Balmer absorption the indicator of past star formation. Their strictest cut, filtering for very high Balmer absorption, selected only 0.2% of the SDSS galaxies, yet 38% of the TDEs are hosted in such galaxies. Using a more relaxed cutoff selects 2.3% of

  15. Intercalation of IR absorber into layered double hydroxides: Preparation, thermal stability and selective IR absorption

    Zhu, Haifeng; Tang, Pinggui [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Feng, Yongjun, E-mail: yjfeng@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Lijing; Li, Dianqing [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer PMIDA anions were intercalated into Mg{sub 2}Al-NO{sub 3} LDH by anion-exchange method. Black-Right-Pointing-Pointer The prepared material has highly selective IR absorption property in 9-11 {mu}m. Black-Right-Pointing-Pointer The obtained material has practical applications as heat-retaining additive. -- Abstract: N-phosphonomethyl aminodiacetic acid (PMIDA) was intercalated into the interlayer spacing of layered double hydroxides (LDH) by an anion-exchange method. The intercalated LDHs were characterized by various techniques such as powder X-ray diffraction (XRD), FT-IR spectroscopy, elemental analysis and simultaneous thermogravimetric and mass spectrometry (TG-MS) in details. The results show the formation of Mg{sub 2}Al-PMIDA LDH based on the expansion of d-spacing from 0.89 nm to 1.22 nm and the disappearance of the characteristic IR absorption band at 1384 cm{sup -1} for NO{sub 3}{sup -} anions. The incorporation of Mg{sub 2}Al-PMIDA LDH into the low density polyethylene (LDPE) as an additive enhances the selectivity of IR absorption in the main wavelength region 9-11 {mu}m for radiant heat loss at night. Mg{sub 2}Al-PMIDA LDH as a heat-retaining additive has practical application in agricultural plastic films.

  16. Radio halos in SZ-selected clusters of galaxies: the making of a halo?

    Bonafede, A; Brüggen, M; Vazza, F; Basu, K; Sommer, M; Ebeling, H; de Gasperin, F; Röttgering, H J A; van Weeren, R J; Cassano, R

    2015-01-01

    Radio halos are synchrotron radio sources detected in some massive galaxy clusters. Their Mpc-size indicates that (re)acceleration processes are taking place in the host cluster. X-ray catalogues of galaxy clusters have been used in the past to search for radio halos and to understand their connection with cluster-cluster mergers and with the thermal component of the intra-cluster medium. More recently, the Sunyaev-Zel'dovich effect has been proven to be a better route to search for massive clusters in a wider redshift range. With the aim of discovering new radio halos and understanding their connection with cluster-cluster mergers, we have selected from the Planck Early source catalog the most massive clusters, and we have observed with the Giant Metrewave Radio Telescope at 323 MHz those objects for which deep observations were not available. We have discovered new peculiar radio emission in three of the observed clusters finding: (i) a radio halo in the cluster RXCJ0949.8+1708; (ii) extended emission in Ab...

  17. Photometric redshifts and clustering of emission line galaxies selected jointly by DES and eBOSS

    Jouvel, S; Comparat, J; Carnero, A; Camacho, H; Abdalla, F B; Kneib, J-P; Merson, A; Lima, M; Sobreira, F; da Costa, Luiz; Prada, F; Zhu, G B; Benoit-Levy, A; De La Macora, A; Kuropatkin, N; Lin, H; Abbott, T M C; Allam, S; Banerji, M; Bertin, E; Brooks, D; Capozzi, D; Kind, M Carrasco; Carretero, J; Castander, F J; Cunha, C E; Desai, S; Doel, P; Eifler, T F; Estrada, J; Neto, A Fausti; 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; Lahav, O; Li, T S; Maia, M A G; March, M; Marshall, J L; Miquel, R; Percival, W J; Plazas, A A; Reil, K; Romer, A K; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Santiago, B; Scarpine, V; Sevilla-Noarbe, I; Santos, M Soares; Suchyta, E; Tarle, G; Thaler, J; Thomas, D; Walker, A; Zhang, Y

    2015-01-01

    We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71\\% and 68\\% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a mean redshift of 0.8 and 0.87, with 15 and 13\\% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6galaxy bias averaged on scales of 1 and 10~...

  18. Herschel-ATLAS: The Surprising Diversity of Dust-Selected Galaxies in the Local Submillimetre Universe

    Clark, Christopher J R; Gomez, Haley L; Maddox, Steven; De Vis, Pieter; Smith, Matthew W L; Eales, Steven A; Baes, Maarten; Bendo, George J; Bourne, Nathan; Driver, Simon P; Dye, Simon; Furlanetto, Christina; Ivison, Rob J; Schofield, Simon P; Robotham, Aaron S G; Rowlands, Kate; Vlahakis, Catherine; van der Werf, Paul; Wright, Angus; de Zotti, Gianfranco

    2015-01-01

    We present the properties of the first 250um blind sample of nearby galaxies (15 < D < 46 Mpc), from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). Herschel's sensitivity allows us to probe the faint end of the dust luminosity function for the first time, spanning a range of stellar mass (7.4 < log$_{10}$ M$_{\\star}$ < 11.3 M$_{\\odot}$), star formation activity (-11.8 < log$_{10}$ SSFR < -8.9 yr$^{-1}$), and gas fraction (3-96 per cent). Our representative sample of the local dusty Universe reveals great diversity, with 0.6 < FUV-Ks < 7.0 and representation across the Hubble Sequence. The median cold dust temperature is 14.6 K, colder than that in the HRS (18.5 K) and Planck ERCSC (17.7 K). The mean dust-to-stellar mass ratio (Md/M$_{\\star}$) in our sample is higher than in these surveys by a factor of 3.7 and 1.8 respectively. Counter-intuitively, we find that the more dust rich a galaxy (defined by Md/M$_{\\star}$), the lower its UV attenuation. Dust selection also ...

  19. LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

    Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

    2014-12-20

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

  20. HST Emission Line Galaxies at z ~ 2: Comparing Physical Properties of Lyman Alpha and Optical Emission Line Selected Galaxies

    Hagen, Alex; Behrens, Christoph; Ciardullo, Robin; Gebhardt, Henry S Grasshorn; Gronwall, Caryl; Bridge, Joanna S; Fox, Derek B; Schneider, Donald P; Trump, Jonathan R; Blanc, Guillermo A; Chiang, Yi-Kuan; Chonis, Taylor S; Finkelstein, Steven L; Hill, Gary J; Jogee, Shardha; Gawiser, Eric

    2015-01-01

    We compare the physical and morphological properties of z ~ 2 Lyman-alpha emitting galaxies (LAEs) identified in the HETDEX Pilot Survey and narrow band studies with those of z ~ 2 optical emission line galaxies (oELGs) identified via HST WFC3 infrared grism spectroscopy. Both sets of galaxies extend over the same range in stellar mass (7.5 < logM < 10.5), size (0.5 < R < 3.0 kpc), and star-formation rate (~1 < SFR < 100). Remarkably, a comparison of the most commonly used physical and morphological parameters -- stellar mass, half-light radius, UV slope, star formation rate, ellipticity, nearest neighbor distance, star formation surface density, specific star formation rate, [O III] luminosity, and [O III] equivalent width -- reveals no statistically significant differences between the populations. This suggests that the processes and conditions which regulate the escape of Ly-alpha from a z ~ 2 star-forming galaxy do not depend on these quantities. In particular, the lack of dependence on ...

  1. Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

    Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

    2016-06-01

    We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}ȯ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed

  2. X-ray-selected galaxy groups in Boötes

    Vajgel, Bruna; Lopes, Paulo A. A. [Observatório do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Jones, Christine; Forman, William R.; Murray, Stephen S.; Goulding, Andrew; Andrade-Santos, Felipe [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-10-10

    We present the X-ray and optical properties of the galaxy groups selected in the Chandra X-Boötes survey. We used follow-up Chandra observations to better define the group sample and their X-ray properties. Group redshifts were measured from the AGN and Galaxy Evolution Survey spectroscopic data. We used photometric data from the NOAO Deep Wide Field Survey to estimate the group richness (N {sub gals}) and the optical luminosity (L {sub opt}). Our final sample comprises 32 systems at z < 1.75 with 14 below z = 0.35. For these 14 systems, we estimate velocity dispersions (σ {sub gr}) and perform a virial analysis to obtain the radii (R {sub 200} and R {sub 500}) and total masses (M {sub 200} and M {sub 500}) for groups with at least 5 galaxy members. We use the Chandra X-ray observations to derive the X-ray luminosity (L{sub X} ). We examine the performance of the group properties σ{sub gr}, L {sub opt}, and L{sub X} , as proxies for the group mass. Understanding how well these observables measure the total mass is important to estimate how precisely the cluster/group mass function is determined. Exploring the scaling relations built with the X-Boötes sample and comparing these with samples from the literature, we find a break in the L{sub X} -M {sub 500} relation at approximately M {sub 500} = 5 × 10{sup 13} M {sub ☉} (for M {sub 500} > 5 × 10{sup 13} M {sub ☉}, M{sub 500}∝L{sub X}{sup 0.61±0.02}, while for M {sub 500} ≤ 5 × 10{sup 13} M {sub ☉}, M{sub 500}∝L{sub X}{sup 0.44±0.05}). Thus, the mass-luminosity relation for galaxy groups cannot be described by the same power law as galaxy clusters. A possible explanation for this break is the dynamical friction, tidal interactions, and projection effects that reduce the velocity dispersion values of the galaxy groups. By extending the cluster luminosity function to the group regime, we predict the number of groups that new X-ray surveys, particularly eROSITA, will detect. Based on our cluster

  3. Selective spatial damping of propagating kink waves due to resonant absorption

    Terradas, J.; Goossens, M.; Verth, G.

    2010-12-01

    Context. There is observational evidence of propagating kink waves driven by photospheric motions. These disturbances, interpreted as kink magnetohydrodynamic (MHD) waves are attenuated as they propagate upwards in the solar corona. Aims: We show that resonant absorption provides a simple explanation to the spatial damping of these waves. Methods: Kink MHD waves are studied using a cylindrical model of solar magnetic flux tubes, which includes a non-uniform layer at the tube boundary. Assuming that the frequency is real and the longitudinal wavenumber complex, the damping length and damping per wavelength produced by resonant absorption are analytically calculated in the thin tube (TT) approximation, valid for coronal waves. This assumption is relaxed in the case of chromospheric tube waves and filament thread waves. Results: The damping length of propagating kink waves due to resonant absorption is a monotonically decreasing function of frequency. For kink waves with low frequencies, the damping length is exactly inversely proportional to frequency, and we denote this as the TGV relation. When moving to high frequencies, the TGV relation continues to be an exceptionally good approximation of the actual dependency of the damping length on frequency. This dependency means that resonant absorption is selective as it favours low-frequency waves and can efficiently remove high-frequency waves from a broad band spectrum of kink waves. The efficiency of the damping due to resonant absorption depends on the properties of the equilibrium model, in particular on the width of the non-uniform layer and the steepness of the variation in the local Alfvén speed. Conclusions: Resonant absorption is an effective mechanism for the spatial damping of propagating kink waves. It is selective because the damping length is inversely proportional to frequency so that the damping becomes more severe with increasing frequency. This means that radial inhomogeneity can cause solar

  4. Selection and mid-infrared spectroscopy of ultraluminous star-forming galaxies at z ∼ 2

    Fang, Guanwen; Kong, Xu; Chen, Yang; Lin, Xuanbin [Center for Astrophysics, University of Science and Technology of China, Anhui, 230026 (China); Huang, Jia-Sheng [National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing 100012 (China); Willner, S. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Wang, Tao, E-mail: xkong@ustc.edu.cn, E-mail: jhuang@cfa.harvard.edu [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093 (China)

    2014-02-01

    Starting from a sample of 24 μm sources in the Extended Groth Strip, we use 3.6-8 μm color criteria to select ultraluminous infrared galaxies (ULIRGs) at z ∼ 2. Spectroscopy from 20-38 μm of 14 objects verifies their nature and gives their redshifts. Multi-wavelength data for these objects imply stellar masses >10{sup 11} M {sub ☉} and star formation rates ≥410 M {sub ☉} yr{sup –1}. Four objects of this sample observed at 1.6 μm (rest-frame visible) with Hubble Space Telescope/WFC3 show diverse morphologies, suggesting that multiple formation processes create ULIRGs. Of the 14 objects, 4 show signs of active galactic nuclei, but the luminosity appears to be dominated by star formation in all cases.

  5. GEMINI/GMOS SPECTROSCOPY OF 26 STRONG-LENSING-SELECTED GALAXY CLUSTER CORES

    We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS) and the Second Red-Sequence Cluster Survey (RCS-2). The 26 galaxy cluster lenses span a redshift range of 0.2 Vir = 7.84 x 1014 M sun h -10.7, which is somewhat higher than predictions for strong-lensing-selected clusters in simulations. The disagreement is not significant considering the large uncertainty in our dynamical data, systematic uncertainties in the velocity dispersion calibration, and limitations of the theoretical modeling. Nevertheless our study represents an important first step toward characterizing large samples of clusters that are identified in a systematic way as systems exhibiting dramatic strong-lensing features.

  6. High velocity blue-shifted FeII absorption in the dwarf star-forming galaxy PHL293B: Evidence for a wind driven supershell?

    Terlevich, R; Bosch, G; Diaz, A I; Hagele, G; Cardaci, M; Firpo, V

    2014-01-01

    X-shooter and ISIS WHT spectra of the starforming galaxy PHL 293B also known as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper. We find broad (FWHM = 1000km/s) and very broad (FWZI = 4000km/s) components in the Balmer lines, narrow absorption components in the Balmer series blueshifted by 800km/s, previously undetected FeII multiplet (42) absorptions also blueshifted by 800km/s, IR CaII triplet stellar absorptions consistent with [Fe/H] < -2.0 and no broad components or blushifted absorptions in the HeI lines. Based on historical records, we found no optical variability at the 5 sigma level of 0.02 mag between 2005 and 2013 and no optical variability at the level of 0.1mag for the past 24 years. The lack of variability rules out transient phenomena like luminous blue variables or SN IIn as the origin of the blue shifted absorptions of HI and FeII. The evidence points to either a young and dense expanding supershell or a stationary cooling wind, in both cases driven by the young cluster w...

  7. Rest-frame optical properties of luminous, radio-selected, broad absorption line quasars

    Runnoe, J. C.; R Ganguly; Brotherton, M. S.; DiPompeo, M. A.

    2013-01-01

    We have obtained IRTF/SpeX spectra of eight moderate-redshift (z=0.7-2.4), radio-selected (log R*~0.4-1.9) broad absorption line (BAL) quasars. The spectra cover the rest-frame optical band. We compare the optical properties of these quasars to those of canonically radio-quiet (log R*1) quasars. With our measurements of the optical properties, particularly the Balmer emission line widths and the continuum luminosity, we have used empirical scaling relations to estimate black hole masses and E...

  8. A LABOCA survey of the Extended Chandra Deep Field South - submillimeter properties of near-IR selected galaxies

    Greve, T R; Walter, F; Smail, I; Zheng, X Z; Knudsen, K K; Coppin, K E K; Kovács, A; Bell, E F; De Breuck, C; Dannerbauer, H; Dickinson, M; Gawiser, E; Lutz, D; Rix, H -W; Schinnerer, E; Alexander, D; Bertoldi, F; Brandt, W N; Chapman, S C; Ivison, R J; Koekemoer, A M; Kreysa, E; Kurczynski, P; Menten, K; Siringo, G; Swinbank, M; Van der Werf, P P

    2009-01-01

    Using the 330hr ESO-MPG 870-micron survey of the Extended Chandra Deep Field South (ECDF-S) obtained with the Large Apex BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX), we have carried out a stacking analysis at submillimeter (submm) wavelengths of a sample of 8266 near-infra-red (near-IR) selected (K_vega <= 20) galaxies, including 893 BzK galaxies, 1253 extremely red objects (EROs) and 737 distant red galaxies (DRGs), selected from the Multi-wavelength Survey by Yale-Chile (MUSYC). We measure average 870-micron fluxes of 0.20+-0.01mJy (20.0sigma), 0.45+-0.04mJy (11.3sigma), 0.42+-0.03mJy (14.0sigma), and 0.41+-0.04mJy (10.3sigma) for the K_vega <= 20, BzK, ERO and DRG samples, respectively. For the BzK, ERO and DRG subsamples, which overlap to some degree and are like to be at z ~ 1-2, this implies an average far-IR luminosity of ~2-6x10^{11} Lsolar and star formation rate of ~40-100Msolar. Splitting the BzK galaxies up into star-forming (sBzK) and passive (pBzK) galaxies, the f...

  9. Comparing Cool Cores in the Planck SZ Selected Samples of Clusters of Galaxies with Cool Cores in X-ray Selected Cluster Samples

    Jones, Christine; Santos, Felipe A.; Forman, William R.; Kraft, Ralph P.; Lovisari, Lorenzo; Arnaud, Monique; Mazzotta, Pasquale; Van Weeren, Reinout J.; Churazov, Eugene; Ferrari, Chiara; Borgani, Stefano; Chandra-Planck Collaboration

    2016-06-01

    The Planck mission provided a representative sample of clusters of galaxies over the entire sky. With completed Chandra observations of 165 Planck ESZ and cosmology sample clusters at zcore and non-cool core clusters in the Planck-selected clusters with the percentages in X-ray selected cluster samples. We find a significantly smaller percentage of cool core clusters in the Planck sample than in X-ray selected cluster samples. We will discuss the primary reasons for this smaller percentage of cool-core clusters in the Planck-selected cluster sample than in X-ray-selected samples.

  10. A New 2MASS/2df Selected Sample of Pairs of Galaxies and Calibration of Merging Rate in the Local Universe

    孙艳春; 徐聪; 何香涛

    2003-01-01

    We present a new sample of 37 close major-merger galaxy pairs, selected from the 2-degree field redshift survey of the two-micron all-sky survey (2MASS) galaxies. The selection criteria for our near-infrared pairs are more closely related to galaxy mass (a very important parameter in galaxy evolution models) than those for optical selected samples. Our sample benefits enormously from the high homogeneity and accuracy of the 2MASS database, and false matchings are minimized by the essentially three-dimensional selection procedure. Taking into account the biases, we find that 1.96 (±0.4)% of galaxies are in close major-merger pairs. This indicates a local merging rate of 1.0%, in good agreement with the results in recent studies of optical selected pairs in the local universe. The results derived with our sample have high confidence.

  11. The Evolution of Early-type Field Galaxies Selected from a NICMOS Map of the Hubble Deep Field North

    Somerville, R; Stanford, S A; Budavari, T; Conselice, C J

    2004-03-03

    The redshift distribution of well-defined samples of distant early-type galaxies offers a means to test the predictions of monolithic and hierarchical galaxy formation scenarios. NICMOS maps of the entire Hubble Deep Field North in the F110W and F160W filters, when combined with the available WFPC2 data, allow us to calculate photometric redshifts and determine the morphological appearance of galaxies at rest-frame optical wavelengths out to z {approx} 2.5. Here we report results for two subsamples of early-type galaxies, defined primarily by their morphologies in the F160W band, which were selected from the NICMOS data down to H{sub 160AB} < 24.0. A primary subsample is defined as the 34 galaxies with early-type galaxy morphologies and early-type galaxy spectral energy distributions. The secondary subsample is defined as those 42 objects which have early-type galaxy morphologies with non-early type galaxy spectral energy distributions. The observed redshift distributions of our two early-type samples do not match that predicted by a monolithic collapse model, which shows an overabundance at z > 1.5. A (V/V{sub max}) test confirms this result. When the effects of passive luminosity evolution are included in the calculation, the mean value of Vmax for the primary sample is 0.22 {+-} 0.05, and 0.31 {+-} 0.04 for all the early-types. A hierarchical formation model better matches the redshift distribution of the HDF-N early-types at z > 1.5, but still does not adequately describe the observed early-types. The hierarchical model predicts significantly bluer colors on average than the observed early-type colors, and underpredicts the observed number of early-types at z {approx} 2. Though the observed redshift distribution of the early-type galaxies in our HDF-NICMOS sample is better matched by a hierarchical galaxy formation model, the reliability of this conclusion is tempered by the restricted sampling area and relatively small number of early-type galaxies selected by

  12. The use of selected neutron absorption resonance filters to suppress spurious events on hot neutron spectrometers

    Resonant absorption can be used as a filter for high energy neutron spectroscopy. Here we report the transmission of eight thin foil filters: erbium, indium, iridium, dysprosium, hafnium, gadolinium, cadmium and samarium, measured using neutron time-of-flight techniques over a range of energies (1 meV to 10 eV). Measured transmission is converted into energy-dependent absorption cross-section which compares closely to tabulated values. Each resonance is characterized from 91 meV (samarium) to 2815 meV (gadolinium) by Lorentzian fits. Possibilities for the use of neutron filters depending on the type of spurious background are discussed and the performance is simulated for a specific example of a hot neutron triple axis spectrometer experiment. - Highlights: • We measured neutron transmission for eight absorption filters using time of flight. • Resonance energies, their selectivity and efficiency are extracted for each filter. • We detail how to choose and optimize filter use in neutron scattering experiments. • Such filtering can be efficiently used to reduce background and spurious signals

  13. The use of selected neutron absorption resonance filters to suppress spurious events on hot neutron spectrometers

    Lançon, D., E-mail: diane.lancon@epfl.ch [Laboratory for Quantum Magnetism, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Institut Laue-Langevin, BP156, 38042 Grenoble Cedex (France); Ewings, R.A.; Stewart, J.R. [ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Jiménez-Ruiz, M. [Institut Laue-Langevin, BP156, 38042 Grenoble Cedex (France); Rønnow, H.M. [Laboratory for Quantum Magnetism, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2015-04-21

    Resonant absorption can be used as a filter for high energy neutron spectroscopy. Here we report the transmission of eight thin foil filters: erbium, indium, iridium, dysprosium, hafnium, gadolinium, cadmium and samarium, measured using neutron time-of-flight techniques over a range of energies (1 meV to 10 eV). Measured transmission is converted into energy-dependent absorption cross-section which compares closely to tabulated values. Each resonance is characterized from 91 meV (samarium) to 2815 meV (gadolinium) by Lorentzian fits. Possibilities for the use of neutron filters depending on the type of spurious background are discussed and the performance is simulated for a specific example of a hot neutron triple axis spectrometer experiment. - Highlights: • We measured neutron transmission for eight absorption filters using time of flight. • Resonance energies, their selectivity and efficiency are extracted for each filter. • We detail how to choose and optimize filter use in neutron scattering experiments. • Such filtering can be efficiently used to reduce background and spurious signals.

  14. Higher prevalence of X-ray selected AGN in intermediate-age galaxies up to z ˜ 1

    Hernán-Caballero, Antonio; Alonso-Herrero, Almudena; Pérez-González, Pablo G.; Barro, Guillermo; Aird, James; Ferreras, Ignacio; Cava, Antonio; Cardiel, Nicolás; Esquej, Pilar; Gallego, Jesús; Nandra, Kirpal; Rodríguez-Zaurín, Javier

    2014-10-01

    We analyse the stellar populations in the host galaxies of 53 X-ray selected optically dull active galactic nuclei (AGN) at 0.34 SHARDS). The spectral resolution of SHARDS allows us to consistently measure the strength of the 4000 Å break, Dn(4000), a reliable age indicator for stellar populations. We confirm that most X-ray selected moderate-luminosity AGN (LX 1010.5 M⊙) and that the observed fraction of galaxies hosting an AGN increases with the stellar mass. A careful selection of random control samples of inactive galaxies allows us to remove the stellar mass and redshift dependences of the AGN fraction to explore trends with several stellar age indicators. We find no significant differences in the distribution of the rest-frame U - V colour for AGN hosts and inactive galaxies, in agreement with previous results. However, we find significantly shallower 4000 Å breaks in AGN hosts, indicative of younger stellar populations. With the help of a model-independent determination of the extinction, we obtain extinction-corrected U - V colours and light-weighted average stellar ages. We find that AGN hosts have younger stellar populations and higher extinction compared to inactive galaxies with the same stellar mass and at the same redshift. We find a highly significant excess of AGN hosts with Dn(4000) ˜ 1.4 and light-weighted average stellar ages of 300-500 Myr, as well as a deficit of AGN in intrinsic red galaxies. We interpret failure in recognizing these trends in previous studies as a consequence of the balancing effect in observed colours of the age-extinction degeneracy.

  15. Variable Reddening and Broad Absorption Lines in the Narrow-line Seyfert 1 Galaxy WPVS 007: an Origin in the Torus

    Leighly, Karen M; Grupe, Dirk; Terndrup, Donald M; Komossa, S

    2015-01-01

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ~2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director's Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the CIV emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variabl...

  16. Differential Absorption as a Factor Influencing the Selective Toxicity of MCPA and MCPB

    Experiments were carried out with autoradiographic and counting techniques to determine if differential absorption was a factor influencing the selective toxicity of the foliar-applied herbicides, 4-chloro-2 methylphenoxyacetic acid (MCPA) and 4-(4-chloro-2-methylphenoxy) butyric acid (MCPB). Treatment of fat hen (Chenopodium album) which is susceptible to both herbicides and black bindweed (Polygonum convolvulus) which is resistant to both, showed that MCPA and MCPB were extensively translocated in the susceptible species; both, however, remained localized in the treated leaves of the resistant black bindweed. Further experiments using broad bean (Vicia faba) which was susceptible to MCPA and resistant to equivalent doses of MCPB showed that considerably more MCPA was translocated throughout the treated plants. Leaf flotation experiments suggested that differential penetration of bean leaf cuticle, may in part at least, explain this difference in toxicity. Greater uptake of MCPA after 6- and 8-h treatment periods was recorded and penetration of both herbicides was generally more rapid through the abaxial surface, reflecting the presence of stomata and the thinner cuticle of the under-surface. Further evidence of the action of cuticle as a selective barrier to herbicide penetration was obtained using cuticle isolated from tomato fruits and onion scale leaves. These results are to be confirmed using bean leaf cuticles. Whilst in the higher plants MCPA is more toxic than MCPB, previous work has shown that MCPB is a more effective inhibitor of lower organisms such as bacteria, fungi and algae. Treatment of mycelial discs of Aspergillus niger showed that absorption of MCPB was more rapid than MCPA, though the differential tended to diminish during the 20-h treatment period. Respiratory inhibition closely followed the uptake pattern. Repeated experiments using mitochondria isolated from A.niger mycelium have demonstrated that greater uptake of MCPB coincided with an

  17. Galaxy evolution in the high redshift, colour-selected cluster RzCS 052 at z=1.02

    Andreon, S.; Puddu, E.; De Propris, R.; Cuillandre, J.-C.

    2008-01-01

    We present deep I and z' imaging of the colour-selected cluster RzCS 052 and study the color-magnitude relation of this cluster, its scatter, the morphological distribution on the red sequence, the luminosity and stellar mass functions of red galaxies and the cluster blue fraction. We find that the stellar populations of early type galaxies in this cluster are uniformly old and that their luminosity function does not show any sign of evolution other than the passive evolution of their stellar...

  18. Radio haloes in Sunyaev-Zel'dovich-selected clusters of galaxies: the making of a halo?

    Bonafede, A.; Intema, H.; Brüggen, M.; Vazza, F.; Basu, K.; Sommer, M.; Ebeling, H.; de Gasperin, F.; Röttgering, H. J. A.; van Weeren, R. J.; Cassano, R.

    2015-12-01

    Radio haloes are synchrotron radio sources detected in some massive galaxy clusters. Their size of Mpc indicates that (re)acceleration processes are taking place in the host cluster. X-ray catalogues of galaxy clusters have been used in the past to search for radio haloes and to understand their connection with cluster-cluster mergers and with the thermal component of the intracluster medium. More recently, the Sunyaev-Zel'dovich effect has been proven to be a better route to search for massive clusters in a wider redshift range. With the aim of discovering new radio haloes and understanding their connection with cluster-cluster mergers, we have selected the most massive clusters from the Planck early source catalogue and we have observed with the Giant Metrewave Radio Telescope at 323 MHz those objects for which deep observations were not available. We have discovered new peculiar radio emission in three of the observed clusters, finding (i) a radio halo in the cluster RXCJ0949.8+1708, (ii) extended emission in Abell 1443 that we classify as a radio halo plus a radio relic, with a bright filament embedded in the radio halo, and (iii) low-power radio emission in CIZA J1938.3+5409 that is ten times below the radio-X-ray correlation and represents the first direct detection of the radio emission in the `upper-limit' region of the radio-X-ray diagram. We discuss the properties of these new radio haloes in the framework of theoretical models for the radio emission.

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

    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 ...

  20. Absorption Line Spectroscopy of Gravitationally-Lensed Galaxies: Further Evidence for an Increased Escape Fraction of Ionizing Photons at High Redshift

    Leethochawalit, Nicha; Ellis, Richard S; Stark, Daniel P; Zitrin, Adi

    2016-01-01

    The fraction of ionizing photons that escape from high redshift star forming galaxies remains a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. In our earlier work, we proposed using the covering fraction of low ionization gas, measured via deep absorption line spectroscopy, as a proxy. We present a significant update using this method, sampling seven gravitationally-lensed sources in the redshift range 4absorption lines, we quantify possible biases and uncertainties. Collectively we find the average escape fraction could be reduced to no less than 11%, excluding the effect of spatial variations. For one of our lense...

  1. The X-ray Properties of Optically-Selected Galaxy Clusters

    Dai, X; Morgan, N D; Dai, Xinyu; Kochanek, Christopher S.; Morgan, Nicholas D.

    2006-01-01

    We stacked the X-ray data from the ROSAT All Sky Survey for over 4,000 clusters selected from the 2MASS catalog and divided into five richness classes. We detected excess X-ray emission over background at the center of the stacked images in all five richness bins. The interrelationships between the mass, X-ray temperature and X-ray luminosity of the stacked clusters agree well with those derived from catalogs of X-ray clusters. Poisson variance in the number of galaxies occupying halos of a given mass leads to significant differences between the average richness at fixed mass and the average mass at fixed richness that we can model relatively easily using a simple model of the halo occupation distribution. These statistical effects probably explain recent results in which optically-selected clusters lie on the same X-ray luminosity-temperature relations as local clusters but have lower optical richnesses than observed for local clusters with the same X-ray properties. When we further binned the clusters by re...

  2. HerMES: The Contribution to the Cosmic Infrared Background from Galaxies Selected by Mass and Redshift

    Viero, M P; Quadri, R F; Arumugam, V; Assef, R J; Bethermin, M; Bock, J; Bridge, C; Conley, A; Cooray, A; Farrah, D; Heinis, S; Ikarashi, S; Ivison, R J; Kohno, K; Marsden, G; Oliver, S J; Roseboom, I G; Schulz, B; Scott, D; Serra, P; Vaccari, M; Vieira, J D; Wang, L; Wardlow, J; Williams, R J; Wilson, G W; Yun, M S; Zemcov, M

    2013-01-01

    We quantify the fraction of the cosmic infrared background (CIB) that originates from galaxies identified in the UV/optical/near-infrared by stacking 81,250 (~35.7 arcmin^2) K-selected sources, split according to their rest-frame U - V vs. V - J colors into 72,216 star-forming and 9,034 quiescent galaxies, on maps from Spitzer/MIPS (24, 70, 160 {\\mu}m), Herschel/SPIRE (250, 350, 500 {\\mu}m), and AzTEC (1100 {\\mu}m). The fraction of the CIB resolved by our catalog is (67 \\pm 16)% at 24 {\\mu}m, (72 \\pm 17)% at 70 {\\mu}m, (76 \\pm 18)% at 160 {\\mu}m, (78 \\pm 18)% at 250 {\\mu}m, (70 \\pm 15)% at 350 {\\mu}m, (67 \\pm 13)% at 500 {\\mu}m, and (52 \\pm 9)% at 1100 {\\mu}m. Of that total, about 95% originates from star-forming galaxies, while the remaining 5% is from apparently quiescent galaxies. The CIB at {\\lambda} 200 {\\mu}m the bulk originates from 1 350{\\mu}m. The contribution from galaxies in the log(M/ M_sun)=9.0$-9.5 (highest) and log(M/ M_sun)=11.0-12.0 (lowest) stellar mass bins contribute the least, both of o...

  3. Spitzer 24 Micron Observations of Optical/Near-Infrared-Selected Extremely Red Galaxies: Evidence for Assembly of Massive Galaxies at Z approximately equal to 1-2?

    Yan, Lin; Choi, Philip I.; Fadda, D.; Marleau, F. R.; Soifer, B. T.; Im, M.; Armus, L.; Frayer, D. T.; Storrie-Lombardi, L. J.; Thompson, D. J.; Teplitz, H. I.; Helou, G.; Appleton, P. N.; Chapman, S.; Fan, F.; Heinrichsen, I.; Lacy, M.; Shupe, D. L.; Squires, G. K.; Surace, J.; Wilson, G.

    2004-01-01

    We carried out direct measurement of the fraction of dusty sources in a sample of extremely red galaxies with (R - Ks) >= 5.3 mag and Ks = 1, and are an order of magnitude too red to be explained by an infrared quiescent spiral or a pure old stellar population at any redshift. Some of these 24 micron-detected EROs could be active galactic nuclei; however, the fraction among the whole ERO sample is probably small, 10%-20%, as suggested by deep X-ray observations as well as optical spectroscopy. Keck optical spectroscopy of a sample of similarly selected EROs in the FLS field suggests that most of the EROs in ELAIS N1 are probably at z 1. The mean 24 micron flux (167 (micro)Jy) of the 24 micron-detected ERO sample roughly corresponds to the rest-frame 12 micron luminosity, (nu)L(nu)(12 micron, of 3x10(exp 10)(deg) solar luminosities at z 1. Using the c IRAS (nu)L(nu)(12 (micron) and infrared luminosity LIR(8-1000 (micron), we infer that the (LIR) of the 24 micron- detected EROs is 3 x 10(exp 11) and 1 x 10(exp 12) solar luminosities at z = 1.0 and similar to that of local luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs). The corresponding SFR would be roughly 50-170 solar masses per year. If the timescale of this starbursting phase is on the order of 108 yr as inferred for the local LIRGs and ULIRGs, the lower limit on the masses of these 24 micron-detected EROs is 5 x 10(exp 9) to 2 x 10(exp 10) solar masses. It is plausible that some of the starburst EROs are in the midst of a violent transformation to become massive early type galaxies at the epoch of z 1-2.

  4. A HIRES Detection of NA I D Absorption in the Spectrum of the QSO PKS 2020-370 Due to the Galaxy Klemola 31A

    Junkkarinen, V. T.; Barlow, T. A.

    1994-12-01

    By using the Keck telescope and HIRES spectrograph we have detected Na I D absorption lines in the spectrum of the QSO PKS 2020-370 (V = 17.5, z = 1.048) due to the galaxy Klemola 31A (z = 0.0288). The PKS 2020-370 line of sight is near an apparent spiral arm only 20" from the nucleus of Klemola 31A which corresponds to 17 kpc (H_o = 50 km s(-1) Mpc(-1) ). The spectrum of PKS 2020-370 has strong Ca II absorption lines (W_λ ~ 350 m Angstroms \\ for the K line) at the galaxy redshift (Boksenberg et al, 1980, ApJ, 242, L145), but previous attempts to detect Na I have resulted in upper limits (Boisse et al. 1988, A&A, 191, 193, Womble, 1992, thesis UCSD). We observed PKS 2020-370 with HIRES in May 1994 at a resolution of 8 km s(-1) FWHM for a total of 90 minutes. The Na I D doublet is detected with a total W_λ for the Na I 5891.6 Angstroms \\ (vac) absorption line of about 160 m Angstroms . The absorption appears as two main velocity components separated by 23 km s(-1) . The optically thin estimate for N(Na I) = 1.0 times 10(12) cm(-2) gives an estimated N(Ca II)/N(Na I) = 5. This value suggests that the gas in Klemola 31A along the QSO line of sight is ``halo like''. Along ``disk like'' lines of sight where Ca is thought to be depleted onto grains in our Galaxy, the N(Ca II)/N(Na I) ratio is usually small (Ca II)/N(Na I) ratios when the line of sight intersects starlight at 25 mag per sq. arcsec (Womble, 1992 thesis UCSD). The PKS 2020-370 sightline is near the optical extent of Klemola 31A but the N(Ca II)/N(Na I) is consistent with the sightline passing through two clouds in the halo. This research has been supported in part by NASA NAS5--29293 and NAG5--1630.

  5. THE ∼0.9 mJy SAMPLE: A MID-INFRARED SPECTROSCOPIC CATALOG OF 150 INFRARED-LUMINOUS, 24 μm SELECTED GALAXIES AT 0.3 ≤ z ≤ 3.5

    We present a catalog of mid-infrared (MIR) spectra of 150 infrared (IR) luminous galaxies in the Spitzer extragalactic first look survey obtained with the IR spectrograph on board the Spitzer Space Telescope. The sample is selected to be brighter than ∼0.9 mJy at 24 μm and it has a redshift distribution in the range [0.3, 3.5], with a peak at z = 1. It primarily comprises ultraluminous IR galaxies (ULIRGs) at z ∼> 1 and luminous IR galaxies at z 2 0-0 S(1) and S(3) lines, and the [Ne V] line. We observe differences in the flux ratios of PAHs in the stacked spectra of IR-luminous galaxies with redshift or luminosity, which cannot be attributed to extinction effects since both the depth and the profile of the silicate absorption feature at 9.7 μm remain the same at z < 1 and z ≥ 1. When placing the observed galaxies on IR color-color diagrams, we find that the wedge defining AGNs comprises most sources with continuum-dominated spectra, but also contains many starbursts and sources with strong silicate absorption at 9.7 μm. The comparison of the 11.3 μm PAH EW and the H-band effective radius, measured from Hubble Space Telescope data, indicates that sources with EWs ≥ 2 μm, are typically more extended than ∼3 kpc. However, there is no strong correlation between the MIR spectral type and the near-IR extent of the sources.

  6. The SCUBA HAlf Degree Extragalactic Survey (SHADES) -- V. Submillimetre properties of near-infrared--selected galaxies in the Subaru/XMM--Newton deep field

    Takagi, T; Shimasaku, K; Coppin, K; Pope, A; Ivison, R J; Hanami, H; Serjeant, S; Clements, D L; Priddey, R S; Dunlop, J S; Takata, T; Aretxaga, I; Chapman, S C; Eales, S A; Farrah, D; Granato, G L; Halpern, M; Hughes, D H; Van Kampen, E; Scott, D; Sekiguchi, K; Smail, I; Vaccari, M

    2007-01-01

    We have studied the submillimetre (submm) properties of the following classes of near-infrared (NIR)-selected massive galaxies at high redshifts: BzK-selected star-forming galaxies (BzKs); distant red galaxies (DRGs); and extremely red objects (EROs). We used the SCUBA HAlf Degree Extragalactic Survey (SHADES), the largest uniform submm survey to date. Partial overlap of SIRIUS/NIR images and SHADES in SXDF has allowed us to identify 4 submm-bright NIR-selected galaxies, which are detected in the mid-infrared, 24 micron, and the radio, 1.4 GHz. We find that all of our submm-bright NIR-selected galaxies satisfy the BzK selection criteria, except for one galaxy whose B-z and z-K colours are however close to the BzK colour boundary. Two of the submm-bright NIR-selected galaxies satisfy all of the selection criteria we considered, i.e. they belong to the BzK-DRG-ERO overlapping population, or `extremely red' BzKs. Although these extremely red BzKs are rare (0.25 arcmin^{-2}), up to 20 % of this population could b...

  7. Mid-IR near-perfect absorption with a SiC photonic crystal with angle-controlled polarization selectivity.

    Devarapu, G C R; Foteinopoulou, S

    2012-06-01

    We theoretically investigate mid-IR absorption enhancement with a SiC one-dimensional photonic crystal (PC) microstructure at the frequency regime of the phonon-polariton band gap, where efficient absorption is unattainable in the bulk material. Our study reveals an intricate relationship between absorption efficiency and the energy velocity of light propagation, that is far more complex than hitherto believed. In particular, our findings suggest that absorption peaks away from the photonic-crystal band edge where energy velocity is minimum. While efficient absorption is still associated with a slow-light mode, the latter is faster by at least an order of magnitude in comparison to the bulk material. Moreover, our calculations suggest that absorption becomes optimal when light gradually slow downs as it enters the PC. Relying on this insight, we achieved near-perfect absorption around the phonon-polariton mid-gap frequency with a PC with a suitably terminated end face. We further demonstrate that the near-perfect absorptive property can be tuned with the incident light angle, to be polarization insensitive or polarization selective. We believe our proposed non-metallic paradigm opens up a new route for harnessing infrared absorption with semiconductor and ionic-crystal materials. PMID:22714331

  8. Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections

    Oteo, I; Bongiovanni, Á; Pérez-García, A M; Cepa, J; Cedrés, B; Ederoclite, A; Sánchez-Portal, M; Aguerri, J A L; Alfaro, E J; Altieri, B; Andreani, P; Aparicio-Villegas, T; Aussel, H; itez, N Ben\\'; Berta, S; Broadhurst, T; Cabrera-Caño, J; Castander, F J; Cerviño, M; Cimatti, A; Cristobal-Hornillos, D; Daddi, E; Elbaz, D; Fernandez-Soto, A; Schreiber, N Förster; Genzel, R; Gonzalez-Delgado, R M; Husillos, C; Infante, L; Floc'h, E Le; Lutz, D; Magnelli, B; Maiolino, R; arquez, I M\\'; inez, V J Mart\\'; Masegosa, J; Matute, I; Moles, M; Molino, A; del Olmo, A; Perea, J; inez, R P\\' erez-Mart\\'; Pintos-Castro, I; Poglitsch, A; Polednikova, J; Popesso, P; Pović, M; Pozzi, F; Prada, F; Quintana, J M; Riguccini, L; Sturm, E; Tacconi, L; Valtchanov, I; Viironen, K

    2013-01-01

    We report the PACS-100um/160um detections of a sample of 42 GALEX-selected and FIR-detected Lyman break galaxies (LBGs) at z ~ 1 located in the COSMOS field and analyze their ultra-violet (UV) to far-infrared (FIR) properties. The detection of these LBGs in the FIR indicates that they have a dust content high enough so that its emission can be directly detected. According to a spectral energy distribution (SED) fitting with stellar population templates to their UV-to-near-IR observed photometry, PACS-detected LBGs tend to be bigger, more massive, dustier, redder in the UV continuum, and UV-brighter than PACS-undetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disk-like galaxies and are located over the green-valley and red sequence of the color-magnitude diagram of galaxies at their redshift. By using their UV and IR emission, we find that PACS-detected LBGs tend to be less dusty and have slightly higher total star-formation rates (SFRs) than other PACS-detected UV-selected galaxies within their same reds...

  9. Lyman break and UV-selected galaxies at $z \\sim 1$ I. Stellar populations from ALHAMBRA survey

    Oteo, I; Cepa, J; Pérez-García, A M; Ederoclite, A; Sánchez-Portal, M; Pintos-Castro, I; Pérez-Martínez, R; Aguerri, J A L; Alfaro, E J; Aparicio-Villegas, T; Benítez, N; Broadhurst, T; Cabrera-Caño, J; Castander, F J; Cerviño, M; Cristobal-Hornillos, D; Fernandez-Soto, A; Gonzalez-Delgado, R M; Husillos, C; Infante, L; Martínez, V J; Márquez, I; Masegosa, J; Matute, I; Moles, M; Molino, A; del Olmo, A; Perea, J; Prada, F; Quintana, J M

    2013-01-01

    We take advantage of the exceptional photometric coverage provided by the combination of GALEX data in the UV and the ALHAMBRA survey in the optical and near-IR to analyze the physical properties of a sample of 1225 GALEX-selected Lyman break galaxies (LBGs) at $0.8 \\lesssim z \\lesssim 1.2$ located in the COSMOS field. This is the largest sample of LBGs studied at that redshift range so far. According to a spectral energy distribution fitting with synthetic stellar population templates, we find that LBGs at $z \\sim 1$ are mostly young galaxies with a median value of 341 Myr and have intermediate dust attenuation, $ \\sim 0.20$. Due to their selection criterion they are UV-bright galaxies and have high dust-corrected total SFRs, with a median value of 46.4 $M_\\odot {\\rm yr}^{-1}$. The median value of the stellar mass of the LBGs in the sample is $\\log{M_*/M_\\odot} = 9.74$. We obtain that the dust-corrected total SFR of LBGs increases with stellar mass and the specific SFR is lower for more massive galaxies (dow...

  10. Strong absorption and selective thermal emission from a mid-infrared metamaterial

    Mason, J A; Wasserman, D

    2011-01-01

    We demonstrate thin-film metamaterials with resonances in the mid-infrared wavelength range. Our structures are numerically modeled and experimentally characterized by reflection and angularly-resolved thermal emission spectroscopy. We demonstrate strong and controllable absorption resonances across the mid-infrared wavelength range. In addition, the polarized thermal emission from these samples is shown to be highly selective and largely independent of emission angles from normal to 45 degrees. Experimental results are compared to numerical models with excellent agreement. Such structures hold promise for large-area, low-cost metamaterial coatings for control of gray- or black-body thermal signatures, as well as for possible mid-IR sensing applications.

  11. Selective two-photon absorptive resonance femtosecond-laser electronic-excitation tagging velocimetry.

    Jiang, Naibo; Halls, Benjamin R; Stauffer, Hans U; Danehy, Paul M; Gord, James R; Roy, Sukesh

    2016-05-15

    Selective two-photon absorptive resonance femtosecond-laser electronic-excitation tagging (STARFLEET), a nonseeded ultrafast-laser-based velocimetry technique, is demonstrated in reactive and nonreactive flows. STARFLEET is pumped via a two-photon resonance in N2 using 202.25 nm 100 fs light. STARFLEET greatly reduces the per-pulse energy required (30 μJ/pulse) to generate the signature FLEET emission compared to the conventional FLEET technique (1.1 mJ/pulse). This reduction in laser energy results in less energy deposited in the flow, which allows for reduced flow perturbations (reactive and nonreactive), increased thermometric accuracy, and less severe damage to materials. Velocity measurements conducted in a free jet of N2 and in a premixed flame show good agreement with theoretical velocities, and further demonstrate the significantly less intrusive nature of STARFLEET. PMID:27176968

  12. Absorption and emission of NIR fluorophores for use in Wavelength Selective Solar Concentrators

    Hellier, Kaitlin; Corrado, Carley; Carter, Sue

    2014-03-01

    Wavelength Selective Solar Concentrators (WSSCs) offer a variety of applications as compared to traditional solar panels. Exploiting the property of power generation with transmission, we have turned our attention to the greenhouse industry. Our current design employs an organic dye (Lumogen Red 305) with an excitation peak in green wavelengths and an emission peak in red wavelengths, specifically targeting wavelengths unused in photosynthesis. To increase the efficiency of the WSSC without disrupting either existing function, we explore the addition of NIR dyes. Presented are the absorption and emission peaks of the dyes deposited into poly-vinyl butyral (PVB), polymethyl methacrylate (PMMA), and (TPU); the quantum yields of these films; and the combined spectra of the dyes with LR305.

  13. Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching

    Sivarajah, I; Wells, J E; Narducci, F A; Smith, W W

    2013-01-01

    Linear Paul r.f. ion traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.

  14. redMaGiC: Selecting Luminous Red Galaxies from the DES Science Verification Data

    Rozo, E; Abate, A; Bonnett, C; Crocce, M; Davis, C; Hoyle, B; Leistedt, B; Peiris, H V; Wechsler, R H; Abbott, T; Abdalla, F B; Banerji, M; Bauer, A H; Benoit-Lévy, A; Bernstein, G M; Bertin, E; Brooks, D; Buckley-Geer, E; Burke, D L; Capozzi, D; Rosell, A Carnero; Carollo, D; Kind, M Carrasco; Carretero, J; Castander, F J; Childress, M J; Cunha, C E; D'Andrea, C B; Davis, T; DePoy, D L; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Eifler, T F; Evrard, A E; Neto, A Fausti; Flaugher, B; Fosalba, P; Frieman, J; Gaztanaga, E; Gerdes, D W; Glazebrook, K; Gruen, D; Gruendl, R A; Honscheid, K; James, D J; Jarvis, M; Kim, A G; Kuehn, K; Kuropatkin, N; Lahav, O; Lidman, C; Lima, M; Maia, M A G; March, M; Martini, P; Melchior, P; Miller, C J; Miquel, R; Mohr, J J; Nichol, R C; Nord, B; O'Neill, C R; Ogando, R; Plazas, A A; Romer, A K; Roodman, A; Sako, M; Sanchez, E; Santiago, B; Schubnell, M; Sevilla-Noarbe, I; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Thaler, J; Thomas, D; Uddin, S; Vikram, V; Walker, A R; Wester, W; Zhang, Y; da Costa, L N

    2015-01-01

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photozs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range $z\\in[0.2,0.8]$. Our fiducial sample has a comoving space density of $10^{-3}\\ (h^{-1} Mpc)^{-3}$, and a median photoz bias ($z_{spec}-z_{photo}$) and scatter $(\\sigma_z/(1+z))$ of 0.005 and 0.017 respectively. The corresponding $5\\sigma$ outlier fraction is 1.4%. We also test our algorit...

  15. Infrared spectral energy distribution decomposition of WISE-selected, hyperluminous hot dust-obscured galaxies

    Fan, Lulu; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K

    2016-01-01

    We utilize a Bayesian approach to fit the observed mid-IR-to-submm/mm spectral energy distributions (SEDs) of 22 WISE-selected and submm-detected, hyperluminous hot dust-obscured galaxies. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are: 1) Hot DOGs in our submm-detected sample are hyperluminous, with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, averagely contributing ~24% of total IR luminosity. 2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submm at rest-frame, while it is very similar to that of QSOs at 10-50um suggesting that the heating sources of Hot DOGs should be buried AGNs. 3) Hot DOGs have both high dust temperatures ~73K and IR luminosity of cold dust. The T-L relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust tem...

  16. redMaGiC: selecting luminous red galaxies from the DES Science Verification data

    Rozo, E.; Rykoff, E. S.; Abate, A.; Bonnett, C.; Crocce, M.; Davis, C.; Hoyle, B.; Leistedt, B.; Peiris, H. V.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carollo, D.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Childress, M. J.; Cunha, C. E.; D'Andrea, C. B.; Davis, T.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Glazebrook, K.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lidman, C.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; O'Neill, C. R.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thaler, J.; Thomas, D.; Uddin, S.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.; da Costa, L. N.

    2016-09-01

    We introduce redMaGiC, an automated algorithm for selecting luminous red galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the colour cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine learning-based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalogue sampling the redshift range z ∈ [0.2, 0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1 Mpc)-3, and a median photo-z bias (zspec - zphoto) and scatter (σz/(1 + z)) of 0.005 and 0.017, respectively. The corresponding 5σ outlier fraction is 1.4 per cent. We also test our algorithm with Sloan Digital Sky Survey Data Release 8 and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1 per cent level.

  17. Herschel-ATLAS: Correlations between Dust and Gas in Local Submm-Selected Galaxies

    Bourne, N; Bendo, G J; Smith, M W L; Clark, C J R; Smith, D J B; Rigby, E E; Baes, M; Leeuw, L L; Maddox, S J; Thompson, M A; Bremer, M N; Cooray, A; Dariush, A; de Zotti, G; Dye, S; Eales, S; Hopwood, R; Ibar, E; Ivison, R J; Jarvis, M J; Michałowski, M J; Rowlands, K; Valiante, E

    2013-01-01

    We present an analysis of CO molecular gas tracers in a sample of 500{\\mu}m-selected Herschel-ATLAS galaxies at z60{\\mu}m), as a result of colder dust being less strongly associated with dense gas. Conversely, CO(2-1) and HI line fluxes both appear to be better correlated with longer wavelengths, suggesting that cold dust is more strongly associated with diffuse atomic and molecular gas phases, consistent with it being at least partially heated by radiation from old stellar populations. The increased scatter at long wavelengths implies that submillimetre fluxes are a poorer tracer of SFR. Fluxes at 22 and 60{\\mu}m are also better correlated with diffuse gas tracers than dense CO(3-2), probably due to very-small-grain emission in the diffuse interstellar medium, which is not correlated with SFR. The FIR/CO luminosity ratio and the dust mass/CO luminosity ratio both decrease with increasing luminosity, as a result of either correlations between mass and metallicity (changing CO/H2) or between CO luminosity and ...

  18. redMaGiC: Selecting Luminous Red Galaxies from the DES Science Verification Data

    Rozo, E.; Rykoff, E. S.; Abate, A.; Bonnett, C.; Crocce, M.; Davis, C.; Hoyle, B.; Leistedt, B.; Peiris, H. V.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carollo, D.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Childress, M. J.; Cunha, C. E.; D'Andrea, C. B.; Davis, T.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Glazebrook, K.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lidman, C.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; O'Neill, C. R.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thaler, J.; Thomas, D.; Uddin, S.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.; da Costa, L. N.

    2016-05-01

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range z ∈ [0.2, 0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1Mpc)-3, and a median photo-z bias (zspec - zphoto) and scatter (σz/(1 + z)) of 0.005 and 0.017 respectively. The corresponding 5σ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1% level.

  19. A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies

    Dong, Xiao-Bo; Yuan, Weimin; Wang, Ting-Gui; Fan, Xiaohui; Zhou, Hongyan; Jiang, Ning

    2012-01-01

    We have conducted a systematic search of low-mass black holes (BHs) in active galactic nuclei (AGNs) with broad Halpha emission lines, aiming at building a homogeneous sample that is more complete than previous ones for fainter, less highly accreting sources. For this purpose, we developed a set of elaborate, automated selection procedures and applied it uniformly to the Fourth Data Release of the Sloan Digital Sky Survey. Special attention is given to AGN--galaxy spectral decomposition and emission-line deblending. We define a sample of 309 type 1 AGNs with BH masses in the range $8 \\times 10^4$--$2 \\times 10^6$ \\msun (with a median of $1.2 \\times 10^6$ solar mass), using the virial mass estimator based on the broad Halpha line. About half of our sample of low-mass BHs differs from that of Greene & Ho, with 61 of them discovered here for the first time. Our new sample picks up more AGNs with low accretion rates: the Eddington ratios of the present sample range from $<~0.01$ to ~1, with 30% below 0.1. ...

  20. redMaGiC: selecting luminous red galaxies from the DES Science Verification data

    Rozo, E. [Univ. of Arizona, Tucson, AZ (United States). et al.

    2016-05-30

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sam- ple of constant comoving density. Additionally, we demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range z ϵ [0.2,0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1Mpc)-3, and a median photo-z bias (zspec zphoto) and scatter (σz=(1 + z)) of 0.005 and 0.017 respectively.The corresponding 5σ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1% level.

  1. Spectroscopic Confirmation of A Radio-Selected Galaxy Overdensity at z = 1.11

    Stanford, S; Stern, D; Holden, B; Spinrad, H

    2004-02-26

    We report the discovery of a galaxy overdensity at z = 1.11 associated with the z = 1.110 high-redshift radio galaxy MG 0442+0202. The group, CL 0442+0202, was found in a near-infrared survey of z > 1 radio galaxies undertaken to identify spatially-coincident regions with a high density of objects red in I - K' color, typical of z > 1 elliptical galaxies. Spectroscopic observations from the Keck I telescope reveal five galaxies within 35'' of MG 0442+0202 at 1.10 < z < 1.11. These member galaxies have broad-band colors and optical spectra consistent with passively-evolving elliptical galaxies formed at high redshift. Archival ROSAT observations reveal a 3{sigma} detection of soft X-ray emission coincident with CL 0442+0202 at a level five times greater than expected for the radio galaxy. These data are suggestive of a rich galaxy cluster and inspired a 45 ks Chandra X-Ray Observatory observation. As expected, the radio galaxy is unresolved to Chandra, but is responsible for approximately half of the observed X-ray flux. The remaining ROSAT flux is resolved into four point sources within 15'' of the radio galaxy, corresponding to a surface density two orders of magnitude higher than average for X-ray sources at these flux levels (S{sub 0.5-2keV} > 5x10{sup -16} ergs cm{sup -2} s{sup -1}). One of these point sources is identified with a radio-quiet, type II quasar at z = 1.863, akin to sources recently reported in deep Chandra surveys. The limit on an extended hot intracluster medium in the Chandra data is S{sub 1-6keV} < 1.9 x 10{sup -15} ergs cm{sup -2} s{sup -1} (3{sigma}, 30'' radius aperture). Though the X-ray observations do not confirm the existence of a massive, bound cluster at z > 1, the success of the optical/near-infrared targeting of early-type systems near the radio galaxy validates searches using radio galaxies as beacons for high-redshift large-scale structure. We interpret CL 0442+0202 to be a massive cluster in the

  2. X-ray absorption evolution in Gamma-Ray Bursts: intergalactic medium or evolutionary signature of their host galaxies?

    Starling, R L C; Tanvir, N R; Scott, A E; Wiersema, K; O'Brien, P T; Levan, A J; Stewart, G C

    2013-01-01

    The intrinsic X-ray emission of Gamma-Ray Bursts (GRBs) is often found to be absorbed over and above the column density through our own galaxy. The extra component is usually assumed to be due to absorbing gas lying within the host galaxy of the GRB itself. There is an apparent correlation between the equivalent column density of hydrogen, N(H,intrinsic) (assuming it to be at the GRB redshift), and redshift, z, with the few z>6 GRBs showing the greatest intrinsic column densities. We investigate the N(H,intrinsic) - z relation using a large sample of Swift GRBs, as well as active galactic nuclei (AGN) and quasar samples, paying particular attention to the spectral energy distributions of the two highest redshift GRBs. Various possible sample biases and systematics that might produce such a correlation are considered, and we conclude that the correlation is very likely to be real. This may indicate either an evolutionary effect in the host galaxy properties, or a contribution from gas along the line-of-sight, ...

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

    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 (900selected 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...

  4. The Atacama Cosmology Telescope: Dynamical Masses for 44 SZ-Selected Galaxy Clusters over 755 Square Degrees

    Sifon, Cristobal; Battaglia, Nick; Hasselfield, Matthew; Menanteau, Felipe; Barrientos, L. Felipe; Bond, J. Richard; Crichton, Devin; Devlin, Mark J.; Dunner, Rolando; Hilton, Matt; Wollack, Edward J.

    2016-01-01

    We present galaxy velocity dispersions and dynamical mass estimates for 44 galaxy clusters selected via the Sunyaev-Zeldovich (SZ) effect by the Atacama Cosmology Telescope. Dynamical masses for 18 clusters are reported here for the first time. Using N-body simulations, we model the different observing strategies used to measure the velocity dispersions and account for systematic effects resulting from these strategies. We find that the galaxy velocity distributions may be treated as isotropic, and that an aperture correction of up to 7 per cent in the velocity dispersion is required if the spectroscopic galaxy sample is sufficiently concentrated towards the cluster centre. Accounting for the radial profile of the velocity dispersion in simulations enables consistent dynamical mass estimates regardless of the observing strategy. Cluster masses M200 are in the range (1 - 15) times 10 (sup 14) Solar Masses. Comparing with masses estimated from the SZ distortion assuming a gas pressure profile derived from X-ray observations gives a mean SZ-to-dynamical mass ratio of 1:10 plus or minus 0:13, but there is an additional 0.14 systematic uncertainty due to the unknown velocity bias; the statistical uncertainty is dominated by the scatter in the mass-velocity dispersion scaling relation. This ratio is consistent with previous determinations at these mass scales.

  5. HerMES: The Contribution to the Cosmic Infrared Background from Galaxies Selected by Mass and Redshift

    Viero, M. P.; Moncelsi, L.; Quadri, R. F.; Arumugam, V.; Assef, R. J.; Béthermin, M.; Bock, J.; Bridge, C.; Casey, C. M.; Conley, A.; Cooray, A.; Farrah, D.; Glenn, J.; Heinis, S.; Ibar, E.; Ikarashi, S.; Ivison, R. J.; Kohno, K.; Marsden, G.; Oliver, S. J.; Roseboom, I. G.; Schulz, B.; Scott, D.; Serra, P.; Vaccari, M.; Vieira, J. D.; Wang, L.; Wardlow, J.; Wilson, G. W.; Yun, M. S.; Zemcov, M.

    2013-12-01

    We quantify the fraction of the cosmic infrared background (CIB) that originates from galaxies identified in the UV/optical/near-infrared by stacking 81,250 (~35.7 arcmin-2) K-selected sources (K AB ~ 200 μm the bulk originates from 1 350 μm. The contribution from galaxies in the log(M/M ⊙) = 9.0-9.5 (lowest) and log(M/M ⊙) = 11.0-12.0 (highest) stellar-mass bins contribute the least—both of order 5%—although the highest stellar-mass bin is a significant contributor to the luminosity density at z >~ 2. The luminosities of the galaxies responsible for the CIB shifts from combinations of "normal" and luminous infrared galaxies (LIRGs) at λ ~ 500 μm. Stacking analyses were performed using SIMSTACK, a novel algorithm designed to account for possible biases in the stacked flux density due to clustering. It is made available to the public at www.astro.caltech.edu/~viero/viero_homepage/toolbox.html. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

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

    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.

  7. X-ray properties of UV-selected star forming galaxies at z~1 in the Hubble Deep Field North

    Laird, E S; Adelberger, K L; Steidel, C C; Reddy, N A

    2005-01-01

    We present an analysis of the X-ray emission from a large sample of ultraviolet (UV) selected, star forming galaxies with 0.74galaxies for which the emission in both UV and X-ray is expected to be predominantly due to star formation. Stacking the X-ray flux from 216 galaxies in the soft and hard bands produces significant detections. The derived mean 2-10 keV rest-frame luminosity is 2.97+/-0.26x10^(40) erg/s, corresponding to an X-ray derived star formation rate (SFR) of 6.0+/-0.6 Msolar/yr. Comparing the X-ray value with the mean UV derived SFR, uncorrected for attenuation, we find that the average UV attenuation correction factor is \\~3. By binning the galaxy sample according to UV magnitude and colour, correlations between UV and X-ray emission are also examined. We find a strong positive correlation between ...

  8. The Atacama Cosmology Telescope: Dynamical masses for 44 SZ-selected galaxy clusters over 755 square degrees

    Sifón, Cristóbal; Menanteau, Felipe; Hasselfield, Matthew; Barrientos, L Felipe; Bond, J Richard; Crichton, Devin; Devlin, Mark J; Dünner, Rolando; Hilton, Matt; Hincks, Adam D; Hlozek, Renée; Huffenberger, Kevin M; Hughes, John P; Infante, Leopoldo; Kosowsky, Arthur; Marsden, Danica; Marriage, Tobias A; Moodley, Kavilan; Niemack, Michael D; Page, Lyman A; Spergel, David N; Staggs, Suzanne T; Trac, Hy; Wollack, Edward J

    2015-01-01

    We present galaxy velocity dispersions and dynamical mass estimates for 44 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect by the Atacama Cosmology Telescope. Dynamical masses for 18 clusters are reported here for the first time. Using N-body simulations, we model the different observing strategies used to measure the velocity dispersions and account for systematic effects resulting from these strategies. We find that the galaxy velocity distributions may be treated as isotropic, and that an aperture correction of up to 7 per cent in the velocity dispersion is required if the spectroscopic galaxy sample is sufficiently concentrated towards the cluster centre. Accounting for the radial profile of the velocity dispersion in simulations enables consistent dynamical mass estimates regardless of the observing strategy. Cluster masses $M_{200}$ are in the range $(1-15)\\times10^{14}M_\\odot$. Comparing with masses estimated from the SZ distortion assuming a gas pressure profile derived from X-ray obse...

  9. NuSTAR reveals an intrinsically x-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

    Teng, Stacy H.; Brandt, W. N.; Harrison, F. A.;

    2014-01-01

    -ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be......We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously...

  10. Multi-Wavelength Studies of Spectacular Ram Pressure Stripping of a Galaxy. I. Discovery of an X-ray Absorption Feature

    Gu, Liyi; Nakazawa, Kazuhiro; Yoshida, Michitoshi; Fujita, Yutaka; Hattori, Takashi; Akahori, Takuya; Makishima, Kazuo

    2013-01-01

    We report the detection of an X-ray absorption feature near the galaxy M86 in the Virgo cluster. The absorber has a column density of 2-3 E20 /cm^2, and its position coincides with the peak of an intracluster HI cloud which was removed from the galaxy NGC 4388 presumably by ram pressure. These results indicate that the HI cloud is located in front of M86 along the line-of-sight, and suggest that the stripping was primarily created by an interaction between NGC 4388 and the hot plasmas of the Virgo cluster, not the M86 halo. By calculating an X-ray temperature map, we further detected an X-ray counterpart of the HI cloud up to about 3' south of M86. It has a temperature of 0.89 keV and a mass of ~4.5 E8 solar mass, exceeding the estimated HI gas mass. The high hot-to-cold gas ratio in the cloud indicates a significant evaporation of the HI gas, probably by thermal conduction from the hotter cluster plasma with a sub-Spitzer rate.

  11. Tidal Disruption Events Prefer Unusual Host Galaxies

    French, K. Decker; Arcavi, Iair; Zabludoff, Ann

    2016-02-01

    Tidal Disruption Events (TDEs) are transient events observed when a star passes close enough to a supermassive black hole to be tidally destroyed. Many TDE candidates have been discovered in host galaxies whose spectra have weak or no line emission yet strong Balmer line absorption, indicating a period of intense star formation that has recently ended. As such, TDE host galaxies fall into the rare class of quiescent Balmer-strong galaxies. Here, we quantify the fraction of galaxies in the Sloan Digital Sky Survey (SDSS) with spectral properties like those of TDE hosts, determining the extent to which TDEs are over-represented in such galaxies. Galaxies whose spectra have Balmer absorption {{H}}{δ }{{A}} - σ(H{δ }{{A}}) > 4 Å (where σ(H{δ }{{A}}) is the error in the Lick {{H}}{δ }{{A}} index) and Hα emission equivalent width (EW) energy-selected TDE Swift J1644 also lies in a galaxy with strong Balmer lines and weak Hα emission, implying a \\gt 80× enhancement in such hosts and providing an observational link between the γ/X-ray-bright and optical/UV-bright TDE classes.

  12. Three intervening galaxy absorbers towards GRB 060418

    Ellison, S. L.; Vreeswijk, P.; Ledoux, C.;

    2006-01-01

    Dust, extinction: galaxies: ISM: quasars: absorption lines: gamma-rays: bursts Udgivelsesdato: 10 August......Dust, extinction: galaxies: ISM: quasars: absorption lines: gamma-rays: bursts Udgivelsesdato: 10 August...

  13. Halpha3: an Halpha imaging survey of HI selected galaxies from ALFALFA. V: The Coma Supercluster survey completion

    Gavazzi, Giuseppe; Viscardi, Elisa; Fossati, Matteo; Savorgnan, Giulia; Fumagalli, Michele; Gutierrez, Leonel; Toledo, Hector Hernandez; Boselli, Alessandro; Giovanelli, Riccardo; Haynes, Martha P

    2015-01-01

    Neutral hydrogen represents the major observable baryonic constituent of galaxies that fuels the formation of stars through the transformation in molecular hydrogen. The emission of the hydrogen recombination line Halpha is the most direct tracer of the process that transforms gas (fuel) into stars. We continue to present Halpha3 (acronym for Halpha-alpha-alpha), an extensive Halpha+[NII] narrow-band imaging campaign of galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA), using the instrumentation available at the San Pedro Martir observatory (Mexico). In only four years since 2011 we were able to complete in 48 nights the Halpha imaging observations of 724 galaxies in the region of the Coma supercluster 10^h < R.A. <16^h; 24^o < Dec. <28^o and 3900selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) and constitute a 97% complete sample. They provide for the first time a complete census of the massive star formation propertie...

  14. The Atacama Cosmology Telescope: the stellar content of galaxy clusters selected using the Sunyaev-Zel'dovich effect

    Hilton, Matt; Sifón, Cristóbal; Baker, Andrew J; Barrientos, L Felipe; Battaglia, Nicholas; Bond, J Richard; Crichton, Devin; Das, Sudeep; Devlin, Mark J; Gralla, Megan; Hajian, Amir; Hincks, Adam D; Hughes, John P; Infante, Leopoldo; Irwin, Kent D; Kosowsky, Arthur; Lin, Yen-Ting; Marriage, Tobias A; Marsden, Danica; Menanteau, Felipe; Moodley, Kavilan; Niemack, Michael D; Nolta, Mike R; Page, Lyman A; Reese, Erik D; Sievers, Jon; Spergel, David N; Wollack, Edward J

    2013-01-01

    We present a first measurement of the stellar mass component of galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect, using 3.6 um and 4.5 um photometry from the Spitzer Space Telescope. Our sample consists of 14 clusters detected by the Atacama Cosmology Telescope (ACT), which span the redshift range 0.27 < z < 1.07 (median z = 0.50), and have dynamical mass measurements, accurate to about 30 per cent, with median M500 = 6.9 x 10^{14} MSun. We measure the 3.6 um and 4.5 um galaxy luminosity functions, finding the characteristic magnitude (m*) and faint-end slope (alpha) to be similar to those for IR-selected cluster samples. We perform the first measurements of the scaling of SZ-observables (Y500 and y0) with both brightest cluster galaxy (BCG) stellar mass and total cluster stellar mass (M500star). We find a significant correlation between BCG stellar mass and Y500 (E(z)^{-2/3} DA^2 Y500 ~ M*^{1.2 +/- 0.6}), although we are not able to obtain a strong constraint on the slope of the relation...

  15. A LABOCA SURVEY OF THE EXTENDED CHANDRA DEEP FIELD SOUTH-SUBMILLIMETER PROPERTIES OF NEAR-INFRARED SELECTED GALAXIES

    Using the 330 hr ESO-MPG 870 μm survey of the Extended Chandra Deep Field South (ECDF-S) obtained with the Large Apex BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX), we have carried out a stacking analysis at submillimeter (submm) wavelengths of a sample of 8266 near-infra-red (near-IR) selected (K vega ≤ 20) galaxies, including 893 BzK galaxies, 1253 extremely red objects (EROs), and 737 distant red galaxies (DRGs), selected from the Multi-wavelength Survey by Yale-Chile (MUSYC). We measure average 870 μm fluxes of 0.22 ± 0.01 mJy (22.0σ), 0.48 ± 0.04 mJy (12.0σ), 0.39 ± 0.03 mJy (13.0σ), and 0.43 ± 0.04 mJy (10.8σ) for the K vega ≤ 20, BzK, ERO, and DRG samples, respectively. For the BzK, ERO, and DRG sub-samples, which overlap to some degree and are likely to be at z ≅ 1-2, this implies an average far-IR luminosity of ∼(1-5) x 1011 Lsun and star formation rate (SFR) of ∼20-90 Msun . Splitting the BzK galaxies into star-forming (sBzK) and passive (pBzK) galaxies, the former is significantly detected (0.50 ± 0.04 mJy, 12.5σ) while the latter is only marginally detected (0.34 ± 0.10 mJy, 3.4σ), thus confirming that the sBzK and pBzK criteria to some extent select obscured, star-forming, and truly passive galaxies, respectively. The K vega ≤ 20 galaxies are found to contribute 7.27 ± 0.34 Jy deg-2 (16.5% ± 5.7%) to the 870 μm extragalactic background light (EBL). sBzK and pBzK galaxies contribute 1.49 ± 0.22 Jy deg-2 (3.4% ± 1.3%) and 0.20 ± 0.14 Jy deg-2 (0.5% ± 0.3%) to the EBL. We present the first delineation of the average submm signal from the K vega ≤ 20 selected galaxies and their contribution to the submm EBL as a function of (photometric) redshift, and find a decline in the average submm signal (and therefore IR luminosity and SFR) by a factor ∼2-3 from z ∼ 2 to z ∼ 0. This is in line with a cosmic star formation history in which the star formation activity in galaxies increases significantly

  16. Absorption of UV-B to blue light radiation by leaf cuticles of selected crop plants

    Plants have protective pigments absorbing destructive shortwave radiation. These pigments have been found in the epidermis and mesophyll of leaves. We studied the absorption characteristics of the leaf cuticle, the outermost part of the epidermis that is directly exposed to radiation. Adaxial leaf cuticles of apple, pear, sour cherry, strawberry, cauliflower, sugarbeet, and 13 other plant species were tested. The UV-B absorption was highest in Citrus aurantium and Citrus maxima (<3 % transmittance) and lowest in sugarbeet and peach (>64 % transmittance). The absorption maxima are at wavelenghts below 320 nm. Significant absorption was also determined at 500 nm, which correlated with cuticle thickness of the plant species (r(2)=0.72). The absorption in the range of 250 to 350 nm is caused by pigments with a high extinction coefficient. This absorption is species dependent and the patterns were designated to three different types. The highest absorption was found in evergreen species. The extraction of cuticular waxes had little effect on absorption. The specific absorption of shortwave radiation by plant cuticles is probably caused by pigments covalently bound to cut in. It is known for some plant species that cuticles can contain the phenolics p-coumaric acid, ferulic acid, and vanillic acid. Mixtures of these phenolics had spectra similar to cuticles. For most species absorption of shortwave radiation by the cuticle alone does not give complete protection

  17. HerMES: The contribution to the cosmic infrared background from galaxies selected by mass and redshift

    Viero, M. P.; Moncelsi, L.; Bock, J.; Bridge, C.; Cooray, A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Quadri, R. F. [Carnegie Observatories, Pasadena, CA 91101 (United States); Arumugam, V.; Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Assef, R. J. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Béthermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Casey, C. M. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conley, A.; Glenn, J. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Heinis, S. [Laboratoire d' Astrophysique de Marseille-LAM, Université d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Ibar, E. [Departamento de Astronomía y Astrofísica, Pontificia Universidad Catolica de Chile, Vicuña Mackenna 4860, Casilla 306, Santiago 22 (Chile); Ikarashi, S.; Kohno, K. [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Oliver, S. J., E-mail: marco.viero@caltech.edu [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); and others

    2013-12-10

    We quantify the fraction of the cosmic infrared background (CIB) that originates from galaxies identified in the UV/optical/near-infrared by stacking 81,250 (∼35.7 arcmin{sup –2}) K-selected sources (K {sub AB} < 24.0) split according to their rest-frame U – V versus V – J colors into 72,216 star-forming and 9034 quiescent galaxies, on maps from Spitzer/MIPS (24 μm), Herschel/PACS (100, 160 μm), Herschel/SPIRE (250, 350, 500 μm), and AzTEC (1100 μm). The fraction of the CIB resolved by our catalog is (69% ± 15%) at 24 μm, (78% ± 17%) at 70 μm, (58% ± 13%) at 100 μm, (78% ± 18%) at 160 μm, (80% ± 17%) at 250 μm, (69% ± 14%) at 350 μm, (65% ± 12%) at 500 μm, and (45% ± 8%) at 1100 μm. Of that total, about 95% originates from star-forming galaxies, while the remaining 5% is from apparently quiescent galaxies. The CIB at λ ≲ 200 μm appears to be sourced predominantly from galaxies at z ≲ 1, while at λ ≳ 200 μm the bulk originates from 1 ≲ z ≲ 2. Galaxies with stellar masses log(M/M {sub ☉}) = 9.5-11 are responsible for the majority of the CIB, with those in the log(M/M {sub ☉}) = 9.5-10 bin contributing mostly at λ < 250 μm, and those in the log(M/M {sub ☉}) = 10-11 bin dominating at λ > 350 μm. The contribution from galaxies in the log(M/M {sub ☉}) = 9.0-9.5 (lowest) and log(M/M {sub ☉}) = 11.0-12.0 (highest) stellar-mass bins contribute the least—both of order 5%—although the highest stellar-mass bin is a significant contributor to the luminosity density at z ≳ 2. The luminosities of the galaxies responsible for the CIB shifts from combinations of 'normal' and luminous infrared galaxies (LIRGs) at λ ≲ 160 μm, to LIRGs at 160 ≲ λ ≲ 500 μm, to finally LIRGs and ultra-luminous infrared galaxies at λ ≳ 500 μm. Stacking analyses were performed using SIMSTACK, a novel algorithm designed to account for possible biases in the stacked flux density due to clustering. It is made available to

  18. High-lying OH absorption, [C II] deficits, and extreme $L_{\\mathrm{FIR}}/M_{\\mathrm{H2}}$ ratios in galaxies

    González-Alfonso, E; Sturm, E; Graciá-Carpio, J; Veilleux, S; Meléndez, M; Lutz, D; Poglitsch, A; Aalto, S; Falstad, N; Spoon, H W W; Farrah, D; Blasco, A; Henkel, C; Contursi, A; Verma, A; Spaans, M; Smith, H A; Ashby, M L N; Hailey-Dunsheath, S; Garc\\'\\ia-Burillo, S; Mart\\'\\in-Pintado, J; van der Werf, P; Meijerink, R; Genzel, R

    2014-01-01

    Herschel/PACS observations of 29 local (Ultra-)Luminous Infrared Galaxies, including both starburst and AGN-dominated sources as diagnosed in the mid-infrared/optical, show that the equivalent width of the absorbing OH 65 um Pi_{3/2} J=9/2-7/2 line (W_{eq}(OH65)) with lower level energy E_{low}~300 K, is anticorrelated with the [C ii]158 um line to far-infrared luminosity ratio, and correlated with the far-infrared luminosity per unit gas mass and with the 60-to-100 um far-infrared color. While all sources are in the active L_{IR}/M_{H2}>50 Lsun/Msun mode as derived from previous CO line studies, the OH65 absorption shows a bimodal distribution with a discontinuity at L_{FIR}/M_{H2}~100 Lsun/Msun. In the most buried sources, OH65 probes material partially responsible for the silicate 9.7 um absorption. Combined with observations of the OH 71 um Pi_{1/2} J=7/2-5/2 doublet (E_{low}~415 K), radiative transfer models characterized by the equivalent dust temperature, Tdust, and the continuum optical depth at 100 u...

  19. Origin and Properties of Strong Mg II Quasar Absorption Line Systems

    2001-01-01

    Strong Mg II quasar absorption line systems provide us with a useful tool to understand the gas that plays an important role in galaxy formation. In this paper, placing the theories of galaxy formation in a cosmological context, we present semi-analytic models and Monte-Carlo simulations for strong Mg II absorbers produced in gaseous galactic haloes and/or galaxy discs. We investigate the redshift path density for the MgII absorption lines and the properties of galaxy/absorber pairs, in particular the anti-correlation between the equivalent width of Mg II absorption line and the projected galaxy-to-sightline distance. The simulated result of the mean redshift path density of strong Mg II systems is consistent with the observational result. The fraction of strong Mg II systems arising from galaxy disks is predicted to be ~ 10% of the total. There exists an anti-correlation between the absorption line equivalent and the projected distance of sightline to galaxy center and galaxy luminosity. We determined that the mean absorbing radius Rabs ≈ 29h-1 kpc(LB/LB*)0.35. After taking selection effects into consideration, this becomes Rabs ≈ 38 h-1 kpc(LB/LB*)0.18, which is in good agreement with the observational result. This shows the importance of considering selection effects when comparing models with observations.

  20. Stellar mass functions of galaxies at 4selected sample in COSMOS/UltraVISTA: limits on the abundance of very massive galaxies

    Stefanon, Mauro; Muzzin, Adam; Brammer, Gabriel G; Dunlop, James S; Franx, Marijin; Fynbo, Johan P U; Labbe, Ivo; Milvang-Jensen, Bo; van Dokkum, Pieter G

    2014-01-01

    We study the population of massive (i.e., $\\log(M_*/M_\\odot)>11$) galaxies at $44$ galaxies with best fit masses $\\log(M_*/M_\\odot)>11$ by 83% implying a rapid growth of very massive galaxies in the first 1.5 Gyr of cosmic history. From the stellar-mass complete sample, we identify one candidate of a very massive ($\\log(M_*/M_\\odot)\\sim11.5$), quiescent galaxy at $z\\sim5.4$, with MIPS $24\\mu$m detection suggesting the presence of a powerful obscured AGN. Finally, we show that the number of massive galaxies at $4galaxies at $3galaxy formation.

  1. Finding {\\eta} Car Analogs in Nearby Galaxies Using Spitzer: I. Candidate Selection

    Khan, Rubab; Kochanek, C S

    2012-01-01

    The late-stage evolution of the most massive stars such as {\\eta} Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of {\\eta} Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of 7 nearby (= 40 M_sun star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude.

  2. WHAT DOES A SUBMILLIMETER GALAXY SELECTION ACTUALLY SELECT? THE DEPENDENCE OF SUBMILLIMETER FLUX DENSITY ON STAR FORMATION RATE AND DUST MASS

    Hayward, Christopher C.; Keres, Dusan; Jonsson, Patrik; Narayanan, Desika; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Cox, T. J., E-mail: chayward@cfa.harvard.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2011-12-20

    We perform three-dimensional dust radiative transfer (RT) calculations on hydrodynamic simulations of isolated and merging disk galaxies in order to quantitatively study the dependence of observed-frame submillimeter (submm) flux density on galaxy properties. We find that submm flux density and star formation rate (SFR) are related in dramatically different ways for quiescently star-forming galaxies and starbursts. Because the stars formed in the merger-induced starburst do not dominate the bolometric luminosity and the rapid drop in dust mass and more compact geometry cause a sharp increase in dust temperature during the burst, starbursts are very inefficient at boosting submm flux density (e.g., a {approx}> 16 Multiplication-Sign boost in SFR yields a {approx}< 2 Multiplication-Sign boost in submm flux density). Moreover, the ratio of submm flux density to SFR differs significantly between the two modes; thus one cannot assume that the galaxies with highest submm flux density are necessarily those with the highest bolometric luminosity or SFR. These results have important consequences for the bright submillimeter-selected galaxy (SMG) population. Among them are: (1) The SMG population is heterogeneous. In addition to merger-driven starbursts, there is a subpopulation of galaxy pairs, where two disks undergoing a major merger but not yet strongly interacting are blended into one submm source because of the large ({approx}> 15'' or {approx}130 kpc at z = 2) beam of single-dish submm telescopes. (2) SMGs must be very massive (M{sub *} {approx}> 6 Multiplication-Sign 10{sup 10} M{sub Sun }). (3) The infall phase makes the SMG duty cycle a factor of a few greater than what is expected for a merger-driven starburst. Finally, we provide fitting functions for SCUBA and AzTEC submm flux densities as a function of SFR and dust mass and bolometric luminosity and dust mass; these should be useful for calculating submm flux density in semi-analytic models and

  3. Low Surface Brightness Galaxies selected from the 40% sky area of the ALFALFA HI survey.I.Sample and statistical properties

    Du, Wei; Lam, Man I; Zhu, Yinan; Lei, Fengjie; Zhou, Zhimin

    2015-01-01

    The population of Low Surface Brightness (LSB) galaxies is crucial for understanding the extremes of galaxy formation and evolution of the universe. As LSB galaxies are mostly rich in gas (HI), the alpha.40-SDSS DR7 sample is absolutely one of the best survey combinations to select a sample of them in the local Universe. Since the sky backgrounds are systematically overestimated for galaxy images by the SDSS photometric pipeline, particularly for luminous galaxies or galaxies with extended low surface brightness outskirts, in this paper, we above all estimated the sky backgrounds of SDSS images in the alpha.40-SDSS DR7 sample, using a precise method of sky subtraction. Once subtracting the sky background, we did surface photometry with the Kron elliptical aperture and fitted geometric parameters with an exponential profile model for each galaxy image. Basing on the photometric and geometric results, we further calculated the B-band central surface brightness, mu_{0}(B), for each galaxy and ultimately defined ...

  4. Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

    2012-01-01

    We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  5. The host galaxy properties of variability selected AGN in the Pan-STARRS1 Medium-Deep Survey

    Heinis, S; Kumar, S; Burgett, W S; Flewelling, H; Huber, M E; Kaiser, N; Wainscoat, R J; Waters, C

    2016-01-01

    We study the properties of 975 active galactic nuclei (AGN) selected by variability in the Pan-STARRS1 Medium-Deep Survey. Using complementary multi wavelength data from the ultraviolet to the far-infrared, we use SED fitting to determine the AGN and host properties at $z<1$, and compare to a well-matched control sample. We confirm the trend previously observed that the variability amplitude decreases with AGN luminosity, but on the other hand, we observe that the slope of this relation steepens with wavelength resulting in a "redder when brighter" trend at low luminosities. Our results show that AGN are hosted by more massive hosts than control sample galaxies, while the restframe, dust-corrected $NUV-r$ color distribution of AGN hosts is similar to control galaxies. We find a positive correlation between the AGN luminosity and star formation rate (SFR), independent of redshift. AGN hosts populate the whole range of SFRs within and outside the Main Sequence of star forming galaxies. Comparing the distribu...

  6. Galaxy evolution in the high redshift, colour-selected cluster RzCS 052 at z=1.02

    Andreon, S; De Propris, R; Cuillandre, J -C

    2008-01-01

    We present deep I and z' imaging of the colour-selected cluster RzCS 052 and study the color-magnitude relation of this cluster, its scatter, the morphological distribution on the red sequence, the luminosity and stellar mass functions of red galaxies and the cluster blue fraction. We find that the stellar populations of early type galaxies in this cluster are uniformly old and that their luminosity function does not show any sign of evolution other than the passive evolution of their stellar populations. We rule out a significant contribution from mergers in the buildup of the red sequence of RzCS 052. The cluster has a large (~30%) blue fraction and and we infer that the evolution of the blue galaxies is faster than an exponentially declining star formation model and that these objects have probably experienced starburst episodes. Mergers are unlikely to be the driver of the observed colour evolution, because of the measured constancy of the mass function, as derived from near-infrared photometry of 32 clus...

  7. First Science with SHARDS: emission line galaxies

    Cava, Antonio

    2012-01-01

    SHARDS (Survey for High-z Absorption Red & Dead Sources) is an unbiased ultra-deep spectro-photometric survey with GTC@OSIRIS aimed at selecting and studying massive passively evolving galaxies at z=1.0-2.3 using a set of 24 medium-band filters (FWHM\\sim17 nm) at 500-950 nm in GOODS-N. Our observing strategy is optimized to detect at z>1 the prominent Mg absorption feature at rest-frame ~280 nm, a distinctive, necessary, and sufficient feature of evolved stellar populations. Nonetheless, the data quality allow a plethora of studies on galaxy populations, including Emission Lines Galaxies (ELGs) about which we have started our first science verification project presented in this contribution.

  8. CO emissions from optically selected galaxies at z~0.1-0.2: Tight anti-correlation between molecular gas fraction and 4000 \\AA break strength

    Morokuma-Matsui, Kana; Sorai, Kazuo; Kuno, Nario

    2015-01-01

    We performed 12CO(J=1-0) (hereafter, CO) observations towards 12 normal star-forming galaxies with stellar mass of Mstar=10^10.6-10^11.3 Msun at z=0.1-0.2 with the 45-m telescope at the Nobeyama Radio Observatory (NRO). The samples are selected with Dn(4000) that is a strength of the 4000 \\AA break, instead of commonly used far-infrared (FIR) flux. We successfully detect the CO emissions from eight galaxies with signal-to-noise ratio (S/N) larger than three, demonstrating the effectiveness of the Dn(4000)-based sample selection. For the first time, we find a tight anti-correlation between Dn(4000) and molecular gas fraction (fmol) using literature data of nearby galaxies in which the galaxies with more fuel for star formation have younger stellar populations. We find that our CO-detected galaxies at z~0.1-0.2 also follow the same relation of nearby galaxies. This implies that the galaxies evolve along this Dn(4000)-fmol relation, and that Dn(4000) seems to be used as a proxy for fmol which requires many time-...

  9. CO Emissions from Optically Selected Galaxies at z˜0.1-0.2: Tight Anti-Correlation Between Molecular Gas Fraction and 4000 Angstrom Break Strength

    Morokuma-Matsui, K.; Baba, J.; Sorai, K.; Kuno, N.

    2015-12-01

    We performed 12CO(J=1-0) (hereafter, CO) observations towards 12 normal star-forming galaxies with M⋆=1010.6-1011.3 M⊙ at z=0.1-0.2 with the 45-m telescope at the Nobeyama Radio Observatory (NRO). The samples are selected with Dn(4000) that is a measure of the 4000 Angstrom break strength, instead of commonly used far-infrared (FIR) flux. We detect the CO emissions from 8 galaxies with signal-to-noise ratio (S/N) larger than 3, demonstrating the effectiveness of the Dn(4000)-based sample selection. We find a tight anti-correlation between Dn(4000) and molecular gas fraction (fmol) using literature data of nearby galaxies in which the galaxies with more fuel for star formation have younger stellar populations. CO-detected galaxies at z˜0.1-0.2 also follow the same relation of nearby galaxies, implying 1) the galaxies evolve along this Dn(4000)-fmol relation, and 2) Dn(4000) seems to be used as a proxy for fmol which requires many time-consuming observations1.

  10. AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies

    Conselice, C J; Georgakakis, A; Almaini, O; Coil, A L; Cooper, M C; Eisenhardt, P; Foucaud, S; Koekemoer, A; Lotz, J; Noeske, K F; Weiner, B; Willmer, C N A

    2006-01-01

    We use deep and wide near infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra Space Telescope imaging to investigate the nature of galaxies that are red in NIR colors. We locate these `distant red galaxies' (DRGs) through the color cut (J-K)_{vega} > 2.3 over 0.7 deg^{2}, where we find 1010 DRG candidates down to K_s = 20.5. We combine 95 high quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J-K)_{vega}>2.3 galaxies with K_s2 systems massive with M_*>10^{11} M_solar. HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact (57%), and the remainder edge-on spirals (7%), and peculiar galaxies (29%). The DRGs at z < 1.4 with high quality spec...

  11. Rest-frame Optical Emission Lines in Far-Infrared Selected Galaxies at z<1.7 from the FMOS-COSMOS Survey

    Kartaltepe, Jeyhan S; Silverman, J D; Kashino, D; Chu, J; Zahid, H; Hasinger, G; Kewley, L; Matsuoka, K; Nagao, T; Riguccini, L; Salvato, M; Schawinski, K; Taniguchi, Y; Treister, E; Capak, P; Daddi, E; Ohta, K

    2015-01-01

    We have used FMOS on Subaru to obtain near-infrared spectroscopy of 123 far-infrared selected galaxies in COSMOS and obtain the key rest-frame optical emission lines. This is the largest sample of infrared galaxies with near-infrared spectroscopy at these redshifts. The far-infrared selection results in a sample of galaxies that are massive systems that span a range of metallicities in comparison with previous optically selected surveys, and thus has a higher AGN fraction and better samples the AGN branch. We establish the presence of AGN and starbursts in this sample of (U)LIRGs selected as Herschel-PACS and Spitzer-MIPS detections in two redshift bins (z~0.7 and z~1.5) and test the redshift dependence of diagnostics used to separate AGN from star-formation dominated galaxies. In addition, we construct a low redshift (z~0.1) comparison sample of infrared selected galaxies and find that the evolution from z~1.5 to today is consistent with an evolving AGN selection line and a range of ISM conditions and metall...

  12. Tunable ultranarrow spectrum selective absorption in a graphene monolayer at terahertz frequency

    Wu, Jun

    2016-06-01

    Complete absorption in a graphene monolayer at terahertz frequency through the critical coupling effect is investigated. It is achieved by sandwiching the graphene monolayer between a dielectric grating and a Bragg grating. The designed graphene absorber exhibits near-unity absorption at resonance but with an ultranarrow spectrum and antenna-like response, which is attributed to the combined effects of guided mode resonance with dielectric grating and the photonic band gap with Bragg grating. In addition to numerical simulation, the electric field distributions are also illustrated to provide a physical understanding of the perfect absorption effect. Furthermore, the absorption performance can be tuned by only changing the Fermi level of graphene, which is beneficial for real application. It is believed that this study may be useful for designing next-generation graphene-based optoelectronic devices.

  13. The MOSFIRE Deep Evolution Field (MOSDEF) Survey: Rest-Frame Optical Spectroscopy For ~1500 H-Selected Galaxies at 1.37 < z < 3.8

    Kriek, Mariska; Reddy, Naveen A; Siana, Brian; Coil, Alison L; Mobasher, Bahram; Freeman, William R; de Groot, Laura; Price, Sedona H; Sanders, Ryan; Shivaei, Irene; Brammer, Gabriel B; Momcheva, Ivelina G; Skelton, Rosalind E; van Dokkum, Pieter G; Whitaker, Katherine E; Aird, James; Azadi, Mojegan; Kassis, Marc; Bullock, James S; Conroy, Charlie; Dave, Romeel; Keres, Dusan; Krumholz, Mark

    2014-01-01

    In this paper we present the MOSFIRE Deep Evolution Field (MOSDEF) survey. The MOSDEF survey aims to obtain moderate-resolution (R=3000-3650) rest-frame optical spectra (~3700-7000 Angstrom) for ~1500 galaxies at 1.37selected in three redshift intervals: 1.37absorption features (e.g., Balmer lines, Ca-II H and K, Mgb, 4000 Angstrom break). Here we present an overview of our survey, the observational strategy, the data reduction and analysis, and the sample characteristics based on spectra obtained during the first 24 nights. To date, we have completed 21 masks, obtaining spectra for 591 ...

  14. Emergence of a Broad-Absorption-Line Outflow in the Narrow-line Seyfert 1 Galaxy WPVS 007

    Leighly, Karen M; Casebeer, Darrin A; Grupe, Dirk

    2009-01-01

    We report results from a 2003 FUSE observation, and reanalysis of a 1996 HST observation of the unusual X-ray transient Narrow-line Seyfert 1 galaxy WPVS 007. The HST FOS spectrum revealed mini-BALs with V_max ~ 900 km s^-1 and FWHM ~ 550 km s^-1. The FUSE spectrum showed that an additional BAL outflow with V_max ~ 6000 km s^-1 and FWHM ~ 3400 km s^-1 had appeared. WPVS 007 is a low-luminosity object in which such a high velocity outflow is not expected; therefore, it is an outlier on the M_V/V_max relationship. Template spectral fitting yielded apparent ionic columns, and a Cloudy analysis showed that the presence of PV requires a high ionization parameter log(U) >= 0 and high column density log(N_H) >= 23 assuming solar abundances and a nominal SED for low-luminosity NLS1s with alpha_ox=-1.28. A recent long Swift observation revealed the first hard X-ray detection and an intrinsic (unabsorbed) alpha_ox ~ -1.9$. Using this SED in our analysis yielded lower column density constraints (log(N_H) >= 22.2 for Z=1...

  15. Ammonia thermometry of star-forming galaxies

    With a goal toward deriving the physical conditions in external galaxies, we present a study of the ammonia (NH3) emission and absorption in a sample of star-forming systems. Using the unique sensitivities to kinetic temperature afforded by the excitation characteristics of several inversion transitions of NH3, we have continued our characterization of the dense gas in star-forming galaxies by measuring the kinetic temperature in a sample of 23 galaxies and one galaxy offset position selected for their high infrared luminosity. We derive kinetic temperatures toward 13 galaxies, 9 of which possess multiple kinetic temperature and/or velocity components. Eight of these galaxies exhibit kinetic temperatures >100 K, which are in many cases at least a factor of two larger than kinetic temperatures derived previously. Furthermore, the derived kinetic temperatures in our galaxy sample, which are in many cases at least a factor of two larger than derived dust temperatures, point to a problem with the common assumption that dust and gas kinetic temperatures are equivalent. As previously suggested, the use of dust emission at wavelengths greater than 160 μm to derive dust temperatures, or dust heating from older stellar populations, may be skewing derived dust temperatures in these galaxies to lower values. We confirm the detection of high-excitation OH 2Π3/2 J = 9/2 absorption toward Arp 220. We also report the first detections of non-metastable NH3 inversion transitions toward external galaxies in the (2,1) (NGC 253, NGC 660, IC 342, and IC 860), (3,1), (3,2), (4,3), (5,4) (all in NGC 660), and (10,9) (Arp 220) transitions.

  16. Rotation of halos in open and closed universes - differentiated merging and natural selection of galaxy types

    Computer simulations are used here to study the properties of galactic halos formed from Gaussian initial density perturbations in both open and closed dark matter universes. It is shown that if galaxies form through gravitational collapse from initial, Gaussian density perturbations, then their luminous parts do not have the original values of either specific angular momentum (ellipticals) or spin parameter lambda (spirals). The rotational properties of a halo depend only weakly on either the halo density or the density of its environment. Variations of the large-scale density of the environment have an expected, dramatic effect on the density of individual halos. Dissipationless merging forces the cores of the merging objects into the core of the merger product. In the process, cores become more bound and lose angular momentum. These findings are extrapolated to propose a model for galaxy formation in which both ellipticals and spirals come into being through mergers. 59 references

  17. The SCUBA HAlf Degree Extragalactic Survey (SHADES) - V. Submillimetre properties of near-infrared-selected galaxies in the Subaru/XMM -Newton deep field

    Takagi, T.; Mortier, A. M. J.; Shimasaku, K.; Coppin, K.; Pope, A.; Ivison, R. J.; Hanami, H.; Serjeant, S.; Clements, D. L.; Priddey, R. S.; Dunlop, J. S.; Takata, T.; Aretxaga, I.; Chapman, S. C.; Eales, S. A.; Farrah, D.; Granato, G. L.; Halpern, M.; Hughes, D. H.; van Kampen, E.; Scott, D.; Sekiguchi, K.; Smail, I.; Vaccari, M.

    2007-11-01

    We have studied the submillimetre (submm) properties of the following classes of near-infrared-selected (NIR-selected) massive galaxies at high redshifts: BzK-selected star-forming galaxies (BzKs); distant red galaxies (DRGs); and extremely red objects (EROs). We used the SCUBA HAlf Degree Extragalactic Survey (SHADES), the largest uniform submm survey to date. Partial overlap of SIRIUS/NIR images and SHADES in Subaru/XMM-Newton deep field has allowed us to identify four submm-bright NIR-selected galaxies, which are detected in the mid-IR, 24μ m, and the radio, 1.4GHz. We find that all of our submm-bright NIR-selected galaxies satisfy the BzK selection criteria, i.e. BzK ≡ (z - K)AB - (B - z)AB >= -0.2, except for one galaxy whose B - z and z - K colours are however close to the BzK colour boundary. Two of the submm-bright NIR-selected galaxies satisfy all of the selection criteria we considered, i.e. they belong to the BzK-DRG-ERO overlapping population, or `extremely red' BzKs. Although these extremely red BzKs are rare (0.25 arcmin-2), up to 20 per cent of this population could be submm galaxies. This fraction is significantly higher than that found for other galaxy populations studied here. Via a stacking analysis, we have detected the 850-μ m flux of submm-faint BzKs and EROs in our SCUBA maps. While the contribution of z ~ 2 BzKs to the submm background is about 10-15 per cent and similar to that from EROs typically at z ~ 1, BzKs have a higher fraction (~30 per cent) of submm flux in resolved sources compared with EROs and submm sources as a whole. From the spectral energy distribution (SED) fitting analysis for both submm-bright and submm-faint BzKs, we found no clear signature that submm-bright BzKs are experiencing a specifically luminous evolutionary phase, compared with submm-faint BzKs. An alternative explanation might be that submm-bright BzKs are more massive than submm-faint ones.

  18. NGC 4656UV: A UV-SELECTED TIDAL DWARF GALAXY CANDIDATE

    We report the discovery of a UV-bright tidal dwarf galaxy (TDG) candidate in the NGC 4631/4656 galaxy group, which we designate NGC 4656UV. Using survey and archival data spanning from 1.4 GHz to the ultraviolet, we investigate the gas kinematics and stellar properties of this system. The H I morphologies of NGC 4656UV and its parent galaxy NGC 4656 are extremely disturbed, with significant amounts of counterrotating and extraplanar gas. From UV-FIR photometry, computed using a new method to correct for surface gradients on faint objects, we find that NGC 4656UV has no significant dust opacity and a blue spectral energy distribution. We compute a star formation rate of 0.027 M☉ yr–1 from the far-ultraviolet flux and measure a total H I mass of 3.8 × 108 M☉ for the object. Evolutionary synthesis modeling indicates that NGC 4656UV is a low-metallicity system whose only major burst of star formation occurred within the last ∼260-290 Myr. The age of the stellar population is consistent with a rough timescale for a recent tidal interaction between NGC 4656 and NGC 4631, although we discuss the true nature of the object—whether it is tidal or pre-existing in origin—in the context of its metallicity being a factor of 10 lower than its parent galaxy. We estimate that NGC 4656UV is either marginally bound or unbound. If bound, it contains relatively low amounts of dark matter. The abundance of archival data allows for a deeper investigation into this dynamic system than is currently possible for most TDG candidates.

  19. Submillimetre observations of WISE-selected high-redshift, luminous, dusty galaxies

    Jones, Suzy F; Stern, Daniel; Assef, Roberto J; Bridge, Carrie R; Eisenhardt, Peter; Petty, Sara; Wu, Jingwen; Tsai, Chao-Wei; Cutri, Roc; Wright, Edward L; Yan, Lin

    2014-01-01

    We present SCUBA-2 850um submillimetre (submm) observations of the fields of 10 dusty, luminous galaxies at z ~ 1.7 - 4.6, detected at 12um and/or 22um by the WISE all-sky survey, but faint or undetected at 3.4um and 4.6um; dubbed hot, dust-obscured galaxies (Hot DOGs). The six detected targets all have total infrared luminosities greater than 10^13 L_sun, with one greater than 10^14 L_sun. Their spectral energy distributions (SEDs) are very blue from mid-infrared to submm wavelengths and not well fitted by standard AGN SED templates, without adding extra dust extinction to fit the WISE 3.4um and 4.6um data. The SCUBA-2 850um observations confirm that the Hot DOGs have less cold and/or more warm dust emission than standard AGN templates, and limit an underlying extended spiral or ULIRG-type galaxy to contribute less than about 2% or 55% of the typical total Hot DOG IR luminosity, respectively. The two most distant and luminous targets have similar observed submm to mid-infrared ratios to the rest, and thus ap...

  20. SPIDERS: the spectroscopic follow-up of X-ray selected clusters of galaxies in SDSS-IV

    Clerc, Nicolas; Zhang, Yu-Ying; Finoguenov, Alexis; Dwelly, Tom; Nandra, Kirpal; Collins, Chris A; Dawson, Kyle; Kneib, Jean-Paul; Rozo, Eduardo; Rykoff, Eli; Sadibekova, Tatyana; Brownstein, Joel R; Lin, Yen-Ting; Ridl, Jethro; Salvato, Mara; Schwope, Axel; Steinmetz, Matthias; Seo, Hee-Jong; Tinker, Jeremy

    2016-01-01

    SPIDERS (The SPectroscopic IDentification of eROSITA Sources) is a program dedicated to the homogeneous and complete spectroscopic follow-up of X-ray AGN and galaxy clusters over a large area ($\\sim$7500 deg$^2$) of the extragalactic sky. SPIDERS is part of the SDSS-IV project, together with the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) and the Time-Domain Spectroscopic Survey (TDSS). This paper describes the largest project within SPIDERS before the launch of eROSITA: an optical spectroscopic survey of X-ray selected, massive ($\\sim 10^{14}$ to $10^{15}~M_{\\odot}$) galaxy clusters discovered in ROSAT and XMM-Newton imaging. The immediate aim is to determine precise ($\\Delta_z \\sim 0.001$) redshifts for 4,000-5,000 of these systems out to $z \\sim 0.6$. The scientific goal of the program is precision cosmology, using clusters as probes of large-scale structure in the expanding Universe. We present the cluster samples, target selection algorithms and observation strategies. We demonstrate the eff...

  1. THE BOSS EMISSION-LINE LENS SURVEY (BELLS). I. A LARGE SPECTROSCOPICALLY SELECTED SAMPLE OF LENS GALAXIES AT REDSHIFT {approx}0.5

    Brownstein, Joel R.; Bolton, Adam S.; Pandey, Parul [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard College Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Seitz, Stella [University Observatory Munich, Scheinstrasse 1, 81679 Muenchen (Germany); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Wood-Vasey, W. Michael [Pittsburgh Center for Particle Physics, Astrophysics, and Cosmology (PITT-PACC), Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, PA 16802 (United States); Weaver, Benjamin A. [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2012-01-01

    We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 {approx}< z {approx}< 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution.

  2. Halpha3: an Halpha imaging survey of HI selected galaxies from ALFALFA. III. Nurture shapes up the Hubble sequence in the Great Wall

    Gavazzi, Giuseppe; Fossati, Matteo; Dotti, Massimo; Fumagalli, Michele; Boselli, Alessandro; Gutierrez, Leonel; Toledo, Hector Hernandez; Giovanelli, Riccardo; Haynes, Martha P

    2013-01-01

    We present the analysis of Halpha3, an Halpha imaging survey of galaxies selected from the HI ALFALFA Survey in the Coma Supercluster. By using the Halpha line as a tracer of the "instantaneous" star formation, complemented with optical colors from SDSS we explore the hypothesis that a morphological sequence of galaxies of progressively earlier type, lower gas-content exists in the neighborhood of the Coma cluster, with specific star formation activity decreasing with increasing local galaxy density and velocity dispersion. In the dwarf regime (8.5<\\log(M*)< 9.5) we identify a 4-step sequence of galaxies with progressively redder colors, i.e. of decreasing specific star formation, from (1) HI-rich Late-Type Galaxies belonging to the blue-cloud exhibiting extended plus nuclear star formation, (2) HI-poor LTGs with nuclear star formation only, (3) HI-poor galaxies with no star formation either extended or nuclear, but with nuclear Post-Star-Burst signature,(4) Early-type Galaxies in the red-sequence, with...

  3. Selective spatial damping of propagating kink waves due to resonant absorption

    Terradas, J; Verth, G

    2010-01-01

    There is observational evidence of propagating kink waves driven by photospheric motions. These disturbances, interpreted as kink magnetohydrodynamic (MHD) waves are attenuated as they propagate upwards in the solar corona. In this paper we show that resonant absorption provides a simple explanation to the spatial damping of these waves. Kink MHD waves are studied using a cylindrical model of solar magnetic flux tubes which includes a non-uniform layer at the tube boundary. Assuming that the frequency is real and the longitudinal wavenumber complex, the damping length and damping per wavelength produced by resonant absorption are analytically calculated. The damping length of propagating kink waves due resonant absorption is a monotonically decreasing function of frequency. For kink waves with low frequencies the damping length is exactly inversely proportional to frequency and we denote this as the TGV relation. When moving to high frequencies the TGV relation continues to be an exceptionally good approximat...

  4. SEARCH FOR GAMMA-RAY EMISSION FROM X-RAY-SELECTED SEYFERT GALAXIES WITH FERMI-LAT

    Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Buehler, R.; Cameron, R. A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d' Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M. [Dipartimento di Fisica ' M. Merlin' dell' Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3,F-91128 Palaiseau (France); Caliandro, G. A., E-mail: mahaya@slac.stanford.edu, E-mail: bechtol@stanford.edu, E-mail: madejski@slac.stanford.edu, E-mail: stawarz@astro.isas.jaxa.jp, E-mail: mahaya@slac.stanford.edu, E-mail: stawarz@astro.isas.jaxa.jp, E-mail: bechtol@stanford.edu, E-mail: madejski@slac.stanford.edu [Institut de Ciencies de l' Espai (IEEE-CSIC), Campus UAB, E-08193 Barcelona (Spain); and others

    2012-03-10

    We report on a systematic investigation of the {gamma}-ray properties of 120 hard X-ray-selected Seyfert galaxies classified as 'radio-quiet' objects, utilizing the three-year accumulation of Fermi Large Area Telescope (LAT) data. Our sample of Seyfert galaxies is selected using the Swift Burst Alert Telescope 58 month catalog, restricting the analysis to the bright sources with average hard X-ray fluxes F{sub 14-195keV} {>=} 2.5 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1} at high Galactic latitudes (|b| > 10 Degree-Sign ). In order to remove 'radio-loud' objects from the sample, we use the 'hard X-ray radio loudness parameter', R{sub rX}, defined as the ratio of the total 1.4 GHz radio to 14-195 keV hard X-ray energy fluxes. Among 120 X-ray bright Seyfert galaxies with R{sub rX} <10{sup -4}, we did not find a statistically significant {gamma}-ray excess (TS > 25) positionally coincident with any target Seyferts, with possible exceptions of ESO 323-G077 and NGC 6814. The mean value of the 95% confidence level {gamma}-ray upper limit for the integrated photon flux above 100 MeV from the analyzed Seyferts is {approx_equal} 4 Multiplication-Sign 10{sup -9} photons cm{sup -2} s{sup -1} , and the upper limits derived for several objects reach {approx_equal} 1 Multiplication-Sign 10{sup -9} photons cm{sup -2} s{sup -1} . Our results indicate that no prominent {gamma}-ray emission component related to active galactic nucleus activity is present in the spectra of Seyferts around GeV energies. The Fermi-LAT upper limits derived for our sample probe the ratio of {gamma}-ray to X-ray luminosities L{sub {gamma}}/L{sub X} < 0.1, and even <0.01 in some cases. The obtained results impose novel constraints on the models for high-energy radiation of 'radio-quiet' Seyfert galaxies.

  5. Galaxies in X-ray Selected Clusters and Groups in Dark Energy Survey Data: Stellar Mass Growth of Bright Central Galaxies Since z~1.2

    Zhang, Y; Mckay, T; Rooney, P; Evrard, A E; Romer, A K; Perfecto, R; Song, J; Desai, S; Mohr, J; Wilcox, H; Bermeo, A; Jeltema, T; Hollowood, D; Bacon, D; Capozzi, D; Collins, C; Das, R; Gerdes, D; Hennig, C; Hilton, M; Hoyle, B; Kay, S; Liddle, A; Mann, R G; Mehrtens, N; Nichol, R C; Papovich, C; Sahlén, M; Soares-Santos, M; Stott, J; Viana, P T; Abbott, T; Abdalla, F B; Banerji, M; Bauer, A H; Benoit-Lévy, A; Bertin, E; Brooks, D; Buckley-Geer, E; Burke, D L; Rosell, A Carnero; Castander, F J; Diehl, H T; Doel, P; Cunha, C E; Eifler, T F; Neto, A Fausti; Fernandez, E; Flaugher, B; Fosalba, P; Frieman, J; Gaztanaga, E; Gruen, D; Gruendl, R A; Honscheid, K; James, D; Kuehn, K; Kuropatkin, N; Lahav, O; Maia, M A G; Makler, M; Marshall, J L; Martini, Paul; Miquel, R; Ogando, R; Plazas, A A; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla, I; Smith, R C; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Tucker, D; Vikram, V; Da Costa, L N

    2015-01-01

    Using the science verification data of the Dark Energy Survey (DES) for a new sample of 106 X-Ray selected clusters and groups, we study the stellar mass growth of Bright Central Galaxies (BCGs) since redshift 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into analysis of a redshift-dependent BCG-cluster mass relation, $m_{*}\\propto(\\frac{M_{200}}{1.5\\times 10^{14}M_{\\odot}})^{0.24\\pm 0.08}(1+z)^{-0.19\\pm0.34}$, and compare the observed relation to the simulation prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of $M_{200, z}=10^{13.8}M_{\\odot}$, at $z=1.0$: $m_{*, BCG}$ appears to have grown by $0.13\\pm0.11$ dex, in tension at $\\sim 2.5 \\sigma$ significance level with the 0.4 dex growth rate expected in the simulation. We show that...

  6. Galaxies in X-Ray Selected Clusters and Groups in Dark Energy Survey Data. I. Stellar Mass Growth of Bright Central Galaxies since z~1.2

    Zhang, Y.; Miller, C.; McKay, T.; Rooney, P.; Evrard, A. E.; Romer, A. K.; Perfecto, R.; Song, J.; Desai, S.; Mohr, J.; Wilcox, H.; Bermeo-Hernandez, A.; Jeltema, T.; Hollowood, D.; Bacon, D.; Capozzi, D.; Collins, C.; Das, R.; Gerdes, D.; Hennig, C.; Hilton, M.; Hoyle, B.; Kay, S.; Liddle, A.; Mann, R. G.; Mehrtens, N.; Nichol, R. C.; Papovich, C.; Sahlén, M.; Soares-Santos, M.; Stott, J.; Viana, P. T.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Castander, F. J.; Diehl, H. T.; Doel, P.; Cunha, C. E.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marshall, J. L.; Martini, Paul; Miquel, R.; Ogando, R.; Plazas, A. A.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla, I.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Tucker, D.; Vikram, V.; da Costa, L. N.

    2016-01-01

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z ~ 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, {m}*∝ ({M}200}/{1.5×{10}14{M}⊙}) 0.24+/-0.08(1+z)-0.19+/- 0.34, and compare the observed relation to the model prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of M200,z = 1013.8 M⊙ at z = 1.0: m*,BCG appears to have grown by 0.13 ± 0.11 dex, in tension at the ˜2.5σ significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z = 1.0 may alleviate this tension in BCG growth rates.

  7. A Wide Area Survey for High-redshift Massive Galaxies. II. Near-infrared Spectroscopy of BzK-selected Massive Star-forming Galaxies

    Onodera, Masato; Daddi, Emanuele; Renzini, Alvio; Kong, Xu; Cimatti, Andrea; Broadhurst, Tom; Alexander, Dave M

    2010-01-01

    Results are presented from NIR spectroscopy of a sample of BzK-selected, massive star-forming galaxies (sBzKs) at 1.5

  8. Spot the difference. Impact of different selection criteria on early-type galaxies observed properties in zCOSMOS 20-k sample

    Moresco, M; Cimatti, A; Zamorani, G; Bolzonella, M; Lamareille, F; Mignoli, M; Zucca, E; Lilly, S J; Carollo, C M; Contini, T; Kneib, J -P; Fevre, O Le; Mainieri, V; Renzini, A; Scodeggio, M; Bardelli, S; Bongiorno, A; Caputi, K; Cucciati, O; de la Torre, S; de Ravel, L; Franzetti, P; Garilli, B; Iovino, A; Kampczyk, P; Knobel, C; Kovac, K; Borgne, J -F Le; Brun, V Le; Maier, C; Pello', R; Peng, Y; Perez-Montero, E; Presotto, V; Silverman, J D; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Barnes, L; Bordoloi, R; Cappi, A; Diener, C; Koekemoer, A M; Floch, E Le; Lopez-Sanjuan, C; McCracken, H J; Nair, P; Oesch, P; Scarlata, C; Scoville, N; Welikala, N

    2013-01-01

    We present the analysis of photometric, spectroscopic and morphological properties for differently selected samples of early-type galaxies up to z=1 extracted from the zCOSMOS-20k spectroscopic survey. This analysis intends to explore the dependence of galaxy properties on the selection criterion adopted, to study the degree of contamination due to blue/star-forming/non-passive outliers, and to provide a comparison between different commonly used selection criteria. We extracted from the zCOSMOS-20k catalog 6 different samples of early-type galaxies based on morphology, optical colors, specific star formation rate, a best-fit to the observed spectral energy distribution, and a criterion combining morphological, spectroscopic and photometric informations. The "morphological" sample has the higher percentage of contamination in colors, specific star formation rate and presence of emission lines, while the "pure passive" sample is the purest, with properties mostly compatible with no star formation activity; how...

  9. UV to IR Luminosities and Dust Attenuation Determined from ~4000 K-selected Galaxies at 1 < z < 3 in the ZFOURGE Survey

    Forrest, Ben; Tran, Kim-Vy H.; Tomczak, Adam R.; Broussard, Adam; Labbé, Ivo; Papovich, Casey; Kriek, Mariska; Allen, Rebecca J.; Cowley, Michael; Dickinson, Mark; Glazebrook, Karl; van Houdt, Josha; Inami, Hanae; Kacprzak, Glenn G.; Kawinwanichakij, Lalitwadee; Kelson, Daniel; McCarthy, Patrick J.; Monson, Andrew; Morrison, Glenn; Nanayakkara, Themiya; Persson, S. Eric; Quadri, Ryan F.; Spitler, Lee R.; Straatman, Caroline; Tilvi, Vithal

    2016-02-01

    We build a set of composite galaxy spectral energy distributions (SEDs) by de-redshifting and scaling multi-wavelength photometry from galaxies in the ZFOURGE survey, covering the CDFS, COSMOS, and UDS fields. From a sample of ˜4000 Ks-band selected galaxies, we define 38 composite galaxy SEDs that yield continuous low-resolution spectra (R ˜ 45) over the rest-frame range 0.1-4 μm. Additionally, we include far infrared photometry from the Spitzer Space Telescope and the Herschel Space Observatory to characterize the infrared properties of our diverse set of composite SEDs. From these composite SEDs we analyze the rest-frame UVJ colors, as well as the ratio of IR to UV light (IRX) and the UV slope (β) in the IRX-β dust relation at 1 Telescopes located at Las Campanas Observatory, Chile.

  10. THE MASSIVE AND DISTANT CLUSTERS OF WISE SURVEY. II. INITIAL SPECTROSCOPIC CONFIRMATION OF z ∼ 1 GALAXY CLUSTERS SELECTED FROM 10,000 deg2

    We present optical and infrared imaging and optical spectroscopy of galaxy clusters which were identified as part of an all-sky search for high-redshift galaxy clusters, the Massive and Distant Clusters of WISE Survey (MaDCoWS). The initial phase of MaDCoWS combined infrared data from the all-sky data release of the Wide-field Infrared Survey Explorer (WISE) with optical data from the Sloan Digital Sky Survey to select probable z ∼ 1 clusters of galaxies over an area of 10,000 deg2. Our spectroscopy confirms 19 new clusters at 0.7 < z < 1.3, half of which are at z > 1, demonstrating the viability of using WISE to identify high-redshift galaxy clusters. The next phase of MaDCoWS will use the greater depth of the AllWISE data release to identify even higher redshift cluster candidates

  11. HIGH-LYING OH ABSORPTION, [C II] DEFICITS, AND EXTREME L {sub FIR}/M {sub H2} RATIOS IN GALAXIES

    González-Alfonso, E.; Blasco, A. [Universidad de Alcalá, Departamento de Física y Matemáticas, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain); Fischer, J. [Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Sturm, E.; Graciá-Carpio, J.; Lutz, D.; Poglitsch, A.; Contursi, A. [Max-Planck-Institute for Extraterrestrial Physics (MPE), Giessenbachstraße 1, D-85748 Garching (Germany); Veilleux, S.; Meléndez, M. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Aalto, S.; Falstad, N. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Spoon, H. W. W. [Cornell University, Astronomy Department, Ithaca, NY 14853 (United States); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn (Germany); Verma, A. [University of Oxford, Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Spaans, M. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Smith, H. A.; Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hailey-Dunsheath, S. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); and others

    2015-02-10

    Herschel/PACS observations of 29 local (ultra)luminous infrared galaxies, including both starburst and active galactic nucleus (AGN) dominated sources as diagnosed in the mid-infrared/optical, show that the equivalent width of the absorbing OH 65 μm Π{sub 3/2} J = 9/2-7/2 line (W {sub eq}(OH65)) with lower level energy E {sub low} ≈ 300 K, is anticorrelated with the [C II]158 μm line to far-infrared luminosity ratio, and correlated with the far-infrared luminosity per unit gas mass and with the 60-to-100 μm far-infrared color. While all sources are in the active L {sub IR}/M {sub H2} > 50L {sub ☉}/M {sub ☉} mode as derived from previous CO line studies, the OH65 absorption shows a bimodal distribution with a discontinuity at L {sub FIR}/M {sub H2} ≈ 100 L {sub ☉}/M {sub ☉}. In the most buried sources, OH65 probes material partially responsible for the silicate 9.7 μm absorption. Combined with observations of the OH 71 μm Π{sub 1/2} J = 7/2-5/2 doublet (E {sub low} ≈ 415 K), radiative transfer models characterized by the equivalent dust temperature, T {sub dust}, and the continuum optical depth at 100 μm, τ{sub 100}, indicate that strong [C II]158 μm deficits are associated with far-IR thick (τ{sub 100} ≳ 0.7, N {sub H} ≳ 10{sup 24} cm{sup –2}), warm (T {sub dust} ≳ 60 K) structures where the OH 65 μm absorption is produced, most likely in circumnuclear disks/tori/cocoons. With their high L {sub FIR}/M {sub H2} ratios and columns, the presence of these structures is expected to give rise to strong [C II] deficits. W {sub eq}(OH65) probes the fraction of infrared luminosity arising from these compact/warm environments, which is ≳ 30%-50% in sources with high W {sub eq}(OH65). Sources with high W {sub eq}(OH65) have surface densities of both L {sub IR} and M {sub H2} higher than inferred from the half-light (CO or UV/optical) radius, tracing coherent structures that represent the most buried/active stage of (circum)nuclear starburst

  12. Starburst Galaxies

    Muxlow, T W B; Richards, A M S; Thrall, H

    2006-01-01

    Star-formation and the Starburst phenomenon are presented with respect to a number of nearby star-forming galaxies where our understanding of the process can be calibrated. Methods of estimating star-formation rates are discussed together with the role played in the investigation of the process by multi-wavelength studies of a few selected starburst galaxies (especially the well studied galaxy M82). Our understanding of nearby systems allows us to study the star-formation history of the Universe by observing high-redshift starburst galaxies. These begin to dominate the radio source populations at centimetric wavelengths at flux densities below a few 10s of Jy. New very sensitive, high resolution telescopes in the sub-mm and radio will revolutionize our understanding of these distant star-forming systems, some of which may contain embedded AGN.

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

    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 0.6selection technique is based on optical and near-infrared broad-band filter photometry. We use a training sample to define a quantity, the Fisher discriminant (linear combination of colours), which correlates best with the desired properties of the target: redshift and [Oii] flux. The proposed selections are simply done by applying a cut on magnitudes and this Fisher discriminant. We used public data and dedicated SDSS 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...

  14. FINDING {eta} CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S., E-mail: khan@astronomy.ohio-state.edu, E-mail: kstanek@astronomy.ohio-state.edu, E-mail: ckochanek@astronomy.ohio-state.edu [Department of Astronomy, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)

    2013-04-10

    The late-stage evolution of the most massive stars such as {eta} Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of {eta} Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby ({approx}< 4 Mpc) galaxies to search for such analogs. We find 34 candidates with a flat or rising mid-IR spectral energy distributions toward longer mid-infrared wavelengths that emit >10{sup 5} L{sub Sun} in the IRAC bands (3.6 to 8.0 {mu}m) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 {+-} 6 surviving candidates. Since we would detect true analogs of {eta} Car for roughly 200 years post-eruption, this implies that the rate of eruptions like {eta} Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M{sub Sun} star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 {mu}m, allowing identification of {eta} Car analogs for millennia rather than centuries post-eruption.

  15. Scaling Properties of a Complete X-ray Selected Galaxy Group Sample

    Lovisari, Lorenzo; Reiprich, Thomas; Schellenberger, Gerrit

    2014-01-01

    Upcoming X-ray surveys like eROSITA require precise calibration between X-ray observables and mass down to the low mass regime to set tight constraints on the fundamental cosmological parameters. Since an individual mass measurement is only possible for a relatively small number of objects it is crucial to have robust and well understood scaling relations that relate the total mass to easily observable quantities. The main goal of this work is to constrain the galaxy group scaling relations c...

  16. Low Surface Brightness Galaxies Selected from the 40% Sky Area of the ALFALFA H I Survey. I. Sample and Statistical Properties

    Du, Wei; Wu, Hong; Lam, Man I.; Zhu, Yinan; Lei, Fengjie; Zhou, Zhimin

    2015-06-01

    The population of low surface brightness (LSB) galaxies, which are objects with central surface brightnesses at least one magnitude fainter than the night sky, is crucial for understanding the extremes of galactic formation and evolution of the universe. As LSB galaxies are mostly rich in gas (H i), the α.40 Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) sample is one of the best survey combinations to select a sample of them in the local universe. Since the sky backgrounds are systematically overestimated for galactic images by the SDSS photometric pipeline, particularly for luminous galaxies or galaxies with extended LSB outskirts, in this paper, we above all estimated the sky backgrounds of SDSS images accurately in both the g and r bands for each galaxy in the α.40 SDSS DR7 sample, using a precise method of sky subtraction. Once subtracting the sky background, we did surface photometry with the Kron elliptical aperture using the SExtractor software and fitted geometric parameters with an exponential profile model using the Galfit software for each galactic image in the α.40 SDSS DR7 sample. Based on the photometric and geometric results, we further calculated the B-band central surface brightness, {{μ }0}(B), for each galaxy and ultimately defined a sample of LSB galaxies consisting of 1129 galaxies with {{μ }0}(B) > 22.5 mag arcsec‑2 and the axis ratio b/a > 0.3 from the 12,423 α.40 SDSS DR7 galaxies. This H i-selected sample of LSB galaxies is a relatively unbiased sample of gas-rich and disk-dominated LSB galaxies, which is complete both in H i observation and the optical magnitude within the limit of the SDSS DR7 photometric survey. This LSB galactic sample spans from 22.5 to 28.3 in {{μ }0}(B) with a fraction of 4% fainter than 25.0 mag arcsec‑2 in B-band central surface brightness and distributes from ‑27.0 to ‑12.3 mag in absolute magnitude in the B band (M(B)), including the 43 faintest galaxies (M(B) > ‑17.3 mag). This sample is

  17. GRB hosts through cosmic time - VLT/X-shooter emission-line spectroscopy of 96 GRB-selected galaxies at 0.1 < z < 3.6

    Krühler, T; Fynbo, J P U; Hartoog, O E; Hjorth, J; Jakobsson, P; Perley, D A; Rossi, A; Schady, P; Schulze, S; Tanvir, N R; Vergani, S D; Wiersema, K; Afonso, P M J; Bolmer, J; Cano, Z; Covino, S; D'Elia, V; Postigo, A de Ugarte; Filgas, R; Friis, M; Graham, J F; Greiner, J; Goldoni, P; Gomboc, A; Hammer, F; Japelj, J; Kann, D A; Kaper, L; Klose, S; Levan, A J; Leloudas, G; Milvang-Jensen, B; Guelbenzu, A Nicuesa; Palazzi, E; Pian, E; Piranomonte, S; Sanchez-Ramirez, R; Savaglio, S; Selsing, J; Tagliaferri, G; Vreeswijk, P M; Watson, D J; Xu, D

    2015-01-01

    We present data and initial results from VLT/X-shooter emission-line spectroscopy of 96 GRB-selected galaxies at 0.1selected galaxies to the locus of local galaxies in the BPT diagram. Oxygen abundances of the galaxies are distributed between 12+log(O/H)=7.9 and 12+log(O/H)=9.0 with a median of 12+log(O/H)~8.5. The fraction of GRB-selected galaxies with super-solar metallic...

  18. X-ray properties of BzK-selected galaxies in the deepest X-ray fields

    Rangel, Cyprian; Laird, Elise; Orange, Philip

    2012-01-01

    We investigate the X-ray properties of BzK-selected galaxies at z $\\sim$ 2 using deep X-ray data in the Chandra Deep Field South and North (CDFS and CDFN). Of these we directly detect in X-rays 49 sBzKs in CDFS and 32 sBzKs in CDFN. Stacking the undetected sources also reveals a significant X-ray signal. Investigating the X-ray detection rate and stacked flux versus the IR excess parameter (i.e. SFRtotal/SFRUV,corr), we find no strong evidence for an increased X-ray detection rate, or a harder X-ray spectrum in IR Excess sBzKs. This is particularly the case when one accounts for the strong correlation between the IR excess parameter and the bolometric IR luminosity (LIR), e.g. when controlling for LIR, the IR Non-Excess sBzKs show a detection rate at least as high. While both direct detections and stacking suggest that the AGN fraction in sBzK galaxies is high, there is no clear evidence for widespread Compton thick activity in either the sBzK population generally, or the IR Excess sBzK subsample. The very ha...

  19. Lens Models of Herschel-Selected Galaxies From High-Resolution Near-IR Observations

    Calanog, J A; Cooray, A; Wardlow, J; Ma, B; Amber, S; Baes, M; Bock, J; Bourne, N; Bussmann, R S; Casey, C M; Chapman, S C; Clements, D L; Conley, A; Dannerbauer, H; DeZotti, G; Dunne, L; Dye, S; Eales, S; Farrah, D; Furlanetto, C; Harris, A I; Ivison, R J; Maddox, S J; Magdis, G; Michalowski, M J; Negrello, M; Nightingale, J; O'Bryan, J M; Oliver, S J; Riechers, D; Scott, D; Serjeant, S; Simpson, J; Smith, M; Timmons, N; Thacker, C; Valiante, E; Vieira, J D

    2014-01-01

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 um-bright candidate lensing systems identified by the Herschel Multi-tiered Extra-galactic Survey (HerMES) and Herschel Astrophysical Terahertz Survey (H-ATLAS). Out of 87 candidates with near-IR imaging, 15 (~17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and pre- vious lensing models for sub-millimeter galaxies. For four new sources that also have high-resolution sub-mm maps, we test for differential lensing between the stellar and dust components and find that the 880 um magnification factor (u_880) is ~1.5 times higher than the near-IR magnification factor (u_NIR), on average. We also find that the ...

  20. An XMM-Newton spectral survey of 12 micron selected galaxies. I. X-ray data

    Brightman, Murray

    2010-01-01

    We present an X-ray spectral analysis of 126 galaxies of the 12 micron galaxy sample. We pay particular attention to Compton thick AGN with the help of new spectral fitting models that we have produced, which are based on Monte-Carlo simulations of X-ray radiative transfer, using both a spherical and torus geometry, and taking into account Compton scattering and Fe fluorescence. We use this data to show that with a torus geometry, unobscured sight lines can achieve a maximum EW of the Fe K\\alpha line of ~150 eV, originally shown by Ghisellini, Haardt & Matt (1994). In order for this to be exceeded, the line of sight must be obscured with N_H>10^23 cm^-2, as we show for one case, NGC 3690. We also calculate flux suppression factors from the simulated data, the main conclusion from which is that for N_H>10^25 cm^-2, the X-ray flux is suppressed by a factor of >10 in all X-ray bands and at all redshifts, revealing the biases present against these extremely heavily obscured systems inherent in all X-ray surve...

  1. Efficient Calculation of Electronic Absorption Spectra by Means of Intensity-Selected TD-DFTB

    Rüger, Robert; Lu, You; Frenzel, Johannes; Heine, Thomas; Visscher, Lucas

    2014-01-01

    During the last two decades density functional based linear response approaches have become the de facto standard for the calculation of optical properties of small and medium-sized molecules. At the heart of these methods is the solution of an eigenvalue equation in the space of single-orbital transitions, whose quickly increasing number makes such calculations costly if not infeasible for larger molecules. This is especially true for time-dependent density functional tight binding (TD-DFTB), where the evaluation of the matrix elements is sufficiently cheap so that relatively large systems can be studied. We propose to do an oscillator strength based truncation of the single-orbital transition space to reduce the computational effort of TD-DFTB based absorption spectra calculations. We show that even a sizeable truncation does not destroy the principal features of the absorption spectrum, while naturally avoiding the unnecessary calculation of excitations with small oscillator strengths. We argue that the re...

  2. Intestinal alkaline phosphatase: selective endocytosis from the enterocyte brush border during fat absorption

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi;

    2007-01-01

    explants. By immunofluorescence microscopy, fat absorption caused a translocation of IAP from the enterocyte brush border to the interior of the cell, whereas other brush-border enzymes were unaffected. By electron microscopy, the translocation occurred by a rapid (5 min) induction of endocytosis via...... clathrin-coated pits. By 60 min, IAP was seen in subapical endosomes and along membranes surrounding fat droplets. IAP is a well-known lipid raft-associated protein, and fat absorption was accompanied by a marked change in the density and morphology of the detergent-resistant membranes harboring IAP. A...... IAP and may contribute to the appearance of the enzyme in serum and surfactant-like particles....

  3. X-ray absorption and selectively excited X-ray emission spectra of atenolol and nadolol

    Full text: The biological function of a drug given by the oral route is ruled by its degree of absorption in the gastrointestinal tract. These absorption characteristics (dissolution, solubility, permeability, metabolism) of the drug are time consuming and expensive to investigate experimentally. The predictive power of traditional theoretical models is quite limited. This is especially so for solubility, where a model predicting values within one order of magnitude of the experimentally determined solubility is accepted by the research field. Aiming at a more detailed understanding of drug solubility, we are carrying out X-ray absorption and X-ray emission spectroscopy on a series of pharmaceutical model substances in solid form and in water solution. Changes in local geometry and electronic structure primarily associated with changes in the way the drug molecules are hydrogen bonded to surrounding molecules are directly reflected in the spectra. Here we present and analyze the spectra of two solid β-adrenoreceptors, atenolol and nadolol, at the carbon, nitrogen and oxygen K edges. Special attention is given to the influence on the spectra of hydrogen bonding. An increased understanding of hydrogen bonding is essential for improving solubility models

  4. Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: sparse methods for statistical selection of relevant absorption bands

    Takahama, Satoshi; Ruggeri, Giulia; Dillner, Ann M.

    2016-07-01

    Various vibrational modes present in molecular mixtures of laboratory and atmospheric aerosols give rise to complex Fourier transform infrared (FT-IR) absorption spectra. Such spectra can be chemically informative, but they often require sophisticated algorithms for quantitative characterization of aerosol composition. Naïve statistical calibration models developed for quantification employ the full suite of wavenumbers available from a set of spectra, leading to loss of mechanistic interpretation between chemical composition and the resulting changes in absorption patterns that underpin their predictive capability. Using sparse representations of the same set of spectra, alternative calibration models can be built in which only a select group of absorption bands are used to make quantitative prediction of various aerosol properties. Such models are desirable as they allow us to relate predicted properties to their underlying molecular structure. In this work, we present an evaluation of four algorithms for achieving sparsity in FT-IR spectroscopy calibration models. Sparse calibration models exclude unnecessary wavenumbers from infrared spectra during the model building process, permitting identification and evaluation of the most relevant vibrational modes of molecules in complex aerosol mixtures required to make quantitative predictions of various measures of aerosol composition. We study two types of models: one which predicts alcohol COH, carboxylic COH, alkane CH, and carbonyl CO functional group (FG) abundances in ambient samples based on laboratory calibration standards and another which predicts thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) mass in new ambient samples by direct calibration of infrared spectra to a set of ambient samples reserved for calibration. We describe the development and selection of each calibration model and evaluate the effect of sparsity on prediction performance. Finally, we ascribe

  5. JET PROPERTIES OF GeV-SELECTED RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES AND POSSIBLE CONNECTION TO THEIR DISK AND CORONA

    Sun, Xiao-Na; Lin, Da-Bin; Liang, En-Wei [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Zhang, Jin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xue, Zi-Wei; Zhang, Shuang-Nan, E-mail: zhang.jin@hotmail.com [Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

    2015-01-01

    The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at the GeV band is tightly correlated with the beaming factor (δ), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With the detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L {sub corona}) to the accretion disk luminosity (L {sub d}) is marginally within the high end of this ratio distribution for an RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with L {sub corona}. However, it is still unclear whether a system with a high L {sub corona}/L {sub d} ratio prefers to power a jet.

  6. JET PROPERTIES OF GeV-SELECTED RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES AND POSSIBLE CONNECTION TO THEIR DISK AND CORONA

    The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at the GeV band is tightly correlated with the beaming factor (δ), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With the detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L corona) to the accretion disk luminosity (L d) is marginally within the high end of this ratio distribution for an RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with L corona. However, it is still unclear whether a system with a high L corona/L d ratio prefers to power a jet

  7. The SEDs, Host Galaxies and Environments of Variability Selected AGN in GOODS-S

    Villforth, Carolin; Sarajedini, Vicki; Koekemoer, Anton

    2012-01-01

    Variability selection has been proposed as a powerful tool for identifying both low-luminosity AGN and those with unusual SEDs. However, a systematic study of sources selected in such a way has been lacking. In this paper, we present the multi-wavelength properties of the variability selected AGN in GOODS South. We demonstrate that variability selection indeed reliably identifies AGN, predominantly of low luminosity. We find contamination from stars as well as a very small sample of sources t...

  8. COLOR-MAGNITUDE RELATIONS OF ACTIVE AND NON-ACTIVE GALAXIES IN THE CHANDRA DEEP FIELDS: HIGH-REDSHIFT CONSTRAINTS AND STELLAR-MASS SELECTION EFFECTS

    clustering in the CMD and the AGN fraction generally increases as the color becomes redder. We also find, for mass-matched samples, that the star formation rates of AGN hosts are typically a factor of ∼ 2-3 larger than those of non-AGN galaxies at z ∼ 0-1, whereas this difference diminishes at z ∼ 1-3. With mass-selection effects taken into account, we find that almost all of the results obtained in this work can reasonably be explained by two main ingredients, color-mass correlation (i.e., X-ray AGNs preferentially reside in massive galaxies that generally tend to be redder than less-massive galaxies) and passive or secular evolution of galaxies. Our results show that the presence of moderate-luminosity AGN activity does not have a significant effect on the colors of galaxies and thus tightly constrain any effects from moderate-luminosity AGN feedback upon color-magnitude properties over the ∼ 80% of cosmic time during which most of galaxy formation occurred.

  9. Spitzer 24micron Observations of Optical/Near-IR Selected Extremely Red Galaxies: Evidence for Assembly of Massive Galaxies at z approximately 1 - 2?

    Yan, Lin; Choi, Philip I.; Fadda, D.; Marleau, F. R.; Soifer, B. T.; Im, M.; Armus, L.; Frayer, D. T.; Storrie-Lombardi, L. J.; Thompson, D. J.; Teplitz, H. I.; Helou, G.; Appleton, P. N.; Chapman, S.; Fan, F.; Heinrichsen, I.; Lacy, M.; Shupe, D. L; Squires, G. K.; Surace, J.; G., Wilson

    2004-01-01

    We carried out the direct measurement of the fraction of dusty sources in a sample of extremely red galaxies with (R-K(sub s)) greater than or equal to 5.3 mag and K(sub s) less than 20.2 mag, using from the Spitzer Space Telescope. Combining deep 24 micrometers, K(sub s)- and R-band data over an area of approximately 64 sq.arcmin in the ELAIS N1 field of the Spitzer First Look Survey (FLS), we find that 50 +/- 60% of our ERO sample have measurable 24 micrometer flux above the 3(sigma) flux limit of 40 microns Jy. This flux limit corresponds to a SFR of 12 solar mass/yr at z approximately 1, much mo previous long wavelength measurement. The 24fJ,m-detected EROs have 24-to2.2 and 24-to-0.7micrometr flux ratios consistent with infrared luminous, dusty sources at z approx. 1, and an order of magnitude too red to be explained by an infrared quiescent spiral or a pure old stellar population at any redshift. Some of these 24 micrometer-detected EROs could be AGN, however, the fraction among the whole ERO sample is probably small, 10-20%, as suggested by deep X-ray observations as well as optical spectroscopy. Keck optical spectroscopy of a sample of similarly selected EROs in the FLS field suggests that most of the EROs in ELAIS Nl are probably at z approx. 1.

  10. Gamma-Ray Burst afterglows as probes of environment and blastwave physics I: absorption by host galaxy gas and dust

    Starling, R L C; Wiersema, K; Rol, E; Curran, P A; Kouveliotou, C; Van der Horst, A J; Heemskerk, M H M

    2006-01-01

    We use a new approach to obtain limits on the absorbing columns towards an initial sample of 10 long Gamma-Ray Bursts observed with BeppoSAX and selected on the basis of their good optical and nIR coverage, from simultaneous fits to nIR, optical and X-ray afterglow data, in count space and including the effects of metallicity. In no cases is a MW-like extinction preferred, when testing MW, LMC and SMC extinction laws. The 2175A bump would in principle be detectable in all these afterglows, but is not present in the data. An SMC-like gas-to-dust ratio or lower value can be ruled out for 4 of the hosts analysed here (assuming SMC metallicity and extinction law) whilst the remainder of the sample have too large an error to discriminate. We provide a more accurate estimate of the line-of-sight extinction and improve upon the uncertainties for the majority of the extinction measurements made in previous studies of this sample. We discuss this method to determine extinction values in comparison with the most common...

  11. NuSTAR reveals an intrinsically X-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

    Teng, Stacy H.; Rigby, J. R. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Alexander, D. M.; Gandhi, P. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Bauer, F. E. [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fiore, F. [Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Hickox, R. C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Ptak, A. F., E-mail: stacy.h.teng@nasa.gov [X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2014-04-10

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin (N{sub H}∼1.2{sub −0.3}{sup +0.3}×10{sup 23} cm{sup –2}) column. The intrinsic X-ray luminosity (L {sub 0.5–30} {sub keV} ∼ 1.0 × 10{sup 43} erg s{sup –1}) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is ∼0.03% compared to the typical values of 2%-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope (α{sub OX} ∼ –1.7). It is a local example of a low-ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  12. FINDING η CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    The late-stage evolution of the most massive stars such as η Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby (∼105 L☉ in the IRAC bands (3.6 to 8.0 μm) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 ± 6 surviving candidates. Since we would detect true analogs of η Car for roughly 200 years post-eruption, this implies that the rate of eruptions like η Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M☉ star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 μm, allowing identification of η Car analogs for millennia rather than centuries post-eruption.

  13. The hidden quasar nucleus of a WISE-selected, hyperluminous, dust-obscured galaxy at z ~ 2.3

    Piconcelli, E; Bianchi, S; Zappacosta, L; Fritz, J; Lanzuisi, G; Miniutti, G; Bongiorno, A; Feruglio, C; Fiore, F; Maiolino, R

    2014-01-01

    We present the first X-ray spectrum of a Hot dust-obscured galaxy (DOG), namely W1835+4355 at z ~ 2.3. Hot DOGs represent a very rare population of hyperluminous (>= 10^47 erg/s), dust-enshrouded objects at z > 2 recently discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a continuum as flat (Gamma ~ 0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kalpha emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L(2-10 keV) ~ 2 x 10^44 erg/s is a fraction (~ 5 x 10^45 erg/s by using several proxies. The Herschel data allow us to constrain the SED up to the sub-mm band, providing a reliable estimate of the quasar contribution (~ 75%) to the IR luminosity as well as the amount of star formation (~ 2100 Msun/yr). Our results thus provide additional pieces of evidence that associate Hot DOGs with an exceptionally dusty phase during which luminous quasars and massive ga...

  14. Percutaneous absorption of selected hydrophilic compounds - an in vitro study on hairless mouse skin

    The objective of this study was to assess 1. the relationship between hydrophobicity and percutaneous absorption; and 2. the validity of the view that the skin can be diffusionally characterized as a simple lipoidal barrier. In the course of the permeability studies, a very slow but gradually accelerating permeation of the hydrophylic compounds was noted, a phenomenon that became very noticeable when the permeation profile was observed over longer periods e.g. 100 hours instead of the conventional 6-12 hours. The initial objective had to be expanded to search for the cause of the increasing permeability of these compounds. With urea reproduceable results were obtained in the preliminary study and therefore urea was chosen for this study. The percutaneous absorption studies of urea, thiourea, glycerol and glucose were executed by means of an in vitro method. The method included the use of a diffusion cell system where the skin was clamped between two diffusion cells. The ether-water partition coefficients of the hydrophylic compounds were determined by a simple radiotracer procedure. The radio-labelled compound was equilibrated between the ether and water phases and the sample taken from the phases were analysed by means of scintillation counting. The ether-water partition coefficients of hydrocortisone and its 21-n-alkyl esters were determined by means of a HPLC method. The significance of this study may be summarized as: 1. it showed errors of interpretation in previous work on the percutaneous absorption of hydrophilic compounds; 2. it confirmed the incompatibility of a simple lipid membrane mechanism with the behaviour of skin; and 3. it formed a basis for the systematic solution of the mechanism of increasing permeability as a function of time phenomenon, encountered with the studied hydrophilic compounds

  15. A Hubble Space Telescope Survey of Extended [OIII]5007A Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Observations

    Schmitt, H R; Antonucci, R; Hutchings, J B; Kinney, A L

    2003-01-01

    We present a Hubble Space Telescope (HST) survey of extended [OIII] emission for a sample of 60 Seyfert galaxies (22 Seyfert 1's and 38 Seyfert 2's), selected based on their far infrared properties. The observations for 42 of these galaxies were done in a snapshot survey with WFPC2. The remaining 18 were obtained from the HST archive, most of which were observed with the same configuration. These observations cover 68% of the objects in the sample defined by Kinney et al. (2000), and create a valuable dataset for the study of the Narrow Line Region (NLR) properties of Seyfert galaxies. In this paper, we present the details of the observations, reductions, and measurements. We also discuss the extended structure of individual sources, and the relation of this emission to the radio and host galaxy morphology. We also address how representative the subsample of [O III]-imaged galaxies is of the entire sample, and possible selection effects that may affect this comparison of the properties of Seyfert 1 and Seyfer...

  16. Filter-free image sensor pixels comprising silicon nanowires with selective color absorption.

    Park, Hyunsung; Dan, Yaping; Seo, Kwanyong; Yu, Young J; Duane, Peter K; Wober, Munib; Crozier, Kenneth B

    2014-01-01

    The organic dye filters of conventional color image sensors achieve the red/green/blue response needed for color imaging, but have disadvantages related to durability, low absorption coefficient, and fabrication complexity. Here, we report a new paradigm for color imaging based on all-silicon nanowire devices and no filters. We fabricate pixels consisting of vertical silicon nanowires with integrated photodetectors, demonstrate that their spectral sensitivities are governed by nanowire radius, and perform color imaging. Our approach is conceptually different from filter-based methods, as absorbed light is converted to photocurrent, ultimately presenting the opportunity for very high photon efficiency. PMID:24588103

  17. Nucleon and heavy-ion total and absorption cross section for selected nuclei

    Approximate solutions of the coupled-channel equations for high-energy composite particle scattering are obtained and are applied to the nuclear scattering problem. Relationships between several approximation procedures are established and discussed. The eikonal formalism is used with a small-angle approximation to calculate the coherent elastic scattering amplitude from which total and absorption cross sections are derived. Detailed comparisons with nucleon--nucleus experiments show agreement within 5 percent, except at lower energies, where the eikonal approximation is of questionable accuracy. Even at these lower energies, agreement is within 15 percent. Tables of cross sections required for cosmic heavy-ion transport and shielding studies are presented

  18. Nucleon and heavy-ion total and absorption cross section for selected nuclei

    Wilson, J. W.; Costner, C. M.

    1975-01-01

    Approximate solutions of the coupled-channel equations for high-energy composite particle scattering are obtained and are applied to the nuclear scattering problem. Relationships between several approximation procedures are established and discussed. The eikonal formalism is used with a small-angle approximation to calculate the coherent elastic scattered amplitude from which total and absorption cross sections are derived. Detailed comparisons with nucleon-nucleus experiments show agreement within 5 percent except at lower energies where the eikonal approximation is of questionable accuracy. Even at these lower energies, agreement is within 15 percent. Tables of cross sections required for cosmic heavy-ion transport and shielding studies are presented.

  19. From a Subtractive to Multiplicative Approach: A concept-driven interactive pathway on the selective absorption of light

    Viennot, Laurence; de Hosson, Cécile

    2015-01-01

    This research documents the aims and the impact of a teaching experiment on how the absorption of light depends on the thickness of the absorbing medium. This teaching experiment is more specifically characterized as bringing to bear a 'concept-driven interactive pathway'. It is designed to make students analyse the absorption of light by a medium as a selective multiplication (i.e. one depending on the wavelength) of the intensity by a factor smaller than one. Six teaching interviews conducted with fourth-year university students were recorded, transcribed and coded. Their analysis led us to evaluate the importance of the main obstacle expected, that is, of restricting the interpretation of absorption/transmission phenomena to the idea of 'less light', or, equivalently, of seeing a multiplication by a factor smaller than one as just a subtraction. The students' comments at the end of the interview introduce a discussion about the links between their intellectual satisfaction, critical attitude and comprehension of the topic.

  20. First Science with SHARDS: emission line galaxies

    Cava, A; Pérez González, P. G.; SHARDS Collaboration

    2012-01-01

    SHARDS (Survey for High-z Absorption Red & Dead Sources) is an unbiased ultra-deep spectro-photometric survey with GTC@OSIRIS aimed at selecting and studying massive passively evolving galaxies at z=1.0-2.3 using a set of 24 medium-band filters (FWHM\\sim17 nm) at 500-950 nm in GOODS-N. Our observing strategy is optimized to detect at z>1 the prominent Mg absorption feature at rest-frame ~280 nm, a distinctive, necessary, and sufficient feature of evolved stellar populations. Nonetheless, the ...

  1. THE CALIBRATION OF STAR FORMATION RATE INDICATORS FOR WISE 22 μm-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

    We study star formation rate (SFR) indicators for Wide-field Infrared Survey Explorer (WISE) 22 μm-selected, star-forming galaxies at 0.01 Hα(obs) + aLMIR increases with the SFR, and show that a nonlinear combination of observed Hα and MIR luminosities gives the best SFR estimates with small scatters and with little dependence on physical parameters. Such a combination of Hα and MIR luminosities for SFR estimates is first applied to the WISE data. Using WISE data, we provide several SFR recipes that are applicable to galaxies with 0.1 ∼☉ yr–1) ∼< 100

  2. Rifampin reduces oral morphine absorption: a case of transdermal buprenorphine selection based on morphine pharmacokinetics.

    Fudin, Jeffrey; Fontenelle, Dania Vanesta; Payne, Annette

    2012-12-01

    A 51-year-old male was referred to the Stratton Veterans Affairs Medical Center Pain Service after hospital admission for endocarditis with a history of heroin use and chronic low back pain. During his hospital stay he experienced a reduction in his serum morphine level ostensibly as a result of concomitant rifampin administration. We hypothesize that diminished absorption was from rifampin-mediated intestinal P-glycoprotein induction, ultimately decreasing serum free morphine and metabolites. The case became more complex in an attempt to balance managed pain, history of substance abuse, completion of antibiotic therapy, and a reasonable pain regimen upon discharge. Ultimately, the patient was titrated onto a buprenorphine transdermal patch, the initiation of which was based on serum free morphine and an extrapolated oral morphine dose by calculation. PMID:23216174

  3. Study of near infrared absorption spectroscopy of selected pairs of organic solvents for quality control applications

    Organic solvents of various combinations and ratios, such as ethanol/commercial petrol; benzene/ethanol; toluene/commercial petrol and toluene/benzene were studied by near infrared (NIR) absorption spectroscopy. NIR spectrometer of 850-1700 nm produced distinctly separable spectral ranges for all the combinations; 1400 to 1650 nm for ethanol/commercial petrol; 1125 to 1150 nm for benzene/ethanol; 1130 to 1150 nm for toluene/commercial petrol and 1175 to 1210 nm for toluene/benzene. The calibration curves were drawn for the given pair concentrations. From the linear fitting parameters it is evident that each pair has different slope, which establishes reliability of the technique. The results revealed that each solvent in the mixture gives a clear trend of spectral region. This may be used for the analysis of mixtures of organic solvents. The technique may be utilized for the quality assurance. (author)

  4. Polar-bulge galaxies

    Reshetnikov, V P; Mosenkov, A V; Sotnikova, N Ya; Bizyaev, D V

    2015-01-01

    Based on SDSS data, we have selected a sample of nine edge-on spiral galaxies with bulges whose major axes show a high inclination to the disk plane. Such objects are called polar-bulge galaxies. They are similar in their morphology to polar-ring galaxies, but the central objects in them have small size and low luminosity. We have performed a photometric analysis of the galaxies in the g and r bands and determined the main characteristics of their bulges and disks. We show that the disks of such galaxies are typical for the disks of spiral galaxies of late morphological types. The integrated characteristics of their bulges are similar to the parameters of normal bulges. The stellar disks of polar-bulge galaxies often show large-scale warps, which can be explained by their interaction with neighboring galaxies or external accretion from outside.

  5. HerMES: ALMA Imaging of Herschel-selected Dusty Star-forming Galaxies

    Bussmann, R S; Fialkov, A; Scudder, J; Hayward, C C; Cowley, W I; Bock, J; Calanog, J; Chapman, S C; Cooray, A; De Bernardis, F; Farrah, D; Fu, Hai; Gavazzi, R; Hopwood, R; Ivison, R J; Jarvis, M; Lacey, C; Loeb, A; Oliver, S J; Perez-Fournon, I; Rigopoulou, D; Roseboom, I G; Scott, Douglas; Smith, A J; Vieira, J D; Wang, L; Wardlow, J

    2015-01-01

    The Herschel Multi-tiered Extragalactic Survey (HerMES) has identified large numbers of dusty star-forming galaxies (DSFGs) over a wide range in redshift. A detailed understanding of these DSFGs is hampered by the poor spatial resolution of Herschel. We present 870um 0.45" imaging obtained in Cycle 0 with the Atacama Large Millimeter/submillimeter Array (ALMA) of a sample of 29 HerMES DSFGs. The ALMA imaging reveals that these DSFGs comprise a total of 62 sources (down to the 5-sigma limit in our ALMA sample; sigma~0.2 mJy). Optical imaging indicates that 36 of the ALMA sources experience a significant flux boost from gravitational lensing (mu>1.1), but only 6 are strongly lensed and show multiple images. We introduce and make use of uvmcmcfit, a general purpose and publicly available Markov chain Monte Carlo visibility plane analysis tool to analyze the source properties. Combined with our previous work on brighter Herschel sources, the lens models presented here tentatively favor intrinsic number counts for...

  6. Selection constraints on high redshift quasar searches in the VISTA kilo-degree infrared galaxy survey

    Findlay, J R; Venemans, B P; Reyle, C; Robin, A C; Bonfield, D G; Bruce, V A; Jarvis, M J

    2011-01-01

    The European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) is a 4-m class survey telescope for wide-field near-infrared imaging. VISTA is currently running a suite of six public surveys, which will shortly deliver their first Europe wide public data releases to ESO. The VISTA Kilo-degree Infrared Galaxy Survey (VIKING) forms a natural intermediate between current wide shallow, and deeper more concentrated surveys, by targeting two patches totalling 1500 sq.deg in the northern and southern hemispheres with measured 5-sigma limiting depths of Z ~ 22.4, Y ~ 21.4, J ~ 20.9, H ~ 19.9 and Ks ~19.3 (Vega). This architecture forms an ideal working parameter space for the discovery of a significant sample of 6.5 <= z <= 7.5 quasars. In the first data release priority has been placed on small areas encompassing a number of fields well sampled at many wavelengths, thereby optimising science gains and synergy whilst ensuring a timely release of the first products. For rare...

  7. Modeling Galaxy-Galaxy Weak Lensing with SDSS Groups

    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...

  8. The BOSS Emission-Line Lens Survey (BELLS). I. A large spectroscopically selected sample of Lens Galaxies at redshift ~ 0.5

    Brownstein, Joel R; Schlegel, David J; Eisenstein, Daniel J; Kochanek, Christopher S; Connolly, Natalia; Maraston, Claudia; Pandey, Parul; Seitz, Stella; Wake, David A; Wood-Vasey, W Michael; Brinkmann, Jon; Schneider, Donald P; Weaver, Benjamin A; 10.1088/0004-637X/744/1/41

    2011-01-01

    We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with redshifts 0.4 \\lesssim z \\lesssim 0.7, discovered spectroscopically by the presence of higher redshift emission-lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens ACS Survey (SLACS: Bolton et al. 2006; 2008) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST Adanced Camera for Surveys (ACS) image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The...

  9. Comparing resonant 2p X-ray absorption of size-selected cobalt clusters on Cu(100) and in a linear Paul Trap

    Zamudio-Bayer, Vicente; Hirsch, Konstantin; Klar, Philipp; Langenberg, Andreas; Lofink, Fabian; Richter, Robert; Rittmann, Jochen; Vogel, Marlene; Moeller, Thomas; Lau, J. Tobias [Technische Universitaet Berlin (Germany). Institut fuer Optik und Atomare Physik; Glaser, Leif; Wurth, Wilfried [Universitaet Hamburg (Germany). Institut fuer Experimentalphysik; von Issendorff, Bernd [Albert-Ludwigs-Universitaet Freiburg (Germany). Fakultaet fuer Physik/FMF

    2008-07-01

    Its element specificity makes resonant X-ray absorption spectroscopy an ideal tool to study deposited clusters at low coverage. At the 2p absorption edges of small, size-selected cobalt clusters on Cu(100), two separate sets of lines are observed which can be interpreted in terms of atomic-like multiplet splitting. For very small clusters (n=1,2,3), these absorption lines show a strong size dependence. The size evolution of 2p X-ray absorption will be discussed in comparison to size-selected free cobalt clusters, recorded recently on mass selected cluster ions in a linear Paul trap at BESSY. Direct comparison of free and deposited clusters under well defined conditions allows to distinguish size-specific properties from cluster-substrate interaction effects. A shift to higher photon energies in deposited clusters indicates screening by substrate valence electrons.

  10. A new sample of X-ray selected narrow emission-line galaxies. II. Looking for True Seyfert 2

    Pons, Estelle

    2016-01-01

    A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been selected on the basis of their emission line ratios and/or X-ray luminosity. We have looked for X-ray unobscured type-2 AGN. As X-ray spectra were not available for our whole sample, we have checked the reliability of using the X-ray hardness ratio (HR) as a probe of the level of obscuration and we found a very good agreement with full spectral fitting results, with only 2% of the sources with apparently unobscured HR turning out to have an obscured spectrum. Despite the fact that type-2 AGN are supposed to be absorbed based on the Unified Model, about 60% of them show no sign or very low level of X-ray obscuration. After subtraction of contaminants to the sample, that is Narrow-Line Seyfert 1 and Compton-thick AGN, the fraction of unobscured Sy2 drops to 47%. For these sourc...

  11. UV to IR Luminosities and Dust Attenuation Determined from ~4000 K-Selected Galaxies at 1

    Forrest, Ben; Tomczak, Adam R; Broussard, Adam; Labbé, Ivo; Papovich, Casey; Kriek, Mariska; Allen, Rebecca J; Cowley, Michael; Dickinson, Mark; Glazebrook, Karl; van Houdt, Josha; Inami, Hanae; Kacprzak, Glenn G; Kawinwanichakij, Lalitwadee; Kelson, Daniel; McCarthy, Patrick J; Monson, Andrew; Morrison, Glenn; Nanayakkara, Themiya; Persson, S Eric; Quadri, Ryan F; Spitler, Lee R; Straatman, Caroline; Tilvi, Vithal

    2016-01-01

    We build a set of composite galaxy SEDs by de-redshifting and scaling multi-wavelength photometry from galaxies in the ZFOURGE survey, covering the CDFS, COSMOS, and UDS fields. From a sample of ~4000 K_s-band selected galaxies, we define 38 composite galaxy SEDs that yield continuous low-resolution spectra (R~45) over the rest-frame range 0.1-4 um. Additionally, we include far infrared photometry from the Spitzer Space Telescope and the Herschel Space Observatory to characterize the infrared properties of our diverse set of composite SEDs. From these composite SEDs we analyze the rest-frame UVJ colors, as well as the ratio of IR to UV light (IRX) and the UV slope ($\\beta$) in the IRX$-\\beta$ dust relation at 1galaxies have considerable scatter, as found for local IR bright sources, but on average appear bluer than expected for their IR fluxes. We measure a tight linear relation between...

  12. Galaxy-dark matter correlations applied to galaxy-galaxy lensing: predictions from the semi-analytic galaxy formation models

    Guzik, Jacek; Seljak, Uros

    2000-01-01

    We use semi-analytic models of galaxy formation combined with high resolution N-body simulations to make predictions for galaxy-dark matter correlations and apply them to galaxy-galaxy lensing. We analyze cross-correlation spectra between the dark matter and different galaxy samples selected by luminosity, color or star formation rate. We compare the predictions to the recent detection by SDSS. We show that the correlation amplitude and the mean tangential shear depend strongly on the luminos...

  13. Speciation model selection by Monte Carlo analysis of optical absorption spectra: Plutonium(IV) nitrate complexes

    Standard modeling approaches can produce the most likely values of the formation constants of metal-ligand complexes if a particular set of species containing the metal ion is known or assumed to exist in solution equilibrium with complexing ligands. Identifying the most likely set of species when more than one set is plausible is a more difficult problem to address quantitatively. A Monte Carlo method of data analysis is described that measures the relative abilities of different speciation models to fit optical spectra of open-shell actinide ions. The best model(s) can be identified from among a larger group of models initially judged to be plausible. The method is demonstrated by analyzing the absorption spectra of aqueous Pu(IV) titrated with nitrate ion at constant 2 molal ionic strength in aqueous perchloric acid. The best speciation model supported by the data is shown to include three Pu(IV) species with nitrate coordination numbers 0, 1, and 2. Formation constants are β1=3.2±0.5 and β2=11.2±1.2, where the uncertainties are 95% confidence limits estimated by propagating raw data uncertainties using Monte Carlo methods. Principal component analysis independently indicates three Pu(IV) complexes in equilibrium. (c) 2000 Society for Applied Spectroscopy

  14. Clustering of galaxies near damped Lyman-alpha systems with (z) = 2.6

    Wolfe, A. M

    1993-01-01

    The galaxy two-point correlation function, xi, at (z) = 2.6 is determined by comparing the number of Ly-alpha-emitting galaxies in narrowband CCD fields selected for the presence of damped L-alpha absorption to their number in randomly selected control fields. Comparisons between the presented determination of (xi), a density-weighted volume average of xi, and model predictions for (xi) at large redshifts show that models in which the clustering pattern is fixed in proper coordinates are highly unlikely, while better agreement is obtained if the clustering pattern is fixed in comoving coordinates. Therefore, clustering of Ly-alpha-emitting galaxies around damped Ly-alpha systems at large redshifts is strong. It is concluded that the faint blue galaxies are drawn from a parent population different from normal galaxies, the presumed offspring of damped Ly-alpha systems.

  15. HerMES: ALMA Imaging of Herschel-selected Dusty Star-forming Galaxies

    Bussmann, R. S.; Riechers, D.; Fialkov, A.; Scudder, J.; Hayward, C. C.; Cowley, W. I.; Bock, J.; Calanog, J.; Chapman, S. C.; Cooray, A.; De Bernardis, F.; Farrah, D.; Fu, Hai; Gavazzi, R.; Hopwood, R.; Ivison, R. J.; Jarvis, M.; Lacey, C.; Loeb, A.; Oliver, S. J.; Pérez-Fournon, I.; Rigopoulou, D.; Roseboom, I. G.; Scott, Douglas; Smith, A. J.; Vieira, J. D.; Wang, L.; Wardlow, J.

    2015-10-01

    The Herschel Multi-tiered Extragalactic Survey (HerMES) has identified large numbers of dusty star-forming galaxies (DSFGs) over a wide range in redshift. A detailed understanding of these DSFGs is hampered by the limited spatial resolution of Herschel. We present 870 μm 0.″45 resolution imaging obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) of a sample of 29 HerMES DSFGs that have far-infrared (FIR) flux densities that lie between the brightest of sources found by Herschel and fainter DSFGs found via ground-based surveys in the submillimeter region. The ALMA imaging reveals that these DSFGs comprise a total of 62 sources (down to the 5σ point-source sensitivity limit in our ALMA sample; σ ≈ 0.2 {mJy}). Optical or near-infrared imaging indicates that 36 of the ALMA sources experience a significant flux boost from gravitational lensing (μ \\gt 1.1), but only six are strongly lensed and show multiple images. We introduce and make use of uvmcmcfit, a general-purpose and publicly available Markov chain Monte Carlo visibility-plane analysis tool to analyze the source properties. Combined with our previous work on brighter Herschel sources, the lens models presented here tentatively favor intrinsic number counts for DSFGs with a break near 8 {mJy} at 880 μ {{m}} and a steep fall-off at higher flux densities. Nearly 70% of the Herschel sources break down into multiple ALMA counterparts, consistent with previous research indicating that the multiplicity rate is high in bright sources discovered in single-dish submillimeter or FIR surveys. The ALMA counterparts to our Herschel targets are located significantly closer to each other than ALMA counterparts to sources found in the LABOCA ECDFS Submillimeter Survey. Theoretical models underpredict the excess number of sources with small separations seen in our ALMA sample. The high multiplicity rate and small projected separations between sources seen in our sample argue in favor of interactions

  16. Spectral Clustering for Optical Confirmation and Redshift Estimation of X-ray Selected Galaxy Cluster Candidates in the SDSS Stripe 82

    Mahmoud, Eman; Shoukry, Amin

    2016-01-01

    We develop a galaxy cluster finding algorithm based on spectral clustering technique to identify optical counterparts and estimate optical redshifts for X-ray selected cluster candidates. As an application, we run our algorithm on a sample of X-ray cluster candidates selected from the third XMM-Newton serendipitous source catalog (3XMM-DR5) that are located in the Stripe 82 of the Sloan Digital Sky Survey (SDSS). Our method works on galaxies described in the color-magnitude feature space. We begin by examining 45 galaxy clusters with published spectroscopic redshifts in the range of 0.1 to 0.8 with a median of 0.36. As a result, we are able to identify their optical counterparts and estimate their photometric redshifts, which have a typical accuracy of 0.025 and agree with the published ones. Then, we investigate another 40 X-ray cluster candidates (from the same cluster survey) with no redshift information in the literature and found that 12 candidates are considered as galaxy clusters in the redshift range ...

  17. The redshifted selected sample of long gamma-ray burst host galaxies: the complete metallicity measurements at $z \\leq 0.41$

    Niino, Yuu; Hashimoto, Tetsuya; Hattori, Takashi; Ishikawa, Shoto; Kashikawa, Nobunari; Kosugi, George; Onoue, Masafusa; Toshikawa, Jun; Yabe, Kiyoto

    2016-01-01

    We present the complete list of host galaxy metallicities for all long GRBs whose redshifts were determined to be $\\leq 0.41$ before the end of March 2014, including newly obtained spectroscopic datasets of the host galaxies of GRB 060614, 090417B, and 130427A. We compare the metallicity distribution of the redshift selected complete sample to the model predictions, and constrain the relation between metallicity and GRB occurrence. We take account of spatial variation of metallicities among star forming regions within a galaxy. We found that the models, in which only low-metallicity stars produce GRBs with a sharp cutoff of GRB production efficiency around 12+log(O/H) $\\sim$ 8.2, can well reproduce the observed distribution, while the models with moderate (or no) metallicity dependence are not consitistent with the observations. This is the first fair estimate of the metallicity distribution of GRB host galaxies based on the redshift selected complete sample in the {\\it Swift} era. We also discuss possible sa...

  18. Hα3: an Hα imaging survey of HI selected galaxies from ALFALFA. VI. The role of bars in quenching star formation from z = 3 to the present epoch

    Gavazzi, G.; Consolandi, G.; Dotti, M.; Fanali, R.; Fossati, M.; Fumagalli, M.; Viscardi, E.; Savorgnan, G.; Boselli, A.; Gutiérrez, L.; Hernández Toledo, H.; Giovanelli, R.; Haynes, M. P.

    2015-08-01

    A growing body of evidence indicates that the star formation rate per unit stellar mass (sSFR) decreases with increasing mass in normal main-sequence star-forming galaxies. Many processes have been advocated as being responsible for this trend (also known as mass quenching), e.g., feedback from active galactic nuclei (AGNs), and the formation of classical bulges. In order to improve our insight into the mechanisms regulating the star formation in normal star-forming galaxies across cosmic epochs, we determine a refined star formation versus stellar mass relation in the local Universe. To this end we use the Hα narrow-band imaging follow-up survey (Hα3) of field galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Coma and Local superclusters. By complementing this local determination with high-redshift measurements from the literature, we reconstruct the star formation history of main-sequence galaxies as a function of stellar mass from the present epoch up to z = 3. In agreement with previous studies, our analysis shows that quenching mechanisms occur above a threshold stellar mass Mknee that evolves with redshift as ∝ (1 + z)2. Moreover, visual morphological classification of individual objects in our local sample reveals a sharp increase in the fraction of visually classified strong bars with mass, hinting that strong bars may contribute to the observed downturn in the sSFR above Mknee. We test this hypothesis using a simple but physically motivated numerical model for bar formation, finding that strong bars can rapidly quench star formation in the central few kpc of field galaxies. We conclude that strong bars contribute significantly to the red colors observed in the inner parts of massive galaxies, although additional mechanisms are likely required to quench the star formation in the outer regions of massive spiral galaxies. Intriguingly, when we extrapolate our model to higher redshifts, we successfully recover the observed

  19. A large population of mid-infrared selected, obscured active galaxies in the Bootes field

    Hickox, R C; Forman, W R; Murray, S S; Brodwin, M; Brown, M J I; Eisenhardt, P R; Stern, D; Kochanek, C S; Eisenstein, D; Cool, R J; Jannuzi, B T; Dey, A; Brand, K; Gorjian, V; Caldwell, N

    2007-01-01

    We identify a population of 640 obscured and 839 unobscured active galactic nuclei (AGNs) at redshifts 0.7~80%. The observed numbers of IRAGNs are comparable to predictions from previous X-ray, optical, and IR luminosity functions, for the given redshifts and IRAC flux limits. We observe a bimodal distribution in R-[4.5] color, suggesting that luminous IR-selected AGNs have either low or significant dust extinction, which may have implications for models of AGN obscuration.

  20. Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets

    Saykally, Richard J; Uejio, Janel S.; Schwartz, Craig P.; Duffin, Andrew M.; Drisdell, Walter S.; Cohen, Ronald C.; Saykally, Richard J.

    2008-01-08

    We describe an approach for characterizing selective binding between oppositely charged ionic functional groups under biologically relevant conditions. Relative shifts in K-shell x-ray absorption spectra of aqueous cations and carboxylate anions indicate the corresponding binding strengths via perturbations of carbonyl antibonding orbitals. XAS spectra measured for aqueous formate and acetate solutions containing lithium, sodium, and potassium cations reveal monotonically stronger binding of the lighter metals, supporting recent results from simulations and other experiments. The carbon K-edge spectra of the acetate carbonyl feature centered near 290 eV clearly indicate a preferential interaction of sodium versus potassium, which was less apparent with formate. These results are in accord with the Law of Matching Water Affinities, relating relative hydration strengths of ions to their respective tendencies to form contact ion pairs. Density functional theory calculations of K-shell spectra support the experimental findings.

  1. Highly Selective Hg (II Ion Detection Based on Linear Blue-Shift of the Maximum Absorption Wavelength of Silver Nanoparticles

    Li Ping Wu

    2012-01-01

    Full Text Available A new method of detecting Hg (II ion with silver nanoparticles (AgNPs is developed in this contribution. When Hg (II ions were added into AgNPs solution, the solution displayed rapid color change and blue shift of the maximum absorption wavelength (Δλ, which was in proportion to the Hg (II ion concentration over the range of 2.0 × 10−7–6.0 × 10−6 mol/L, with detection limit (3σ of 6.6 × 10−9 mol/L. Under the same experimental conditions, other metal ions did not interfere. Thus, we propose a rapid, simple and highly selective method for detecting Hg (II ion.

  2. B and R CCD surface photometry of selected low surface brightness galaxies in the region of the Fornax cluster

    The recent discoveries of large numbers of low surface brightness (LSB) galaxies in clusters and of the extreme LSB giant galaxy Malin 1 are changing our view of the galactic contents of the Universe. In this paper we describe B and R band CCD photometry of a sample of LSB galaxies previously identified from photographic plates of the Fornax cluster. This sample contains some of the lowest surface brightness galaxies known, one having the same central surface brightness as Main 1. The objects in this sample have a wide range of morphologies, and galaxies of similar appearance may have very different (B-R) colours. The range of (B-R) colours for this sample (almost all of which would have been described as dE from their B band morphology alone) is as large as that of the entire Hubble sequence. (author)

  3. Optimum selection of filters and scintillators for absorption measurements of plasma electron temperature

    The paper presents an analysis of optimum selection of the thickness of filters and scintillators, performed in order to achieve the maximum attenuation of line radiation from impurity ions occuring in hydrogen plasma. This radiation usually leads to errors in an estimation of plasma electron temperature. The calculations of 80 various sets of Al-filters and Ne 102A scintillators are performed. The paper introduces a universal parameter which is determined as a ratio of relative bremstrahlung intensities, recorded by the system with a scintillator of finite thickness, and by that with the scintillator of infinite thickness. Such a parameter enables to convert the theoretical curves for infinitely thick scintillator into the curves, for the scintillator used in a particular experiment. (author)

  4. STAR FORMATION RATES AND STELLAR MASSES OF Hα SELECTED STAR-FORMING GALAXIES AT z = 0.84: A QUANTIFICATION OF THE DOWNSIZING

    In this work we analyze the physical properties of a sample of 153 star-forming galaxies at z ∼ 0.84, selected by their Hα flux with a narrowband filter. B-band luminosities of the objects are higher than those of local star-forming galaxies. Most of the galaxies are located in the blue cloud, though some objects are detected in the green valley and in the red sequence. After the extinction correction is applied, virtually all these red galaxies move to the blue sequence, unveiling their dusty nature. A check on the extinction law reveals that the typical extinction law for local starbursts is well suited for our sample but with E(B - V)stars = 0.55 E(B - V)gas. We compare star formation rates (SFRs) measured with different tracers (Hα, far-ultraviolet, and infrared), finding that they agree within a factor of three after extinction correction. We find a correlation between the ratios SFRFUV/SFRHα, SFRIR/SFRHα, and the EW(Hα) (i.e., weighted age), which accounts for part of the scatter. We obtain stellar mass estimations by fitting templates to multi-wavelength photometry. The typical stellar mass of a galaxy within our sample is ∼1010 Msun. The SFR is correlated with stellar mass and the specific SFR decreases with it, indicating that massive galaxies are less affected by star formation processes than less massive ones. This result is consistent with the downsizing scenario. To quantify this downsizing we estimated the quenching mass MQ for our sample at z ∼ 0.84, finding that it declines from MQ ∼ 1012 Msun at z ∼ 0.84 to MQ ∼ 8 x 1010 Msun at the local universe.

  5. Shocked POststarbust Galaxy Survey. I. Candidate Post-starbust Galaxies with Emission Line Ratios Consistent with Shocks

    Alatalo, Katherine; Cales, Sabrina L.; Rich, Jeffrey A.; Appleton, Philip N.; Kewley, Lisa J.; Lacy, Mark; Lanz, Lauranne; Medling, Anne M.; Nyland, Kristina

    2016-06-01

    There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench “quietly.” Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z = 0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an “E+A” selection. SPOGs* have a 13% 1.4 GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this sample of

  6. Origins of the thick disk of the galaxy as traced by metal-poor stars selected from RAVE

    Ruchti G.R.

    2012-02-01

    Full Text Available Models of the formation of the thick disk of the Milky Way Galaxy make specific predictions about the chemical abundance properties of the metal-weak (and oldest stellar population in the thick disk. We have undertaken the study of the elemental abundances and kinematic properties of a sample of 319 candidate metal-poor thick-disk stars selected from the RAVE spectroscopic survey of bright stars. Our aim is to differentiate among the present scenarios of the formation of the thick disk. In this study, we measured the abundances of several alpha-elements and found that the thick-disk [alpha/Fe] ratios are enhanced, implying that enrichment proceeded by purely core-collapse supernovae. Further, the sample probes distances ranging out to about 2 kpc from the Sun, allowing for the investigation of the gradients in the thick disk. I will discuss the results from these investigations and how they compare to the predictions made by present models of the formation of the thick disk.

  7. The clustering properties of radio-selected AGN and star-forming galaxies up to redshifts z~3

    Magliocchetti, M; Brusa, M; Salvato, M; Laigle, C; McCracken, H J; Ilbert, O

    2016-01-01

    We present the clustering properties of a complete sample of 968 radio sources detected at 1.4 GHz by the VLA-COSMOS survey with radio fluxes brighter than 0.15 mJy. Ninety-two per cent have redshift determinations from the Laigle et al. (2016) catalogue. Based on their radio-luminosity, these objects have been divided into two populations of 644 AGN and 247 star-forming galaxies. We find r_0=11.7^{+1.0}_{-1.1} Mpc for the clustering length of the whole sample, while r_0=11.2^{+2.5}_{-3.3} Mpc and r_0=7.8^{+1.6}_{-2.1} Mpc (r_0=6.8^{+1.4}_{-1.8} Mpc if we restrict our analysis to z/M_halo/M_halo/M_halo<~10^{-2.1}, result which clearly indicates the cosmic process of stellar build-up as one moves towards the more local universe. Comparisons between the observed space density of radio-selected AGN and that of dark matter haloes shows that about one in two haloes is associated with a black hole in its radio-active phase. This suggests that the radio-active phase is a recurrent phenomenon.

  8. Comparing the Host Galaxies of Type Ia, Type II, and Type Ibc Supernovae

    Shao, X.; Liang, Y. C.; Dennefeld, M.; Chen, X. Y.; Zhong, G. H.; Hammer, F.; Deng, L. C.; Flores, H.; Zhang, B.; Shi, W. B.; Zhou, L.

    2014-08-01

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D n (4000), Hδ A , stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D n (4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D n (4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (~0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  9. Comparing the host galaxies of type Ia, type II, and type Ibc supernovae

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters Dn(4000), HδA, stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low Dn(4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high Dn(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (∼0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  10. The Biases of Optical Line-Ratio Selection for Active Galactic Nuclei and the Intrinsic Relationship between Black Hole Accretion and Galaxy Star Formation

    Trump, Jonathan R.; Sun, Mouyuan; Zeimann, Gregory R.; Luck, Cuyler; Bridge, Joanna S.; Grier, Catherine J.; Hagen, Alex; Juneau, Stephanie; Montero-Dorta, Antonio; Rosario, David J.; Brandt, W. Niel; Ciardullo, Robin; Schneider, Donald P.

    2015-09-01

    We use 317,000 emission-line galaxies from the Sloan Digital Sky Survey to investigate line-ratio selection of active galactic nuclei (AGNs). In particular, we demonstrate that “star formation (SF) dilution” by H ii regions causes a significant bias against AGN selection in low-mass, blue, star-forming, disk-dominated galaxies. This bias is responsible for the observed preference of AGNs among high-mass, green, moderately star-forming, bulge-dominated hosts. We account for the bias and simulate the intrinsic population of emission-line AGNs using a physically motivated Eddington ratio distribution, intrinsic AGN narrow line region line ratios, a luminosity-dependent {L}{bol}/L[{{O}} {{III}}] bolometric correction, and the observed {M}{BH}-σ relation. These simulations indicate that, in massive ({log}({M}*/{M}⊙ )≳ 10) galaxies, AGN accretion is correlated with specific star formation rate (SFR) but is otherwise uniform with stellar mass. There is some hint of lower black hole occupation in low-mass ({log}({M}*/{M}⊙ )≲ 10) hosts, although our modeling is limited by uncertainties in measuring and interpreting the velocity dispersions of low-mass galaxies. The presence of SF dilution means that AGNs contribute little to the observed strong optical emission lines (e.g., [{{O}} {{III}}] and {{H}}α ) in low-mass and star-forming hosts. However the AGN population recovered by our modeling indicates that feedback by typical (low- to moderate-accretion) low-redshift AGNs has nearly uniform efficiency at all stellar masses, SFRs, and morphologies. Taken together, our characterization of the observational bias and resultant AGN occupation function suggest that AGNs are unlikely to be the dominant source of SF quenching in galaxies, but instead are fueled by the same gas which drives SF activity.

  11. The Contribution of Radio Selected Star Forming Galaxies to the IR Energy Density Budget

    Seymour, N; Moss, D; McHardy, I; Zoghbi, A; Rieke, G; Page, M; Hopkins, A; Loaring, N

    2008-01-01

    We have used several different methods (radio morphology, radio spectral index, mid-IR to radio and near-IR to radio flux density ratios) to discriminate between AGN and SFGs in faint, sub-mJy radio surveys. We find that the latter two methods are the most powerful with current multi-wavelength data, but that future radio surveys with eMERLIN, LOFAR etc. (and ultimately the SKA) will greatly increase the power of the morphology and spectral index methods. As an example of the science possible we derive the IR luminosity density from the radio-selected SFGs using the radio/IR luminosity correlation. We also examine the contribution by luminosity to the total IR luminosity density and find evidence that fraction of LIRGs remains constant or decreases above z=1 while the relative fraction of ULIRGs continues to increase up to z=2.5.

  12. HerMES: Unveiling obscured star formation - the far infrared luminosity function of ultraviolet-selected galaxies at z~1.5

    Heinis, S; Béthermin, M; Aussel, H; Bock, J; Boselli, A; Burgarella, D; Conley, A; Cooray, A; Farrah, D; Ibar, E; Ilbert, O; Ivison, R J; Magdis, G; Marsden, G; Oliver, S J; Page, M J; Rodighiero, G; Roehlly, Y; Schulz, B; Scott, Douglas; Smith, A J; Viero, M; Wang, L; Zemcov, M

    2012-01-01

    We study the far-infrared (IR) and sub-millimeter properties of a sample of ultraviolet (UV) selected galaxies at z\\sim1.5. Using stacking at 250, 350 and 500 um from Herschel Space Observatory SPIRE imaging of the COSMOS field obtained within the HerMES key program, we derive the mean IR luminosity as a function of both UV luminosity and slope of the UV continuum beta. The IR to UV luminosity ratio is roughly constant over most of the UV luminosity range we explore. We also find that the IR to UV luminosity ratio is correlated with beta. We observe a correlation that underestimates the correlation derived from low-redshift starburst galaxies, but is in good agreement with the correlation derived from local normal star-forming galaxies. Using these results we reconstruct the IR luminosity function of our UV-selected sample. This luminosity function recovers the IR luminosity functions measured from IR selected samples at the faintest luminosities (Lir ~ 10^{11} L_sun), but might underestimate them at the brig...

  13. Galaxy Zoo Hubble: Crowdsourced Morphologies for 169,944 Galaxies at 0

    Willett, Kyle; Galloway, Melanie; Fortson, Lucy; Bamford, Steven; Masters, Karen; Lintott, Chris; Simmons, Brooke; Cheung, Edmond; Schawinski, Kevin; Scarlata, Claudia; Beck, Melanie; Galaxy Zoo volunteers

    2016-01-01

    The Galaxy Zoo project uses crowdsourced visual classifications to create large and statistically robust catalogs of detailed galaxy morphology. We present initial results for the Galaxy Zoo: Hubble dataset, which includes 169,944 images of galaxies selected from the AEGIS, COSMOS, GEMS, and GOODS surveys. The galaxies span a redshift range of 0Zoo: Hubble catalog.

  14. In situ Studies of Soft- and Reactive Landing of Mass-Selected Ions Using Infrared Reflection Absorption Spectroscopy

    Hu, Qichi; Wang, Peng; Gassman, Paul L.; Laskin, Julia

    2009-09-01

    Grazing incidence infrared reflection absorption spectroscopy (IRRAS) for in situ and in real time characterization of substrates modified by soft- and reactive landing (SL and RL) of complex ions was implemented on a mass-selected ion deposition instrument. Ions produced by electrospray ionization were mass-selected using a quadrupole mass filter and deposited onto inert and reactive self-assembled monolayer (SAM) surfaces. Surface composition during and after ion deposition was monitored using IRRAS. Physisorption of a cyclic peptide, Garmicidin S (GS), was studied for 8 hrs during deposition and additional 12 hrs after the end of deposition. The integrated signal of the characteristic amide bands followed a linear increase during the deposition and stayed unchanged after the deposition was finished. Similar linear increase in IRRAS signal was obtained following reactive deposition of the protonated dodecanediamine onto SAMs of dithiobis (succinimidyl undecanoate) (NHS-SAM) and 16-mercaptohexadecanoic acid fluoride (COF-SAM) on gold. IRRAS allowed us to monitor for the first time the formation of the amide bond between reactive SAM surfaces and the projectile molecule.

  15. Galaxies probing galaxies: cool halo gas from a z = 0.47 post-starburst galaxy

    Rubin, Kate H. R.; Prochaska, J. Xavier; Koo, David C.; Phillips, Andrew C.; Weiner, Benjamin J.

    2009-01-01

    We study the cool gas around a galaxy at z = 0.4729 using Keck/LRIS spectroscopy of a bright (B = 21.7) background galaxy at z = 0.6942 at a transverse distance of 16.5/h_70 kpc. The background galaxy spectrum reveals strong FeII, MgII, MgI, and CaII absorption at the redshift of the foreground galaxy, with a MgII 2796 rest equivalent width of 3.93 +/- 0.08 Angstroms, indicative of a velocity width exceeding 400 km/s. Because the background galaxy is large (> 4/h_70 kpc), the high covering fr...

  16. Global dust attenuation in disc galaxies: strong variation with specific star formation and stellar mass, and the importance of sample selection

    Devour, Brian

    2016-01-01

    We study the relative dust attenuation-inclination relation in 78,721 nearby galaxies using the axis ratio dependence of optical-NIR colour, as measured by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Wide-field Infrared Survey Explorer (WISE). In order to avoid to the greatest extent possible attenuation-driven biases, we carefully select galaxies using dust attenuation-independent near- and mid-IR luminosities and colours. Relative u-band attenuation between face-on and edge-on disc galaxies along the star forming main sequence varies from ~0.55 mag up to ~1.55 mag. The strength of the relative attenuation varies strongly with both specific star formation rate and galaxy luminosity (or stellar mass). The dependence of relative attenuation on luminosity is not monotonic, but rather peaks at $M_{3.4\\mu m} \\approx -21.5$, corresponding to $M_* \\approx 3\\times 10^{10}M_{Sun}$. This behavior stands seemingly in contrast to some older studies; we show that older works failed...

  17. The Spectrally Resolved Lyman-alpha Emission of Three Lyman-alpha Selected Field Galaxies at z~2.4 from the HETDEX Pilot Survey

    Chonis, Taylor S; Hill, Gary J; Adams, Joshua J; Finkelstein, Steven L; Gebhardt, Karl; Kollmeier, Juna A; Ciardullo, Robin; Drory, Niv; Gronwall, Caryl; Hagen, Alex; Overzier, Roderik A; Song, Mimi; Zeimann, Gregory R

    2013-01-01

    We present new results on the spectrally resolved Lyman-alpha (LyA) emission of three LyA emitting field galaxies at z~2.4 with high LyA equivalent width (>100 Angstroms) and LyA luminosity (~10^43 erg/s). At 120 km/s (FWHM) spectral resolution, the prominent double-peaked LyA profile straddles the systemic velocity, where the velocity zero-point is determined from spectroscopy of the galaxies' rest-frame optical nebular emission lines. The average velocity offset from systemic of the stronger redshifted emission component for our sample is 176 km/s while the average total separation between the redshifted and main blueshifted emission components is 380 km/s. These measurements are a factor of ~2 smaller than for UV continuum-selected galaxies that show LyA in emission with lower LyA equivalent width. We compare our LyA spectra to the predicted line profiles of a spherical "expanding shell" LyA radiative transfer grid that models large-scale galaxy outflows. Specifically blueward of the systemic velocity wher...

  18. THE CLOWES-CAMPUSANO LARGE QUASAR GROUP SURVEY. I. GALEX SELECTED SAMPLE OF LYMAN BREAK GALAXIES AT z ∼ 1

    The nature of galaxy structures on large scales is a key observational prediction for current models of galaxy formation. The Sloan Digital Sky Survey (SDSS) and the 2dF galaxy survey have revealed a number of structures on 40-150 h-1 Mpc scales at low redshifts, and some even larger ones. To constrain galaxy number densities, luminosities, and stellar populations in large structures at higher redshift, we have investigated two sheet-like structures of galaxies at z = 0.8 and 1.3 spanning 150 h-1 comoving Mpc embedded in large quasar groups (LQGs) extending over at least 200 h-1 Mpc. We present first results of an analysis of these sheet-like structures using two contiguous 1 deg Galaxy Evolution Explorer (GALEX) fields (FUV and NUV) cross-correlated with optical data from the SDSS. We derive a sample of 462 Lyman break galaxy (LBG) candidates coincident with the sheets. Using the GALEX and SDSS data, we show that the overall average spectral energy distribution of a LBG galaxy at z ∼ 1 is flat (in fλ) in the rest-frame wavelength range from 1500 A to 4000 A, implying evolved populations of stars in the LBGs. From the luminosity functions we get indications for overdensities in the two LQGs compared to their foreground regions. Similar conclusions come from the calculation of the 2-point correlation function, showing a 2σ overdensity for the LBGs in the z ∼ 0.8 LQG on scales of 1.6 to 4.8 Mpc, indicating similar correlation scales for our LBG sample as their z ∼ 3 counterparts.

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

    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. GALAXY CLUSTERS IN THE LINE OF SIGHT TO BACKGROUND QUASARS. III. MULTI-OBJECT SPECTROSCOPY

    Andrews, H.; Barrientos, L. F.; Padilla, N.; Lacerna, I. [Instituto de Astrofisica, Pontificia Universidad Catolica de Chile, Avenida Vicuna Mackenna 4860, Santiago (Chile); Lopez, S.; Lira, P.; Maureira, M. J. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Gilbank, D. G. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Ellingson, E. [Center for Astrophysics and Space Astronomy, University of Colorado at Boulder, Campus Box 389, Boulder, CO 80309-0389 (United States); Gladders, M. D. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Yee, H. K. C., E-mail: barrientos@astro.puc.cl [Department of Astronomy and Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8 (Canada)

    2013-09-01

    We present Gemini/GMOS-S multi-object spectroscopy of 31 galaxy cluster candidates at redshifts between 0.2 and 1.0 and centered on QSO sight lines taken from Lopez et al. The targets were selected based on the presence of an intervening Mg II absorption system at a similar redshift to that of a galaxy cluster candidate lying at a projected distance <2 h{sub 71}{sup -1} Mpc from the QSO sight line (a {sup p}hotometric hit{sup )}. The absorption systems span rest-frame equivalent widths between 0.015 and 2.028 A. Our aim was three-fold: (1) to identify the absorbing galaxies and determine their impact parameters, (2) to confirm the galaxy cluster candidates in the vicinity of each quasar sightline, and (3) to determine whether the absorbing galaxies reside in galaxy clusters. In this way, we are able to characterize the absorption systems associated with cluster members. Our main findings are as follows. (1) We identified 10 out of 24 absorbing galaxies with redshifts between 0.2509 {<=} z{sub gal} {<=} 1.0955, up to an impact parameter of 142 h{sub 71}{sup -1} kpc and a maximum velocity difference of 280 km s{sup -1}. (2) We spectroscopically confirmed 20 out of 31 cluster/group candidates, with most of the confirmed clusters/groups at z < 0.7. This relatively low efficiency results from the fact that we centered our observations on the QSO location, and thus occasionally some of the cluster centers were outside the instrument field of view. (3) Following from the results above, we spectroscopically confirmed of 10 out of 14 photometric hits within {approx}650 km s{sup -1} from galaxy clusters/groups, in addition to two new ones related to galaxy group environments. These numbers imply efficiencies of 71% in finding such systems with MOS spectroscopy. This is a remarkable result since we defined a photometric hit as those cluster-absorber pairs having a redshift difference {Delta}z = 0.1. The general population of our confirmed absorbing galaxies have luminosities

  1. AEGIS: Demographics of X-ray and Optically Selected AGNs

    Yan, Renbin; Newman, Jeffrey A; Coil, Alison L; Willmer, Christopher N A; Laird, Elise S; Georgakakis, Antonis; Aird, James; Barmby, Pauline; Bundy, Kevin; Cooper, Michael C; Davis, Marc; Faber, S M; Fang, Taotao; Griffith, Roger L; Koekemoer, Anton M; Koo, David C; Nandra, Kirpal; Park, Shinae Q; Sarajedini, Vicki L; Weiner, Benjamin J; Willner, S P

    2010-01-01

    We develop a new diagnostic method to classify galaxies into AGN hosts, star-forming galaxies, and absorption-dominated galaxies, by combining the [OIII]/Hbeta ratio with optical color. This can be used to robustly select AGNs in galaxy samples at intermediate redshifts (z10^44 erg/s in our sample are not detected in our 200ks Chandra images, most likely due to moderate or heavy absorption by gas near the AGN. The 2-10 keV detection rate of Seyfert 2's at z~0.6 suggests their column density distribution and C ompton-thick fraction are similar to that of local Seyferts. We recommend combining multiple sample selection techniques to obtain as complete an AGN sample as possible.

  2. The HI absorption 'Zoo'

    Gereb, K; Morganti, R; Oosterloo, T A

    2014-01-01

    We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of widths, shapes and kinematical properties. We characterize the HI spectra of the individual detections using the busy function (Westmeier et al. 2014). With the goal of identifying different morphological structures of HI, we study the kinematical and radio source properties of the detections as function of their width. Narrow lines (FWHM = 500 km/s). These detections are good candidates for being HI outflows. The detection rate of HI outflows is 5 percent in the total radio AGN sample. This fraction represents a lower limit, however it could suggests that, if outflows are a characteristic phenomenon of all radio sources, they would have a short depletion timescale compared to the lifetime of the AGN. Blueshifted and broad/asymmetric lines are more often present among young...

  3. THE SPECTRALLY RESOLVED Lyα EMISSION OF THREE Lyα-SELECTED FIELD GALAXIES AT z ∼ 2.4 FROM THE HETDEX PILOT SURVEY

    Chonis, Taylor S.; Finkelstein, Steven L.; Gebhardt, Karl; Overzier, Roderik A.; Song, Mimi [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Blanc, Guillermo A.; Adams, Joshua J.; Kollmeier, Juna A. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Hill, Gary J.; Drory, Niv [McDonald Observatory, University of Texas at Austin, 2515 Speedway, Stop C1402, Austin, TX 78712 (United States); Ciardullo, Robin; Gronwall, Caryl; Hagen, Alex; Zeimann, Gregory R., E-mail: tschonis@astro.as.utexas.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2013-10-01

    We present new results on the spectrally resolved Lyα emission of three Lyα-emitting field galaxies at z ∼ 2.4 with high Lyα equivalent width (>100 Å) and Lyα luminosity (∼10{sup 43} erg s{sup –1}). At 120 km s{sup –1} (FWHM) spectral resolution, the prominent double-peaked Lyα profile straddles the systemic velocity, where the velocity zero point is determined from spectroscopy of the galaxies' rest-frame optical nebular emission lines. The average velocity offset from systemic of the stronger redshifted emission component for our sample is 176 km s{sup –1} while the average total separation between the redshifted and main blueshifted emission components is 380 km s{sup –1}. These measurements are a factor of ∼2 smaller than for UV-continuum-selected galaxies that show Lyα in emission with lower Lyα equivalent widths. We compare our Lyα spectra to the predicted line profiles of a spherical 'expanding shell' Lyα radiative transfer grid that models large-scale galaxy outflows. Specifically, blueward of the systemic velocity where two galaxies show a weak, highly blueshifted (by ∼1000 km s{sup –1}) tertiary emission peak, the model line profiles are a relatively poor representation of the observed spectra. Since the neutral gas column density has a dominant influence over the shape of the Lyα line profile, we caution against equating the observed Lyα velocity offset with a physical outflow velocity, especially at lower spectral resolution where the unresolved Lyα velocity offset is a convoluted function of several degenerate parameters. Referring to rest-frame ultraviolet and optical Hubble Space Telescope imaging, we find that galaxy-galaxy interactions may play an important role in inducing a starburst that results in copious Lyα emission as well as perturbing the gas distribution and velocity field, both of which have strong influence over the Lyα emission line profile.

  4. THE SPECTRALLY RESOLVED Lyα EMISSION OF THREE Lyα-SELECTED FIELD GALAXIES AT z ∼ 2.4 FROM THE HETDEX PILOT SURVEY

    We present new results on the spectrally resolved Lyα emission of three Lyα-emitting field galaxies at z ∼ 2.4 with high Lyα equivalent width (>100 Å) and Lyα luminosity (∼1043 erg s–1). At 120 km s–1 (FWHM) spectral resolution, the prominent double-peaked Lyα profile straddles the systemic velocity, where the velocity zero point is determined from spectroscopy of the galaxies' rest-frame optical nebular emission lines. The average velocity offset from systemic of the stronger redshifted emission component for our sample is 176 km s–1 while the average total separation between the redshifted and main blueshifted emission components is 380 km s–1. These measurements are a factor of ∼2 smaller than for UV-continuum-selected galaxies that show Lyα in emission with lower Lyα equivalent widths. We compare our Lyα spectra to the predicted line profiles of a spherical 'expanding shell' Lyα radiative transfer grid that models large-scale galaxy outflows. Specifically, blueward of the systemic velocity where two galaxies show a weak, highly blueshifted (by ∼1000 km s–1) tertiary emission peak, the model line profiles are a relatively poor representation of the observed spectra. Since the neutral gas column density has a dominant influence over the shape of the Lyα line profile, we caution against equating the observed Lyα velocity offset with a physical outflow velocity, especially at lower spectral resolution where the unresolved Lyα velocity offset is a convoluted function of several degenerate parameters. Referring to rest-frame ultraviolet and optical Hubble Space Telescope imaging, we find that galaxy-galaxy interactions may play an important role in inducing a starburst that results in copious Lyα emission as well as perturbing the gas distribution and velocity field, both of which have strong influence over the Lyα emission line profile

  5. The Biases of Optical Line-Ratio Selection for Active Galactic Nuclei, and the Intrinsic Relationship between Black Hole Accretion and Galaxy Star Formation

    Trump, Jonathan R; Zeimann, Gregory R; Luck, Cuyler; Bridge, Joanna S; Grier, Catherine J; Hagen, Alex; Juneau, Stephanie; Montero-Dorta, Antonio; Rosario, David J; Brandt, W Niel; Ciardullo, Robin; Schneider, Donald P

    2015-01-01

    We use 317,000 emission-line galaxies from the Sloan Digital Sky Survey to investigate line-ratio selection of active galactic nuclei (AGNs). In particular, we demonstrate that "star formation dilution" by HII regions causes a significant bias against AGN selection in low-mass, blue, star-forming, disk-dominated galaxies. This bias is responsible for the observed preference of AGNs among high-mass, green, moderately star-forming, bulge-dominated hosts. We account for the bias and simulate the intrinsic population of emission-line AGNs using a physically-motivated Eddington ratio distribution, intrinsic AGN narrow line region line ratios, a luminosity-dependent Lbol/L[OIII] bolometric correction, and the observed Mbh-sigma relation. These simulations indicate that, in massive (log(M*/Msun) > 10) galaxies, AGN accretion is correlated with specific star formation rate but is otherwise uniform with stellar mass. There is some hint of lower black hole occupation in low-mass (log(M*/Msun) < 10) hosts, although o...

  6. Brightest Cluster Galaxy Identification

    Leisman, Luke; Haarsma, D. B.; Sebald, D. A.; ACCEPT Team

    2011-01-01

    Brightest cluster galaxies (BCGs) play an important role in several fields of astronomical research. The literature includes many different methods and criteria for identifying the BCG in the cluster, such as choosing the brightest galaxy, the galaxy nearest the X-ray peak, or the galaxy with the most extended profile. Here we examine a sample of 75 clusters from the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT) and the Sloan Digital Sky Survey (SDSS), measuring masked magnitudes and profiles for BCG candidates in each cluster. We first identified galaxies by hand; in 15% of clusters at least one team member selected a different galaxy than the others.We also applied 6 other identification methods to the ACCEPT sample; in 30% of clusters at least one of these methods selected a different galaxy than the other methods. We then developed an algorithm that weighs brightness, profile, and proximity to the X-ray peak and centroid. This algorithm incorporates the advantages of by-hand identification (weighing multiple properties) and automated selection (repeatable and consistent). The BCG population chosen by the algorithm is more uniform in its properties than populations selected by other methods, particularly in the relation between absolute magnitude (a proxy for galaxy mass) and average gas temperature (a proxy for cluster mass). This work supported by a Barry M. Goldwater Scholarship and a Sid Jansma Summer Research Fellowship.

  7. Cosmic Metallicity from ZnII-Selected QSO Absorption Line Systems Near Redshift z=1.2

    Monier, Eric

    2010-09-01

    We have searched nearly 15,000 strong intervening MgII systems in SDSS quasar spectra to measure spectral regions where weak, unsaturated metal lines are predicted to exist, with the aim of finding a representative sample of the strongest metal-line column density systems in the universe. These systems are clearly damped Lyman-alpha {DLA} systems, which track cosmologically intervening neutral gas regions that fall along the sightlines to background quasars. We propose STIS G230L spectroscopy of seven strong-ZnII-selected systems from this sample in order to measure their Lyman-alpha absorption profiles and derive their HI column densities. Since Zn is not depleted onto grains, measurement of N{HI} allows a direct measurement of the metal abundance in such systems. We expect the results to be representative of the upper envelope of the distribution of neutral-gas-phase metallicities near redshift z=1.2. If these systems are high-N{HI} DLAs {e.g., 6E21 atoms/cm^2} they will have metallicities typical of those normally found in DLAs {e.g., one-tenth solar}. However, if they are low-N{HI} DLAs {e.g., 2E20 atoms/cm(2) }, they will have supersolar metallicities. Since these DLAs are selected on the basis of their extreme metal-line properties, analysis of their metallicities and dust-to-gas ratios will lead to strong constraints on the range of properties exhibited by DLA systems.

  8. Species selective preconcentration and quantification of gold nanoparticles using cloud point extraction and electrothermal atomic absorption spectrometry

    Highlights: ► We optimized cloud point extraction and ET-AAS parameters for Au-NPs measurement. ► A selective ligand (sodium thiosulphate) is introduced for species separation. ► A limit of detection of 5 ng Au-NP per L is achieved for aqueous samples. ► Measurement of samples with high natural organic mater content is possible. ► Real water samples including wastewater treatment plant effluent were analyzed. - Abstract: The determination of metallic nanoparticles in environmental samples requires sample pretreatment that ideally combines pre-concentration and species selectivity. With cloud point extraction (CPE) using the surfactant Triton X-114 we present a simple and cost effective separation technique that meets both criteria. Effective separation of ionic gold species and Au nanoparticles (Au-NPs) is achieved by using sodium thiosulphate as a complexing agent. The extraction efficiency for Au-NP ranged from 1.01 ± 0.06 (particle size 2 nm) to 0.52 ± 0.16 (particle size 150 nm). An enrichment factor of 80 and a low limit of detection of 5 ng L−1 is achieved using electrothermal atomic absorption spectrometry (ET-AAS) for quantification. TEM measurements showed that the particle size is not affected by the CPE process. Natural organic matter (NOM) is tolerated up to a concentration of 10 mg L−1. The precision of the method expressed as the standard deviation of 12 replicates at an Au-NP concentration of 100 ng L−1 is 9.5%. A relation between particle concentration and the extraction efficiency was not observed. Spiking experiments showed a recovery higher than 91% for environmental water samples.

  9. Sulfur K-edge absorption spectroscopy on selected biological systems; Schwefel-K-Kanten-Absorptionsspektroskopie an ausgewaehlten biologischen Systemen

    Lichtenberg, Henning

    2008-07-15

    Sulfur is an essential element in organisms. In this thesis investigations of sulfur compounds in selected biological systems by XANES (X-ray Absorption Near Edge Structure) spectroscopy are reported. XANES spectroscopy at the sulfur K-edge provides an excellent tool to gain information about the local environments of sulfur atoms in intact biological samples - no extraction processes are required. Spatially resolved measurements using a Kirkpatrick-Baez mirror focusing system were carried out to investigate the infection of wheat leaves by rust fungi. The results give information about changes in the sulfur metabolism of the host induced by the parasite and about the extension of the infection into visibly uninfected plant tissue. Furthermore, XANES spectra of microbial mats from sulfidic caves were measured. These mats are dominated by microbial groups involved in cycling sulfur. Additionally, the influence of sulfate deprivation and H{sub 2}S exposure on sulfur compounds in onion was investigated. To gain an insight into the thermal degradation of organic material the influence of roasting of sulfur compounds in coffee beans was studied. (orig.)

  10. The Roadmap for Unification in Galaxy Group Selection. I. A Search for Extended X-ray Emission in the CNOC2 Survey

    Finoguenov, A.; Connelly, J. L.; Parker, L. C.; Wilman, D. J.; Mulchaey, J. S.; Saglia, R. P.; Balogh, M. L.; Bower, R. G.; McGee, S. L.

    2009-10-01

    X-ray properties of galaxy groups can unlock some of the most challenging research topics in modern extragalactic astronomy: the growth of structure and its influence on galaxy formation. Only with the advent of the Chandra and XMM-Newton facilities have X-ray observations reached the depths required to address these questions in a satisfactory manner. Here we present an X-ray imaging study of two patches from the CNOC2 spectroscopic galaxy survey using combined Chandra and XMM-Newton data. A state of the art extended source finding algorithm has been applied, and the resultant source catalog, including redshifts from a spectroscopic follow-up program, is presented. The total number of spectroscopically identified groups is 25 spanning a redshift range 0.04-0.79. Approximately 50% of CNOC2 spectroscopically selected groups in the deeper X-ray (RA14h) field are likely X-ray detections, compared to 20% in the shallower (RA21h) field. Statistical modeling shows that this is consistent with expectations, assuming an expected evolution of the LX -M relation. A significant detection of a stacked shear signal for both spectroscopic and X-ray groups indicates that both samples contain real groups of about the expected mass. We conclude that the current area and depth of X-ray and spectroscopic facilities provide a unique window of opportunity at z ~ 0.4 to test the X-ray appearance of galaxy groups selected in various ways. There is at present no evidence that the correlation between X-ray luminosity and velocity dispersion evolves significantly with redshift, which implies that catalogs based on either method can be fairly compared and modeled. Based on observations with the ESA/NASA XMM-Newton science mission; the European Southern Observatory, Chile; NASA/ESA Chandra X-ray Observatory.

  11. Absorption coefficients of selected explosives and related compounds in the range of 0.1-2.8 THz.

    Chen, Jian; Chen, Yunqing; Zhao, Hongwei; Bastiaans, Glenn J; Zhang, X-C

    2007-09-17

    We have investigated the absorption spectra of seventeen explosives and related compounds (ERCs) by using terahertz time-domain spectroscopy in the 0.1-2.8 THz region. Most of these substances show characteristic absorption features in this frequency range. The measured absorption coefficients of these ERCs form a database, which is of great importance for biochemical, defense and security related applications. PMID:19547570

  12. Selective absorption of water from different oil–water emulsions with Psy-cl-poly(AAm) synthesized using irradiation copolymerization method

    B S Kaith; Kiran Kumar

    2007-08-01

    The present paper deals with the functionalization of psyllium with acrylamide under the influence of gamma radiation using hexamethylene tetramine as a crosslinker. The polymer synthesized was characterized using FTIR spectroscopy, scanning electron microscopy and thermogravimetric analysis. The superabsorbent was then used further for the selective absorption of water from different oil–water emulsions.

  13. Selective Flow Injection Analysis of Ultra-trace Amounts of Cr(VI), Preconcentration of It by Solvent Extraction, and Determination by Electrothermal Atomic Absorption Spectrometry (ETAAS)

    Nielsen, Steffen; Sturup, Stefan; Spliid, Henrik;

    1999-01-01

    A rapid, robust, sensitive and selective time-based flow injection (FI) on-line solvent extraction system interfaced with electrothermal atomic absorption spectrometry (ETAAS) is described for analyzing ultra-trace amounts of Cr(VI). The sample is initially mixed on-line with isobutyl methyl ketone...

  14. The PDS starburst galaxies

    Coziol, R; Quast, G; Contini, T; Davoust, E

    1998-01-01

    (Abridged) We discuss the nature of the galaxies found in the Pico dos Dias Survey (PDS) for young stellar objects. The PDS galaxies were selected from the IRAS Point Source catalog. They have flux density of moderate or high quality at 12, 25 and 60 $\\mu$m and spectral indices in the ranges $-3.00 \\leq criteria allowed the detection of 382 galaxies, which are a mixture of starburst and Seyfert galaxies. The starburst galaxies show an excess of FIR luminosity and their IRAS colors are significantly different from those of Seyfert galaxies -- 99% of the starburst galaxies in our sample have a spectral index $\\alpha(60,25) -2.5$. This color cut--off also marks a change in the dominant morphologies of the galaxies: the normal IRAS galaxies are preferentially late--type spirals (Sb and later), while the starbursts are more numerous among early--type spirals (earlier than Sbc). No difference is found between the starbursts detected in the FIR and those detected on the basis of UV excess. The PDS starburst galaxie...

  15. MULTI-WAVELENGTH STUDY OF A COMPLETE IRAC 3.6 μm SELECTED GALAXY SAMPLE: A FAIR CENSUS OF RED AND BLUE POPULATIONS AT REDSHIFTS 0.4-1.2

    We present a multi-wavelength study of a 3.6 μm selected galaxy sample in the Extended Groth Strip (EGS). The sample is complete for galaxies with stellar mass >109.5 M☉ and redshift 0.4 3σ errors) is about 3.5%. A new method of validation based on pair statistics confirms the estimate of standard deviation even for galaxies lacking spectroscopic redshifts. Basic galaxy properties measured include rest-frame U – B colors, B- and K-band absolute magnitudes, and stellar masses. We divide the sample into quiescent and star-forming galaxies according to their rest-frame U – B colors and 24-3.6 μm flux density ratios and derive rest K-band luminosity functions and stellar mass functions for quiescent, star-forming, and all galaxies. The results show that massive, quiescent galaxies were in place by z ≈ 1, but lower mass galaxies generally ceased their star formation at later epochs.

  16. Multi-Wavelength Study of a Complete IRAC 3.6micron-Selected Galaxy Sample: a Fair Census of Red and Blue Populations at Redshifts 0.4-1

    Huang, J -S; Willmer, C N A; Rigopoulou, D; Koo, D; Newman, J; Shu, C; Ashby, M L N; Barmby, P; Coil, A; Luo, Z; Magdis, G; Wang, T; Weiner, B; Willner, S P; Zheng, X Z; Fazio, G G

    2012-01-01

    We present a multi-wavelength study of a 3.6 $\\mu$m-selected galaxy sample in the Extended Groth strip. The sample is complete for galaxies with stellar mass $>10^{9.5}$ \\Msun and redshift $0.4}3\\sigma$ errors) is about 3.5%. A new method of validation based on pair statistics confirms the estimate of standard deviation even for galaxies lacking spectroscopic redshifts. Basic galaxy properties measured include rest-frame $U-B$ colors, $B$- and $K$-band absolute magnitudes, and stellar masses. We divide the sample into quiescent and star-forming galaxies according to their rest-frame $U-B$ colors and 24 to 3.6 \\micron\\ flux density ratios and derive rest $K$-band luminosity functions and stellar mass functions for quiescent, star forming, and all galaxies. The results show that massive, quiescent galaxies were in place by $z\\approx1$, but lower mass galaxies generally ceased their star formation at later epochs.

  17. The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters

    McDonald, M.; et al.

    2014-09-24

    We present the results of an X-ray analysis of 80 galaxy clusters selected in the 2500 deg(2) South Pole Telescope survey and observed with the Chandra X-ray Observatory. We divide the full sample into subsamples of ~20 clusters based on redshift and central density, performing a joint X-ray spectral fit to all clusters in a subsample simultaneously, assuming self-similarity of the temperature profile. This approach allows us to constrain the shape of the temperature profile over 0 < r < 1.5R (500), which would be impossible on a per-cluster basis, since the observations of individual clusters have, on average, 2000 X-ray counts. The results presented here represent the first constraints on the evolution of the average temperature profile from z = 0 to z = 1.2. We find that high-z (0.6 < z < 1.2) clusters are slightly (~30%) cooler both in the inner (r < 0.1R (500)) and outer (r > R (500)) regions than their low-z (0.3 < z < 0.6) counterparts. Combining the average temperature profile with measured gas density profiles from our earlier work, we infer the average pressure and entropy profiles for each subsample. Confirming earlier results from this data set, we find an absence of strong cool cores at high z, manifested in this analysis as a significantly lower observed pressure in the central 0.1R (500) of the high-z cool-core subset of clusters compared to the low-z cool-core subset. Overall, our observed pressure profiles agree well with earlier lower-redshift measurements, suggesting minimal redshift evolution in the pressure profile outside of the core. We find no measurable redshift evolution in the entropy profile at r lsim 0.7R (500)—this may reflect a long-standing balance between cooling and feedback over long timescales and large physical scales. We observe a slight flattening of the entropy profile at r gsim R (500) in our high-z subsample. This flattening is consistent with a temperature bias due to the enhanced (~3×) rate at which group-mass (~2

  18. The redshift evolution of the mean temperature, pressure, and entropy profiles in 80 SPT-selected galaxy clusters

    We present the results of an X-ray analysis of 80 galaxy clusters selected in the 2500 deg2 South Pole Telescope survey and observed with the Chandra X-ray Observatory. We divide the full sample into subsamples of ∼20 clusters based on redshift and central density, performing a joint X-ray spectral fit to all clusters in a subsample simultaneously, assuming self-similarity of the temperature profile. This approach allows us to constrain the shape of the temperature profile over 0 < r < 1.5R 500, which would be impossible on a per-cluster basis, since the observations of individual clusters have, on average, 2000 X-ray counts. The results presented here represent the first constraints on the evolution of the average temperature profile from z = 0 to z = 1.2. We find that high-z (0.6 < z < 1.2) clusters are slightly (∼30%) cooler both in the inner (r < 0.1R 500) and outer (r > R 500) regions than their low-z (0.3 < z < 0.6) counterparts. Combining the average temperature profile with measured gas density profiles from our earlier work, we infer the average pressure and entropy profiles for each subsample. Confirming earlier results from this data set, we find an absence of strong cool cores at high z, manifested in this analysis as a significantly lower observed pressure in the central 0.1R 500 of the high-z cool-core subset of clusters compared to the low-z cool-core subset. Overall, our observed pressure profiles agree well with earlier lower-redshift measurements, suggesting minimal redshift evolution in the pressure profile outside of the core. We find no measurable redshift evolution in the entropy profile at r ≲ 0.7R 500—this may reflect a long-standing balance between cooling and feedback over long timescales and large physical scales. We observe a slight flattening of the entropy profile at r ≳ R 500 in our high-z subsample. This flattening is consistent with a temperature bias due to the enhanced (∼3×) rate at which group-mass (∼2 keV) halos

  19. The role of bars in quenching star formation from z = 3 to the present epoch. Halpha3: an Halpha imaging survey of HI selected galaxies from ALFALFA, VI

    Gavazzi, G; Dotti, M; Fanali, R; Fossati, M; Fumagalli, M; Viscardi, E; Savorgnan, G; Boselli, A; Gutiérrez, L; Toledo, H Hernández; Giovanelli, R; Haynes, M P

    2015-01-01

    A growing body of evidence indicates that the star formation rate per unit stellar mass (sSFR) decreases with increasing mass in normal "main-sequence" star forming galaxies. Many processes have been advocated as responsible for such a trend (also known as mass quenching), e.g., feedback from active galactic nuclei (AGNs), and the formation of classical bulges. We determine a refined star formation versus stellar mass relation in the local Universe. To this aim we use the Halpha narrow-band imaging follow-up survey (Halpha3) of field galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Coma and Local superclusters. By complementing this local determination with high-redshift measurements from the literature, we reconstruct the star formation history of main-sequence galaxies as a function of stellar mass from the present epoch up to z=3. In agreement with previous studies, our analysis shows that quenching mechanisms occur above a threshold stellar mass M_knee that evolves with redsh...

  20. The SCUBA-2 Cosmology Legacy Survey: blank-field number counts of 450um-selected galaxies and their contribution to the cosmic infrared background

    Geach, J E; Coppin, K E K; Dunlop, J S; Halpern, M; Smail, Ian; van der Werf, P; Serjeant, S; Farrah, D; Roseboom, I; Targett, T; Arumugam, V; Asboth, V; Blain, A; Chrysostomou, A; Clarke, C; Ivison, R J; Jones, S L; Karim, A; Mackenzie, T; Meijerink, R; Michalowski, M J; Scott, D; Simpson, J; Swinbank, A M; Alexander, D; Almaini, O; Aretxaga, I; Best, P; Chapman, S; Clements, D L; Conselice, C; Danielson, A L R; Eales, S; Edge, A C; Gibb, A; Hughes, D; Jenness, T; Knudsen, K K; Lacey, C; Marsden, G; McMahon, R; Oliver, S; Page, M J; Peacock, J A; Rigopoulou, D; Robson, E I; Spaans, M; Stevens, J; Webb, T M A; Willott, C; Wilson, C D; Zemcov, M

    2012-01-01

    The first deep blank-field 450um map (1-sigma~1.3mJy) from the SCUBA-2 Cosmology Legacy Survey (S2CLS), conducted with the James Clerk Maxwell Telescope (JCMT) is presented. Our map covers 140 arcmin^2 of the COSMOS field, in the footprint of the HST CANDELS area. Using 60 submillimetre galaxies (SMGs) detected at >3.75-sigma, we evaluate the number counts of 450um-selected galaxies with flux densities S_450>5mJy. The 8-arcsec JCMT beam and high sensitivity of SCUBA-2 now make it possible to directly resolve a larger fraction of the cosmic infrared background (CIB, peaking at ~200um) into the individual galaxies responsible for its emission than has previously been possible at this wavelength. At S_450>5mJy we resolve (7.4[+/-]0.7)x10^-2 MJy/sr of the CIB at 450um (equivalent to 16[+/-]7% of the absolute brightness measured by COBE at this wavelength) into point sources. A further ~40% of the CIB can be recovered through a statistical stack of 24um emitters in this field, indicating that the majority (~60%) o...

  1. The roadmap for unification in galaxy group selection:. I. A search for extended X-ray emission in the CNOC2 survey

    Finoguenov, A; Parker, L C; Wilman, D J; Mulchaey, J S; Saglia, R P; Balogh, M L; Bower, R G; McGee, S L

    2009-01-01

    X-ray properties of galaxy groups can unlock some of the most challenging research topics in modern extragalactic astronomy: the growth of structure and its influence on galaxy formation. Only with the advent of the Chandra and XMM facilities have X-ray observations reached the depths required to address these questions in a satisfactory manner. Here we present an X-ray imaging study of two patches from the CNOC2 spectroscopic galaxy survey using combined Chandra and XMM data. A state of the art extended source finding algorithm has been applied, and the resultant source catalog, including redshifts from a spectroscopic follow-up program, is presented. The total number of spectroscopically identified groups is 25 spanning a redshift range 0.04-0.79. Approximately 50% of CNOC2 spectroscopically selected groups in the deeper X-ray (RA14h) field are likely X-ray detections, compared to 20% in the shallower (RA21h) field. Statistical modeling shows that this is consistent with expectations, assuming an expected e...

  2. Galaxy Clusters in the Line of Sight to Background Quasars - III Multi-Object Spectroscopy

    Andrews, H; Lopez, S; Lira, P; Padilla, N; Gilbank, D G; Lacerna, I; Maureira, M J; Ellingson, E; Gladders, M D; Yee, H K C

    2013-01-01

    We present Gemini/GMOS-S multi-object spectroscopy of 31 galaxy cluster candidates at redshifts between 0.2 and 1.0 and centered on QSO sight-lines taken from Lopez et al. (2008). The targets were selected based on the presence of a intervening MgII absorption system at a similar redshift to that of a galaxy cluster candidate lying at a projected distance < 2 h^{-1}Mpc from the QSO sight-line (a 'photometric-hit'). The absorption systems span rest-frame equivalent widths between 0.015 and 2.028 angstroms. Our aim was 3-fold: 1) identify the absorbing galaxies and determine their impact parameters, 2) confirm the galaxy cluster candidates in the vicinity of each quasar sightline, and 3) determine whether the absorbing galaxies reside in galaxy clusters. Our main findings are: 1) the identification of 10 out of 24 absorbing galaxies with redshifts up to 1.0955. 2) The spectroscopic confirmation of 20 out of 31 cluster/group candidates, with most of the confirmed clusters/groups at z < 0.7. 3) Following fr...

  3. The central region of the Fornax cluster; 2, A catalog and photometric properties of galaxies in selected CCD fields

    Hilker, M; Richtler, T; Infante, L; Quintana, H

    1998-01-01

    We present a photometric catalog (based on V and I photometry) of galaxies in the central regions of the Fornax galaxy cluster. Our 11 CCD fields cover 0.17 degrees in total. The limiting surface brightness is around 24 mag arsec^-2, similar to that of Ferguson's (1989, AJ 98, 367) catalog, whereas our limiting total magnitude is around V = 22 mag, about two magnitudes fainter. It is the surface brightness limit, however, that prevents us from detecting the counterparts of the faintest Local Group dwarf spheroidals. The photometric properties of all objects are presented as a catalog. The properties and fit parameters of the surface brightness profiles for a sub-sample are presented as a second catalog (both catalogs are available in electronic form at the CDS). We can only add 4 new dwarf galaxies to Ferguson's catalog. However, we confirm that the dwarf galaxies in Fornax follow a similar surface brightness-magnitude relation as the Local Group dwarfs. They also follow the color (metallicity) - relation see...

  4. HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample

    Toribio, M C; Giovanelli, R; Haynes, M P; Masters, K L

    2011-01-01

    We report results from a study of the HI content and stellar properties of nearby galaxies detected by the Arecibo Legacy Fast ALFA blind 21-cm line survey and the Sloan Digital Sky Survey in two declination strips covering a total area of 9 hr X 16 deg. Our analysis seeks to assemble a control sample of galaxies suitable for providing absolute measures of the HI content of gaseous objects. From a database of ~15,000 HI detections, we have assembled three samples of gas-rich galaxies expected to show little or no evidence of interaction with their surroundings that could provide adequate HI standards. The most reliable results are obtained with a sample of 5647 sources found in low density environments, as defined by a nearest neighbor approach. The other two samples contain several hundred relatively isolated galaxies each, as determined from standard isolation algorithms. We find that isolated objects are not particularly gas-rich compared to their low-density-environment counterparts, while they suffer fro...

  5. First spectroscopic measurements of [OIII] emission from Lyman-alpha selected galaxies at z ~ 3.1

    McLinden, Emily M; Rhoads, James E; Malhotra, Sangeeta; Hibon, Pascale; Richardson, Mark L A; Cresci, Giovanni; Quirrenbach, Andreas; Pasquali, Anna; Bian, Fuyan; Fan, Xiaohui; Woodward, Charles E

    2010-01-01

    We present the first spectroscopic measurements of the [OIII] 5007 A line in two z ~ 3.1 Lyman-alpha emitting galaxies (LAEs) using the new near-infrared instrument LUCIFER on the 8.4m Large Binocular Telescope (LBT). We also describe the optical imaging and spectroscopic observations used to identify these Lyman-alpha emitting galaxies. Using the [OIII] line we have measured accurate systemic redshifts for these two galaxies, and discovered a velocity offset between the [OIII] and Ly-alpha lines in both, with the Ly-alpha line peaking 284 and 142 km/s redward of the systemic velocity. These velocity offsets imply that there are powerful outflows in high-redshift LAEs. They also ease the transmission of Ly-alpha photons through the intergalactic medium around the galaxies. By measuring these offsets directly, we can refine both Ly-alpha-based tests for reionization, and Ly-alpha luminosity function measurements where the Ly-alpha forest affects the blue wing of the line. Our work also provides the first direc...

  6. Global dust attenuation in disc galaxies: strong variation with specific star formation and stellar mass, and the importance of sample selection

    Devour, Brian M.; Bell, Eric F.

    2016-06-01

    We study the relative dust attenuation-inclination relation in 78 721 nearby galaxies using the axis ratio dependence of optical-near-IR colour, as measured by the Sloan Digital Sky Survey, the Two Micron All Sky Survey, and the Wide-field Infrared Survey Explorer. In order to avoid to the greatest extent possible attenuation-driven biases, we carefully select galaxies using dust attenuation-independent near- and mid-IR luminosities and colours. Relative u-band attenuation between face-on and edge-on disc galaxies along the star-forming main sequence varies from ˜0.55 mag up to ˜1.55 mag. The strength of the relative attenuation varies strongly with both specific star formation rate and galaxy luminosity (or stellar mass). The dependence of relative attenuation on luminosity is not monotonic, but rather peaks at M3.4 μm ≈ -21.5, corresponding to M* ≈ 3 × 1010 M⊙. This behaviour stands seemingly in contrast to some older studies; we show that older works failed to reliably probe to higher luminosities, and were insensitive to the decrease in attenuation with increasing luminosity for the brightest star-forming discs. Back-of-the-envelope scaling relations predict the strong variation of dust optical depth with specific star formation rate and stellar mass. More in-depth comparisons using the scaling relations to model the relative attenuation require the inclusion of star-dust geometry to reproduce the details of these variations (especially at high luminosities), highlighting the importance of these geometrical effects.

  7. Absorption features of high redshift galactic winds

    Fangano, A P M; Richter, P

    2007-01-01

    The environment of high-redshift galaxies is characterized by both wind-driven outflowing gas and gravitationally infalling streams. To investigate such galaxy-IGM interplay we have generated synthetic optical absorption line spectra piercing the volume surrounding a starbursting analog of a Lyman Break Galaxy selected in a $z \\approx 3$ output from a SPH simulation, including a detailed treatment of mechanical feedback from winds. Distributions for several observable species (HI, CIII, CIV, SiII, SiIII, SiIV, OVI, OVII, and OVIII) have been derived by post-processing the simulation outputs. The hot wind material is characterized by the presence of high-ionization species such as OVI, OVII, and OVIII (the latter two observable only in X-ray bands); the colder ($T<10^{5.5}$ K) infalling streams can be instead identified by the combined presence of SiII, SiIII, and CIII optical absorption together with OVI that surrounds the cooler gas clumps. However, both line profile and Pixel Optical Depth analysis of th...

  8. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers: III. A Galaxy Sample Complete to 0.01 L* and Evidence for Environmental Effects

    Burchett, Joseph N; Bordoloi, Rongmon; Werk, Jessica K; Prochaska, J Xavier; Tumlinson, Jason; Willmer, C N A; O'Meara, John; Katz, Neal

    2015-01-01

    We employ a blindly selected sample of low-redshift C IV absorption systems identified in spectra from the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS), combined with galaxy data from the Sloan Digital Sky Survey (SDSS), to study the metal-enriched circumgalactic medium (CGM) with ~100% completeness for galaxy luminosities L > 0.01 L* at z ~0.1 L* galaxies (7/8) than for less luminous galaxies (1/10). We also find that the occurrence of C IV absorbers depends strongly on the broader environment: 67% (8/12) of galaxies with rho < 150 kpc in regions of low galaxy density (regions with fewer than ten 0.1 L* galaxies within 1 Mpc) have affiliated C IV absorption while none (0/9) of the galaxies in denser regions show C IV within rho < 150 kpc. The reduced detection rate of C IV in denser environments persists for massive group dark matter halos. In contrast, H I is pervasive in the CGM without regard to mass or environment, although some of these Ly-alpha absorbers could arise in unrelated...

  9. Properties of a Chemically Enriched Lya Absorption System at z=0.167 and Implications for the Total Baryons in Extended Gaseous Envelopes Around Galaxies

    Chen, Hsiao-Wen; Prochaska, Jason X.; Lanzetta, Kenneth M.

    2001-01-01

    We present a detailed analysis of the chemical abundances, ionization state, and origin of a partial Lyman limit system (N(HI) ~ 10^{16} cm^{-2}) at low redshift (z=0.167 towards PKS0405-1219). We also present the first estimate of the total baryons in extended gaseous envelopes around galaxies based on a simple photoionization model for the Lya absorbers. We find that extended gaseous envelopes can explain between 5--20% of the total baryons predicted by the big bang nucleosynthesis model.

  10. The Seyfert galaxy population

    A large sample of Seyfert galaxies, many of which are Markarian galaxies, has been observed with the WSRT in lambda 21 cm continuum radiation. The results are presented, and the number of radio detected Seyferts has now increased considerably. A number of accurate optical positions are given that were needed to identify radio sources with the Seyfert galaxies observed. Optical and radio luminosity functions of Seyfert galaxies are derived. The results are compared with such functions for other categories of objects that may be related to these galaxies. The discussions focus on the possible connections between normal galaxies, Seyferts, and optically selected quasars. Three investigations are reported on individual objects that are related to Seyfert galaxies. WSRT observations of four bright, optically selected quasars are presented. The identification of an X-ray discovered BL Lacertae object is discussed. Its radio emission is on a much lower level than for other BL Lacs. Perhaps it is a radio-quiet object in this class, suggesting a comparable difference in radio emission for BL Lacs as is known for quasars. Photo-electric photometry for the Seyfert galaxy NGC 1566 is reported. Besides a monitoring programme, multi-aperture photometry is described. (Auth.)

  11. Element-selective trace detection of toxic species in environmental samples using chromatographic techniques and derivative diode laser absorption spectrometry

    Koch, J.; Zybin, A.; Niemax, K.

    1998-10-01

    Very sensitive laser absorption techniques based on a double-beam scheme with logarithmic processing of the detector signals and wavelength modulation of laser diodes are presented. Detection limits equivalent to 10-7 absorption per square root of detection bandwidth are obtained if sufficient laser power is available and if the absorption is also subject to additional modulation. The analytical versatility of these techniques is demonstrated by quantitative analysis of very low concentrations of (i) Cr(VI) species in tap water and (ii) chlorinated poly-aromatics (chlorophenols) in plant extracts, both after chromatographic separation. The atomic absorption measurements were performed in an air-acetylene flame (Cr) and in a low-pressure microwave-induced plasma (chlorophenols).

  12. Stellar Populations of Elliptical Galaxies in the Local Universe

    Zhu, Guangtun; Moustakas, John

    2010-01-01

    We have reanalyzed the images of nearby red-sequence galaxies in the Sloan Digital Sky Survey, and have carefully selected 1,923 elliptical galaxies with velocity dispersion sigma>70 km/s and at redshifts z~ L^{\\ast}) and the highest velocity dispersion ellipticals favor high-density environments. The average spectra depend strongly on sigma: they are much bluer and have stronger (but still weak) emission lines at low sigma. At fixed sigma, the average spectra also depend on environment, though less so. We show for the first time that field elliptical galaxies have a slightly bluer stellar continuum, especially at wavelengths , and the alpha-element absorption indices such as Mg b are only slightly stronger in rich group galaxies. An analysis based on simple stellar populations (SSPs) reveals a strong sigma dependence of SSP age, metallicity and alpha-abundance: more massive elliptical galaxies are older, more metal-rich and more strongly alpha-enhanced. On average, the SSP-equivalent ages of galaxies in rich...

  13. Properties of QSO Metal Line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies

    Boksenberg, Alec

    2014-01-01

    Using Voigt-profile-fitting procedures on Keck HIRES spectra of nine QSOs we identify 1099 CIV absorber components clumped in 201 systems outside the Lyman forest over 1.6 < z < 4.4. With associated SiIV, CII, SiII and NV where available we investigate bulk statistical and ionization properties of the components and systems and find no significant change in redshift for CIV and SiIV while CII, SiII and NV change substantially. The CIV components exhibit strong clustering but no clustering is detected for systems on scales from 150 km/s out to 50000 km/s. We conclude the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find the generally accepted means of radiative escape by transparent channels from th...

  14. MULTI-WAVELENGTH STUDY OF A COMPLETE IRAC 3.6 {mu}m SELECTED GALAXY SAMPLE: A FAIR CENSUS OF RED AND BLUE POPULATIONS AT REDSHIFTS 0.4-1.2

    Huang, J.-S. [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Faber, S. M.; Koo, D. [University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Willmer, C. N. A.; Weiner, B. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Rigopoulou, D.; Magdis, G. [Department of Astrophysics, Oxford University, Keble Road, Oxford OX1 3RH (United Kingdom); Newman, J. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O' Hara Street, Pittsburgh, PA 15260 (United States); Shu, C.; Luo, Z. [Shanghai Key Lab for Astrophysics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China); Ashby, M. L. N.; Wang, T.; Willner, S. P.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS65, Cambridge, MA 02138 (United States); Barmby, P. [Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7 (Canada); Coil, A. [Department of Physics and Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Zheng, X. Z. [Purple Mountain Observatory, Nanjing (China)

    2013-03-20

    We present a multi-wavelength study of a 3.6 {mu}m selected galaxy sample in the Extended Groth Strip (EGS). The sample is complete for galaxies with stellar mass >10{sup 9.5} M{sub Sun} and redshift 0.4 < z < 1.2. In this redshift range, the Infrared Array Camera 3.6 {mu}m band measures the rest-frame near-infrared band, permitting nearly unbiased selection with respect to both quiescent and star-forming galaxies. The numerous spectroscopic redshifts available in the EGS are used to train an artificial neural network to estimate photometric redshifts. The distribution of photometric redshift errors is Gaussian with standard deviation {approx}0.025(1 + z), and the fraction of redshift failures (>3{sigma} errors) is about 3.5%. A new method of validation based on pair statistics confirms the estimate of standard deviation even for galaxies lacking spectroscopic redshifts. Basic galaxy properties measured include rest-frame U - B colors, B- and K-band absolute magnitudes, and stellar masses. We divide the sample into quiescent and star-forming galaxies according to their rest-frame U - B colors and 24-3.6 {mu}m flux density ratios and derive rest K-band luminosity functions and stellar mass functions for quiescent, star-forming, and all galaxies. The results show that massive, quiescent galaxies were in place by z Almost-Equal-To 1, but lower mass galaxies generally ceased their star formation at later epochs.

  15. The Herschel PEP/HerMES luminosity function - I. Probing the evolution of PACS selected Galaxies to z ≃ 4

    Gruppioni, C.; Pozzi, F.; Rodighiero, G.; Delvecchio, I.; Berta, S.; Pozzetti, L.; Zamorani, G.; Andreani, P.; Cimatti, A.; Ilbert, O.; Le Floc'h, E.; Lutz, D.; Magnelli, B.; Marchetti, L.; Monaco, P.; Nordon, R.; Oliver, S.; Popesso, P.; Riguccini, L.; Roseboom, I.; Rosario, D. J.; Sargent, M.; Vaccari, M.; Altieri, B.; Aussel, H.; Bongiovanni, A.; Cepa, J.; Daddi, E.; Domínguez-Sánchez, H.; Elbaz, D.; Förster Schreiber, N.; Genzel, R.; Iribarrem, A.; Magliocchetti, M.; Maiolino, R.; Poglitsch, A.; Pérez García, A.; Sanchez-Portal, M.; Sturm, E.; Tacconi, L.; Valtchanov, I.; Amblard, A.; Arumugam, V.; Bethermin, M.; Bock, J.; Boselli, A.; Buat, V.; Burgarella, D.; Castro-Rodríguez, N.; Cava, A.; Chanial, P.; Clements, D. L.; Conley, A.; Cooray, A.; Dowell, C. D.; Dwek, E.; Eales, S.; Franceschini, A.; Glenn, J.; Griffin, M.; Hatziminaoglou, E.; Ibar, E.; Isaak, K.; Ivison, R. J.; Lagache, G.; Levenson, L.; Lu, N.; Madden, S.; Maffei, B.; Mainetti, G.; Nguyen, H. T.; O'Halloran, B.; Page, M. J.; Panuzzo, P.; Papageorgiou, A.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rigopoulou, D.; Rowan-Robinson, M.; Schulz, B.; Scott, D.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vigroux, L.; Wang, L.; Wright, G.; Xu, C. K.; Zemcov, M.; Bardelli, S.; Carollo, M.; Contini, T.; Le Févre, O.; Lilly, S.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Zucca, E.

    2013-06-01

    We exploit the deep and extended far-IR data sets (at 70, 100 and 160 μm) of the Herschel Guaranteed Time Observation (GTO) PACS Evolutionary Probe (PEP) Survey, in combination with the Herschel Multi-tiered Extragalactic Survey data at 250, 350 and 500 μm, to derive the evolution of the rest-frame 35-, 60-, 90- and total infrared (IR) luminosity functions (LFs) up to z ˜ 4. We detect very strong luminosity evolution for the total IR LF (LIR ∝ (1 + z)3.55 ± 0.10 up to z ˜ 2, and ∝ (1 + z)1.62 ± 0.51 at 2 < z ≲ 4) combined with a density evolution (∝(1 + z)-0.57 ± 0.22 up to z ˜ 1 and ∝ (1 + z)-3.92 ± 0.34 at 1 < z ≲ 4). In agreement with previous findings, the IR luminosity density (ρIR) increases steeply to z ˜ 1, then flattens between z ˜ 1 and z ˜ 3 to decrease at z ≳ 3. Galaxies with different spectral energy distributions, masses and specific star formation rates (SFRs) evolve in very different ways and this large and deep statistical sample is the first one allowing us to separately study the different evolutionary behaviours of the individual IR populations contributing to ρIR. Galaxies occupying the well-established SFR-stellar mass main sequence (MS) are found to dominate both the total IR LF and ρIR at all redshifts, with the contribution from off-MS sources (≥0.6 dex above MS) being nearly constant (˜20 per cent of the total ρIR) and showing no significant signs of increase with increasing z over the whole 0.8 < z < 2.2 range. Sources with mass in the range 10 ≤ log(M/M⊙) ≤ 11 are found to dominate the total IR LF, with more massive galaxies prevailing at the bright end of the high-z (≳2) LF. A two-fold evolutionary scheme for IR galaxies is envisaged: on the one hand, a starburst-dominated phase in which the Super Massive Black Holes (SMBH) grows and is obscured by dust (possibly triggered by a major merging event), is followed by an AGN-dominated phase, then evolving towards a local elliptical. On the other hand

  16. HI Absorption in Merger Remnants

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  17. ALMA Imaging and Gravitational Lens Models of South Pole Telescope—Selected Dusty, Star-Forming Galaxies at High Redshifts

    Spilker, J. S.; Marrone, D. P.; Aravena, M.; Béthermin, M.; Bothwell, M. S.; Carlstrom, J. E.; Chapman, S. C.; Crawford, T. M.; de Breuck, C.; Fassnacht, C. D.; Gonzalez, A. H.; Greve, T. R.; Hezaveh, Y.; Litke, K.; Ma, J.; Malkan, M.; Rotermund, K. M.; Strandet, M.; Vieira, J. D.; Weiss, A.; Welikala, N.

    2016-08-01

    The South Pole Telescope has discovered 100 gravitationally lensed, high-redshift, dusty, star-forming galaxies (DSFGs). We present 0.″5 resolution 870 μ {{m}} Atacama Large Millimeter/submillimeter Array imaging of a sample of 47 DSFGs spanning z=1.9{--}5.7, and construct gravitational lens models of these sources. Our visibility-based lens modeling incorporates several sources of residual interferometric calibration uncertainty, allowing us to properly account for noise in the observations. At least 70% of the sources are strongly lensed by foreground galaxies ({μ }870μ {{m}}\\gt 2), with a median magnification of {μ }870μ {{m}}=6.3, extending to {μ }870μ {{m}}\\gt 30. We compare the intrinsic size distribution of the strongly lensed sources to a similar number of unlensed DSFGs and find no significant differences in spite of a bias between the magnification and intrinsic source size. This may indicate that the true size distribution of DSFGs is relatively narrow. We use the source sizes to constrain the wavelength at which the dust optical depth is unity and find this wavelength to be correlated with the dust temperature. This correlation leads to discrepancies in dust mass estimates of a factor of two compared to estimates using a single value for this wavelength. We investigate the relationship between the [C ii] line and the far-infrared luminosity and find that the same correlation between the [C ii]/{L}{{FIR}} ratio and {{{Σ }}}{{FIR}} found for low-redshift star-forming galaxies applies to high-redshift galaxies and extends at least two orders of magnitude higher in {{{Σ }}}{{FIR}}. This lends further credence to the claim that the compactness of the IR-emitting region is the controlling parameter in establishing the “[C ii] deficit.”

  18. Neutral and ionized gas distribution in and around the radio galaxy Coma A

    Morganti, R.; Oosterloo, T.; Tadhunter, C. N.; Wills, K. A.

    2000-01-01

    HI absorption has been detected with the WSRT against both lobes of the radio galaxy Coma A. This radio galaxy could be expanding in a particularly gas rich environment, perhaps the result from interactions/mergers between the dominant giant galaxy (associated with the radio galaxy) and less massive galaxies in the same group.

  19. Determination of selected metals in urban runoff and related estuarine sediments by neutron activation and atomic absorption

    Pollution sources for Newport Bay, California are of a nonpoint nature. To assess the heavy metals loading of the runoff into the Bay, 18 water samples, taken during dry and rainy periods, have been analyzed for Mn, Cu, Zn, and Pb, using atomic absorption spectrometry (AAS). In addition, 7 sediment cores from the Upper Bay and 5 sediment grab samples from the Lower Bay were analyzed for Cr, Mn, Fe, Co, Cu, Zn, and Pb. Instrumental neutron activation analysis (INAA) was used for Cr, Fe, and Co, whereas Mn, Cu, and Pb were determined by AAS. Zinc was determined by both of these techniques. Three major streams pass into Newport Bay carrying: (1) agricultural and to some extent urban and residential runoff (70-90%), (2) urban runoff (10-30%), and (3) residential runoff (<5%). The levels of Zn and Pb are much higher under storm conditions, e.g., 338 μg/l Zn and 425 μg/l Pb, than during dry weather, where typical concentrations are 20 μg/l Zn and 9 μg/l Pb. For Cu there is a moderate increase from about 10 μg/l in dry weather to a maximum of 54 μg/l under storm conditions. Soil erosion appears to be responsible for high Mn values (max. 1230 μg/l) in agricultural storm runoff. The cleansing action of a storm is evidenced by high concentrations in the beginning, and much lower levels towards the end of the storm.Vertical profiles of heavy metals in sediment cores indicate that Zn and Pb are the only metals of those investigated that show clearly increased levels in the uppermost layers. Typical enrichment ratios are 2.0 for Zn and 5.5 for Pb. Maximum concentrations of Zn and Pb in sediments from the Upper Bay were 300 ppm and 132 ppm, respectively. The highest Pb value was found close to the mouth of the urban drainage channel. Dating of selected cores was carried out by the Pb-210 method. Mass injection rates into Upper Newport Bay for Zn and Pb of anthropogenic origin were estimated to be 6.0 and 6.5 tons/yr, respectively

  20. The Most Luminous Heavily Obscured Quasars Have a High Merger Fraction: Morphological Study of WISE-selected Hot Dust-obscured Galaxies

    Fan, Lulu; Han, Yunkun; Fang, Guanwen; Gao, Ying; Zhang, Dandan; Jiang, Xiaoming; Wu, Qiaoqian; Yang, Jun; Li, Zhao

    2016-05-01

    Previous studies have shown that Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick active galactic nuclei (AGNs). High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host morphology of 18 Hot DOGs at z ∼ 3 using Hubble Space Telescope/WFC3 imaging. We find that Hot DOGs have a high merger fraction (62 ± 14%). By fitting the surface brightness profiles, we find that the distribution of Sérsic indices in our Hot DOG sample peaks around 2, which suggests that most Hot DOGs have transforming morphologies. We also derive the AGN bolometric luminosity (∼1014 L ⊙) of our Hot DOG sample by using IR spectral energy distributions decomposition. The derived merger fraction and AGN bolometric luminosity relation is well consistent with the variability-based model prediction. Both the high merger fraction in an IR-luminous AGN sample and relatively low merger fraction in a UV/optical-selected, unobscured AGN sample can be expected in the merger-driven evolutionary model. Finally, we conclude that Hot DOGs are merger-driven and may represent a transit phase during the evolution of massive galaxies, transforming from the dusty starburst-dominated phase to the unobscured QSO phase.

  1. The galaxy ancestor problem

    Disney, Mike

    2011-01-01

    HST finds galaxies whose Tolman dimming should exceed 10 mag. Could evolution alone explain these as our ancestor galaxies? Or could they be representatives of quite a different dynasty whose descendants are no longer prominent today? We explore this latter hypothesis and argue that Surface Brightness Selection Effects naturally bring into focus quite different dynasties from different redshifts. Thus the HST z=7 galaxies could be examples of galaxies whose descendants are both too small and too choked with dust to be recognizable in our neighborhood easily today. Conversely the ancestors of the Milky Way and its obvious neighbors will have completely sunk below the sky at z>1.2 although their diffuse light could account for the missing Reionization flux. This Succeeding Prominent Dynasties Hypothesis (SPDH) fits the existing observations both naturally and well,including the bizarre distributions of galaxy surface brightnesses found in deep fields, the angular size ~ inverse (1+z) law,'Downsizing' which turn...

  2. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers: II. Program Design, Absorption-line Measurements, and Absorber Statistics

    Burchett, Joseph N.; Tripp, Todd M.; Prochaska, J. Xavier; Werk, Jessica K.; Tumlinson, Jason; O'Meara, John M.; Bordoloi, Rongmon; Katz, Neal; Willmer, C. N. A.

    2015-01-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). We have identified 42 absorbers at z < 0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasi...

  3. Monitoring of elemental composition of honey from selected regions of Ghana using Instrumental Neutron Activation Analysis and Atomic Absorption Spectroscopy

    Honey is a sweet, thick and viscid fluid collected from beehives and usually found in cells of the honey comb. It is produced from nectar collected from various flowers by honeybees and processed. Among the important uses, pure and undiluted honey serves as natural sweetener and contains a broad variety of vitamins for human consumption. Due to its global demand, monitoring of the quality of honey is of great significance. In this study, honey samples were collected systematically from farmers and retailers in the Brong Ahafo, Ashanti and Greater Accra regions of Ghana. The sampling was done along the farmer-to-trader channels, to assess the quality of honey produced from various regions and to trace the sources of elemental contamination. Physicochemical studies; pH, electrical conductivity and specific gravity were done. The levels of selected toxic heavy metals (Hg, Pb, Cd, V, Cr, As) and essential metals (K, Na, Ca, Mg, Mn, Cu, Fe, Co) in the honey samples were analysed using instrumental neutron activation analysis (INAA). Flame atomic absorption spectrophotometry (FAAS) was also employed to determine elements such as Pb, Co, Cr and Fe. All the honey samples were found to be acidic, with pH ranging from 3.60 to 6.10. The acidity of honey is significant as it inhibits the growth of microorganisms. The values agrees favourably with the permitted pH limits of 3.40 to 3.60 for good quality honey, set by the National Honey Board of United States. The electrical conductivities measured ranged from 11.9 μS/cm to 44.4 μS/cm. The values were within the acceptable limits set by Ghana Standards Authority and other organizations (<800 μS/cm). The specific gravity of the honey samples analysed ranged from 1.297 to 2.031. These values were higher than the values (1.2081 to 1.2270) reported in Libyan Honey. However, these values were closer to the average specific gravity (1.425) value reported in other studies. These variations in the specific gravity may be related to

  4. Broad Band Properties of the BAT Selected AGN

    Mushotzky, Richard; Winter, Lisa; Tueller, Jack

    2008-01-01

    I will present the x-ray spectral properties of approx.150 BAT selected ACN focusing on the issues of spectral complexity, x-ray absorption and its distribution and that contribution of sources to the x-ray background. If time permits we will also present the nature of the host galaxies of the ACN and their relationship to merger candidates.

  5. THE ATACAMA COSMOLOGY TELESCOPE: PHYSICAL PROPERTIES AND PURITY OF A GALAXY CLUSTER SAMPLE SELECTED VIA THE SUNYAEV-ZEL'DOVICH EFFECT

    We present optical and X-ray properties for the first confirmed galaxy cluster sample selected by the Sunyaev-Zel'dovich effect (SZE) from 148 GHz maps over 455 deg2 of sky made with the Atacama Cosmology Telescope (ACT). These maps, coupled with multi-band imaging on 4 m class optical telescopes, have yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066. Of these 23 clusters, 10 are newly discovered. The selection of this sample is approximately mass limited and essentially independent of redshift. We provide optical positions, images, redshifts, and X-ray fluxes and luminosities for the full sample, and X-ray temperatures of an important subset. The mass limit of the full sample is around 8.0 x 1014 Msun, with a number distribution that peaks around a redshift of 0.4. For the 10 highest significance SZE-selected cluster candidates, all of which are optically confirmed, the mass threshold is 1 x 1015 Msun and the redshift range is 0.167-1.066. Archival observations from Chandra, XMM-Newton, and ROSAT provide X-ray luminosities and temperatures that are broadly consistent with this mass threshold. Our optical follow-up procedure also allowed us to assess the purity of the ACT cluster sample. Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported sample represents one of the largest SZE-selected sample of massive clusters over all redshifts within a cosmologically significant survey volume, which will enable cosmological studies as well as future studies on the evolution, morphology, and stellar populations in the most massive clusters in the universe.

  6. The Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected Via the Sunyaev-Zel'Dovich Effect

    Menanteau, Felipe; Gonzalez, Jorge; Juin, Jean-Baptiste; Marriage, Tobias; Reese, Erik D.; Acquaviva, Viviana; Aguirre, Paula; Appel, John Willam; Baker, Andrew J.; Barrientos, L. Felipe; Battistelli, Elia S.; Bond, Richard; Das, Supeed; Deshpande, Amruta J.; Devlin, Mark J.; Dicker, Simon; Dunkley, Joanna; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hernandez-Monteagudo, Carlos; Wollack, Ed

    2010-01-01

    We present optical and X-ray properties for the first confirmed galaxy cluster sample selected by the Sunyaev-Zel'dovich Effect from 148 GHz maps over 455 square degrees of sky made with the Atacama Cosmology Telescope. These maps. coupled with multi-band imaging on 4-meter-class optical telescopes, have yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066. Of these 23 clusters, 10 are newly discovered. The selection of this sample is approximately mass limited and essentially independent of redshift. We provide optical positions, images, redshifts and X-ray fluxes and luminosities for the full sample, and X-ray temperatures of an important subset. The mass limit of the full sample is around 8.0 x 10(exp 14) Stellar Mass. with a number distribution that peaks around a redshift of 0.4. For the 10 highest significance SZE-selected cluster candidates, all of which are optically confirmed, the mass threshold is 1 x 10(exp 15) Stellar Mass and the redshift range is 0.167 to 1.066. Archival observations from Chandra, XMM-Newton. and ROSAT provide X-ray luminosities and temperatures that are broadly consistent with this mass threshold. Our optical follow-up procedure also allowed us to assess the purity of the ACT cluster sample. Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported sample represents one of the largest SZE-selected sample of massive clusters over all redshifts within a cosmologically-significant survey volume, which will enable cosmological studies as well as future studies on the evolution, morphology, and stellar populations in the most massive clusters in the Universe.

  7. Absolute photo-absorption cross sections and electronic state spectroscopy of selected fluorinated hydrocarbons relevant to the plasma processing industry

    Photo-absorption cross sections have been measured for methyl iodide, CF3I (310 nm>λ>110 nm) and dichlorodifluoromethane, CCl2F2 (225 nm>λ>110 nm) using synchrotron radiation. Electron energy loss spectroscopy was also used to probe the electronic and vibronic excitation of CF3I. Electronic states have been assigned to each of the observed absorption bands incorporating both valence and Rydberg transitions. The measured VUV cross sections are used to derive the photolysis rates in the terrestrial atmosphere and hence determine the potential importance of each gas in global warming and ozone depletion

  8. Visibility of galaxies

    It is stated that counts of galaxies could be seriously biased by selection effects, largely influenced by the brightness of the night sky. To illustrate this suppose the Earth were situated near the center of a giant elliptical galaxy. The mean surface brightness of the sky would then appear some 8 to 9 mag. brighter than is observed from our position in the Galaxy. Extragalactic space would then appear to be empty void; spiral and irregular galaxies would be invisible, and all that could be easily detected would be the core regions of galaxy ellipticals very similar to our own. Much of the Universe would be blinded by the surface brightness of the parent galaxy. This blinding, however, is a relative matter and the question arises as to what extent we are blinded by the spiral galaxy in which we exist. Strong indirect evidence exists that our knowledge of galaxies is heavily biased by the sky background, and the true population of extragalactic space may be very different from that seen. Other relevant work is also discussed, and further investigational work is indicated. (U.K.)

  9. Determination of the dynamical structure of galaxies using optical spectra

    De Rijcke, S.; Dejonghe, H.

    1998-01-01

    Galaxy spectra are a rich source of kinematical information since the shapes of the absorption lines reflect the movement of stars along the line-of-sight. We present a technique to directly build a dynamical model for a galaxy by fitting model spectra, calculated from a dynamical model, to the observed galaxy spectra. Using synthetic spectra from a known galaxy model we demonstrate that this technique indeed recovers the essential dynamical characteristics of the galaxy model. Moreover, the ...

  10. AEGIS: DEMOGRAPHICS OF X-RAY AND OPTICALLY SELECTED ACTIVE GALACTIC NUCLEI

    We develop a new diagnostic method to classify galaxies into active galactic nucleus (AGN) hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hβ ratio with rest-frame U - B color. This can be used to robustly select AGNs in galaxy samples at intermediate redshifts (z AB bol > 1044 erg s-1 in our sample are not detected in our 200 ks Chandra images, most likely due to moderate or heavy absorption by gas near the AGN. The 2-7 keV detection rate of Seyfert 2s at z ∼ 0.6 suggests that their column density distribution and Compton-thick fraction are similar to that of local Seyferts. Multiple sample selection techniques are needed to obtain as complete a sample as possible.

  11. VizieR Online Data Catalog: SPOGS. I. SDSS Shocked POststarburst Galaxy cand. (Alatalo+, 2016)

    Alatalo, K.; Cales, S. L.; Rich, J. A.; Appleton, P. N.; Kewley, L. J.; Lacy, M.; Lanz, L.; Medling, A. M.; Nyland, K.

    2016-07-01

    There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench "quietly". Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY, 2011ApJS..195...13O) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z=0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an "E+A" selection. SPOGs* have a 13% 1.4GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this

  12. A nanoporous 3D zinc(II) metal–organic framework for selective absorption of benzaldehyde and formaldehyde

    A new 3D nanoporous metal–organic framework (MOF), [[Zn4O(C24H15N6O6)2(H2O)2]·6H2O·DMF]n (1) based on 4,4′,4″-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB) ligand was solvothermally synthesized and characterized by single–crystal X-ray diffraction, Powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and Brunauer–Emmett–Teller (BET) analyses. X-ray single crystal diffraction analysis reveals that 1 exhibits a 3D network with new kvh1 topology. Semi-empirical (AM1) calculations were carried out to obtain stable conformers for TATAB ligand. In addition, the absorption of two typical aldehydes (benzaldehyde and formaldehyde) in the presence of 1 was investigated and the effect of the aldehyde concentration, exposure time and temperature was studied. It was found that compound 1 has a potential for the absorption of aldehydes under mild conditions. - Graphical abstract: Absorption of two typical aldehydes (formaldehyde and benzaldehyde) by solvothermally synthesized of a 3D nano-porous MOF based on TATAB tricarboxylate ligand and Zn (NO3)2·6H2O. - Highlights: • We present a 3D Zn(II)-MOF with TATAB linker by solvothermal method. • The framework possesses a new kvh1 topology. • The framework displays formaldehyde and benzaldehyde absorption property. • Conformational analysis was performed to determine the stable linker geometry

  13. Narrow-line X-Ray-selected Galaxies in the Chandra-COSMOS Field. II. Optically Elusive X-Ray AGNs

    Pons, E.; Elvis, M.; Civano, F.; Watson, M. G.

    2016-06-01

    In the Chandra-COSMOS (C-COSMOS) survey, we have looked for X-ray-selected active galactic nuclei (AGNs), which are not detected as such in the optical, the so-called elusive AGNs. A previous study based on XMM-Newton and Sloan Digital Sky Survey observations has found a sample of 31 X-ray AGNs optically misclassified as star-forming (SF) galaxies at z\\lt 0.4, including 17 elusive Sy2s. Using Chandra observations provides a sample of fainter X-ray sources and so, for a given X-ray luminosity, extends to higher redshifts. To study the elusive Sy2s in the C-COSMOS field, we have removed the NLS1s that contaminate the narrow-line sample. Surprisingly, the contribution of NLS1s is much lower in the C-COSMOS sample (less than 10% of the optically misclassified X-ray AGNs) than in Pons & Watson. The optical misclassification of the X-ray AGNs ({L}{{X}}\\gt {10}42 {erg} {{{s}}}-1) can be explained by the intrinsic weakness of these AGNs, in addition to, in some cases, optical dilution by the host galaxies. Interestingly, we found the fraction of elusive Sy2s (narrow emission-line objects) optically misclassified as SF galaxies up to z∼ 1.4 to be 10% ± 3% to 17% ± 4%, compared to the 6% ± 1.5% of the Pons & Watson work (up to z∼ 0.4). This result seems to indicate an evolution with redshift of the number of elusive Sy2s.

  14. The STIS GTO Galaxy Nuclear Dynamics Project: The Stellar Dynamics in the Center of the Galaxy NGC 1023

    Bower, G. A.; Green, R. F.; Gebhardt, K.; Bender, R.; STIS Team

    1999-12-01

    The STIS Investigation Definition Team is conducting a long-term program to confirm the presence of dark compact objects (presumably supermassive black holes, hereafter BHs) in the nuclei of several galaxies based on preliminary evidence from earlier studies, and to search for evidence of BHs in a sample of galaxies where the ground-based dynamical evidence for a BH is non-existent or weak. Through this program, we will contribute to the effort toward understanding the demographics of BHs, which are interesting for two reasons. Firstly, present data indicate a possible relationship between the mass of a BH and the mass of the galaxy spheroid within which it is embedded, thus suggesting that BH formation may be closely linked to the formation of galaxy bulges. Secondly, the demographics of local BHs provide a constraint on the accretion properties of quasars at earlier cosmological epochs. In this talk and others by our team in this session, we present preliminary results from our STIS spectroscopy of a selection of galaxies from our program. The primary observational diagnostic of a dark compact mass is measuring and interpreting the nuclear stellar dynamics in the sphere of influence of the candidate BH. The observations involve long-slit spectroscopy of a galaxy nucleus with the wavelength coverage including the strong Ca II triplet absorption lines near 8600 Angstroms. After calibrating the spectrum, we measure the stellar dynamics using the Fourier Correlation Quotient method. These measurements map the nuclear gravitational potential. Using the observed stellar dynamics and surface brightness distribution as input, we fit galaxy dynamical models to these observations to determine if there is evidence for a dark compact object. This talk presents this methodology applied to NGC 1023, which was the first galaxy observed in our program. Support for this work was provided to the STIS IDT by NASA.

  15. The COS Absorption Survey of Baryon Harbors (CASBaH): Probing the Circumgalactic Media of Galaxies from z = 0 to z = 1.5

    Tripp, Todd

    2014-10-01

    In Cycle 17, we obtained high S/N, far-ultraviolet COS spectra of nine QSOs at 0.92 data will be mined for some time, but ultimately the usefulness of the database is limited by the FUV wavelength range of the original observations. To fully exploit these unique HST observations to study the circumgalactic medium during the golden age of star formation (0.5 1800 A) spectroscopy of the same QSOs with STIS and COS to fully cover the H I Lya and Lyman series from z = 0 out to z = z(QSO) and significantly improve the statistics of far-UV lines and diagnostics. With these data we will (1) obtain precise metallicities of the cool CGM with added coverage of H I Lya and Lyman series lines (often not covered in current data at z > 0.5), (2) constrain the metallicity and mass of the warm-hot gas from, e.g, OVI/NeVIII + broad Lya constraints, (3) measure relative abundances (instead of assuming them) using banks of ions accessible only in the far-UV, (4) study absorber redshift evolution with the expanded samples at 0.5 < z < 1.5, (5) obtain more complete and accurate identification of weak lines, which is difficult without constraints on Lya at 0.5 < z < z(QSO), and (6) investigate statistical absorber-galaxy relationships in the epoch of peak star formation.

  16. {\\it NuSTAR} Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

    Teng, Stacy H; Harrison, F A; Luo, B; Alexander, D M; Bauer, F E; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Fabian, A C; Farrah, D; Fiore, F; Gandhi, P; Grefenstette, B W; Hailey, C J; Hickox, R C; Madsen, K K; Ptak, A F; Rigby, J R; Risaliti, G; Saez, C; Stern, D; Veilleux, S; Walton, D J; Wik, D R; Zhang, W W

    2014-01-01

    We present high-energy (3--30 keV) {\\it NuSTAR} observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5--8 keV) data from {\\it Chandra}. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5--30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin (N$_{\\rm H} \\sim1.2^{+0.3}_{-0.3}\\times10^{23}$ cm$^{-2}$) column. The intrinsic X-ray luminosity (L$_{\\rm 0.5-30 keV}\\sim1.0\\times10^{43}$ erg s$^{1}$) is extremely weak relative to the bolometric luminosity where the 2--10 keV to bolometric luminosity ratio is $\\sim$0.03% compared to the typical values of 2--15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope ($\\alpha_{\\rm OX}\\sim-1.7$). It is a local example of a low-ionization broad absorpti...

  17. The Mean Star Formation Rate of X-ray selected Active Galaxies and its Evolution from z=2.5: Results from PEP-Herschel

    Rosario, D J; Lutz, D; Shao, L; Maiolino, R; Alexander, D M; Altieri, B; Andreani, P; Aussel, H; Bauer, F E; Berta, S; Bongiovanni, A; Brandt, W N; Brusa, M; Cepa, J; Cimatti, A; Cox, T J; Daddi, E; Elbaz, D; Fontana, A; Schreiber, N M Förster; Genzel, R; Grazian, A; Floch, E Le; Magnelli, B; Mainieri, V; Netzer, H; Nordon, R; Garcia, I Pérez; Poglitsch, A; Popesso, P; Pozzi, F; Riguccini, L; Rodighiero, G; Salvato, M; Sanchez-Portal, M; Sturm, E; Tacconi, L J; Valtchanov, I; Wuyts, S

    2012-01-01

    (Abridged) We study relationships between the SFR and the nuclear properties of X-ray selected AGNs out to z=2.5, using far-IR data in three extragalactic deep fields as part of the PACS Evolutionary Probe (PEP) program. Guided by studies of intrinsic infra-red AGN SEDs, we show that the majority of the FIR emission in AGNs is produced by cold dust heated by star-formation. We uncover characteristic redshift-dependent trends between the mean FIR luminosity (L_fir) and accretion luminosity (L_agn) of AGNs. At low AGN luminosities, accretion and SFR are uncorrelated at all redshifts, consistent with a scenario where most low-luminosity AGNs are primarily fueled by secular processes in their host galaxies. At high AGN luminosities, a significant correlation is observed between L_fir and L_agn, but only among AGNs at low and moderate redshifts (z1). This suggests that the role of mergers in SMBH-galaxy co-evolution is less important at these epochs. At all redshifts, we find essentially no relationship between L_...

  18. The Herschel PEP/HerMES Luminosity Function. I: Probing the Evolution of PACS selected Galaxies to z~4

    Gruppioni, C; Rodighiero, G; Delvecchio, I; Berta, S; Pozzetti, L; Zamorani, G; Andreani, P; Cimatti, A; Ilbert, O; Floch, E Le; Lutz, D; Magnelli, B; Marchetti, L; Monaco, P; Nordon, R; Oliver, S; Popesso, P; Riguccini, L; Roseboom, I; Rosario, D J; Sargent, M; Vaccari, M; Altieri, B; Aussel, H; Bongiovanni, A; Cepa, J; Daddi, E; Dominguez-Sanchez, H; Elbaz, D; Forster-Schreiber, N; Genzel, R; Iribarrem, A; Magliocchetti, M; Maiolino, R; Poglitsch, A; Garcia, A Perez; Sanchez-Portal, M; Sturm, E; Tacconi, L; Valtchanov, I; Amblard, A; Arumugam, V; Bethermin, M; Bock, J; Boselli, A; Buat, V; Burgarella, D; Castro-Rodriguez, N; Cava, A; Chanial, P; Clements, D L; Conley, A; Cooray, A; Dowell, C D; Dwek, E; Eales, S; Franceschini, A; Glenn, J; Griffin, M; Halpern, M; Hatziminaoglou, E; Ibar, E; Isaak, K; Ivison, R J; Lagache, G; Levenson, L; Lu, N; Madden, S; Maffei, B; Mainetti, G; Nguyen, H T; Halloran, B O; Page, M J; Panuzzo, P; Papageorgiou, A; Pearson, C P; Perez-Fournon, I; Pohlen, M; Rigopoulou, D; Rowan-Robinson, M; Schulz, B; Scott, D; Seymour, N; Shupe, D L; Smith, A J; Stevens, J A; Symeonidis, M; Trichas, M; Tugwell, K E; Vigroux, L; Wang, L; Wright, G; Xu, C K; Zemcov, M; Bardelli, S; Carollo, M; Contini, T; Fevre, O Le; Lilly, S; Mainieri, V; Renzini, A; Scodeggio, M; Zucca, E

    2013-01-01

    We exploit the deep and extended far infrared data sets (at 70, 100 and 160 um) of the Herschel GTO PACS Evolutionary Probe (PEP) Survey, in combination with the HERschel Multi tiered Extragalactic Survey (HerMES) data at 250, 350 and 500 um, to derive the evolution of the restframe 35 um, 60 um, 90 um, and total infrared (IR) luminosity functions (LFs) up to z~4. We detect very strong luminosity evolution for the total IR LF combined with a density evolution. In agreement with previous findings, the IR luminosity density increases steeply to z~1, then flattens between z~1 and z~3 to decrease at z greater than 3. Galaxies with different SEDs, masses and sSFRs evolve in very different ways and this large and deep statistical sample is the first one allowing us to separately study the different evolutionary behaviours of the individual IR populations contributing to the IR luminosity density. Galaxies occupying the well established SFR/stellar mass main sequence (MS) are found to dominate both the total IR LF a...

  19. ALMA Imaging and Gravitational Lens Models of South Pole Telescope-Selected Dusty, Star-Forming Galaxies at High Redshifts

    Spilker, Justin; Aravena, Manuel; Bethermin, Matthieu; Bothwell, Matt; Carlstrom, John; Chapman, Scott; Crawford, Tom; de Breuck, Carlos; Fassnacht, Chris; Gonzalez, Anthony; Greve, Thomas; Hezaveh, Yashar; Litke, Katrina; Ma, Jingzhe; Malkan, Matt; Rotermund, Kaja; Strandet, Maria; Vieira, Joaquin; Weiss, Axel; Welikala, Niraj

    2016-01-01

    The South Pole Telescope has discovered one hundred gravitationally lensed, high-redshift, dusty, star-forming galaxies (DSFGs). We present 0.5" resolution 870um Atacama Large Millimeter/submillimeter Array imaging of a sample of 47 DSFGs spanning z=1.9-5.7, and construct gravitational lens models of these sources. Our visibility-based lens modeling incorporates several sources of residual interferometric calibration uncertainty, allowing us to properly account for noise in the observations. At least 70% of the sources are strongly lensed by foreground galaxies (mu_870um > 2), with a median magnification mu_870um = 6.3, extending to mu_870um > 30. We compare the intrinsic size distribution of the strongly lensed sources to a similar number of unlensed DSFGs and find no significant differences in spite of a bias between the magnification and intrinsic source size. This may indicate that the true size distribution of DSFGs is relatively narrow. We use the source sizes to constrain the wavelength at which the du...

  20. Half of the Most Luminous Quasars May Be Obscured: Investigating the Nature of WISE-Selected Hot Dust-Obscured Galaxies

    Assef, R. J.; Eisenhardt, P. R. M.; Stern, D.; Tsai, C.-W.; Wu, J.; Wylezalek, D.; Blain, A. W.; Bridge, C. R.; Donoso, E.; Gonzales, A.; Griffith, R. L.; Jarrett, T. H.

    2015-05-01

    The Wide-field Infrared Survey Explorer mission has unveiled a rare population of high-redshift (z = 1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities {{L}IR}\\gt {{10}13} {{L}⊙ }, and sometimes exceeding {{10}14} {{L}⊙ }. Previous work has shown that their dust temperatures and overall far-infrared spectral energy distributions (SEDs) are significantly hotter than expected to be powered by star formation. We present here an analysis of the rest-frame optical through mid-infrared SEDs for a large sample of these so-called “hot, dust-obscured galaxies” (Hot DOGs). We find that the SEDs of Hot DOGs are generally well modeled by the combination of a luminous, yet obscured active galactic nuclei (AGNs) that dominates the rest-frame emission at λ \\gt 1 μ m and the bolometric luminosity output, and a less luminous host galaxy that is responsible for the bulk of the rest optical/UV emission. Even though the stellar mass of the host galaxies may be as large as 1011-1012 M⊙, the AGN emission, with a range of luminosities comparable to those of the most luminous QSOs known, require that either Hot DOGs have black hole masses significantly in excess of the local relations, or that they radiate significantly above the Eddington limit, at a level at least 10 times more efficiently than z ˜ 2 QSOs. We show that, while rare, the number density of Hot DOGs is comparable to that of equally luminous but unobscured (i.e., Type 1) QSOs. This may be at odds with the trend suggested at lower luminosities for the fraction of obscured AGNs to decrease with increasing luminosity. That trend may, instead, reverse at higher luminosities. Alternatively, Hot DOGs may not be the torus-obscured counterparts of the known optically selected, largely unobscured, hyper-luminous QSOs, and may represent a new component of the galaxy evolution paradigm. Finally, we discuss the environments of Hot DOGs and statistically show that these objects are in regions as dense as

  1. The relationship between stellar mass, gas metallicity, and star formation rate for Hα-selected galaxies at z ≈ 0.8 from the NewHα survey

    Reyes, Mithi A. de los [Department of Physics, North Carolina State University, Raleigh, NC (United States); Ly, Chun; Lee, Janice C.; Peeples, Molly S.; Feddersen, Jesse [Space Telescope Science Institute, Baltimore, MD (United States); Salim, Samir [Astronomy Department, Indiana University, Bloomington, IN (United States); Momcheva, Ivelina [Astronomy Department, Yale University, New Haven, CT (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY (United States); Ouchi, Masami; Ono, Yoshiaki [Institute for the Physics and Mathematics of the Universe, TODIAS, University of Tokyo (Japan); Finn, Rose, E-mail: madelosr@ncsu.edu [Physics Department of Physics and Astronomy, Siena College, Loudonville, NY (United States)

    2015-02-01

    Using a sample of 299 Hα-selected galaxies at z≈0.8, we study the relationship between galaxy stellar mass, gas-phase metallicity, and star formation rate (SFR), and compare to previous results. We use deep optical spectra obtained with the IMACS spectrograph at the Magellan telescope to measure strong oxygen lines. We combine these spectra and metallicities with (1) rest-frame UV-to-optical imaging, which allows us to determine stellar masses and dust attenuation corrections, and (2) Hα narrowband imaging, which provides a robust measurement of the instantaneous SFR. Our sample spans stellar masses of ∼10{sup 9}–6 × 10{sup 11} M{sub ⊙}, SFRs of 0.4–270 M{sub ⊙} yr{sup −1}, and metal abundances of 12+log(O/H)≈8.3–9.1 (≈0.4–2.6 Z{sub ⊙}). The correlations that we find between the Hα-based SFR and stellar mass (i.e., the star-forming “main sequence”) and between the stellar mass and metallicity are both consistent with previous z∼1 studies of star-forming galaxies. We then study the relationship between the three properties using various plane-fitting techniques and a curve-fitting projection. In all cases, we exclude strong dependence of the M{sub ⋆}–Z relation on SFR, but are unable to distinguish between moderate and no dependence. Our results are consistent with previous mass–metallicity–SFR studies. We check whether data set limitations may obscure a strong dependence on the SFR by using mock samples drawn from the Sloan Digital Sky Survey. These experiments reveal that the adopted signal-to-noise ratio cuts may have a significant effect on the measured dependence. Further work is needed to investigate these results, and to test whether a “fundamental metallicity relation” or a “fundamental plane” describes star-forming galaxies across cosmic time.

  2. Selective determination of antimony(III) and antimony(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone by atomic-absorption spectrometry with a carbon-tube atomizer.

    Kamada, T; Yamamoto, Y

    1977-05-01

    The extraction behaviour of antimony(III) and antimony(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone in organic solvents has been investigated by means of frameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of antimony(III) and differential determination of antimony(III) and antimony(V) have been developed. With ammonium pyrrolidinedithiocarbamate and methyl isobutyl ketone, when the aqueous phase/solvent volume ratio is 50 ml/10 ml and the injection volume in the carbon tube is 20 mul, the sensitivity for antimony is 0.2 ng/ml for 1% absorption. The relative standard deviations are ca. 2%. Interferences by many metal ions can be prevented by masking with EDTA. The proposed methods have been applied satisfactorily to determination of antimony(III) and antimony(V) in various types of water. PMID:18962096

  3. A nanoporous 3D zinc(II) metal–organic framework for selective absorption of benzaldehyde and formaldehyde

    Moradpour, Tahereh [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Abbasi, Alireza, E-mail: aabbassi@khayam.ut.ac.ir [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Van Hecke, Kristof [XStruct, Department of Inorganic and Physical Chemistry, Ghent University, Krigslaan 281-S3, Ghent B-9000 (Belgium)

    2015-08-15

    A new 3D nanoporous metal–organic framework (MOF), [[Zn{sub 4}O(C{sub 24}H{sub 15}N{sub 6}O{sub 6}){sub 2}(H{sub 2}O){sub 2}]·6H{sub 2}O·DMF]{sub n} (1) based on 4,4′,4″-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB) ligand was solvothermally synthesized and characterized by single–crystal X-ray diffraction, Powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and Brunauer–Emmett–Teller (BET) analyses. X-ray single crystal diffraction analysis reveals that 1 exhibits a 3D network with new kvh1 topology. Semi-empirical (AM1) calculations were carried out to obtain stable conformers for TATAB ligand. In addition, the absorption of two typical aldehydes (benzaldehyde and formaldehyde) in the presence of 1 was investigated and the effect of the aldehyde concentration, exposure time and temperature was studied. It was found that compound 1 has a potential for the absorption of aldehydes under mild conditions. - Graphical abstract: Absorption of two typical aldehydes (formaldehyde and benzaldehyde) by solvothermally synthesized of a 3D nano-porous MOF based on TATAB tricarboxylate ligand and Zn (NO{sub 3}){sub 2}·6H{sub 2}O. - Highlights: • We present a 3D Zn(II)-MOF with TATAB linker by solvothermal method. • The framework possesses a new kvh1 topology. • The framework displays formaldehyde and benzaldehyde absorption property. • Conformational analysis was performed to determine the stable linker geometry.

  4. MgII absorption systems with W_0 > 0.1 \\AA for a radio selected sample of 77 QSOs and their associated magnetic fields at high redshifts

    Bernet, M L; Lilly, S J

    2010-01-01

    We present a catalogue of MgII absorption systems obtained from high resolution UVES/VLT data of 77 QSOs in the redshift range 0.6 0.1 \\AA. The statistical properties of our sample are found to be in agreement with those from previous work in the literature. However, we point out that the previously observed increase with redshift of dN/dz for weak absorbers, pertains exclusively to very weak absorbers with W_0 0.3 \\AA, the weaker systems do not contribute significantly to the observed Rotation Measure of the background quasars. This is possibly due to the higher impact parameters of the weak systems compared to strong ones, suggesting that the high column density magnetized material that is responsible for the Faraday Rotation is located within about 50 kpc of the galaxies. Finally, we show that this result also rules out the possibility that some unexpected secondary correlation between the quasar redshift and its intrinsic Rotation Measure is responsible for the associati on of high Rotation Measure and ...

  5. Raman and absorption spectrophotometric studies of selected lanthanide, californium-doped lanthanide, and actinide trihalides in the solid state

    The solid-state absorption spectra of Cf(III) ions as a dopant in lanthanide trihalide hosts (LnCl3: Ln = Ce, Sm, and Y; LnBr3: Ln = Ce, Sm, Tb, and Y; LnI3: Ln = Ce and Y) have been recorded. The spectra of Cf(III) have been correlated with the various crystal structures. The phonon Raman spectra and solid-state absorption spectra of PmF3, PmCl3, PmBr3, and two crystal modifications of PmI3 have been recorded. Symmetry assignments have been made for the Raman-active bands for these trihalides and also the sesquioxide. The room-temperature absorption spectra have been correlated to crystal field effects. The symmetry assignments of the Raman-active phonon modes have been made based on polarized Raman spectra from single crystals of YF3-type orthorhombic TbF3 and PuBr3-type orthorhombic NdBr3. Raman spectra of other isostructural lanthanide compounds have been recorded and compared. Symmetry assignments for these compounds have been made by analogy to the single-crystal assignments. Raman spectra have been obtained and catalogued for a number of actinide compounds. Symmetry assignments have been made for the observed Raman-active phonon bands in this work based on the assignments made for isostructural lanthanide compounds. 29 figs., 22 tabs

  6. The impact of solvents on the singlet and triplet states of selected fluorine corroles - absorption, fluorescence, and optoacoustic studies.

    Bursa, Bartosz; Wróbel, Danuta; Barszcz, Bolesław; Kotkowiak, Michał; Vakuliuk, Olena; Gryko, Daniel T; Kolanowski, Łukasz; Baraniak, Marek; Lota, Grzegorz

    2016-03-01

    This paper examines the influence of aprotic solvents on the spectroscopic properties as well as the energy deactivation of two free-base corrole dyes substituted with C6F5 and/or 4-NO2C6H4 groups. Absorption, fluorescence and laser-induced optoacoustic spectroscopy have been used to follow the singlet and triplet states of fluorine corroles belonging to the A2B and A3 type in toluene (TL), chloroform (CL), dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and also in solvent mixtures. Changes in the absorption and fluorescence spectra are influenced by the type of solvent mixture. The fluorescence behaviors of the two investigated corroles were extremely different - fluorescence of the nitro-corrole in TL is dramatically quenched in the presence of DMF. In contrast, fluorescence quenching of fluorine corroles in DMF-TL mixtures is substantially weakened. Absorption, fluorescence, triplet population as well as singlet oxygen generation parameters are evaluated. The spectral experimental data are supported by quantum chemical calculations - time-dependent density functional theory (TD-DFT) and cyclic voltammetry experiments. The presented results are discussed from a viewpoint of aggregation, tautomerization, and deprotonation effects occurring in the corroles. PMID:26890961

  7. A Multi-Wavelength Study of Low Redshift Clusters of Galaxies I. Comparison of X-ray and Mid-Infrared Selected AGNs

    Atlee, David W.; Martini, Paul; Assef, Roberto J.; Kelson, Daniel D.; Mulchaey, John S.

    2011-01-01

    Clusters of galaxies have long been used as laboratories for the study of galaxy evolution, but despite intense, recent interest in feedback between AGNs and their hosts, the impact of environment on these relationships remains poorly constrained. We present results from a study of AGNs and their host galaxies found in low-redshift galaxy clusters. We fit model spectral energy distributions (SEDs) to the combined visible and mid-infrared (MIR) photometry of cluster members and use these model...

  8. Verifying the mass-metallicity relation in damped Lyman-alpha selected galaxies at 0.1

    Christensen, Lise Bech; Møller, P.; Fynbo, J. P. U.;

    2014-01-01

    A scaling relation has recently been suggested to combine the galaxy mass-metallicity (MZ) relation with metallicities of damped Lyman-alpha systems (DLAs) in quasar spectra. Based on this relation the stellar masses of the absorbing galaxies can be predicted. We test this prediction by measuring...... the stellar masses of 12 galaxies in confirmed DLA absorber - galaxy pairs in the redshift range 0.1z...

  9. Galaxy Formation

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function of...

  10. Active Galaxies

    Kilerci Eser, Ece

    Galaxy formation and evolution is one of the main research themes of modern astronomy. Active galaxies such as Active Galactic Nuclei (AGN) and Ultraluminous Infrared Galaxies (ULIRGs) are important evolutionary stages of galaxies. The ULIRG stage is mostly associated with galaxy mergers and...... interactions. During the interactions of gas-rich galaxies, the gas inflows towards the centers of the galaxies and can trigger both star formation and AGN activity. The ULIRG stage includes rapid star formation activity and fast black hole growth that is enshrouded by dust. Once the AGN emission is...... one is related to the mass estimates of supermassive black holes (SMBHs). Mass estimates of SMBHs are important to understand the formation and evolution of SMBHs and their host galaxies. Black hole masses in Type 1 AGN are measured with the reverberation mapping (RM) technique. Reverberation mapping...

  11. Quiescent Galaxies in the 3D-HST Survey: Spectroscopic Confirmation of a Large Number of Galaxies With Relatively Old Stellar Populations at z Approx. 2

    Tease, Katherine Whitaker; vanDokkum, Pieter G.; Brammer, Gabriel; Momcheva, Ivelina; Skelton, Rosalind; Franx, Marijin; Kriek, Mariska; Labbe, Ivo; Fumagalli, Mattia; Lundgren, Britt F.; Nelson, Erica J.; Patel, Shannon G.; Rix, Hans-Walter

    2013-01-01

    Quiescent galaxies at z approx. 2 have been identified in large numbers based on rest-frame colors, but only a small number of these galaxies have been spectroscopically confirmed to show that their rest-frame optical spectra show either strong Balmer or metal absorption lines. Here, we median stack the rest-frame optical spectra for 171 photometrically quiescent galaxies at 1.4 < z < 2.2 from the 3D-HST grism survey. In addition to H (4861 ),we unambiguously identify metal absorption lines in the stacked spectrum, including the G band (4304 ),Mgi (5175 ), and Na i (5894 ). This finding demonstrates that galaxies with relatively old stellar populations already existed when the universe was approx. 3 Gyr old, and that rest-frame color selection techniques can efficiently select them. We find an average age of 1.3+0.10.3 Gyr when fitting a simple stellar population to the entire stack. We confirm our previous result from medium-band photometry that the stellar age varies with the colors of quiescent galaxies: the reddest 80 of galaxies are dominated by metal lines and have a relatively old mean age of 1.6+0.50.4 Gyr, whereas the bluest (and brightest) galaxies have strong Balmer lines and a spectroscopic age of 0.9+0.20.1 Gyr. Although the spectrum is dominated by an evolved stellar population, we also find [O iii] and H emission. Interestingly, this emission is more centrally concentrated than the continuum with LOiii = 1.7+/- 0.3 x 10(exp 40) erg/s, indicating residual central star formation or nuclear activity.

  12. QUIESCENT GALAXIES IN THE 3D-HST SURVEY: SPECTROSCOPIC CONFIRMATION OF A LARGE NUMBER OF GALAXIES WITH RELATIVELY OLD STELLAR POPULATIONS AT z {approx} 2

    Whitaker, Katherine E. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Van Dokkum, Pieter G.; Momcheva, Ivelina G.; Skelton, Rosalind; Nelson, Erica J. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Brammer, Gabriel [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Franx, Marijn; Labbe, Ivo; Fumagalli, Mattia; Patel, Shannon G. [Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands); Kriek, Mariska [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Lundgren, Britt F. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Rix, Hans-Walter, E-mail: kate.whitaker@nasa.gov [Max Planck Institut fur Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2013-06-20

    Quiescent galaxies at z {approx} 2 have been identified in large numbers based on rest-frame colors, but only a small number of these galaxies have been spectroscopically confirmed to show that their rest-frame optical spectra show either strong Balmer or metal absorption lines. Here, we median stack the rest-frame optical spectra for 171 photometrically quiescent galaxies at 1.4 < z < 2.2 from the 3D-HST grism survey. In addition to H{beta} ({lambda}4861 A), we unambiguously identify metal absorption lines in the stacked spectrum, including the G band ({lambda}4304 A), Mg I ({lambda}5175 A), and Na I ({lambda}5894 A). This finding demonstrates that galaxies with relatively old stellar populations already existed when the universe was {approx}3 Gyr old, and that rest-frame color selection techniques can efficiently select them. We find an average age of 1.3{sup +0.1}{sub -0.3} Gyr when fitting a simple stellar population to the entire stack. We confirm our previous result from medium-band photometry that the stellar age varies with the colors of quiescent galaxies: the reddest 80% of galaxies are dominated by metal lines and have a relatively old mean age of 1.6{sup +0.5}{sub -0.4} Gyr, whereas the bluest (and brightest) galaxies have strong Balmer lines and a spectroscopic age of 0.9{sup +0.2}{sub -0.1} Gyr. Although the spectrum is dominated by an evolved stellar population, we also find [O III] and H{beta} emission. Interestingly, this emission is more centrally concentrated than the continuum with L{sub OIII}=1.7{+-}0.3 Multiplication-Sign 10{sup 40} erg s{sup -1}, indicating residual central star formation or nuclear activity.

  13. High-Resolution Near-Infrared Spectroscopy of an Equivalent Width-Selected Sample of Starbursting Dwarf Galaxies

    Maseda, Michael V.; VanDerWeL, Arjen; DaChuna, Elisabete; Rix, Hans-Walter; Pacafichi, Camilla; Momcheva, Ivelina; Brammer, Gabriel B.; Franx, Marijn; VanDokkum, Pieter; Bell, Eric F.; Ferguson, Harry C.; Fumagalli, Mattia; Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M.; Lundgren, Britt F.; Marchesini, Danilo; Nelson, Erica J.; Patel, Shannon; Skelton, Rosalind E.; Straughn, Amber N.; Trump, Jonathan R.; Weiner, Benjamin J.; Whitaker, Katherine E.; Wuyts, Stijn

    2013-01-01

    Spectroscopic observations from the Large Binocular Telescope and the Very Large Telescope reveal kinematically narrow lines (approx. 50 km/s) for a sample of 14 Extreme Emission Line Galaxies (EELGs) at redshifts 1.4 < zeta < 2.3. These measurements imply that the total dynamical masses of these systems are low ( 3 × 10(exp 9) M). Their large [O III]5007 equivalent widths (500 - 1100 A) and faint blue continuum emission imply young ages of 10-100 Myr and stellar masses of 10(exp 8)-10(exp 9) M, confirming the presence of a violent starburst. The stellar mass formed in this vigorous starburst phase thus represents a large fraction of the total (dynamical) mass, without a significantly massive underlying population of older stars. The occurrence of such intense events in shallow potentials strongly suggests that supernova-driven winds must be of critical importance in the subsequent evolution of these systems.

  14. F-VIPGI: a new adapted version of VIPGI for FORS2 spectroscopy. Application to a sample of 16 X-ray selected galaxy clusters at 0.6 < z < 1.2

    Nastasi, Alessandro; Fassbender, Rene; Boehringer, Hans; Pierini, Daniele; Verdugo, Miguel; Garilli, Bianca; Franzetti, Paolo

    2013-01-01

    The goal of this paper is twofold. Firstly, we present F-VIPGI, a new version of the VIMOS Interactive Pipeline and Graphical Interface (VIPGI) adapted to handle FORS2 spectroscopic data. Secondly, we investigate the spectro-photometric properties of a sample of galaxies residing in distant X-ray selected galaxy clusters, the optical spectra of which were reduced with this new pipeline. We provide basic technical information about the innovations of the new software and, as a demonstration of the capabilities of the new pipeline, we show results obtained for 16 distant (0.65 < z < 1.25) X-ray luminous galaxy clusters selected within the XMM-Newton Distant Cluster Project. We performed a spectral indices analysis of the extracted optical spectra of their members, based on which we created a library of composite high signal-to-noise ratio spectra representative of passive and star-forming galaxies residing in distant galaxy clusters. The spectroscopic templates are provided to the community in electronic ...

  15. Photon energy selection for dual energy γ- and/or X-ray absorption composition measurements in oil-water-gas mixtures

    Dual energy γ- and/or X-ray absorption techniques can be used to monitor the composition of oil-water-gas mixtures in pipes. Criteria for the selection of the two photon energies and their relative intensities are developed, that maximise the precision of the mixture composition determination. A correction for the effects of pressure and temperature changes is presented. Changes of the salinity of the water and variations of the mixture composition in time and space, even in the case of bubble flow, are shown to deteriorate the results. (author)

  16. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers. II. Program Design, Absorption-line Measurements, and Absorber Statistics

    Burchett, Joseph N.; Tripp, Todd M.; Prochaska, J. Xavier; Werk, Jessica K.; Tumlinson, Jason; O'Meara, John M.; Bordoloi, Rongmon; Katz, Neal; Willmer, C. N. A.

    2015-12-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium, we have conducted a blind survey for C iv absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope Cosmic Origins Spectrograph. We have identified 42 absorbers at z critical density of the universe (ΩC iv = 10.0 ± 1.5 × 10-8) from z ˜ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power law, also consistent with independent theoretical predictions. As the data also probe heavy element ions in addition to C iv at the same redshifts, we identify, measure, and search for correlations between column densities of these species where components appear to be aligned in velocity. Among these ion-ion correlations, we find evidence for tight correlations between C ii and Si ii, C ii and Si iii, and C iv and Si iv, suggesting that these pairs of species arise in similar ionization conditions. However, the evidence for correlations decreases as the difference in ionization potential increases. Finally, when controlling for observational bias, we find only marginal evidence for a correlation (86.8% likelihood) between the Doppler line width b(C iv) and column density N(C iv).

  17. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers: II. Program Design, Absorption-line Measurements, and Absorber Statistics

    Burchett, Joseph N; Prochaska, J Xavier; Werk, Jessica K; Tumlinson, Jason; O'Meara, John M; Bordoloi, Rongmon; Katz, Neal; Willmer, C N A

    2015-01-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). We have identified 42 absorbers at z < 0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasing C IV absorber number density per comoving path length (dN/dX = 7.5 +/- 1.1) and modestly increasing mass density relative to the critical density of the Universe (Omega(C IV) = 10.0 +/- 1.5 x 10^-8 ) from z ~ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power-law, also consistent with independent theoretical predictions. As the data also probe...

  18. Effects of collisions and interactions on star formation in galaxy pairs in the field

    Perez, Josefa; Tissera, Patricia B.; Lambas, Diego G.

    2005-01-01

    By using cosmological simulations, we studied the effects of galaxy interactionson the star formation activity in the local Universe. We selected galaxy pairs from the 3D galaxy distribution according to a proximity criterion. The 2D galaxy catalog was constructed by projecting the 3D total galaxy distribution and then selecting projected galaxy pairs. The analysis of the 3D galaxy pair catalog showed that an enhancement of the star formation activity can be statistically correlated with prox...

  19. A nanoporous 3D zinc(II) metal-organic framework for selective absorption of benzaldehyde and formaldehyde

    Moradpour, Tahereh; Abbasi, Alireza; Van Hecke, Kristof

    2015-08-01

    A new 3D nanoporous metal-organic framework (MOF), [[Zn4O(C24H15N6O6)2(H2O)2]·6H2O·DMF]n (1) based on 4,4‧,4″-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB) ligand was solvothermally synthesized and characterized by single-crystal X-ray diffraction, Powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and Brunauer-Emmett-Teller (BET) analyses. X-ray single crystal diffraction analysis reveals that 1 exhibits a 3D network with new kvh1 topology. Semi-empirical (AM1) calculations were carried out to obtain stable conformers for TATAB ligand. In addition, the absorption of two typical aldehydes (benzaldehyde and formaldehyde) in the presence of 1 was investigated and the effect of the aldehyde concentration, exposure time and temperature was studied. It was found that compound 1 has a potential for the absorption of aldehydes under mild conditions.

  20. Triggering star formation by galaxy-galaxy interactions

    Tissera, P B; Alonso, M S; Coldwell, G V; Tissera, Patricia B.; Lambas, Diego G.

    2003-01-01

    We analyzed the effects of having a close companion on the star formation activity of galaxies in 8K galaxy pair catalog selected from the 2dFGRS. We found that, statistically, galaxies with $r_{\\rm p} < 25 {\\rm h^{-1}}$ kpc and $\\Delta V < 100 {\\rm km/s}$ have enhanced star formation with respect to isolated galaxies with the same luminosity and redshift distribution. Our results suggest that the physical processes at work during tidal interactions can overcome the effects of environment, expect in dense regions.

  1. Triggering star formation by galaxy-galaxy interactions

    Tissera, Patricia B.; Lambas, Diego G.; Alonso, M. Sol; Coldwell, Georgina

    2003-01-01

    We analyzed the effects of having a close companion on the star formation activity of galaxies in 8K galaxy pair catalog selected from the 2dFGRS. We found that, statistically, galaxies with $r_{\\rm p} < 25 {\\rm h^{-1}}$ kpc and $\\Delta V < 100 {\\rm km/s}$ have enhanced star formation with respect to isolated galaxies with the same luminosity and redshift distribution. Our results suggest that the physical processes at work during tidal interactions can overcome the effects of environment, ex...

  2. Galaxies in x-ray selected clusters and groups in Dark Energy Survey Data I: Stellar mass growth of bright central galaxies since Z similar to 1.2

    Zhang, Y.; Miller, C.; McKay, T.; Rooney, P.; Evrard, A. E.; Romer, A. K.; Perfecto, R.; Song, J; Desai, S.; Mohr, J. J.; Vikram, V.

    2016-01-10

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z similar to 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, m(*) proportional to (M-200/1.5 x 10(14)M(circle dot))(0.24 +/- 0.08)(1+z)(-0.19 +/- 0.34), and compare the observed relation to the model prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of M-200,M-z = 10(13.8)M(circle dot); at z = 1.0: m(*, BCG) appears to have grown by 0.13 +/- 0.11 dex, in tension at the similar to 2.5 sigma significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z = 1.0 may alleviate this tension in BCG growth rates.

  3. Determination of Trace Metals (Co, Cu, Cd, Pb, Fe, Ni and Mn in Selected Sweets of Different Shops of Karachi City by Atomic Absorption Spectroscopy

    M. Akhyar Farrukh

    2004-01-01

    Full Text Available The study presented was concerned with the determination of level of iron, nickel, cobalt, copper, lead, manganese and cadmium in different sweets (Gulab Jamun, White Chum Chum, Colored Chum Chum, Khopre ki Mithai, Qalaqand, Bhashani Chum Chum, Basin ka Lado and Patesa collected from selected shops of Karachi city. Concentration of selected trace metals were estimated using atomic absorption spectrometer. Results obtained from study show high concentration of iron and manganese in all the sweets. High concentration of iron may be due to the cooking utensils rich of iron. Use of manganese in alloys may be responsible of such high concentration of manganese in sweets. Metal load in sweets of all shops seem in the limits offered by RDA for respective metals. All food colors used in making sweets are permitted food colors, because sweets show no abnormal metal load.

  4. Bright X-ray galaxies in SDSS filaments

    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.

  5. Executing SADI services in Galaxy

    Egaña Aranguren, Mikel; Rodríguez González, Alejandro; Wilkinson, Mark D

    2014-01-01

    Background: In recent years Galaxy has become a popular workflow management system in bioinformatics, due to its ease of installation, use and extension. The availability of Semantic Web-oriented tools in Galaxy, however, is limited. This is also the case for Semantic Web Services such as those provided by the SADI project, i.e. services that consume and produce RDF. Here we present SADI-Galaxy, a tool generator that deploys selected SADI Services as typical Galaxy tools. Results: SADI-Ga...

  6. FTIR spectrometer with 30 m optical cell and its applications to the sensitive measurements of selective and nonselective absorption spectra

    Ponomarev, Yu. N.; Solodov, A. A.; Solodov, A. M.; Petrova, T. M.; Naumenko, O. V.

    2016-07-01

    A description of the spectroscopic complex at V.E. Zuev Institute of Atmospheric Optics, SB RAS, operating in a wide spectral range with high threshold sensitivity to the absorption coefficient is presented. Measurements of weak lines and nonselective spectra of CO2 and H2O were performed based on the built setup. As new application of this setup, positions and intensities of 152 weak lines of H2O were measured between 2400 and 2560 cm-1 with threshold sensitivity of 8.6×10-10 cm-1, and compared with available calculated and experimental data. Essential deviations between the new intensity measurements and calculated data accepted in HITRAN 2012 and GEISA 2015 forthcoming release are found.

  7. The Atacama Cosmology Telescope: Sunyaev-Zel'dovich Selected Galaxy Clusters at 148 GHz from Three Seasons of Data

    Hasselfield, Matthew; Marriage, Tobias A; Addison, Graeme E; Barrientos, L Felipe; Battaglia, Nick; Battistelli, Elia S; Bond, J Richard; Crichton, Devin; Das, Sudeep; Devlin, Mark J; Dicker, Simon R; Dunkley, Joanna; Dunner, Rolando; Fowler, Joseph W; Gralla, Megan B; Hajian, Amir; Halpern, Mark; Hincks, Adam D; Hlozek, Renée; Hughes, John P; Infante, Leopoldo; Irwin, Kent D; Kosowsky, Arthur; Marsden, Danica; Menanteau, Felipe; Moodley, Kavilan; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Partridge, Bruce; Reese, Erik D; Schmitt, Benjamin L; Sehgal, Neelima; Sherwin, Blake D; Sievers, Jon; Sifón, Cristóbal; Spergel, David N; Staggs, Suzanne T; Swetz, Daniel S; Switzer, Eric R; Thornton, Robert; Trac, Hy; Wollack, Edward J

    2013-01-01

    [Abridged] We present a catalog of 68 galaxy clusters, of which 19 are new discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in the Atacama Cosmology Telescope (ACT) survey of 504 square degrees on the celestial equator. A subsample of 48 clusters within the 270 square degree region overlapping SDSS Stripe 82 is estimated to be 90% complete for M_500c > 4.5e14 Msun and 0.15 < z < 0.8. While matched filters are used to detect the clusters, the sample is studied further through a "Profile Based Amplitude Analysis" using a single filter at a fixed \\theta_500 = 5.9' angular scale. This new approach takes advantage of the "Universal Pressure Profile" (UPP) to break the degeneracy between the cluster extent (R_500) and the integrated Compton parameter (Y_500). The UPP scalings are found to be nearly identical to an adiabatic model, while a model incorporating non-thermal pressure better matches dynamical mass measurements and masses from the South Pole Telescope. A complete, high signal ...

  8. A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

    Cracco, V; Berton, M; Di Mille, F; Foschini, L; La Mura, G; Rafanelli, P

    2016-01-01

    We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole masses and higher Eddington ratios than classic broad-line Seyfert 1 (BLS1s), but they also appear to be active galactic nuclei (AGNs) contiguous with BLS1s and sharing with them common properties. Strong Fe II emission does not seem to be a distinctive property of NLS1s, as low values of Fe II/H$\\beta$ are equally observed in these AGNs. Our data indicate that Fe II and Ca II kinematics are consistent with the one of H$\\beta$. On the contrary, O I $\\lambda$8446 seems to be systematically narrower and it is likely emitted by gas of the broad-line region more distant from the ionizing source and showing different physical properties. Finally, almost all NLS1s of our ...

  9. Chandra X-Ray and Hubble Space Telescope Imaging of Optically Selected Kiloparsec-scale Binary Active Galactic Nuclei. II. Host Galaxy Morphology and AGN Activity

    Shangguan, Jinyi; Liu, Xin; Ho, Luis C.; Shen, Yue; Peng, Chien Y.; Greene, Jenny E.; Strauss, Michael A.

    2016-05-01

    Binary active galactic nuclei (AGNs) provide clues to how gas-rich mergers trigger and fuel AGNs and how supermassive black hole (SMBH) pairs evolve in a gas-rich environment. While significant effort has been invested in their identification, the detailed properties of binary AGNs and their host galaxies are still poorly constrained. In a companion paper, we examined the nature of ionizing sources in the double nuclei of four kiloparsec-scale binary AGNs with redshifts between 0.1 and 0.2. Here, we present their host galaxy morphology based on F336W (U-band) and F105W (Y-band) images taken by the Wide Field Camera 3 on board the Hubble Space Telescope. Our targets have double-peaked narrow emission lines and were confirmed to host binary AGNs with follow-up observations. We find that kiloparsec-scale binary AGNs occur in galaxy mergers with diverse morphological types. There are three major mergers with intermediate morphologies and a minor merger with a dominant disk component. We estimate the masses of the SMBHs from their host bulge stellar masses and obtain Eddington ratios for each AGN. Compared with a representative control sample drawn at the same redshift and stellar mass, the AGN luminosities and Eddington ratios of our binary AGNs are similar to those of single AGNs. The U ‑ Y color maps indicate that clumpy star-forming regions could significantly affect the X-ray detection of binary AGNs, e.g., the hardness ratio. Considering the weak X-ray emission in AGNs triggered in merger systems, we suggest that samples of X-ray-selected AGNs may be biased against gas-rich mergers. Based, in part, on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program number GO 12363.

  10. THE ATACAMA COSMOLOGY TELESCOPE: DYNAMICAL MASSES AND SCALING RELATIONS FOR A SAMPLE OF MASSIVE SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTERS ,

    We present the first dynamical mass estimates and scaling relations for a sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The sample consists of 16 massive clusters detected with the Atacama Cosmology Telescope (ACT) over a 455 deg2 area of the southern sky. Deep multi-object spectroscopic observations were taken to secure intermediate-resolution (R ∼ 700-800) spectra and redshifts for ≈60 member galaxies on average per cluster. The dynamical masses M200c of the clusters have been calculated using simulation-based scaling relations between velocity dispersion and mass. The sample has a median redshift z = 0.50 and a median mass M200c≅12×1014 h70-1 Msun with a lower limit M200c≅6×1014 h70-1 Msun, consistent with the expectations for the ACT southern sky survey. These masses are compared to the ACT SZE properties of the sample, specifically, the match-filtered central SZE amplitude y0-tilde, the central Compton parameter y0, and the integrated Compton signal Y200c, which we use to derive SZE-mass scaling relations. All SZE estimators correlate with dynamical mass with low intrinsic scatter (∼< 20%), in agreement with numerical simulations. We explore the effects of various systematic effects on these scaling relations, including the correlation between observables and the influence of dynamically disturbed clusters. Using the three-dimensional information available, we divide the sample into relaxed and disturbed clusters and find that ∼50% of the clusters are disturbed. There are hints that disturbed systems might bias the scaling relations, but given the current sample sizes, these differences are not significant; further studies including more clusters are required to assess the impact of these clusters on the scaling relations

  11. The clustering evolution of dusty star-forming galaxies

    Cowley, William I.; Lacey, Cedric G.; Baugh, Carlton M.; Cole, Shaun

    2016-05-01

    We present predictions for the clustering of galaxies selected by their emission at far infra-red (FIR) and sub-millimetre wavelengths. This includes the first predictions for the effect of clustering biases induced by the coarse angular resolution of single-dish telescopes at these wavelengths. We combine a new version of the GALFORM model of galaxy formation with a self-consistent model for calculating the absorption and re-emission of radiation by interstellar dust. Model galaxies selected at 850 μm reside in dark matter halos of mass Mhalo ˜ 1011.5 - 1012 h-1 M⊙, independent of redshift (for 0.2 ≲ z ≲ 4) or flux (for 0.25 ≲ S850μm ≲ 4 mJy). At z ˜ 2.5, the brightest galaxies (S850μm > 4 mJy) exhibit a correlation length of r0=5.5_{-0.5}^{+0.3} h-1 Mpc, consistent with observations. We show that these galaxies have descendants with stellar masses M⋆ ˜ 1011 h-1 M⊙ occupying halos spanning a broad range in mass Mhalo ˜ 1012 - 1014 h-1 M⊙. The FIR emissivity at shorter wavelengths (250, 350 and 500 μm) is also dominated by galaxies in the halo mass range Mhalo ˜ 1011.5 - 1012 h-1 M⊙, again independent of redshift (for 0.5 ≲ z ≲ 5). We compare our predictions for the angular power spectrum of cosmic infra-red background anisotropies at these wavelengths with observations, finding agreement to within a factor of ˜2 over all scales and wavelengths, an improvement over earlier versions of the model. Simulating images at 850 μm, we show that confusion effects boost the measured angular correlation function on all scales by a factor of ˜4. This has important consequences, potentially leading to inferred halo masses being overestimated by an order of magnitude.

  12. Galaxies appear simpler than expected

    Disney, M J; Garcia-Appadoo, D A; West, A A; Dalcanton, J J; Cortese, L

    2008-01-01

    Galaxies are complex systems the evolution of which apparently results from the interplay of dynamics, star formation, chemical enrichment, and feedback from supernova explosions and supermassive black holes. The hierarchical theory of galaxy formation holds that galaxies are assembled from smaller pieces, through numerous mergers of cold dark matter. The properties of an individual galaxy should be controlled by six independent parameters including mass, angular-momentum, baryon-fraction, age and size, as well as by the accidents of its recent haphazard merger history. Here we report that a sample of galaxies that were first detected through their neutral hydrogen radio-frequency emission, and are thus free of optical selection effects, shows five independent correlations among six independent observables, despite having a wide range of properties. This implies that the structure of these galaxies must be controlled by a single parameter, although we cannot identify this parameter from our dataset. Such a de...

  13. Optical variability of infrared power law-selected galaxies & X-ray sources in the goods-south field

    Alison Klesman

    2007-01-01

    Full Text Available We investigate the use of optical variabil- ity over 6 months to identify AGNs in the GOODS-South field. Photometry was per- formed on a sample of 24 infrared power law-selected AGN candidates and 104 X-ray sources with optical counterparts. We find that while the majority of variable objects are unobscured AGN, 30% of IR-only selected candidates show evidence of AGN via optical variability.

  14. Growing Galaxies Gently

    2010-10-01

    New observations from ESO's Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. In the first few billion years after the Big Bang the mass of a typical galaxy increased dramatically and understanding why this happened is one of the hottest problems in modern astrophysics. The results appear in the 14 October issue of the journal Nature. The first galaxies formed well before the Universe was one billion years old and were much smaller than the giant systems - including the Milky Way - that we see today. So somehow the average galaxy size has increased as the Universe has evolved. Galaxies often collide and then merge to form larger systems and this process is certainly an important growth mechanism. However, an additional, gentler way has been proposed. A European team of astronomers has used ESO's Very Large Telescope to test this very different idea - that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early Universe and forming new stars from this primitive material. Just as a commercial company can expand either by merging with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways - by merging with other galaxies or by accreting material. The team leader, Giovanni Cresci (Osservatorio Astrofisico di Arcetri) says: "The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe." The discovery will have a major impact on our understanding of the evolution of the Universe from the Big Bang to the present day. Theories of galaxy formation and evolution may have to be re-written. The group began by selecting three very distant galaxies to see if they could find evidence

  15. TOUGH: Observational aspects of gamma-ray burst host galaxies

    Hjorth, Jens; Jaunsen, Andreas O; Levan, Andrew J; Milvang-Jensen, Bo; Watson, Darach; Gorosabel, Javier; Fynbo, Johan P U; Michałowski, Michał J; Tanvir, Nial R; Jakobsson, Páll; Møller, Palle; Schulze, Steve; Krühler, Thomas

    2012-01-01

    GRB-selected galaxies are broadly known to be faint, blue, young, star-forming dwarf galaxies. This insight, however, is based in part on heterogeneous samples of optically selected, lower-redshift galaxies. To study the statistical properties of GRB-selected galaxies we here introduce The Optically Unbiased GRB Host (TOUGH) complete sample of 69 X-ray selected Swift GRB host galaxies spanning the redshift range 0.03-6.30 and summarise the first results of a large observational survey of these galaxies.

  16. The host galaxies of X-ray selected Active Galactic Nuclei to z=2.5: Structure, star-formation and their relationships from CANDELS and Herschel/PACS

    Rosario, D J; van der Wel, A; Kartaltepe, J; Lang, P; Santini, P; Wuyts, S; Lutz, D; Rafelski, M; Villforth, C; Alexander, D M; Bauer, F E; Bell, E F; Berta, S; Brandt, W N; Conselice, C J; Dekel, A; Faber, S M; Ferguson, H C; Genzel, R; Grogin, N A; Kocevski, D D; Koekemoer, A M; Koo, D C; Lotz, J M; Magnelli, B; Maiolino, R; Mozena, M; Mullaney, J R; Papovich, C J; Popesso, P; Tacconi, L J; Trump, J R; Avadhuta, S; Bassett, R; Bell, A; Bernyk, M; Bournaud, F; Cassata, P; Cheung, E; Croton, D; Donley, J; DeGroot, L; Guedes, J; Hathi, N; Herrington, J; Hilton, M; Lai, K; Lani, C; Martig, M; McGrath, E; Mutch, S; Mortlock, A; McPartland, C; O'Leary, E; Peth, M; Pillepich, A; Poole, G; Snyder, D; Straughn, A; Telford, O; Tonini, C; Wandro, P

    2014-01-01

    We study the relationship between the structure and star-formation rate (SFR) of X-ray selected low and moderate luminosity active galactic nuclei (AGNs) in the two Chandra Deep Fields, using Hubble Space Telescope imaging from the Cosmic Assembly Near Infrared Extragalactic Legacy Survey (CANDELS) and deep far-infrared maps from the PEP+GOODS-Herschel survey. We derive detailed distributions of structural parameters and FIR luminosities from carefully constructed control samples of galaxies, which we then compare to those of the AGNs. At z~1, AGNs show slightly diskier light profiles than massive inactive (non-AGN) galaxies, as well as modestly higher levels of gross galaxy disturbance (as measured by visual signatures of interactions and clumpy structure). In contrast, at z~2, AGNs show similar levels of galaxy disturbance as inactive galaxies, but display a red central light enhancement, which may arise due to a more pronounced bulge in AGN hosts or due to extinguished nuclear light. We undertake a number ...

  17. A Near-Infrared Spectroscopic Survey of K-selected Galaxies at z ~ 2.3: Comparison of Stellar Population Synthesis Codes and Constraints from the Rest-frame NIR

    Muzzin, Adam; van Dokkum, Pieter G; Labbé, Ivo; Kriek, Mariska; Franx, Marijn

    2009-01-01

    We present SED modeling of a sample of 34 K-selected galaxies at z ~ 2.3. These galaxies have NIR spectroscopy that samples the rest-frame Balmer/4000A break as well as deep photometry in thirteen broadband filters. New to our analysis is IRAC data that extend the SEDs into the rest-frame NIR. Comparing parameters determined from SED fits with and without the IRAC data we find that the IRAC photometry significantly improves the confidence intervals of Tau, A_v, stellar mass, and SFR for individual galaxies, but does not systematically alter the mean parameters of the sample. We use the IRAC data to assess how well current stellar population synthesis codes describe the rest-frame NIR SEDs of young galaxies where discrepancies between treatments of the TP-AGB phase of stellar evolution are most pronounced. The models of Bruzual & Charlot (2003), Maraston (2005), and Charlot & Bruzual (2008) all successfully reproduce the SEDs of our galaxies with < 5% differences in the quality of fit; however, the ...

  18. The Atacama Cosmology Telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data

    We present a catalog of 68 galaxy clusters, of which 19 are new discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in the Atacama Cosmology Telescope (ACT) survey on the celestial equator. With this addition, the ACT collaboration has reported a total of 91 optically confirmed, SZ detected clusters. The 504 square degree survey region includes 270 square degrees of overlap with SDSS Stripe 82, permitting the confirmation of SZ cluster candidates in deep archival optical data. The subsample of 48 clusters within Stripe 82 is estimated to be 90% complete for M500c > 4.5 × 1014Msun and redshifts 0.15 500 = 5.'9 angular scale. This new approach incorporates the cluster redshift along with prior information on the cluster pressure profile to fix the relationship between the cluster characteristic size (R500) and the integrated Compton parameter (Y500). We adopt a one-parameter family of ''Universal Pressure Profiles'' (UPP) with associated scaling laws, derived from X-ray measurements of nearby clusters, as a baseline model. Three additional models of cluster physics are used to investigate a range of scaling relations beyond the UPP prescription. Assuming a concordance cosmology, the UPP scalings are found to be nearly identical to an adiabatic model, while a model incorporating non-thermal pressure better matches dynamical mass measurements and masses from the South Pole Telescope. A high signal to noise ratio subsample of 15 ACT clusters with complete optical follow-up is used to obtain cosmological constraints. We demonstrate, using fixed scaling relations, how the constraints depend on the assumed gas model if only SZ measurements are used, and show that constraints from SZ data are limited by uncertainty in the scaling relation parameters rather than sample size or measurement uncertainty. We next add in seven clusters from the ACT Southern survey, including their dynamical mass measurements, which are based on galaxy velocity dispersions and

  19. The Atacama Cosmology Telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data

    Hasselfield, Matthew; Hlozek, Renée [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Hilton, Matt [Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, 4041 (South Africa); Marriage, Tobias A.; Crichton, Devin; Gralla, Megan B. [Dept. of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Addison, Graeme E.; Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada); Barrientos, L. Felipe; Dünner, Rolando [Departamento de Astronomía y Astrofísica, Facultad de Física, Pontificía Universidad Católica, Casilla 306, Santiago 22 (Chile); Battaglia, Nicholas [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Battistelli, Elia S. [Department of Physics, University of Rome ' ' La Sapienza' ' , Piazzale Aldo Moro 5, I-00185 Rome (Italy); Bond, J. Richard; Hajian, Amir; Hincks, Adam D. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, M5S 3H8 (Canada); Das, Sudeep [High Energy Physics Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, IL 60439 (United States); Devlin, Mark J.; Dicker, Simon R. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Dunkley, Joanna [Department of Astrophysics, Oxford University, Oxford, OX1 3RH (United Kingdom); Fowler, Joseph W., E-mail: mhasse@astro.princeton.edu, E-mail: hiltonm@ukzn.ac.za, E-mail: marriage@pha.jhu.edu [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); and others

    2013-07-01

    We present a catalog of 68 galaxy clusters, of which 19 are new discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in the Atacama Cosmology Telescope (ACT) survey on the celestial equator. With this addition, the ACT collaboration has reported a total of 91 optically confirmed, SZ detected clusters. The 504 square degree survey region includes 270 square degrees of overlap with SDSS Stripe 82, permitting the confirmation of SZ cluster candidates in deep archival optical data. The subsample of 48 clusters within Stripe 82 is estimated to be 90% complete for M{sub 500c} > 4.5 × 10{sup 14}M{sub s}un and redshifts 0.15 < z < 0.8. While a full suite of matched filters is used to detect the clusters, the sample is studied further through a ''Profile Based Amplitude Analysis'' using a statistic derived from a single filter at a fixed θ{sub 500} = 5.'9 angular scale. This new approach incorporates the cluster redshift along with prior information on the cluster pressure profile to fix the relationship between the cluster characteristic size (R{sub 500}) and the integrated Compton parameter (Y{sub 500}). We adopt a one-parameter family of ''Universal Pressure Profiles'' (UPP) with associated scaling laws, derived from X-ray measurements of nearby clusters, as a baseline model. Three additional models of cluster physics are used to investigate a range of scaling relations beyond the UPP prescription. Assuming a concordance cosmology, the UPP scalings are found to be nearly identical to an adiabatic model, while a model incorporating non-thermal pressure better matches dynamical mass measurements and masses from the South Pole Telescope. A high signal to noise ratio subsample of 15 ACT clusters with complete optical follow-up is used to obtain cosmological constraints. We demonstrate, using fixed scaling relations, how the constraints depend on the assumed gas model if only SZ measurements are used, and

  20. An Examination of Biomedical Intellectual Reputation in Relationship to Graduates' Productivity, Regional Innovation and Absorptive Capacity at Selected Universities Worldwide

    Cavanaugh, Gesulla

    2014-01-01

    The purpose of this study was first to determine factors associated with intellectual reputation, specifically among selected biomedical departments worldwide within the university setting. Second, the study aimed to examine intellectual reputation in relationship to doctoral graduates' productivity in the biomedical sciences and in relationship…