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Sample records for extragalactic survey swire

  1. The SCUBA Half-Degree Extragalactic Survey (SHADES) - VIII. The Nature of Faint Submm Galaxies in SHADES, SWIRE and SXDF Surveys

    CERN Document Server

    Clements, D L; Babbedge, T; Oliver, S; Rowan-Robinson, M; Davoodi, P; Ivison, R; Farrah, D; Dunlop, J; Shupe, Dave; Waddington, I; Simpson, C; Furusawa, H; Serjeant, S; Afonso-Luis, A; Alexander, D M; Aretxaga, I; Blain, A; Borys, C; Chapman, S; Coppin, K; Dunne, L; Dye, S; Eales, S A; Evans, T; Fang, F; Frayer, D; Fox, M; Gear, W K; Greve, T R; Halpern, M; Hughes, D H; Jenness, T; Lonsdale, C J; Mortier, A M J; Page, M J; Pope, A; Priddey, R S; Rawlings, S; Savage, R S; Scott, D; Scott, S E; Sekiguchi, K; Smail, I; Smith, H E; Stevens, J A; Surace, J; Takagi, T; Van Kampen, E

    2008-01-01

    We present the optical-to-submm spectral energy distributions for 33 radio & mid-IR identified submillimetre galaxies discovered via the SHADES 850 micron SCUBA imaging in the Subaru-XMM Deep Field (SXDF). Optical data for the sources comes from the Subaru-XMM Deep Field (SXDF) and mid- and far-IR fluxes from SWIRE. We obtain photometric redshift estimates for our sources using optical and IRAC 3.6 and 4.5 micron fluxes. We then fit spectral energy distribution (SED) templates to the longer wavelength data to determine the nature of the far-IR emission that dominates the bolometric luminosity of these sources. The infrared template fits are also used to resolve ambiguous identifications and cases of redshift aliasing. The redshift distribution obtained broadly matches previous results for submm sources and on the SHADES SXDF field. Our template fitting finds that AGN, present in about 10% of sources, do not contribute significantly to their bolometric luminosity. Dust heating by starbursts, with either Ar...

  2. Photometric redshifts in the SWIRE Survey

    CERN Document Server

    Rowan-Robinson, Michael; Oliver, Seb; Trichas, Markos; Berta, Stefano; Lonsdale, Carol; Smith, Gene; Shupe, David; Surace, Jason; Arnouts, Stephane; LeFevre, Olivier; Afonso-Luis, Alejandro; Perez-Fournon, Ismael; Hatziminaoglou, Evanthia; Polletta, Maria; Farrah, Duncan; Vaccari, Mattia

    2008-01-01

    We present the SWIRE Photometric Redshift Catalogue, 1024750 redshifts of unprecedented reliability and accuracy. Our method is based on fixed galaxy and QSO templates applied to data at 0.36-4.5 mu, and on a set of 4 infrared emission templates fitted to infrared excess data at 3.6-170 mu. The code involves two passes through the data, to try to optimize recognition of AGN dust tori. A few carefully justified priors are used and are the key to supression of outliers. Extinction, A_V, is allowed as a free parameter. We use a set of 5982 spectroscopic redshifts, taken from the literature and from our own spectroscopic surveys, to analyze the performance of our method as a function of the number of photometric bands used in the solution and the reduced chi^2. For 7 photometric bands the rms value of (z_{phot}-z_{spec})/(1+z_{spec}) is 3.5%, and the percentage of catastrophic outliers is ~1%. We discuss the redshift distributions at 3.6 and 24 mu. In individual fields, structure in the redshift distribution corr...

  3. Extragalactic HI Surveys

    CERN Document Server

    Giovanelli, Riccardo

    2015-01-01

    We review the results of HI line surveys of extragalactic sources in the local Universe. In the last two decades major efforts have been made in establishing on firm statistical grounds the properties of the HI source population, the two most prominent being the HI Parkes All Sky Survey (HIPASS) and the Arecibo Legacy Fast ALFA survey (ALFALFA). We review the choices of technical parameters in the design and optimization of spectro-photometric "blind" HI surveys, which for the first time produced extensive HI-selected data sets. Particular attention is given to the relationship between optical and HI populations, the differences in their clustering properties and the importance of HI-selected samples in contributing to the understanding of apparent conflicts between observation and theory on the abundance of low mass halos. The last section of this paper provides an overview of currently ongoing and planned surveys which will explore the cosmic evolution of properties of the HI population.

  4. Keck spectroscopy of z=1-3 ULIRGs from the Spitzer SWIRE survey

    CERN Document Server

    Berta, S; Siana, B; Farrah, D; Smith, H E; Polletta, M; Franceschini, A; Fritz, J; Pérez-Fournon, I; Rowan-Robinson, M; Shupe, D; Surace, J

    2007-01-01

    (Abridged) High-redshift ultra luminous infrared galaxies contribute the bulk of the cosmic IR background and are the best candidates for very massive galaxies in formation at z>1.5. We present Keck/LRIS optical spectroscopy of 35 z>1.4 luminous IR galaxies in the Spitzer Wide-area Infra-Red Extragalactic survey (SWIRE) northern fields (Lockman Hole, ELAIS-N1, ELAIS-N2). The primary targets belong to the ``IR-peak'' class of galaxies, having the 1.6 micron (restframe) stellar feature detected in the IRAC Spitzer channels.The spectral energy distributions of the main targets are thoroughly analyzed, by means of spectro-photometric synthesis and multi-component fits (stars + starburst dust + AGN torus). The IR-peak selection technique is confirmed to successfully select objects above z=1.4, though some of the observed sources lie at lower redshift than expected. Among the 16 galaxies with spectroscopic redshift, 62% host an AGN component, two thirds being type-1 and one third type-2 objects. The selection, limi...

  5. Keck spectroscopy of z = 1-3 ULIRGs from the Spitzer SWIRE survey

    Science.gov (United States)

    Berta, S.; Lonsdale, C. J.; Siana, B.; Farrah, D.; Smith, H. E.; Polletta, M. C.; Franceschini, A.; Fritz, J.; Perez-Fournon, I.; Rowan-Robinson, M.; Shupe, D.; Surace, J.

    2007-05-01

    Context: High-redshift ultra luminous infrared galaxies contribute the bulk of the cosmic IR background and are the best candidates for very massive galaxies in formation at z>1.5. Aims: It is necessary to identify the energy source for their huge luminosities, starburst or AGN activity, in order to correctly interpret the role of ULIRGs in galaxy evolution, and compute reliable estimates of their star formation rates, stellar masses, and accretion luminosities. Methods: We present Keck/LRIS optical spectroscopy of 35 z≥1.4 luminous IR galaxies in the Spitzer Wide-area Infra-Red Extragalactic survey (SWIRE) northern fields (Lockman Hole, ELAIS-N1, ELAIS-N2). The primary targets belong to the "IR-peak" class of galaxies, having the 1.6 μm (restframe) stellar feature detected in the IRAC Spitzer channels. The spectral energy distributions of the main targets are thoroughly analyzed, by means of spectro-photometric synthesis and multi-component fits (stars + starburst dust + AGN torus). Results: The IR-peak selection technique is confirmed to successfully select objects above z=1.4, though some of the observed sources lie at lower redshift than expected. Among the 16 galaxies with spectroscopic redshift, 62% host an AGN component, two thirds being type-1 and one third type-2 objects. The selection, limited to r'1011 M_⊙) galaxies. The presence of an AGN component provides a plausible explanation for the spectroscopic/photometric redshift discrepancies, as the torus produces an apparent shift of the peak to longer wavelengths. These sources are analyzed in IRAC and optical-IR color spaces. In addition to the IR-peak galaxies, we present redshifts and spectral properties for 150 objects, out of a total of 301 sources on slits. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and made possible by the generous financial support of

  6. THE STAR FORMATION HISTORY OF BCGs TO z = 1.8 FROM THE SpARCS/SWIRE SURVEY: EVIDENCE FOR SIGNIFICANT IN SITU STAR FORMATION AT HIGH REDSHIFT

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Tracy M. A.; Bonaventura, Nina [McGill University, 3600 rue University, Montreal, QC H3A 2T8 (Canada); Muzzin, Adam [Leiden Observatory, University of Leiden, P.O. Box 9514, 2300 RA Leiden (Netherlands); Noble, Allison; Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Geach, James [Centre for Astrophysics Research, University of Hertfordshire, Hatfield, Hertfordshire AL109AB (United Kingdom); Hezevah, Yashar [Kavli Institue for Particle Physics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Lidman, Chris [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Wilson, Gillian [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Surace, Jason [Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States); Shupe, David [NASA Herschel Science Center, IPAC, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

    2015-12-01

    We present the results of an MIPS-24 μm study of the brightest cluster galaxies (BCGs) of 535 high-redshift galaxy clusters. The clusters are drawn from the Spitzer Adaptation of the Red-Sequence Cluster Survey, which effectively provides a sample selected on total stellar mass, over 0.2 < z < 1.8 within the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey fields. Twenty percent, or 106 clusters, have spectroscopically confirmed redshifts, and the rest have redshifts estimated from the color of their red sequence. A comparison with the public SWIRE images detects 125 individual BCGs at 24 μm ≳ 100 μJy, or 23%. The luminosity-limited detection rate of BCGs in similar richness clusters (N{sub gal} > 12) increases rapidly with redshift. Above z ∼ 1, an average of ∼20% of the sample have 24 μm inferred infrared luminosities of L{sub IR} > 10{sup 12} L{sub ⊙}, while the fraction below z ∼ 1 exhibiting such luminosities is <1%. The Spitzer-IRAC colors indicate the bulk of the 24 μm detected population is predominantly powered by star formation, with only 7/125 galaxies lying within the color region inhabited by active galactic nuclei (AGNs). Simple arguments limit the star formation activity to several hundred million years and this may therefore be indicative of the timescale for AGN feedback to halt the star formation. Below redshift z ∼ 1, there is not enough star formation to significantly contribute to the overall stellar mass of the BCG population, and therefore BCG growth is likely dominated by dry mergers. Above z ∼ 1, however, the inferred star formation would double the stellar mass of the BCGs and is comparable to the mass assembly predicted by simulations through dry mergers. We cannot yet constrain the process driving the star formation for the overall sample, though a single object studied in detail is consistent with a gas-rich merger.

  7. Parametric modelling of the 3.6um to 8um colour distributions of galaxies in the SWIRE Survey

    CERN Document Server

    Davoodi, P; Evans, T; Fang, F; Farrah, D; Gonzalez-Solares, E; Jarrett, T; Lonsdale, C; Oliver, S; Polletta, M C; Rowan-Robinson, M; Savage, R S; Shupe, D L; Siana, B; Smith, H E; Surace, J; Waddington, I; Xu, C K; Babbedge, Tom; Davoodi, Payam; Evans, Tracey; Fang, Fan; Farrah, Duncan; Gonzalez-Solares, Eduardo; Jarrett, Tom; Lonsdale, Carol; Oliver, Seb; Polletta, Maria del Carmen; Rowan-Robinson, Michael; Savage, Richard S.; Shupe, David L.; Siana, Brian; Smith, Harding E.; Surace, Jason; Waddington, Ian

    2006-01-01

    We fit a parametric model comprising a mixture of multi-dimensional Gaussian functions to the 3.6 to 8um colour and optical photo-z distribution of galaxy populations in the ELAIS-N1 and Lockman Fields of SWIRE. For 16,698 sources in ELAIS-N1 we find our data are best modelled (in the sense of the Bayesian Information Criterion) by the sum of four Gaussian distributions or modes (C_a, C_b, C_c and C_d). We compare the fit of our empirical model with predictions from existing semi-analytic and phenomological models. We infer that our empirical model provides a better description of the mid-infrared colour distribution of the SWIRE survey than these existing models. This colour distribution test is thus a powerful model discriminator and complementary to comparisons of number counts. We use our model to provide a galaxy classification scheme and explore the nature of the galaxies in the different modes of the model. C_a consists of dusty star-forming systems such as ULIRG's. Low redshift late-type spirals are f...

  8. The VISTA Deep Extragalactic Observations (VIDEO) Survey

    CERN Document Server

    Jarvis, Matt J; Bruce, V A; Geach, J E; McAlpine, K; McLure, R J; Gonzalez-Solares, E; Irwin, M; Lewis, J; Yoldas, A Kupcu; Andreon, S; Cross, N J G; Emerson, J P; Dalton, G; Dunlop, J S; Hodgkin, S T; Fevre, O Le; Karouzos, M; Meisenheimer, K; Oliver, S; Rawlings, S; Simpson, C; Smail, I; Smith, D J B; Sullivan, M; Sutherland, W; White, S V; Zwart, J T L

    2012-01-01

    In this paper we describe the first data release of the the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey. VIDEO is a ~12degree^2 survey in the near-infrared Z,Y,J,H and K_s bands, specifically designed to enable the evolution of galaxies and large structures to be traced as a function of both epoch and environment from the present day out to z=4, and active galactic nuclei (AGN) and the most massive galaxies up to and into the epoch of reionization. With its depth and area, VIDEO will be able to fully explore the period in the Universe where AGN and starburst activity were at their peak and the first galaxy clusters were beginning to virialize. VIDEO therefore offers a unique data set with which to investigate the interplay between AGN, starbursts and environment, and the role of feedback at a time when it was potentially most crucial. We provide data over the VIDEO-XMM3 tile, which also covers the Canada-France-Hawaii-Telescope Legacy Survey Deep-...

  9. The Spitzer Archival Far-InfraRed Extragalactic Survey

    CERN Document Server

    Hanish, D; Teplitz, H; Desai, V; Armus, L; Brinkworth, C; Brooke, T; Colbert, J; Edwards, L; Fadda, D; Frayer, D; Huynh, M; Lacy, M; Murphy, E; Noriega-Crespo, A; Paladini, R; Scarlata, C; Shenoy, S

    2015-01-01

    We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer Space Telescope. The SAFIRES products consist of far-infrared data in two wavelength bands (70 um and 160 um) across approximately 180 square degrees of sky, with source lists containing far-infrared fluxes for almost 40,000 extragalactic point sources. Thus, SAFIRES provides a large, robust archival far-infrared data set suitable for many scientific goals.

  10. THE SPITZER ARCHIVAL FAR-INFRARED EXTRAGALACTIC SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Hanish, D. J.; Capak, P.; Teplitz, H. I.; Desai, V.; Armus, L.; Brinkworth, C.; Brooke, T.; Colbert, J.; Fadda, D.; Noriega-Crespo, A.; Paladini, R. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 E California Blvd., Pasadena, CA 91125 (United States); Edwards, L. [Astronomy Department, 260 Whitney Avenue, Yale University, New Haven, CT 06511 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Huynh, M. [International Centre for Radio Astronomy Research, M468, University of Western Australia, Crawley, WA 6009 (Australia); Lacy, M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Murphy, E. [The Observatories of the Carnegie Institution for Science, CA 91101 (United States); Scarlata, C. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Shenoy, S., E-mail: danish@alumni.caltech.edu [Space Science Division, NASA Ames Research Center, M/S 245-6, Moffett Field, CA 94035 (United States)

    2015-03-15

    We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared (FIR) extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer Space Telescope. The SAFIRES products consist of FIR data in two wavelength bands (70 and 160 μm) across approximately 180 square degrees of sky, with source lists containing far-infrared fluxes for almost 40,000 extragalactic point sources. Thus, SAFIRES provides a large, robust archival far-infrared data set suitable for many scientific goals.

  11. HST LEGUS - Legacy Extragalactic UV Survey

    Science.gov (United States)

    Calzetti, Daniela; LEGUS Team

    2017-01-01

    LEGUS (Legacy ExtraGalactic UV Survey) is a cycle 21 Hubble Space Telescope Treasury program designed to provide a definite characterization of the links between star formation on two fundamental scales: those of individual stars, stellar clusters and associations on parsec scales, and of galaxy disks on kilo-parsec scales.In order to achieve this goal, LEGUS has obtained multi-color images of 50 nearby star-forming galaxies, in the distance range 3-16 Mpc. Wavelength coverage spans five bands (NUV, U, B, V, and I) by combining new WFC3 observations with archival ACS imaging data, when available. The galaxies were carefully selected to sample the full range of galaxy mass, morphology, star formation rate (SFR), sSFR (specific SFR=SFR/mass), metallicity, internal structure (rings, bars), and interaction state found in the Local Volume where HST can resolve and age-date young stellar populations on parsec scales. Many of the galaxies are well-known, iconic ones, with a wealth of additional information available in a number of archives. The multi-color HST images are being used to secure complete inventories of the young stars, star clusters, and structures of the galaxies, together with the characterization of their ages, masses, and extinctions.I will briefly introduce a few highlights on the scientific results obtained so far by the LEGUS team, in addition to describing the high-level science products the team plans to release to the community, in order to enable a wide range of additional scientific applications.

  12. Extragalactic radio continuum surveys and the transformation of radio astronomy

    Science.gov (United States)

    Norris, Ray P.

    2017-10-01

    Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide fresh insights for understanding the evolution of galaxies, measuring the evolution of the cosmic star-formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected phenomena. This Review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.

  13. The Wide Area VISTA Extra-galactic Survey (WAVES)

    CERN Document Server

    Driver, Simon P; Meyer, Martin; Power, Chris; Robotham, Aaron S G; Baldry, Ivan K; Liske, Jochen; Norberg, Peder

    2015-01-01

    The "Wide Area VISTA Extra-galactic Survey" (WAVES) is a 4MOST Consortium Design Reference Survey which will use the VISTA/4MOST facility to spectroscopically survey ~2million galaxies to $r_{\\rm AB} < 22$ mag. WAVES consists of two interlocking galaxy surveys ("WAVES-Deep" and "WAVES-Wide"), providing the next two steps beyond the highly successful 1M galaxy Sloan Digital Sky Survey and the 250k Galaxy And Mass Assembly survey. WAVES will enable an unprecedented study of the distribution and evolution of mass, energy, and structures extending from 1-kpc dwarf galaxies in the local void to the morphologies of 200-Mpc filaments at $z\\sim1$. A key aim of both surveys will be to compare comprehensive empirical observations of the spatial properties of galaxies, groups, and filaments, against state-of-the-art numerical simulations to distinguish between various Dark Matter models.

  14. An Extragalactic Spectroscopic Survey of the SSA22 Field

    CERN Document Server

    Saez, C; Bauer, F E; Stern, D; Gonzales, A; Rreza, I; Alexander, D M; Matsuda, Y; Geach, J E; Harrison, F A; Havashino, T

    2015-01-01

    We present VLT VIMOS, Keck DEIMOS and Keck LRIS multi-object spectra of 367 sources in the field of the z ~ 3.09 protocluster SSA22. Sources are spectroscopically classified via template matching, allowing new identifications for 206 extragalactic sources, including 36 z > 2 Lyman-break galaxies (LBGs) and Lyman-a emitters (LAEs), 8 protocluster members, and 94 X-ray sources from the ~ 400 ks Chandra deep survey of SSA22. Additionally, in the area covered by our study, we have increased by ~ 4, 13, and 6 times the number of reliable redshifts of sources at 1.0 3.4, and with X-Ray emission, respectively. We compare our results with past spectroscopic surveys of SSA22 to investigate the completeness of the LBGs and the X-Ray properties of the new spectroscopically-classified sources in the SSA22 field.

  15. The Arecibo Legacy Fast ALFA (ALFALFA) Extragalactic HI Survey

    CERN Document Server

    Haynes, Martha P

    2008-01-01

    The Arecibo Legacy Fast ALFA (ALFALFA) survey is a program aimed at obtaining a census of HI-bearing objects over a cosmologically significant volume of the local universe. When complete in ~3-4 years, it will cover 7000 square degrees of high latitude sky using the 305m telescope and the seven-beam Arecibo L-band feed array (ALFA). As of May 1, 2008, almost 60% of the required observations are complete and a catalog exists in preliminary form for 25% of the final sky area. ALFALFA is detecting about twice as many HI sources as predicted based on previously published HI mass functions and should deliver a final catalog of >25000 extragalactic HI sources. ALFALFA will detect hundreds of galaxies with HI masses less than 10**7.5 solar masses and similarly large numbers greater than 10**10.3 Msun. Its centroiding accuracy allows for the immediate identification of highly probably optical counterparts to each HI detection. Fewer than 3% of all extragalactic HI sources, and 10**9.5 Msun cannot be identified with ...

  16. The ESO-Spitzer Imaging extragalactic Survey (ESIS) II: VIMOS I,z wide field imaging of ELAIS-S1 and selection of distant massive galaxies

    CERN Document Server

    Berta, S; Franceschini, A; Held, E; Rizzi, L; Rodighiero, G; Cimatti, A; Dias, J E; Feruglio, C; La Franca, F; Lonsdale, C J; Maiolino, R; Matute, I; Rowan-Robinson, M; Sacchi, N; Zamorani, G

    2008-01-01

    (abridged) The ESIS survey is the optical follow up of the SWIRE/Spitzer in the ELAIS-S1 region of the sky. In the era of observational cosmology, the main efforts are focused on the study of galaxy evolution and its environmental dependence. Wide area, multiwavelength, extragalactic surveys are needed in order to probe sufficiently large volumes, minimize cosmic variance and find significant numbers of rare objects. We present VIMOS I and z band imaging belonging to the ESIS survey. A total of ~4 deg2 were targeted in I and ~1 deg2 in z. More than 300000 galaxies have been detected in the I band and ~50000 in the z band. Object coordinates are defined within an uncertainty of ~0.2 arcsec r.m.s., with respect to GSC 2.2. We reach a 90% average completeness at 23.1 and 22.5 mag (Vega) in the I and z bands, respectively. On the basis of IRAC colors, we identified galaxies having the 1.6 um stellar peak shifted to z=1-3. The new I, z band data provide reliable constraints to avoid low-redshift interlopers and re...

  17. The Herschel Multi-tiered Extragalactic Survey: HerMES

    CERN Document Server

    Oliver, S J; Altieri, B; Amblard, A; Arumugam, V; Aussel, H; Babbedge, T; Beelen, A; Béthermin, M; Blain, A; Boselli, A; Bridge, C; Brisbin, D; Buat, V; Burgarella, D; Castro-Rodríguez, N; Cava, A; Chanial, P; Cirasuolo, M; Clements, D L; Conley, A; Conversi, L; Cooray, A; Dowell, C D; Dubois, E N; Dwek, E; Dye, S; Eales, S; Elbaz, D; Farrah, D; Feltre, A; Ferrero, P; Fiolet, N; Fox, M; Franceschini, A; Gear, W; Giovannoli, E; Glenn, J; Gong, Y; Solares, E A González; Griffin, M; Halpern, M; Harwit, M; Hatziminaoglou, E; Heinis, S; Hurley, P; Hwang, H S; Hyde, A; Ibar, E; Ilbert, O; Isaak, K; Ivison, R J; Lagache, G; Floc'h, E Le; Levenson, L; Faro, B Lo; Lu, N; Madden, S; Maffei, B; Magdis, G; Mainetti, G; Marchetti, L; Marsden, G; Marshall, J; Mortier, A M J; Nguyen, H T; O'Halloran, B; Omont, A; Page, M J; Panuzzo, P; Papageorgiou, A; Patel, H; Pearson, C P; Pérez-Fournon, I; Pohlen, M; Rawlings, J I; Raymond, G; Rigopoulou, D; Riguccini, L; Rizzo, D; Rodighiero, G; Roseboom, I G; Rowan-Robinson, M; Portal, M Sánchez; Schulz, B; Scott, Douglas; Seymour, N; Shupe, D L; Smith, A J; Stevens, J A; Symeonidis, M; Trichas, M; Tugwell, K E; Vaccari, M; Valtchanov, I; Vieira, J D; Viero, M; Vigroux, L; Wang, L; Ward, R; Wardlow, J; Wright, G; Xu, C K; Zemcov, M

    2012-01-01

    The Herschel Multi-tiered Extragalactic Survey, HerMES, is a legacy program designed to map a set of nested fields totalling ~380 deg^2. Fields range in size from 0.01 to ~20 deg^2, using Herschel-SPIRE (at 250, 350 and 500 \\mu m), and Herschel-PACS (at 100 and 160 \\mu m), with an additional wider component of 270 deg^2 with SPIRE alone. These bands cover the peak of the redshifted thermal spectral energy distribution from interstellar dust and thus capture the re-processed optical and ultra-violet radiation from star formation that has been absorbed by dust, and are critical for forming a complete multi-wavelength understanding of galaxy formation and evolution. The survey will detect of order 100,000 galaxies at 5\\sigma in some of the best studied fields in the sky. Additionally, HerMES is closely coordinated with the PACS Evolutionary Probe survey. Making maximum use of the full spectrum of ancillary data, from radio to X-ray wavelengths, it is designed to: facilitate redshift determination; rapidly identi...

  18. Legacy Extragalactic UV Survey (LEGUS) With the Hubble Space Telescope. I. Survey Description

    NARCIS (Netherlands)

    Calzetti, D.; Lee, J.C.; Sabbi, E.; Adamo, A.; Smith, L.J.; Andrews, J.E.; Ubeda, L.; Bright, S.N.; Thilker, D.; Aloisi, A.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; da Silva, R.; de Mink, S.E.; Dobbs, C.; Elmegreen, B.G.; Elmegreen, D.M.; Evans, A.S.; Fumagalli, M.; Gallagher III, J.S.; Gouliermis, D.A.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Kim, H.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nair, P.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Ryon, J.E.; Schaerer, D.; Schiminovich, D.; Tosi, M.; Van Dyk, S.D.; Walterbos, R.; Whitmore, B.C.; Wofford, A.

    2015-01-01

    The Legacy ExtraGalactic UV Survey (LEGUS) is a Cycle 21 Treasury program on the Hubble Space Telescope aimed at the investigation of star formation and its relation with galactic environment in nearby galaxies, from the scales of individual stars to those of ~kiloparsec-size clustered structures.

  19. Legacy Extragalactic UV Survey (LEGUS) With the Hubble Space Telescope. I. Survey Description

    NARCIS (Netherlands)

    Calzetti, D.; Lee, J.C.; Sabbi, E.; Adamo, A.; Smith, L.J.; Andrews, J.E.; Ubeda, L.; Bright, S.N.; Thilker, D.; Aloisi, A.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; da Silva, R.; de Mink, S.E.; Dobbs, C.; Elmegreen, B.G.; Elmegreen, D.M.; Evans, A.S.; Fumagalli, M.; Gallagher III, J.S.; Gouliermis, D.A.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Kim, H.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nair, P.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Ryon, J.E.; Schaerer, D.; Schiminovich, D.; Tosi, M.; Van Dyk, S.D.; Walterbos, R.; Whitmore, B.C.; Wofford, A.

    2015-01-01

    The Legacy ExtraGalactic UV Survey (LEGUS) is a Cycle 21 Treasury program on the Hubble Space Telescope aimed at the investigation of star formation and its relation with galactic environment in nearby galaxies, from the scales of individual stars to those of ~kiloparsec-size clustered structures. F

  20. NED in the Era of Very Large Extragalactic Surveys

    Science.gov (United States)

    Fadda, Dario; Mazzarella, J. M.; Ogle, P. M.; Madore, B. F.; Ebert, R.; Baker, K.; Chan, H.; Chen, X.; Frayer, C.; Helou, G.; Jacobson, J. D.; LaGue, C.; Lo, T. M.; Pevunova, O.; Schmitz, M.; Terek, S.; Steer, I.

    2014-01-01

    The NASA/IPAC Extragalactic Database (NED) is in the process of rapid expansion both from the growth of the astrophysics literature and from very large sky surveys containing hundreds of millions of objects. Over the last year alone, over 3 million objects from more than 5 thousand journal articles have been folded into NED. In the same time period, approximately 60 million UV sources from the GALEX All-Sky Survey and Medium Imaging Survey catalogs have been fully integrated into the database. A new data processing approach has been developed to fold in very large catalogs. Firstly, a new NED layer is created to contain the entries from a catalog. Subsequently, the new entries are cross-matched with existent NED objects following a rule-based statistical approach. This new layer currently contains approximately 500 million near-infrared sources from the 2MASS Point Source Catalog. In future releases, we expect to fully integrate this catalog while loading a new layer of hundreds of millions of sources from the new All-WISE survey. To make accessible this wealth of new data, NED is undergoing a major user interface upgrade. As a result of a "near-position" search, the new interface is able to display sources from very large catalogs which have not yet been cross-matched with other NED objects. Navigation and searches have been simplified and enriched. For instance, the "by-parameters" search has been completely revamped and long searches are now queued and executed in the background. The latest release includes a new tool to explore galaxy environments and a guide for authors documenting the best practices to publish data in the major astrophysical journals. Researchers are encouraged to visit the NED exhibit for a demonstration of these and other new capabilities.

  1. Uncovering hidden black holes with extragalactic X-ray surveys

    Science.gov (United States)

    Hickox, Ryan C.

    2017-08-01

    Despite remarkable progress over the past decades, our picture of black hole evolution has remained incomplete due to the challenges of detecting the mysterious "elusive" AGN that are highly obscured or hidden beneath the light of their host galaxies. I will present recent studies by our group and colleagues that use X-ray and multiwavelength extragalactic surveys (particularly with Chandra, NuSTAR, and WISE) to uncover the full population of AGN. Including these elusive AGN in our picture has helped illustrate that AGN accretion is a surprisingly universal, yet highly stochastic process, and has shown that AGN obscuration is linked to processes in galaxy evolution. I will conclude by forecasting the exciting science in this area that will be enabled by future observatories including the Lynx concept X-ray mission. This work is supported by the National Science Foundation through grant numbers 1515404 and 1554584, and NASA through grant numbers NNX15AP24G, NNX15AU32H, and NNX16AN48G.

  2. The North Ecliptic Pole Extragalactic Background LIght Fluctuations Survey

    Science.gov (United States)

    Bock, James; Zemcov, Michael; Cooray, Asantha; Smidt, Joseph; Serjeant, Stephen; Malkan, Matt; Matsuhara, Hideo; Matsumoto, Toshia; Matsuura, Shuji; Clements, David; Pearson, Chris; Im, Myung Shin

    2013-10-01

    We propose to image 6 deg^2 in the North Ecliptic Pole (NEP) with IRAC to determine the origin of Extragalactic Background Light (EBL) fluctuations. These Spitzer images will be combined with CIBER data at 1.1 and 1.6 um, and Akari data at 2.4, 3.2, and 4.1 um, to probe the spectrum and band-to-band correlations of the fluctuations. The fluctuations have been reported by Spitzer and Akari, and are now positively detected in new and CIBER data, but their origin is controversial. This multi-wavelength analysis will allow us to determine if EBL fluctuations arise from epoch of reionization galaxies or diffuse intra-halo light emission both by measuring their spectral energy distribution (SED) from 1.0 to 4.5 um, and by measuring the cross-correlation between different bands. The analysis uses multiple field combinations in Spitzer, CIBER and Akari data to carry out a robust measurement with multiple data combinations for internal consistency tests. In addition, the proposed survey will be used in conjunction with Akari and Herschel data in the NEP survey that has the most comprehensive multi-band infrared coverage of any degree-scale field on the sky and the best available constraints on dust phases (e.g. PAH, silicate absorption, AGN dust tori, GMCs) in galaxies. We will use this multi-wavelength coverage to cross-identify IRAC counterparts to Herschel and Akari sources and obtain SEDs of dusty, star bursting galaxies at z ~ 1 to 3 from the UV to radio, and obtain accurate PAH luminosities of Akari 7.7 um-rest detected galaxies and AGNs.

  3. The VVDS-SWIRE-GALEX-CFHTLS surveys: Physical properties of galaxies at z below 1.2 from photometric data

    CERN Document Server

    Walcher, C J; Vergani, D; Arnouts, S; Buat, V; Charlot, S; Tresse, L; Le Fèvre, O; Bolzonella, M; Brinchmann, J; Pozzetti, L; Zamorani, G; Bottini, D; Garilli, B; Le Brun, V; MacCagni, D; Milliard, B; Scaramella, R; Scodeggio, M; Vettolani, G; Zanichelli, A; Adami, C; Bardelli, S; Cappi, A; Ciliegi, P; Contini, T; Franzetti, P; Foucaud, S; Gavignaud, I; Guzzo, L; Ilbert, O; Iovino, A; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Radovich, M; Zucca, E; Lonsdale, C; Martin, D C

    2008-01-01

    We intend to show that it is possible to derive the physical parameters of galaxies from their broad-band spectral energy distribution out to a redshift of 1.2. This method has the potential to yield the physical parameters of all galaxies in a single field in a homogeneous way. We use an extensive dataset, assembled in the context of the VVDS survey, which reaches from the UV to the IR and covers a sample of 84073 galaxies over an area of 0.89 deg$^2$. We also use a library of 100000 model galaxies with a large variety of star formation histories (in particular including late bursts of star formation). We find that we can determine the physical parameters stellar mass, age and star formation rate with good confidence. We validate the star formation rate determinations in particular by comparing it to a sample of spectroscopically observed galaxies with an emission line measurement. We use our sample to build the number density function of galaxies as a function of stellar mass, specific star formation rate a...

  4. HELP-ing Extragalactic Surveys : The Herschel Extragalactic Legacy Project and the Coming of Age of Multi-Wavelength Astrophysics

    Science.gov (United States)

    Vaccari, M.

    2015-06-01

    How did galaxies form and evolve? This is one of the most challenging questions in astronomy to- day. Answering it requires a careful combination of observational and theoretical work to reliably determine the observed properties of cosmic bodies over large portions of the distant Universe on the one hand, and accurately model the physical processes driving their evolution on the other. Most importantly, it requires bringing together disparate multi-wavelength and multi-resolution spectro-photometric datasets in an homogeneous and well-characterized manner so that they are suitable for a rigorous statistical analysis. The Herschel Extragalactic Legacy Project (HELP) funded by the EC FP7 SPACE program aims to achieve this goal by combining the expertise of optical, infrared and radio astronomers to provide a multi-wavelength database for the dis- tant Universe as an accessible value-added resource for the astronomical community. It will do so by bringing together multi-wavelength datasets covering the 1000 deg2 mapped by Herschel extragalactic surveys and thus creating a joint lasting legacy from several ambitious sky surveys.

  5. The Spitzer Extragalactic Representative Volume Survey (SERVS): survey definition and goals

    CERN Document Server

    Mauduit, J -C; Farrah, D; Surace, J A; Jarvis, M; Oliver, S; Maraston, C; Vaccari, M; Marchetti, L; Zeimann, G; Gonzalez-Solares, E A; Pforr, J; Petric, A O; Henriques, B; Thomas, P A; Afonso, J; Rettura, A; Wilson, G; Falder, J T; Geach, J E; Huynh, M; Norris, R P; Seymour, N; Richards, G T; Stanford, S A; Alexander, D M; Becker, R H; Best, P N; Bizzocchi, L; Bonfield, D; Castro, N; Cava, A; Chapman, S; Christopher, N; Clements, D L; Covone, G; Dubois, N; Dunlop, J S; Dyke, E; Edge, A; Ferguson, H C; Foucaud, S; Franceschini, A; Gal, R R; Grant, J K; Grossi, M; Hatziminaoglou, E; Hickey, S; Hodge, J A; Huang, J -S; Ivison, R J; Kim, M; LeFevre, O; Lehnert, M; Lonsdale, C J; Lubin, L M; McLure, R J; Messias, H; Martinez-Sansigre, A; Mortier, A M J; Nielsen, D M; Ouchi, M; Parish, G; Perez-Fournon, I; Pierre, M; Rawlings, S; Readhead, A; Ridgway, S E; Rigopoulou, D; Romer, A K; Rosebloom, I G; Rottgering, H J A; Rowan-Robinson, M; Sajina, A; Simpson, C J; Smail, I; Squires, G K; Stevens, J A; Taylor, R; Trichas, M; Urrutia, T; van Kampen, E; Verma, A; Xu, C K

    2012-01-01

    We present the Spitzer Extragalactic Representative Volume Survey (SERVS), an 18 square degrees medium-deep survey at 3.6 and 4.5 microns with the post-cryogenic Spitzer Space Telescope to ~2 microJy (AB=23.1) depth of five highly observed astronomical fields (ELAIS-N1, ELAIS-S1, Lockman Hole, Chandra Deep Field South and XMM-LSS). SERVS is designed to enable the study of galaxy evolution as a function of environment from z~5 to the present day, and is the first extragalactic survey both large enough and deep enough to put rare objects such as luminous quasars and galaxy clusters at z>1 into their cosmological context. SERVS is designed to overlap with several key surveys at optical, near- through far-infrared, submillimeter and radio wavelengths to provide an unprecedented view of the formation and evolution of massive galaxies. In this paper, we discuss the SERVS survey design, the data processing flow from image reduction and mosaicing to catalogs, as well as coverage of ancillary data from other surveys i...

  6. GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue

    CERN Document Server

    Hurley-Walker, Natasha; Hancock, Paul J; Franzen, Thomas M O; Hindson, Luke; Kapinska, Anna D; Morgan, John; Offringa, Andre R; Wayth, Randall B; Wu, Chen; Zheng, Q; Murphy, Tara; Bell, Martin E; Dwarakanath, K S; For, Bi-Qing; Gaensler, Bryan M; Johnston-Hollitt, Melanie; Lenc, Emil; Procopio, Pietro; Staveley-Smith, Lister; Ekers, Ron; Bowman, Judd D; Briggs, Frank; Cappallo, R J; Deshpande, Avinash A; Greenhill, Lincoln; Hazelton, Brynah J; Kaplan, David L; Lonsdale, Colin J; McWhirter, S R; Mitchell, Daniel A; Morales, Miguel F; Morgan, Edward; Oberoi, Divya; Ord, Stephen M; Prabu, T; Shankar, N Udaya; Srivani, K S; Subrahmanyan, Ravi; Tingay, Steven J; Webster, Rachel L; Williams, Andrew; Williams, Christopher L

    2016-01-01

    Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array (SKA1 LOW) precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalogue, utilising the first year of observations. The catalogue covers 24,831 square degrees, over declinations south of $+30^\\circ$ and Galactic latitudes outside $10^\\circ$ of the Galactic plane, excluding some areas such as the Magellanic Clouds. It contains 307,455 radio sources with 20 separate flux density measurements across 72--231MHz, selected from a time- and frequency- integrated image centred at 200MHz, with a resolution of $\\approx 2$'. Over the catalogued region, we estimate that the catalogue is 90% complete at 170mJy, and 50% complete at 55mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97% above the detection threshold of $5\\sigma$, which itself is typically 50mJy. These observations constitute the w...

  7. GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue

    Science.gov (United States)

    Hurley-Walker, N.; Callingham, J. R.; Hancock, P. J.; Franzen, T. M. O.; Hindson, L.; Kapińska, A. D.; Morgan, J.; Offringa, A. R.; Wayth, R. B.; Wu, C.; Zheng, Q.; Murphy, T.; Bell, M. E.; Dwarakanath, K. S.; For, B.; Gaensler, B. M.; Johnston-Hollitt, M.; Lenc, E.; Procopio, P.; Staveley-Smith, L.; Ekers, R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Greenhill, L.; Hazelton, B. J.; Kaplan, D. L.; Lonsdale, C. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Webster, R. L.; Williams, A.; Williams, C. L.

    2017-01-01

    Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalogue, utilizing the first year of observations. The catalogue covers 24 831 square degrees, over declinations south of +30° and Galactic latitudes outside 10° of the Galactic plane, excluding some areas such as the Magellanic Clouds. It contains 307 455 radio sources with 20 separate flux density measurements across 72-231 MHz, selected from a time- and frequency-integrated image centred at 200 MHz, with a resolution of ≈2 arcmin. Over the catalogued region, we estimate that the catalogue is 90 per cent complete at 170 mJy, and 50 per cent complete at 55 mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97 per cent above the detection threshold of 5σ, which itself is typically 50 mJy. These observations constitute the widest fractional bandwidth and largest sky area survey at radio frequencies to date, and calibrate the low-frequency flux density scale of the southern sky to better than 10 per cent. This paper presents details of the flagging, imaging, mosaicking and source extraction/characterization, as well as estimates of the completeness and reliability. All source measurements and images are available online.1 This is the first in a series of publications describing the GLEAM survey results.

  8. DISCOVERY OF A METER-WAVELENGTH RADIO TRANSIENT IN THE SWIRE DEEP FIELD: 1046+59

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, T. R.; Kassim, N. E. [US Naval Research Laboratory, Code 7213, Washington, DC 20375 (United States); Hyman, S. D. [Department of Physics and Engineering, Sweet Briar College, Sweet Briar, VA 24595 (United States); Lazio, T. J. W., E-mail: ted.jaeger.ctr@nrl.navy.mill [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91106 (United States)

    2012-04-15

    We report the results of a low frequency radio variability and slow transient search using archival observations from the Very Long Array. We selected six 325 MHz radio observations from the spring of 2006, each centered on the Spitzer-Space-Telescope Wide-area Infrared Extragalactic Survey (SWIRE) Deep Field: 1046+59. Observations were spaced between one day to three months, with a typical single-epoch peak flux sensitivity below 0.2 mJy beam{sup -1} near the field pointing center. We describe the observation parameters, data post-processing, and search methodology used to identify variable and transient emission. Our search revealed multiple variable sources and the presence of one, day-scale transient event with no apparent astronomical counterpart. This detection implies a transient rate of 1 {+-} 1 event per 6.5 deg{sup 2} per 72 observing hours in the direction of 1046+59 and an isotropic transient surface density {Sigma} = 0.12 deg{sup -2}at 95% confidence for sources with average peak flux density higher than 2.1 mJy over 12 hr.

  9. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    NARCIS (Netherlands)

    Grogin, Norman A.; Kocevski, Dale D.; Faber, S. M.; Ferguson, Henry C.; Koekemoer, Anton M.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Castellano, Marco; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dahlen, Tomas; Dave, Romeel; de Mello, Duilia F.; Dekel, Avishai; Dickinson, Mark; Dolch, Timothy; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Fontana, Adriano; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Haeussler, Boris; Hopkins, Philip F.; Huang, Jia-Sheng; Huang, Kuang-Han; Jha, Saurabh W.; Kartaltepe, Jeyhan S.; Kirshner, Robert P.; Koo, David C.; Lai, Kamson; Lee, Kyoung-Soo; Li, Weidong; Lotz, Jennifer M.; Lucas, Ray A.; Madau, Piero; McCarthy, Patrick J.; McGrath, Elizabeth J.; McIntosh, Daniel H.; McLure, Ross J.; Mobasher, Bahram; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Niemi, Sami-Matias; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Rajan, Abhijith; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rodney, Steven A.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Strolger, Louis-Gregory; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; van der Wel, Arjen; Villforth, Carolin; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yan, Hao-Jing; Yun, Min S.

    2011-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the

  10. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    NARCIS (Netherlands)

    Grogin, Norman A.; Kocevski, Dale D.; Faber, S. M.; Ferguson, Henry C.; Koekemoer, Anton M.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Castellano, Marco; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dahlen, Tomas; Dave, Romeel; de Mello, Duilia F.; Dekel, Avishai; Dickinson, Mark; Dolch, Timothy; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Fontana, Adriano; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Haeussler, Boris; Hopkins, Philip F.; Huang, Jia-Sheng; Huang, Kuang-Han; Jha, Saurabh W.; Kartaltepe, Jeyhan S.; Kirshner, Robert P.; Koo, David C.; Lai, Kamson; Lee, Kyoung-Soo; Li, Weidong; Lotz, Jennifer M.; Lucas, Ray A.; Madau, Piero; McCarthy, Patrick J.; McGrath, Elizabeth J.; McIntosh, Daniel H.; McLure, Ross J.; Mobasher, Bahram; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Niemi, Sami-Matias; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Rajan, Abhijith; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rodney, Steven A.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Strolger, Louis-Gregory; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; van der Wel, Arjen; Villforth, Carolin; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yan, Hao-Jing; Yun, Min S.

    2011-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-

  11. A Survey of HC3N in Extragalactic Sources - Is HC3N a Tracer of Activity in ULIRGs?

    DEFF Research Database (Denmark)

    Lindberg, Karl Johan Erik; Aalto, S.; Costagliola, F.;

    2011-01-01

    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections, and ...

  12. A survey of HC3N in extragalactic sources Is HC3N a tracer of activity in ULIRGs?

    NARCIS (Netherlands)

    Lindberg, J. E.; Aalto, S.; Costagliola, F.; Perez-Beaupuits, J. -P.; Monje, R.; Muller, S.

    2011-01-01

    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections, and to

  13. A survey of the Milagro Sky for extragalactic TeV sources

    Science.gov (United States)

    Barber, Ahron; Linnemann, James

    2010-10-01

    I am presenting the results from a survey of the Milagro sky map for extragalactic sources corresponding to locations of extragalactic objects from three different lists of TeV emitting objects: Fermi Bright Source List (3 month), TeVCat Catalog, and a list of objects from the VERITAS Blazar Key Science Project. Between the 3 lists, there are a total of 123 independent candidate sources to survey in the Milagro Sky. My analysis of these lists uses the False Discovery Rate Method (FDR) used previously by Milagro to analyze the galactic plane region of the Milagro sky map (Abdo et al., AJL 2009). The result from searching these lists found that only one source, Markarian 421, is detected by Milagro. Two other sources, Mrk 501 and IES 0502 +675, have a statistical significance near, but below, the boundary selected by FDR for these data. However, it is not evident that they are actually detected from the FDR analysis.

  14. Legacy ExtraGalactic UV Survey (LEGUS) with The Hubble Space Telescope. I. Survey Description

    CERN Document Server

    Calzetti, D; Sabbi, E; Adamo, A; Smith, L J; Andrews, J E; Ubeda, L; Bright, S N; Thilker, D; Aloisi, A; Brown, T M; Chandar, R; Christian, C; Cignoni, M; Clayton, G C; da Silva, R; de Mink, S E; Dobbs, C; Elmegreen, B G; Elmegreen, D M; Evans, A S; Fumagalli, M; Gallagher, J S; Gouliermis, D A; Grebel, E K; Herrero, A; Hunter, D A; Johnson, K E; Kennicutt, R C; Kim, H; Krumholz, M R; Lennon, D; Levay, K; Martin, C; Nair, P; Nota, A; Oestlin, G; Pellerin, A; Prieto, J; Regan, M W; Ryon, J E; Schaerer, D; Schiminovich, D; Tosi, M; Van Dyk, S D; Walterbos, R; Whitmore, B C; Wofford, A; .,

    2014-01-01

    The Legacy ExtraGalactic UV Survey (LEGUS) is a Cycle 21 Treasury program on the Hubble Space Telescope, aimed at the investigation of star formation and its relation with galactic environment in nearby galaxies, from the scales of individual stars to those of ~kpc-size clustered structures. Five-band imaging, from the near-ultraviolet to the I-band, with the Wide Field Camera 3, plus parallel optical imaging with the Advanced Camera for Surveys, is being collected for selected pointings of 50 galaxies within the local 12 Mpc. The filters used for the observations with the Wide Field Camera 3 are: F275W(2,704 A), F336W(3,355 A), F438W(4,325 A), F555W(5,308 A), and F814W(8,024 A); the parallel observations with the Advanced Camera for Surveys use the filters: F435W(4,328 A), F606W(5,921 A), and F814W(8,057 A). The multi-band images are yielding accurate recent (<~50 Myr) star formation histories from resolved massive stars and the extinction-corrected ages and masses of star clusters and associations. The e...

  15. Extragalactic radio surveys in the pre-Square Kilometre Array era

    Science.gov (United States)

    Simpson, Chris

    2017-07-01

    The era of the Square Kilometre Array is almost upon us, and pathfinder telescopes are already in operation. This brief review summarizes our current knowledge of extragalactic radio sources, accumulated through six decades of continuum surveys at the low-frequency end of the electromagnetic spectrum and the extensive complementary observations at other wavelengths necessary to gain this understanding. The relationships between radio survey data and surveys at other wavelengths are discussed. Some of the outstanding questions are identified and prospects over the next few years are outlined.

  16. Galaxy Counts at 24 Microns in the SWIRE Fields

    CERN Document Server

    Shupe, David L; Lonsdale, Carol J; Masci, Frank; Evans, Tracey; Fang, Fan; Oliver, Sebastian; Vaccari, Mattia; Rodighiero, Giulia; Padgett, Deborah; Surace, Jason A; Xu, C Kevin; Berta, Stefano; Pozzi, Francesca; Franceschini, Alberto; Babbedge, Thomas; Gonzales-Solares, Eduardo; Siana, Brian D; Farrah, Duncan; Frayer, David T; Smith, H E; Polletta, Maria; Owen, Frazer; Perez-Fournon, Ismael

    2007-01-01

    This paper presents galaxy source counts at 24 microns in the six Spitzer Wide-field InfraRed Extragalactic (SWIRE) fields. The source counts are compared to counts in other fields, and to model predictions that have been updated since the launch of Spitzer. This analysis confirms a very steep rise in the Euclidean-normalized differential number counts between 2 mJy and 0.3 mJy. Variations in the counts between fields show the effects of sample variance in the flux range 0.5-10 mJy, up to 100% larger than Poisson errors. Nonetheless, a "shoulder" in the normalized counts persists at around 3 mJy. The peak of the normalized counts at 0.3 mJy is higher and narrower than most models predict. In the ELAIS N1 field, the 24 micron data are combined with Spitzer-IRAC data and five-band optical imaging, and these bandmerged data are fit with photometric redshift templates. Above 1 mJy the counts are dominated by galaxies at z less than 0.3. By 300 microJy, about 25% are between z ~ 0.3-0.8, and a significant fraction...

  17. INTEGRAL/IBIS deep extragalactic survey: M81, LMC and 3C 273/Coma fields

    CERN Document Server

    Mereminskiy, Ilya A; Lutovinov, Alexander A; Sazonov, Sergey Yu; Revnivtsev, Mikhail G; Sunyaev, Rashid A

    2016-01-01

    We present results of deep surveys of three extragalactic fields, M81 (exposure of 9.7 Ms), LMC (6.8 Ms) and 3C 273/Coma (9.3 Ms), in the hard X-ray (17-60 keV) energy band with the IBIS telescope onboard the INTEGRAL observatory, based on 12 years of observations (2003-2015). The combined survey reaches a $4\\sigma$ peak sensitivity of 0.18 mCrab (2.6$\\times$10$^{-12}$ erg s$^{-1}$ cm$^{-2}$) and sensitivity better than 0.25 and 0.87 mCrab over 10% and 90% of its full area of 4900 deg$^{2}$, respectively. We have detected in total 147 sources at $S/N>4\\sigma$, including 37 sources observed in hard X-rays for the first time. The survey is dominated by extragalactic sources, mostly by active galactic nuclei (AGN). The sample of identified sources contains 98 AGN (including 64 Seyfert galaxies, 7 LINERs, 3 XBONGs, 16 blazars and 8 AGN of unclear optical class), two galaxy clusters (Coma and Abell 3266), 17 objects located in the Large and Small Magellanic Clouds (13 high- and 2 low-mass X-ray binaries and 2 X-ra...

  18. CANDELS: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey

    Science.gov (United States)

    Grogin, Norman A.; Koekemoer, anton M.; Faber, S. M.; Ferguson, Henry C.; Kocevski, Dale D.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; DeMello, Duilla; Gardner, Jonathan P.; Straughn, Amber N.

    2011-01-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.

  19. The NuSTAR Extragalactic Surveys: Overview And Catalog From The Cosmos Field

    DEFF Research Database (Denmark)

    Civano, F.; Hickox, R. C.; Puccetti, S.

    2015-01-01

    To provide the census of the sources contributing to the X-ray background peak above 10 keV, Nuclear Spectroscopic Telescope Array (NuSTAR) is performing extragalactic surveys using a three-tier "wedding cake" approach. We present the NuSTAR survey of the COSMOS field, the medium sensitivity...

  20. The Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole field

    CERN Document Server

    Baronchelli, I; Rodighiero, G; Franceschini, A; Capak, P L; Mei, S; Vaccari, M; Marchetti, L; Hibon, P; Sedgwick, C; Pearson, C; Serjeant, S; Menèndez-Delmestre, K; Salvato, M; Malkan, M; Teplitz, H I; Hayes, M; Colbert, J; Papovich, C; Devlin, M; Kovacs, A; Scott, K S; Surace, J; Kirkpatrick, J D; Atek, H; Urrutia, T; Scoville, N Z; Takeuchi, T T

    2016-01-01

    We present the Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole (SEP) field. The large area covered (7.7 deg$^2$), together with one of the lowest Galactic cirrus emissions in the entire sky and a very extensive coverage by Spitzer, Herschel, Akari, and GALEX, make the SIMES field ideal for extragalactic studies. The elongated geometry of the SIMES area ($\\approx$4:1), allowing for a significant cosmic variance reduction, further improves the quality of statistical studies in this field. Here we present the reduction and photometric measurements of the Spitzer/IRAC data. The survey reaches a depth of 1.93 and 1.75 $\\mu$Jy (1$\\sigma$) at 3.6 and 4.5 $\\mu$m, respectively. We discuss the multiwavelength IRAC--based catalog, completed with optical, mid-- and far--IR observations. We detect 341,000 sources with F$_{3.6\\mu m} \\geq 3\\sigma$. Of these, 10% have an associated 24 $\\mu$m counterpart, while 2.7% have an associated SPIRE source. We release the catalog through the NASA/IPAC Infrare...

  1. The Spitzer-IRAC/MIPS Extragalactic Survey (SIMES) in the South Ecliptic Pole Field

    Science.gov (United States)

    Baronchelli, I.; Scarlata, C.; Rodighiero, G.; Franceschini, A.; Capak, P. L.; Mei, S.; Vaccari, M.; Marchetti, L.; Hibon, P.; Sedgwick, C.; Pearson, C.; Serjeant, S.; Menéndez-Delmestre, K.; Salvato, M.; Malkan, M.; Teplitz, H. I.; Hayes, M.; Colbert, J.; Papovich, C.; Devlin, M.; Kovacs, A.; Scott, K. S.; Surace, J.; Kirkpatrick, J. D.; Atek, H.; Urrutia, T.; Scoville, N. Z.; Takeuchi, T. T.

    2016-03-01

    We present the Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole field. The large area covered (7.7 deg2), together with one of the lowest Galactic cirrus emissions in the entire sky and a very extensive coverage by Spitzer, Herschel, Akari, and GALEX, make the SIMES field ideal for extragalactic studies. The elongated geometry of the SIMES area (≈4:1), allowing for significant cosmic variance reduction, further improves the quality of statistical studies in this field. Here we present the reduction and photometric measurements of the Spitzer/IRAC data. The survey reaches depths of 1.93 and 1.75 μJy (1σ) at 3.6 and 4.5 μm, respectively. We discuss the multiwavelength IRAC-based catalog, completed with optical, mid-, and far-IR observations. We detect 341,000 sources with {F}3.6μ {{m}}≥slant 3σ . Of these, 10% have an associated 24 μm counterpart, while 2.7% have an associated SPIRE source. We release the catalog through the NASA/IPAC Infrared Science Archive. Two scientific applications of these IRAC data are presented in this paper. First, we compute integral number counts at 3.6 μm. Second, we use the [3.6]-[4.5] color index to identify galaxy clusters at z > 1.3. We select 27 clusters in the full area, a result consistent with previous studies at similar depth.

  2. HELP-ing Extragalactic Surveys : The Herschel Extragalactic Legacy Project and The Coming of Age of Multi-Wavelength Astrophysics

    CERN Document Server

    Vaccari, Mattia

    2016-01-01

    How did galaxies form and evolve? This is one of the most challenging questions in astronomy to- day. Answering it requires a careful combination of observational and theoretical work to reliably determine the observed properties of cosmic bodies over large portions of the distant Universe on the one hand, and accurately model the physical processes driving their evolution on the other. Most importantly, it requires bringing together disparate multi-wavelength and multi-resolution spectro-photometric datasets in an homogeneous and well-characterized manner so that they are suitable for a rigorous statistical analysis. The Herschel Extragalactic Legacy Project (HELP) funded by the EC FP7 SPACE program aims to achieve this goal by combining the expertise of optical, infrared and radio astronomers to provide a multi-wavelength database for the dis- tant Universe as an accessible value-added resource for the astronomical community. It will do so by bringing together multi-wavelength datasets covering the 1000 deg...

  3. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Full spectroscopic data and auxiliary information release (PDR-2)

    CERN Document Server

    Scodeggio, M; Garilli, B; Granett, B R; Bolzonella, M; de la Torre, S; Abbas, U; Adami, C; Arnouts, S; Bottini, D; Cappi, A; Coupon, J; Cucciati, O; Davidzon, I; Franzetti, P; Fritz, A; Iovino, A; Krywult, J; Brun, V Le; Févre, O Le; Maccagni, D; Malek, K; Marchetti, A; Marulli, F; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Bel, J; Branchini, E; De Lucia, G; Ilbert, O; McCracken, H J; Moutard, T; Peacock, J A; Zamorani, G; Burden, A; Fumana, M; Jullo, E; Marinoni, C; Mellier, Y; Moscardini, L; Percival, W J

    2016-01-01

    We present the full public data release (PDR-2) of the VIMOS Public Extragalactic Redshift Survey (VIPERS), performed at the ESO VLT. We release redshifts, spectra, CFHTLS magnitudes and ancillary information (as masks and weights) for a complete sample of 86,775 galaxies (plus 4,732 other objects, including stars and serendipitous galaxies); we also include their full photometrically-selected parent catalogue. The sample is magnitude limited to i_AB = 2 are shown to have a confidence level of 96% or larger and make up 88% of all measured galaxy redshifts (76,552 out of 86,775), constituting the VIPERS prime catalogue for statistical investigations. For this sample the rms redshift error, estimated using repeated measurements of about 3,000 galaxies, is found to be sigma_z = 0.00054(1+z). All data are available at http://vipers.inaf.it and on the ESO Archive.

  4. The NuSTAR Extragalactic Surveys: Overview and Catalog from the COSMOS Field

    CERN Document Server

    Civano, F; Puccetti, S; Comastri, A; Mullaney, J R; Zappacosta, L; LaMassa, S M; Aird, J; Alexander, D M; Ballantyne, D R; Bauer, F E; Brandt, W N; Boggs, S E; Christensen, F E; Craig, W W; Del-Moro, A; Elvis, M; Forster, K; Gandhi, P; Grefenstette, B W; Hailey, C J; Harrison, F A; Lansbury, G B; Luo, B; Madsen, K; Saez, C; Stern, D; Treister, E; Urry, M C; Wik, D R; Zhang, W

    2015-01-01

    To provide the census of the sources contributing to the X-ray background peak above 10 keV, NuSTAR is performing extragalactic surveys using a three-tier "wedding cake" approach. We present the NuSTAR survey of the COSMOS field, the medium sensitivity and medium area tier, covering 1.7 deg2 and overlapping with both Chandra and XMM-Newton data. This survey consists of 121 observations for a total exposure of ~3 Ms. To fully exploit these data, we developed a new detection strategy, carefully tested through extensive simulations. The survey sensitivity at 20% completeness is 5.9, 2.9 and 6.4 x 10^-14 erg/cm2/s in the 3-24 keV, 3-8 keV and 8-24 keV bands, respectively. By combining detections in 3 bands, we have a sample of 91 NuSTAR sources with 10^42 -10^45.5 erg/s luminosities and redshift z=0.04-2.5. Thirty two sources are detected in the 8-24 keV band with fluxes ~100 times fainter than sources detected by Swift-BAT. Of the 91 detections, all but four are associated with a Chandra and/or XMM-Newton point-...

  5. Extragalactic Transients in the Era of Wide-Field Radio Surveys. I. Detection Rates and Light Curve Characteristics

    CERN Document Server

    Metzger, Brian D; Berger, Edo

    2015-01-01

    The impending era of wide-field radio surveys has the potential to revolutionize our understanding of astrophysical transients. Here we evaluate the prospects of a wide range of planned and hypothetical radio surveys using the properties and volumetric rates of known and hypothetical classes of extragalactic synchrotron radio transients (e.g., on- and off-axis gamma-ray bursts [GRB], supernovae, tidal disruption events [TDE], compact object mergers). Utilizing these sources and physically motivated considerations we assess the allowed phase-space of radio luminosity and peak timescale for extragalactic transients. We also include for the first time effects such as redshift evolution of the rates, K-corrections, and non-Euclidean luminosity distance, which affect the detection rates of the most sensitive surveys. The number of detected events is calculated by means of a Monte Carlo method, using the various survey properties (depth, cadence, area) and realistic detection criteria that include a cut on the mini...

  6. GLEAM: The GaLactic and Extragalactic All-sky MWA survey

    CERN Document Server

    Wayth, R B; Bell, M E; Callingham, J R; Dwarakanath, K S; Franzen, T M O; For, B -Q; Gaensler, B; Hancock, P; Hindson, L; Hurley-Walker, N; Jackson, C A; Johnston-Hollitt, M; Kapinska, A D; McKinley, B; Morgan, J; Offringa, A R; Procopio, P; Staveley-Smith, L; Wu, C; Zheng, Q; Trott, C M; Bernardi, G; Bowman, J D; Briggs, F; Cappallo, R J; Corey, B E; Deshpande, A A; Emrich, D; Goeke, R; Greenhill, L J; Hazelton, B J; Kaplan, D L; Kasper, J C; Kratzenberg, E; Lonsdale, C J; Lynch, M J; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Ord, S M; Prabu, T; Rogers, A E E; Roshi, A; Shankar, N Udaya; Srivani, K S; Subrahmanyan, R; Tingay, S J; Waterson, M; Webster, R L; Whitney, A R; Williams, A; Williams, C L

    2015-01-01

    GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination +25 deg at frequencies between 72 and 231 MHz, made with the Murchison Widefield Array (MWA) using a drift scan method that makes efficient use of the MWA's very large field-of-view. We present the observation details, imaging strategies and theoretical sensitivity for GLEAM. The survey ran for two years, the first year using 40 kHz frequency resolution and 0.5 s time resolution; the second year using 10 kHz frequency resolution and 2 s time resolution. The resulting image resolution and sensitivity depends on observing frequency, sky pointing and image weighting scheme. At 154 MHz the image resolution is approximately 2.5 x 2.2/cos(DEC+26.7) arcmin with sensitivity to structures up to ~10 deg in angular size. We provide tables to calculate the expected thermal noise for GLEAM mosaics depending on pointing and frequency and discuss limitations to achieving theoretical noise in Stokes I images. We...

  7. The Australia Telescope 20GHz (AT20G) Survey: analysis of the extragalactic source sample

    CERN Document Server

    Massardi, Marcella; end_of_the_skype_highlighting, Tara Murphy begin_of_the_skype_highlighting end_of_the_skype_highlighting begin_of_the_skype_highlighting; Mahony, Elizabeth; Hancock, Paul J; Chhetri, Rajan; De Zotti, Gianfranco; Sadler, Elaine M; Burke-Spolaor, Sarah; Calabretta, Mark; Edwards, Philip G; Ekers, Jennifer A; Jackson, Carole A; Kesteven, Michael J; Newton-McGee, Katherine; Phillips, Chris; Ricci, Roberto; Roberts, Paul; Sault, Robert J; Staveley-Smith, Lister; Subrahmanyan, Ravi; Walker, Mark A; Wilson, Warwick E

    2010-01-01

    The Australia Telescope 20 GHz (AT20G) survey is a blind survey of the whole Southern sky at 20 GHz with follow-up observations at 4.8, 8.6, and 20 GHz carried out with the Australia Telescope Compact Array (ATCA). In this paper we present an analysis of radio spectral properties in total intensity and polarisation, sizes, optical identifications, and redshifts of the sample of the 5808 extragalactic sources in the survey catalogue of confirmed sources over the whole Southern sky excluding the strip at Galactic latitude |b|500mJy, to 60% for S<100mJy. There is also a clear spectral steepening at higher frequencies with the median spectral index decreasing from -0.16 between 4.8 and 8.6GHz to -0.28 between 8.6 and 20GHz. Simultaneous observations in polarisation are available for all the sources at all the frequencies. 768 sources have a good quality detection of polarised flux density at 20GHz; 467 of them were also detected in polarisation at 4.8 and/or at 8.6GHz so that it has been possible to compare th...

  8. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- UDS Field

    Science.gov (United States)

    Faber, Sandra

    2010-09-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the ?rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions are selected from the SpitzerExtragalactic Deep Survey {SEDS} to provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of ?ve widely separated ?elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a ?Wide? imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a ?Deep? imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.In combination with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef?cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12064, is part of the Wide mosaic survey, which has thefollowing field centers and sizes: Field ID RA{2000} Dec{2000} WFC3 Dim. PA on sky UDS 02 17 38 -05 12 02 4x11 270 COSMOS 10 00 31 +02 24 00 4x11 180 EGS 14 19 31 +52 54 10 3x15 41 Science highlights from the Wide program: * Underlying structural properties of galaxies as revealed by WFC3-IR images sensitive to older stars {beyond the 4000-A break} and less affected by dust than ACS. A key redshift is z 2, where star-formation peaks, QSOs are most abundant, and where restframe B-band is still accessible to WFC3. Sample questions include: - Structure in young

  9. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Star formation history of passive galaxies

    CERN Document Server

    Siudek, M; Scodeggio, M; Garilli, B; Pollo, A; Haines, C P; Fritz, A; Bolzonella, M; de la Torre, S; Granett, B R; Guzzo, L; Abbas, U; Adami, C; Bottini, D; Cappi, A; Cucciati, O; De Lucia, G; Davidzon, I; Franzetti, P; Iovino, A; Krywult, J; Brun, V Le; Fèvre, O Le; Maccagni, D; Marchetti, A; Marulli, F; Polletta, M; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Arnouts, S; Bel, J; Branchini, E; Ilbert, O; Gargiulo, A; Moscardini, L; Takeuchi, T T; Zamorani, G

    2016-01-01

    We trace the evolution and the star formation history of passive galaxies, using a subset of the VIMOS Public Extragalactic Redshift Survey (VIPERS). We extracted from the VIPERS survey a sample of passive galaxies in the redshift range 0.4

  10. The SCUBA HAlf Degree Extragalactic Survey (SHADES) -- VI. 350 micron mapping of submillimetre galaxies

    CERN Document Server

    Coppin, Kristen; Scott, Douglas; Borys, Colin; Dunlop, James; Dunne, Loretta; Ivison, Rob; Wagg, Jeff; Aretxaga, Itziar; Battistelli, Elia; Benson, Andrew; Blain, Andrew; Chapman, Scott; Clements, Dave; Dye, Simon; Farrah, Duncan; Hughes, David; Jenness, Tim; van Kampen, Eelco; Lacey, Cedric; Mortier, Angela; Pope, Alexandra; Priddey, Robert; Serjeant, Stephen; Smail, Ian; Stevens, Jason; Vaccari, Mattia

    2007-01-01

    A follow-up survey using the Submillimetre High-Angular Resolution Camera (SHARC-II) at 350 microns has been carried out to map the regions around several 850 micron-selected sources from the Submillimetre HAlf Degree Extragalactic Survey (SHADES). These observations probe the infrared luminosities and hence star-formation rates in the largest existing, most robust sample of submillimetre galaxies (SMGs). We measure 350 micron flux densities for 24 850 micron sources, seven of which are detected at >2.5-sigma within a 10 arcsec search radius of the 850 micron positions. When results from the literature are included the total number of 350 micron flux density constraints of SHADES SMGs is 31, with 15 detections. We fit a modified blackbody to the far-infrared (FIR) photometry of each SMG, and confirm that typical SMGs are dust-rich (Mdust~9x10^8 Msun), luminous (Lfir~2x10^12 Lsun), star-forming galaxies with intrinsic dust temperatures of ~35 K and star-formation rates of ~400 Msun/yr. We have measured the tem...

  11. CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey

    CERN Document Server

    Grogin, Norman A; Faber, S M; Ferguson, Henry C; Koekemoer, Anton M; Riess, Adam G; Acquaviva, Viviana; Alexander, David M; Almaini, Omar; Ashby, Matthew L N; Barden, Marco; Bell, Eric F; Bournaud, Frédéric; Brown, Thomas M; Caputi, Karina I; Casertano, Stefano; Cassata, Paolo; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J; Cooray, Asantha Roshan; Croton, Darren J; Daddi, Emanuele; Dahlen, Tomas; Davé, Romeel; de Mello, Duília F; Dekel, Avishai; Dickinson, Mark; Dolch, Timothy; Donley, Jennifer L; Dunlop, James S; Dutton, Aaron A; Elbaz, David; Fazio, Giovanni G; Filippenko, Alexei V; Finkelstein, Steven L; Fontana, Adriano; Gardner, Jonathan P; Garnavich, Peter M; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P; Häussler, Boris; Hopkins, Philip F; Huang, Jia-Sheng; Huang, Kuang-Han; Jha, Saurabh W; Kartaltepe, Jeyhan S; Kirshner, Robert P; Koo, David C; Lai, Kamson; Lee, Kyoung-Soo; Li, Weidong; Lotz, Jennifer M; Lucas, Ray A; Madau, Piero; McCarthy, Patrick J; McGrath, Elizabeth J; McIntosh, Daniel H; McLure, Ross J; Mobasher, Bahram; Moustakas, Leonidas A; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A; Niemi, Sami-Matias; Noeske, Kai G; Papovich, Casey J; Pentericci, Laura; Pope, Alexandra; Primack, Joel R; Rajan, Abhijith; Ravindranath, Swara; Reddy, Naveen A; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R; Rodney, Steven A; Rosario, David J; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Somerville, Rachel S; Spinrad, Hyron; Straughn, Amber N; Strolger, Louis-Gregory; Telford, Olivia; Teplitz, Harry I; Trump, Jonathan R; van der Wel, Arjen; Villforth, Carolin; Wechsler, Risa H; Weiner, Benjamin J; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yan, Hao-Jing; Yun, Min S

    2011-01-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from redshift $z \\sim 8$ to 1.5. It will image more than 250,000 distant galaxies using three separate cameras on board the Hubble Space Telescope, from the mid-UV to near-IR. It will also find and measure Type Ia SNe beyond $z > 1.5$ and test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected. Each has multi-wavelength data from Spitzer\\ and other facilities, plus extensive spectroscopy of the brighter galaxies; additional ancillary data are still arriving. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of $10^9 M_\\odot$ out to $z \\sim 2$, and down to the knee of the UV luminosity function of galaxies out to $z \\sim 8$. The survey covers approximately 800 square arcminutes and is divided into two parts. The CANDELS/Dee...

  12. The discrepancy in the mid-infrared continuum and the features of polycyclic aromatic hydrocarbons for Spitzer and Herschel SWIRE-field galaxies

    CERN Document Server

    Zhu, Yi-Nan

    2014-01-01

    On the basis of observations by Spitzer and Herschel, we present and analyse the correlations between various monochromatic infrared (IR) luminosities for star-forming galaxies, selected from two northern Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) fields. The 24- and 70 micron luminosities (L[24] and L[70]), which are dominated by the continuum of very small grains (VSGs) and warm dust in thermal equilibrium, respectively, correlate tightly with ongoing star formation. The contribution from cool dust excited by evolved stars also increases as the wavelength increases in the far-infrared (FIR) wavelength range. The spectral features of ionized polycyclic aromatic hydrocarbons (PAHs) around rest-frame 8 micron are excited by the moderated radiation field related to evolved stars as well, rather than by the intensive radiation field related to young stars. Even though the carriers of PAHs could be treated as types of VSG with a smaller scale, the radiation condition between PAHs and classic VSGs see...

  13. The VIMOS Public Extragalactic Redshift Survey: Measuring the growth rate of structure around cosmic voids

    CERN Document Server

    Hawken, A J; Iovino, A; Guzzo, L; Peacock, J A; de la Torre, S; Garilli, B; Bolzonella, M; Scodeggio, M; Abbas, U; Adami, C; Bottini, D; Cappi, A; Cucciati, O; Davidzon, I; Fritz, A; Franzetti, P; Krywult, J; Brun, V Le; Fevre, O Le; Maccagni, D; Małek, K; Marulli, F; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Arnouts, S; Bel, J; Branchini, E; De Lucia, G; Ilbert, O; Moscardini, L; Percival, W J

    2016-01-01

    We identified voids in the completed VIMOS Public Extragalactic Redshift Survey (VIPERS), using an algorithm based on searching for empty spheres. We measured the cross-correlation between the centres of voids and the complete galaxy catalogue. The cross-correlation function exhibits a clear anisotropy in both VIPERS fields (W1 and W4), which is characteristic of linear redshift space distortions. By measuring the projected cross-correlation and then deprojecting it we are able to estimate the undistorted cross-correlation function. We propose that given a sufficiently well measured cross-correlation function one should be able to measure the linear growth rate of structure by applying a simple linear Gaussian streaming model for the redshift space distortions (RSD). Our study of voids in 306 mock galaxy catalogues mimicking the VIPERS fields would suggest that VIPERS is capable of measuring $\\beta$ with an error of around $25\\%$. Applying our method to the VIPERS data, we find a value for the redshift space ...

  14. Spitzer 70 and 160-micron Observations of the Extragalactic First Look Survey

    CERN Document Server

    Frayer, D T; Yan, L; Marleau, F R; Choi, P I; Helou, G; Soifer, B T; Appleton, P N; Armus, L; Beck, R; Dole, H; Engelbracht, C W; Fang, F; Gordon, K D; Heinrichsen, I; Henderson, D; Hesselroth, T; Im, M; Kelly, D M; Lacy, M; Laine, S; Latter, W B; Mahoney, W; Makovoz, D; Masci, F J; Morrison, J E; Moshir, M; Noriega-Crespo, A; Padgett, D L; Pesenson, M; Shupe, D L; Squires, G K; Storrie-Lombardi, L J; Surace, J A; Teplitz, H I; Wilson, G

    2005-01-01

    We present Spitzer 70um and 160um observations of the Spitzer extragalactic First Look Survey (xFLS). The data reduction techniques and the methods for producing co-added mosaics and source catalogs are discussed. Currently, 26% of the 70um sample and 49% of the 160um-selected sources have redshifts. The majority of sources with redshifts are star-forming galaxies at z<0.5, while about 5% have infrared colors consistent with AGN. The observed infrared colors agree with the spectral energy distribution (SEDs) of local galaxies previously determined from IRAS and ISO data. The average 160um/70um color temperature for the dust is Td~= 30+/-5 K, and the average 70um/24um spectral index is alpha~= 2.4+/-0.4. The observed infrared to radio correlation varies with redshift as expected out to z~1 based on the SEDs of local galaxies. The xFLS number counts at 70um and 160um are consistent within uncertainties with the models of galaxy evolution, but there are indications that the current models may require slight m...

  15. Atacama Cosmology Telescope: Extragalactic Sources at 148 GHz in the 2008 Survey

    CERN Document Server

    Marriage, T A; Lin, Y -T; Marsden, D; Nolta, M R; Partridge, B; Ade, P A R; Aguirre, P; Amiri, M; Appel, J W; Barrientos, L F; Battistelli, E S; Bond, J R; Brown, B; Burger, B; Chervenak, J; Das, S; Devlin, M J; Dicker, S R; Doriese, W B; Dunkley, J; Dunner, R; Essinger-Hileman, T; Fisher, R P; Fowler, J W; Hajian, A; Halpern, M; Hasselfield, M; Hernandez-Monteagudo, C; Hilton, G C; Hilton, M; Hincks, A D; Hlozek, R; Huffenberger, K M; Hughes, D H; Hughes, J P; Infante, L; Irwin, K D; Kaul, M; Klein, J; Kosowsky, A; Lau, J M; Limon, M; Lupton, R H; Martocci, K; Mauskopf, P; Menanteau, F; Moodley, K; Moseley, H; Netterfield, C B; Niemack, M D; Page, L A; Parker, L; Quintana, H; Reid, B; Sehgal, N; Sherwin, B D; Sievers, J; Spergel, D N; Staggs, S T; Swetz, D S; Switzer, E R; Thornton, R; Trac, H; Tucker, C; Warne, R; Wilson, G; Wollack, E; Zhao, Y

    2010-01-01

    We report on extragalactic sources detected in a 455 square-degree map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low redshift X-ray selected galaxy clusters. Estimates of the radio to mm-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50 mJy) 148 GHz-selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of $...

  16. An Enhanced Multiwavelength Photometric Catalog for the Spitzer Extragalactic Representative Volume Survey

    Science.gov (United States)

    Nyland, Kristina

    2017-01-01

    Although our knowledge of the physics of galaxy evolution has made great strides over the past few decades, we still lack a complete understanding of the formation and growth of galaxies at high redshift. The Spitzer Extragalactic Representative Volume Survey (SERVS) aims to address this issue through deep Spitzer observations at [3.6] and [4.5] microns of 4 million sources distributed over five well-studied “deep fields” with abundant ancillary data from ground-based near-infrared surveys. The large SERVS footprint covers 18 square degrees and will provide a census of the multiwavelength properties of massive galaxies in the redshift range z = 1-6. A critical aspect of the scientific success and legacy value of SERVS is the construction of a robust source catalog. While multiwavelength source catalogs of the SERVS fields have been generated using traditional techniques, the photometric accuracy of these catalogs is limited by their inability to correctly measure fluxes of individual sources that are blended and/or inherently faint in the IRAC bands. To improve upon this shortfall and maximize the scientific impact of SERVS, we are using The Tractor image modeling code to produce a more accurate and complete multiwavelength source catalog. The Tractor optimizes a likelihood for the source properties given an image cut-out, light profile model, and the PSF information. Thus, The Tractor uses the source properties at the fiducial, highest-resolution band as a prior to more accurately measure the source properties in the lower-resolution images at longer wavelengths. We provide an overview of our parallelized implementation of The Tractor, discuss the subsequent improvements to the SERVS photometry, and suggest future applications.

  17. Blind Extragalactic HI Surveys with the Arecibo and Green Bank Telescopes: I. Simulations and Strategies for Survey Design

    Science.gov (United States)

    Giovanelli, R.; Haynes, M. P.; Spekkens, K.; Springob, C. M.; Masters, K. L.; Saintonge, A.; Catinella, B.; Kent, B.; Maddalena, R. J.; Magnani, L.; Koopmann, R. A.

    2003-12-01

    The currently popular Λ CDM framework of evolution of cosmic structure predicts a population of low mass halos that far exceeds that of dwarf galaxies. Low mass halos could, however, have retained little of their initial baryonic mass fraction, and their star formation efficiency could be very low. The possibility of detecting such systems in the 21 cm HI line has been investigated by several teams, and blind extragalactic HI surveys have been undertaken to date, pushing estimates of the HI Mass Function to limits approaching 107 M⊙ (Zwaan et al. 1997, Rosenberg and Schneider 2002, Zwaan et al. 2003). Extrapolations of those estimates to 106 M⊙ disagree with each other quite substantially. Since these low mass objects may represent the population of low mass halos predicted to exist by numerical Λ CDM simulations, the determination of their space density and its possible dependence on galaxy environment remains an important goal. Systems of very low HI mass can only be detected at relatively small distances. It thus becomes important to optimize the survey design, matching it to the local characteristics of the cosmic density field. We present results of various survey simulations, some currently underway with the single-beam Arecibo and Green Bank telescopes and future ones that will be enabled with the advent of the Arecibo L-band feed array in late 2004. This work is partially funded by NSF grant AST-0307661.

  18. Gravitational lensing statistics with extragalactic surveys - II. Analysis of the Jodrell Bank-VLA Astrometric Survey

    NARCIS (Netherlands)

    Helbig, P; Marlow, D; Quast, R; Wilkinson, PN; Browne, IWA; Koopmans, LVE

    We present constraints on the cosmological constant lambda(0) from gravitational lensing statistics of the Jodrell Bank-VLA Astrometric Survey (JVAS). Although this is the largest gravitational lens survey which has been analysed, cosmological constraints are only comparable to those from optical

  19. The many facets of extragalactic radio surveys: towards new scientific challenges

    Science.gov (United States)

    2015-10-01

    Radio continuum surveys are a powerful tool to detect large number of objects over a wide range of redshifts and obtain information on the intensity, polarization and distribution properties of radio sources across the sky. They are essential to answer to fundamental questions of modern astrophysics. Radio astronomy is in the midst of a transformation. Developments in high-speed digital signal processing and broad-band optical fibre links between antennas have enabled significant upgrades of the existing radio facilities (e-MERLIN, JVLA, ATCA-CABB, eEVN, APERTIF), and are leading to next-generation radio telescopes (LOFAR, MWA, ASKAP, MeerKAT). All these efforts will ultimately lead to the realization of the Square Kilometre Array (SKA), which, owing to advances in sensitivity, field-of-view, frequency range and spectral resolution, will yield transformational science in many astrophysical research fields. The purpose of this meeting is to explore new scientific perspectives offered by modern radio surveys, focusing on synergies allowed by multi-frequency, multi-resolution observations. We will bring together researchers working on wide aspects of the physics and evolution of extra-galactic radio sources, from star-forming galaxies to AGNs and clusters of galaxies, including their role as cosmological probes. The organization of this conference has been inspired by the recent celebration of the 50th anniversary of the Northern Cross Radio Telescope in Medicina (BO), whose pioneering B2 and B3 surveys provided a significant contribution to radio astronomical studies for many decades afterwards. The conference was organized by the Istituto di Radioastronomia (INAF), and was held at the CNR Research Area in Bologna, on 20-23 October 2015. This Conference has received support from the following bodies and funding agencies: National Institute for Astrophysics (INAF), ASTRON, RadioNet3 (through the European Union’s Seventh Framework Programme for research

  20. The VIMOS Public Extragalactic Redshift Survey (VIPERS). PCA-based automatic cleaning and reconstruction of survey spectra

    Science.gov (United States)

    Marchetti, A.; Garilli, B.; Granett, B. R.; Guzzo, L.; Iovino, A.; Scodeggio, M.; Bolzonella, M.; de la Torre, S.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; Coupon, J.; De Lucia, G.; Ilbert, O.; Moutard, T.; Moscardini, L.; Zamorani, G.

    2017-03-01

    Context. Identifying spurious reduction artefacts in galaxy spectra is a challenge for large surveys. Aims: We present an algorithm for identifying and repairing spurious residual features in sky-subtracted galaxy spectra by using data from the VIMOS Public Extragalactic Redshift Survey (VIPERS) as a test case. Methods: The algorithm uses principal component analysis (PCA) applied to the galaxy spectra in the observed frame to identify sky line residuals imprinted at characteristic wavelengths. We further model the galaxy spectra in the rest-frame using PCA to estimate the most probable continuum in the corrupted spectral regions, which are then repaired. Results: We apply the method to 90 000 spectra from the VIPERS survey and compare the results with a subset for which careful editing was performed by hand. We find that the automatic technique reproduces the time-consuming manual cleaning in a uniform and objective manner across a large data sample. The mask data products produced in this work are released together with the VIPERS second public data release (PDR-2). based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA at the Canada-France-Hawaii Telescope (CFHT), that is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, which is a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/.

  1. Gravitational lensing statistics with extragalactic surveys; 2, Analysis of the Jodrell Bank-VLA Astrometric Survey

    NARCIS (Netherlands)

    Helbig, P.; Marlow, D. R.; Quast, R.; Wilkinson, P. N.; Browne, I. W. A.; Koopmans, L. V. E.

    1999-01-01

    Published in: Astron. Astrophys. Suppl. Ser. 136 (1999) no. 2, pp.297-305 citations recorded in [Science Citation Index] Abstract: We present constraints on the cosmological constant $lambda_{0}$ from gravitational lensing statistics of the Jodrell Bank-VLA Astrometric Survey (JVAS). Although this

  2. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Star formation history of passive red galaxies

    Science.gov (United States)

    Siudek, M.; Małek, K.; Scodeggio, M.; Garilli, B.; Pollo, A.; Haines, C. P.; Fritz, A.; Bolzonella, M.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; De Lucia, G.; Davidzon, I.; Franzetti, P.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Marchetti, A.; Marulli, F.; Polletta, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; Ilbert, O.; Gargiulo, A.; Moscardini, L.; Takeuchi, T. T.; Zamorani, G.

    2017-01-01

    Aims: We trace the evolution and the star formation history of passive red galaxies, using a subset of the VIMOS Public Extragalactic Redshift Survey (VIPERS). The detailed spectral analysis of stellar populations of intermediate-redshift passive red galaxies allows the build up of their stellar content to be followed over the last 8 billion years. Methods: We extracted a sample of passive red galaxies in the redshift range 0.4 relation for intermediate-redshift passive red galaxies. Results: We find that at z 1 stellar populations in low-mass passive red galaxies are younger than in high-mass passive red galaxies, similar to what is observed at the present epoch. Over the full analyzed redshift range 0.4 relations of D4000 and HδA with stellar mass has not changed significantly with redshift. Assuming a single burst formation, this implies that high-mass passive red galaxies formed their stars at zform 1.7, while low-mass galaxies formed their main stellar populations more recently, at zform 1. The consistency of these results, which were obtained using two independent estimators of the formation redshift (D4000 and HδA), further strengthens a scenario in which star formation proceeds from higher to lower mass systems as time passes, i.e., what has become known as the downsizing picture. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope

  3. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY-THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

    NARCIS (Netherlands)

    Koekemoer, Anton M.; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; Lotz, Jennifer M.; Lucas, Ray A.; McGrath, Elizabeth J.; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G.; Rodney, Steve A.; Strolger, Louis; Casertano, Stefano; Castellano, Marco; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Cassata, Paolo; Challis, Peter J.; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dave, Romeel; de Mello, Duilia F.; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Frazer, Chris; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G.; Haeussler, Boris; Herrington, Jessica; Hopkins, Philip F.; Huang, Jia-Sheng; Jha, Saurabh W.; Johnson, Andrew; Kartaltepe, Jeyhan S.; Khostovan, Ali A.; Kirshner, Robert P.; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J.; McIntosh, Daniel H.; McLure, Ross J.; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Nielsen, Jennifer L.; Niemi, Sami; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R.; Wandro, Pat; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S.

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z approximate to 1.5-8, and to study

  4. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY-THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

    NARCIS (Netherlands)

    Koekemoer, Anton M.; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; Lotz, Jennifer M.; Lucas, Ray A.; McGrath, Elizabeth J.; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G.; Rodney, Steve A.; Strolger, Louis; Casertano, Stefano; Castellano, Marco; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Cassata, Paolo; Challis, Peter J.; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dave, Romeel; de Mello, Duilia F.; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Frazer, Chris; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G.; Haeussler, Boris; Herrington, Jessica; Hopkins, Philip F.; Huang, Jia-Sheng; Jha, Saurabh W.; Johnson, Andrew; Kartaltepe, Jeyhan S.; Khostovan, Ali A.; Kirshner, Robert P.; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J.; McIntosh, Daniel H.; McLure, Ross J.; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Nielsen, Jennifer L.; Niemi, Sami; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R.; Wandro, Pat; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S.

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z approximate to 1.5-8, and to study

  5. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Hierarchical scaling and biasing

    Science.gov (United States)

    Cappi, A.; Marulli, F.; Bel, J.; Cucciati, O.; Branchini, E.; de la Torre, S.; Moscardini, L.; Bolzonella, M.; Guzzo, L.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Coupon, J.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Granett, B. R.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Schimd, C.; Schlagenhaufer, H.; Wolk, M.; Zamorani, G.

    2015-07-01

    Aims: Building on the two-point correlation function analyses of the VIMOS Public Extragalactic Redshift Survey (VIPERS), we investigate the higher-order correlation properties of the same galaxy samples to test the hierarchical scaling hypothesis at z ~ 1 and the dependence on galaxy luminosity, stellar mass, and redshift. With this work we also aim to assess possible deviations from the linearity of galaxy bias independently from a previously performed analysis of our survey. Methods: We have measured the count probability distribution function in spherical cells of varying radii (3 ≤ R ≤ 10 h-1 Mpc), deriving σ8g (the galaxy rms at 8 h-1 Mpc), the volume-averaged two-, three-, and four-point correlation functions and the normalized skewness S3g and kurtosis S4g for different volume-limited subsamples, covering the following ranges: -19.5 ≤ MB(z = 1.1) - 5log (h) ≤ -21.0 in absolute magnitude, 9.0 ≤ log (M∗/M⊙h-2) ≤ 11.0 in stellar mass, and 0.5 ≤ zfollowing. 1) The hierarchical scaling between the volume-averaged two- and three-point and two- and four-point correlation functions holds throughout the whole range of scale and redshift we could test. 2) We do not find a significant dependence of S3g on luminosity (below z = 0.9 the value of S3g decreases with luminosity, but only at 1σ-level). 3) We do not detect a significant dependence of S3g and S4g on scale, except beyond z ~ 0.9, where S3g and S4g have higher values on large scales (R ≥ 10 h-1 Mpc): this increase is mainly due to one of the two CFHTLS Wide Fields observed by VIPERS and can be explained as a consequence of sample variance, consistently with our analysis of mock catalogs. 4) We do not detect a significant evolution of S3g and S4g with redshift (apart from the increase of their values with scale in the last redshift bin). 5) σ8g increases with luminosity, but does not show significant evolution with redshift. As a consequence, the linear bias factor b = σ8g/σ8m, where σ8

  6. MAMBO 1.2mm observations of luminous starbursts at z~2 in the SWIRE fields

    CERN Document Server

    Lonsdale, C J; Omont, A; Shupe, D; Berta, S; Zylka, R; Siana, B; Lutz, D; Farrah, D; Smith, H E; Lagache, G; De Breuck, C; Owen, F; Beelen, A; Weedman, D; Franceschini, A; Clements, D; Tacconi, L; Afonso-Luis, A; Pérez-Fournon, I; Cox, P; Bertoldi, F

    2008-01-01

    We report on--off pointed MAMBO observations at 1.2 mm of 61 Spitzer-selected star-forming galaxies from the SWIRE survey. The sources are selected on the basis of bright 24um fluxes (f_24um>0.4mJy) and of stellar dominated near-infrared spectral energy distributions in order to favor z~2 starburst galaxies. The average 1.2mm flux for the whole sample is 1.5+/-0.2 mJy. Our analysis focuses on 29 sources in the Lockman Hole field where the average 1.2mm flux (1.9+/-0.3 mJy) is higher than in other fields (1.1+/-0.2 mJy). The analysis of the sources multi-wavelength spectral energy distributions indicates that they are starburst galaxies with far-infrared luminosities ~10^12-10^13.3 Lsun, and stellar masses of ~0.2-6 x10^11 M_sun. Compared to sub-millimeter selected galaxies (SMGs), the SWIRE-MAMBO sources are among those with the largest 24um/millimeter flux ratios. The origin of such large ratios is investigated by comparing the average mid-infrared spectra and the stacked far-infrared spectral energy distrib...

  7. A Survey of HC3N in Extragalactic Sources - Is HC3N a Tracer of Activity in ULIRGs?

    CERN Document Server

    Lindberg, J E; Costagliola, F; Pérez-Beaupuits, J -P; Monje, R; Muller, S

    2011-01-01

    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections, and to compare HC3N with other molecular tracers (HCN, HNC), as well as other properties (silicate absorption strength, IR flux density ratios, C II flux, and megamaser activity). Methods. We present mm IRAM 30 m, OSO 20 m, and SEST observations of HC3N rotational lines (mainly the J = 10-9 transition) and of the J = 1-0 transitions of HCN and HNC. Our combined HC3N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies. Results. A preliminary definition "HC3N-luminous galaxy" is made based upon the HC3N/HCN ratio. Most (~80 %) HC3N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (~60 % or more) of t...

  8. A Survey of HC3N in Extragalactic Sources - Is HC3N a Tracer of Activity in ULIRGs?

    DEFF Research Database (Denmark)

    Lindberg, Karl Johan Erik; Aalto, S.; Costagliola, F.;

    2011-01-01

    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections......) and of the J = 1-0 transitions of HCN and HNC. Our combined HC3N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies. Results. A preliminary definition "HC3N-luminous galaxy" is made based upon the HC3N/HCN ratio....... Most (~80 %) HC3N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (~60 % or more) of the HC3N-luminous galaxies in the sample present OH mega- or strong kilomaser activity. A possible explanation is that both HC3N and OH megamasers need warm dust for their excitation...

  9. S-CANDELS: The Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Survey. Survey Design, Photometry, and Deep IRAC Source Counts

    CERN Document Server

    Ashby, M L N; Fazio, G G; Dunlop, J S; Egami, E; Faber, S M; Ferguson, H C; Grogin, N A; Hora, J L; Huang, J -S; Koekemoer, A M; Labbe, I; Wang, Z

    2015-01-01

    The Spitzer-Cosmic Assembly Deep Near-Infrared Extragalactic Legacy Survey (S-CANDELS; PI G. Fazio) is a Cycle 8 Exploration Program designed to detect galaxies at very high redshifts (z > 5). To mitigate the effects of cosmic variance and also to take advantage of deep coextensive coverage in multiple bands by the Hubble Space Telescope Multi-Cycle Treasury Program CANDELS, S-CANDELS was carried out within five widely separated extragalactic fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the HST Deep Field North, and the Extended Groth Strip. S-CANDELS builds upon the existing coverage of these fields from the Spitzer Extended Deep Survey (SEDS) by increasing the integration time from 12 hours to a total of 50 hours but within a smaller area, 0.16 square degrees. The additional depth significantly increases the survey completeness at faint magnitudes. This paper describes the S-CANDELS survey design, processing, and publicly-available data products. We present IRAC dual-...

  10. The VIMOS Public Extragalactic Redshift Survey (VIPERS): Galaxy segregation inside filaments at $z \\simeq 0.7$

    CERN Document Server

    Malavasi, N; Vibert, D; de la Torre, S; Moutard, T; Pichon, C; Davidzon, I; Kraljic, K; Bolzonella, M; Guzzo, L; Garilli, B; Scodeggio, M; Granett, B R; Abbas, U; Adami, C; Bottini, D; Cappi, A; Cucciati, O; Franzetti, P; Fritz, A; Iovino, A; Krywult, J; Brun, V Le; Fèvre, O Le; Maccagni, D; Małek, K; Marulli, F; Polletta, M; Pollo, A; Tasca, L; Tojeiro, R; Vergani, D; Zanichelli, A; Bel, J; Branchini, E; Coupon, J; De Lucia, G; Dubois, Y; Hawken, A; Ilbert, O; Laigle, C; Moscardini, L; Sousbie, T; Treyer, M; Zamorani, G

    2016-01-01

    We present the first quantitative detection of large-scale filamentary structure at $z \\simeq 0.7$ in the large cosmological volume probed by the VIMOS Public Extragalactic Redshift Survey (VIPERS). We use simulations to show the capability of VIPERS to recover robust topological features in the galaxy distribution, in particular the filamentary network. We then investigate how galaxies with different stellar masses and stellar activities are distributed around the filaments and find a significant segregation, with the most massive or quiescent galaxies being closer to the filament axis than less massive or active galaxies. The signal persists even after down-weighting the contribution of peak regions. Our results suggest that massive and quiescent galaxies assemble their stellar mass through successive mergers during their migration along filaments towards the nodes of the cosmic web. On the other hand, low-mass star-forming galaxies prefer the outer edge of filaments, a vorticity rich region dominated by sm...

  11. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Never mind the gaps: comparing techniques to restore homogeneous sky coverage

    CERN Document Server

    Cucciati, O; Branchini, E; Marulli, F; Iovino, A; Moscardini, L; Bel, J; Cappi, A; Peacock, J A; de la Torre, S; Bolzonella, M; Guzzo, L; Polletta, M; Fritz, A; Adami, C; Bottini, D; Coupon, J; Davidzon, I; Franzetti, P; Fumana, M; Garilli, B; Krywult, J; Malek, K; Paioro, L; Pollo, A; Scodeggio, M; Tasca, L A M; Vergani, D; Zanichelli, A; Di Porto, C; Zamorani, G

    2014-01-01

    [Abridged] Non-uniform sampling and gaps in sky coverage are common in galaxy redshift surveys but these effects can degrade galaxy counts-in-cells and density estimates. We carry out a comparison of methods that aim to fill the gaps to correct for the systematic effects. Our study is motivated by the analysis of the VIMOS Extragalactic Redshift Survey (VIPERS), a flux-limited survey (i<22.5) based on one-pass observations with VIMOS, with gaps covering 25% of the surveyed area and a mean sampling rate of 35%. Our findings are applicable to other surveys with similar observing strategies. We compare 1) two algorithms based on photometric redshift, that assign redshifts to galaxies based on the spectroscopic redshifts of the nearest neighbours, 2) two Bayesian methods, the Wiener filter and the Poisson-Lognormal filter. Using galaxy mock catalogues we quantify the accuracy of the counts-in-cells measurements on scales of R=5 and 8 Mpc/h after applying each of these methods. We also study how they perform to...

  12. GaLactic and Extragalactic All-Sky MWA-eXtended (GLEAM-X) survey: Pilot observations

    Science.gov (United States)

    Hurley-Walker, N.; Seymour, N.; Staveley-Smith, L.; Johnston-Hollitt, M.; Kapinska, A.; McKinley, B.

    2017-01-01

    This proposal is a pilot study for the extension of the highly successful GaLactic and Extragalactic MWA (GLEAM) survey (Wayth et al. 2015). The aim is to test out new observing strategies and data reduction techniques suitable for exploiting the longer baselines of the extended phase 2 MWA array. Deeper and wide surveys at higher resolution will enable a legion of science capabilities pertaining to galaxy evolution, clusters and the cosmic web, whilst maintaining the advantages over LOFAR including larger field-of-view, wider frequency coverage and better sensitivity to extended emission. We will continue the successful drift scan mode observing to test the feasibility of a large-area survey in 2017-B and onward. We will also target a single deep area with a bright calibrator source to establish the utility of focussed deep observations. In both cases, we will be exploring calibrating and imaging strategies across 72-231 MHz with the new long baselines. The published extragalactic sky catalogue (Hurley-Walker et al. 2017) improves the prospects for good ionospheric calibration in this new regime, as well as trivialising flux calibration. The new Alternative Data Release of the TIFR GMRT Sky Survey (TGSS-ADR1; Intema et al. 2016), which has 30" resolution and covers the proposed observing area, allows us to test whether our calibration and imaging strategy correctly recovers the true structure of (high surface-brightness) resolved sources. GLEAM-X will have lower noise, higher surface brightness sensitivity, and have considerably wider bandwidth than TGSS. These properties will enable a wide range of science, such as: Detecting and characterising cluster relics and haloes beyond z=0.45; Accurately determining radio source counts at multiple frequencies; Measuring the low-v luminosity function to z 0.5; Performing Galactic plane science such as HII region detection and cosmic tomography; Determining the typical ionospheric diffractive scale at the MRO, feeding into

  13. The NuSTAR Extragalactic Surveys: Initial Results and Catalog from the Extended Chandra Deep Field South

    CERN Document Server

    Mullaney, J R; Aird, J; Alexander, D M; Civano, F M; Hickox, R C; Lansbury, G B; Ajello, M; Assef, R; Ballantyne, D R; Balokovic, M; Bauer, F E; Brandt, W N; Boggs, S E; Brightman, M; Christensen, F E; Comastri, A; Craig, W W; Elvis, M; Forster, K; Gandhi, P; Grefenstette, B W; Hailey, C J; Harrison, F A; Koss, M; LaMassa, S M; Luo, B; Madsen, K K; Puccetti, S; Saez, C; Stern, D; Treister, E; Urry, C M; Wik, D R; Zappacosta, L; Zhang, W

    2015-01-01

    We present initial results and the source catalog from the NuSTAR survey of the Extended Chandra Deep Field South (hereafter, ECDFS) - currently the deepest contiguous component of the NuSTAR extragalactic survey program. The survey covers the full ~30 arcmin x 30 arcmin area of this field to a maximum depth of ~360 ks (~220 ks when corrected for vignetting at 3-24 keV), reaching sensitivity limits of ~1.3 x 10^-14 erg/cm2/s (3-8 keV), ~3.4 x 10^-14 erg/cm2/s (8-24 keV) and ~3.0 x 10^-14 erg/cm2/s (3-24 keV). Fifty four (54) sources are detected over the full field, although five of these are found to lie below our significance threshold once contaminating flux from neighboring (i.e., blended) sources is taken into account. Of the remaining 49 that are significant, 19 are detected in the 8-24 keV band. The 8-24 keV to 3-8 keV band ratios of the twelve sources that are detected in both bands span the range 0.39-1.7, corresponding to a photon index range of Gamma ~ 0.5-2.3, with a median photon index of 1.70 +/...

  14. The VIMOS Public Extragalactic Redshift Survey (VIPERS). A Support Vector Machine classification of galaxies, stars and AGNs

    CERN Document Server

    Malek, K; Pollo, A; Fritz, A; Garilli, B; Scodeggio, M; Iovino, A; Granett, B R; Abbas, U; Adami, C; Arnouts, S; Bel, J; Bolzonella, M; Bottini, D; Branchini, E; Cappi, A; Coupon, J; Cucciati, O; Davidzon, I; De Lucia, G; de la Torre, S; Franzetti, P; Fumana, M; Guzzo, L; Ilbert, O; Krywult, J; Brun, V Le; Fevre, O Le; Maccagni, D; Marulli, F; McCracken, H J; Paioro, L; Polletta, M; Schlagenhaufer, H; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Burden, A; Di Porto, C; Marchetti, A; Marinoni, C; Mellier, Y; Moscardini, L; Nichol, R C; Peacock, J A; Percival, W J; Phleps, S; Wolk, M; Zamorani, G

    2013-01-01

    The aim of this work is to develop a comprehensive method for classifying sources in large sky surveys and we apply the techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS). Using the optical (u*, g', r', i') and NIR data (z', Ks), we develop a classifier for identifying stars, AGNs and galaxies improving the purity of the VIPERS sample. Support Vector Machine (SVM) supervised learning algorithms allow the automatic classification of objects into two or more classes based on a multidimensional parameter space. In this work, we tailored the SVM for classifying stars, AGNs and galaxies, and applied this classification to the VIPERS data. We train the SVM using spectroscopically confirmed sources from the VIPERS and VVDS surveys. We tested two SVM classifiers and concluded that including NIR data can significantly improve the efficiency of the classifier. The self-check of the best optical + NIR classifier has shown a 97% accuracy in the classification of galaxies, 97 for stars, and 95 for AGNs ...

  15. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South Field, Non-SNe-Searched Visits

    Science.gov (United States)

    Faber, Sandra

    2011-10-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the ?rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions selected from the SpitzerExtragalactic Deep Survey {SEDS} provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of ?ve widely separated ?elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a ?Wide? imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a ?Deep? imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.When combined with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef?cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12064, is part of the Wide mosaic survey, which has thefollowing field centers and sizes: Field ID RA{2000} Dec{2000} WFC3 Dim. PA on sky UDS 02 17 38 -05 12 02 4x11 270 COSMOS 10 00 31 +02 24 00 4x11 180 EGS 14 19 31 +52 54 10 3x15 41 Science highlights from the Wide program: * Underlying structural properties of galaxies as revealed by WFC3-IR images sensitive to older stars {beyond the 4000-A break} and less affected by dust than ACS. A key redshift is z 2, where star-formation peaks, QSOs are most abundant, and where restframe B-band is still accessible to WFC3. Sample questions include: - Structure in young vs. old

  16. The European large area ISO survey - III. 90-mu m extragalactic source counts

    DEFF Research Database (Denmark)

    Efstathiou, A.; Oliver, S.; Rowan-Robinson, M.

    2000-01-01

    We present results and source counts at 90 mum extracted from the preliminary analysis of the European Large Area ISO Survey (ELAIS). The survey covered about 12 deg(2) of the sky in four main areas and was carried out with the ISOPHOT instrument onboard the Infrared Space Observatory (ISO...

  17. The European large area ISO survey - III. 90-mu m extragalactic source counts

    DEFF Research Database (Denmark)

    Efstathiou, A.; Oliver, S.; Rowan-Robinson, M.

    2000-01-01

    We present results and source counts at 90 mum extracted from the preliminary analysis of the European Large Area ISO Survey (ELAIS). The survey covered about 12 deg(2) of the sky in four main areas and was carried out with the ISOPHOT instrument onboard the Infrared Space Observatory (ISO...

  18. Multi-wavelength extragalactic surveys and the role of MeerKAT and SALT

    CERN Document Server

    Jarvis, Matt J

    2011-01-01

    In these proceedings I discuss a range of surveys that are currently underway at optical, near-infrared and far-infrared wavelengths that have large components accessible to both the Southern African Large Telescope (SALT) and the Meer Karoo Array Telescope (MeerKAT). Particular attention is paid to the surveys currently underway with ESO's VISTA telescope, which will provide the ideal data from which to select targets for SALT spectroscopy whilst also providing the necessary depth and photometric redshift accuracy to trace the uJy radio population, found through the proposed MeerKAT surveys. Such surveys will lead to an accurate picture of evolution of star-formation and accretion activity traced at radio wavelengths. Furthermore, SALT spectroscopy could play a crucial role in following up Herschel surveys with its large collecting area and blue sensitivity which occupies a niche in instrumentation on 8- and 10-m class telescopes.

  19. Deep Extragalactic Surveys around the Ecliptic Poles with AKARI (ASTRO-F)

    CERN Document Server

    Matsuhara, H; Matsuura, S; Nakagawa, T; Kawada, M; Oyama, Y; Pearson, C P; Oyabu, S; Takagi, T; Serjeant, S; White, G J; Hanami, H; Watarai, H; Takeuchi, T T; Kodama, T; Arimoto, N; Okamura, S; Lee, H M; Pak, S; Im, M S; Lee, M G; Kim, W; Jeong, W S; Imai, K; Fujishiro, N; Shirahata, M; Suzuki, T; Ihara, C; Sakon, I; Matsuhara, Hideo; Wada, Takehiko; Matsuura, Shuji; Nakagawa, Takao; Kawada, Mitsunobu; Oyama, Youichi; Pearson, Chris P.; Oyabu, Shinki; Takagi, Toshinobu; Serjeant, Stephen; White, Glenn J.; Hanami, Hitoshi; Watarai, Hidenori; Takeuchi, Tsutomu T.; Kodama, Tadayuki; Arimoto, Nobuo; Okamura, Sadanori; Lee, Hyung Mok; Pak, Soojong; Im, Myung Shin; Lee, Myung Gyoon; Kim, Woojung; Jeong, Woong Seob; Imai, Koji; Fujishiro, Naofumi; Shirahata, Mai; Suzuki, Toyoaki; Ihara, Chiaki; Sakon, Itsuki

    2006-01-01

    AKARI (formerly ASTRO-F) is an infrared space telescope designed for an all-sky survey at 10-180 (mu)m, and deep pointed surveys of selected areas at 2-180 (mu)m. The deep pointed surveys with AKARI will significantly advance our understanding of galaxy evolution, the structure formation of the Universe, the nature of the buried AGNs, and the cosmic infrared background. Here we describe the important characteristics of the AKARI mission: the orbit, and the attitude control system, and investigate the optimum survey area based on the updated pre-flight sensitivities of AKARI, taking into account the cirrus confusion noise as well as the surface density of bright stars. The North Ecliptic Pole (NEP) is concluded to be the best area for 2-26 (mu)m deep surveys, while the low-cirrus noise regions around the South Ecliptic Pole (SEP) are worth considering for 50-180 (mu)m pointed surveys to high sensitivities limited by the galaxy confusion noise. Current observational plans of these pointed surveys are described ...

  20. Source finding, parametrization and classification for the extragalactic Effelsberg-Bonn HI Survey

    CERN Document Server

    Flöer, Lars; Kerp, Jürgen

    2014-01-01

    Context. Source extraction for large-scale HI surveys currently involves large amounts of manual labor. For data volumes expected from future HI surveys with upcoming facilities, this approach is not feasible any longer. Aims. We describe the implementation of a fully automated source finding, parametrization, and classification pipeline for the Effelsberg-Bonn HI Survey (EBHIS). With future radio astronomical facilities in mind, we want to explore the feasibility of a completely automated approach to source extraction for large-scale HI surveys. Methods. Source finding is implemented using wavelet denoising methods, which previous studies show to be a powerful tool, especially in the presence of data defects. For parametrization, we automate baseline fitting, mask optimization, and other tasks based on well-established algorithms, currently used interactively. For the classification of candidates, we implement an artificial neural network which is trained on a candidate set comprised of false positives from ...

  1. VIMOS Public Extragalactic Redshift Survey (VIPERS). The decline of cosmic star formation: quenching, mass, and environment connections

    CERN Document Server

    Cucciati, O; Bolzonella, M; Granett, B R; De Lucia, G; Branchini, E; Zamorani, G; Iovino, A; Garilli, B; Guzzo, L; Scodeggio, M; de la Torre, S; Abbas, U; Adami, C; Arnouts, S; Bottini, D; Cappi, A; Franzetti, P; Fritz, A; Krywult, J; Brun, V Le; Fevre, O Le; Maccagni, D; Malek, K; Marulli, F; Moutard, T; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Bel, J; Blaizot, J; Coupon, J; Hawken, A; Ilbert, O; Moscardini, L; Peacock, J A; Gargiulo, A

    2016-01-01

    [Abridged] We use the final data of the VIMOS Public Extragalactic Redshift Survey (VIPERS) to investigate the effect of environment on the evolution of galaxies between $z=0.5$ and $z=0.9$. We characterise local environment in terms of the density contrast smoothed over a cylindrical kernel, the scale of which is defined by the distance to the $5^{th}$ nearest neighbour. We find that more massive galaxies tend to reside in higher-density environments over the full redshift range explored. Defining star-forming and passive galaxies through their (NUV$-r$) vs ($r-K$) colours, we then quantify the fraction of star-forming over passive galaxies, $f_{\\rm ap}$, as a function of environment at fixed stellar mass. $f_{\\rm ap}$ is higher in low-density regions for galaxies with masses ranging from $\\log(\\mathcal{M}/\\mathcal{M}_\\odot)=10.38$ (the lowest value explored) to at least $\\log(\\mathcal{M}/\\mathcal{M}_\\odot)\\sim11.3$, although with decreasing significance going from smaller to larger masses. This is the first...

  2. Source finding, parametrization, and classification for the extragalactic Effelsberg-Bonn H i Survey

    Science.gov (United States)

    Flöer, L.; Winkel, B.; Kerp, J.

    2014-09-01

    Context. Source extraction for large-scale H i surveys currently involves large amounts of manual labor. For data volumes expected from future H i surveys with upcoming facilities, this approach is not feasible any longer. Aims: We describe the implementation of a fully automated source finding, parametrization, and classification pipeline for the Effelsberg-Bonn H i Survey (EBHIS). With future radio astronomical facilities in mind, we want to explore the feasibility of a completely automated approach to source extraction for large-scale H i surveys. Methods: Source finding is implemented using wavelet denoising methods, which previous studies show to be a powerful tool, especially in the presence of data defects. For parametrization, we automate baseline fitting, mask optimization, and other tasks based on well-established algorithms, currently used interactively. For the classification of candidates, we implement an artificial neural network, which is trained on a candidate set comprised of false positives from real data and simulated sources. Using simulated data, we perform a thorough analysis of the algorithms implemented. Results: We compare the results from our simulations to the parametrization accuracy of the H i Parkes All-Sky Survey (HIPASS) survey. Even though HIPASS is more sensitive than EBHIS in its current state, the parametrization accuracy and classification reliability match or surpass the manual approach used for HIPASS data.

  3. Spectroscopic Confusion: Its Impact on Current and Future Extragalactic HI Surveys

    CERN Document Server

    Jones, Michael G; Haynes, Martha P; Giovanelli, Riccardo

    2015-01-01

    We present a comprehensive model to predict the rate of spectroscopic confusion in HI surveys, and demonstrate good agreement with the observable confusion in existing surveys. Generically the action of confusion on the HI mass function was found to be a suppression of the number count of sources below the `knee', and an enhancement above it. This results in a bias, whereby the `knee' mass is increased and the faint end slope is steepened. For ALFALFA and HIPASS we find that the maximum impact this bias can have on the Schechter fit parameters is similar in magnitude to the published random errors. On the other hand, the impact of confusion on the HI mass functions of upcoming medium depth interferometric surveys, will be below the level of the random errors. In addition, we find that previous estimates of the number of detections for upcoming surveys with SKA-precursor telescopes may have been too optimistic, as the framework implemented here results in number counts between 60% and 75% of those previously p...

  4. The VIMOS Public Extragalactic Redshift Survey (VIPERS). A support vector machine classification of galaxies, stars, and AGNs

    Science.gov (United States)

    Małek, K.; Solarz, A.; Pollo, A.; Fritz, A.; Garilli, B.; Scodeggio, M.; Iovino, A.; Granett, B. R.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Branchini, E.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; de la Torre, S.; Franzetti, P.; Fumana, M.; Guzzo, L.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fevre, O.; Maccagni, D.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Schlagenhaufer, H.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.; Zamorani, G.

    2013-09-01

    Aims: The aim of this work is to develop a comprehensive method for classifying sources in large sky surveys and to apply the techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS). Using the optical (u∗,g',r',i') and near-infrared (NIR) data (z', Ks), we develop a classifier, based on broad-band photometry, for identifying stars, active galactic nuclei (AGNs), and galaxies, thereby improving the purity of the VIPERS sample. Methods: Support vector machine (SVM) supervised learning algorithms allow the automatic classification of objects into two or more classes based on a multidimensional parameter space. In this work, we tailored the SVM to classifying stars, AGNs, and galaxies and applied this classification to the VIPERS data. We trained the SVM using spectroscopically confirmed sources from the VIPERS and VVDS surveys. Results: We tested two SVM classifiers and concluded that including NIR data can significantly improve the efficiency of the classifier. The self-check of the best optical + NIR classifier has shown 97% accuracy in the classification of galaxies, 97% for stars, and 95% for AGNs in the 5-dimensional colour space. In the test of VIPERS sources with 99% redshift confidence, the classifier gives an accuracy equal to 94% for galaxies, 93% for stars, and 82% for AGNs. The method was applied to sources with low-quality spectra to verify their classification, hence increasing the security of measurements for almost 4900 objects. Conclusions: We conclude that the SVM algorithm trained on a carefully selected sample of galaxies, AGNs, and stars outperforms simple colour-colour selection methods and can be regarded as a very efficient classification method particularly suitable for modern large surveys. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programme 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint

  5. HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen

    CERN Document Server

    Minchin, R F; Boyce, P J; De Blok, W J G; Parker, Q A; Banks, G D; Freeman, K C; García, D A; Grossi, M; Haynes, R F; Knezek, P M; Lang, R H; Malin, D F; Price, R M; Stewart, I M; Wright, A E

    2003-01-01

    We have carried out an extremely long integration-time (9000 s/beam) 21-cm blind survey of 60 square degrees in Centaurus using the Parkes multibeam system. We find that the noise continues to fall as sqrt(t) throughout, enabling us to reach an HI column-density limit of 4.2 x 10^18 cm^-2 for galaxies with a velocity width of 200 km/s in the central 32 square degree region, making this the deepest survey to date in terms of column density sensitivity. The HI data are complemented by very deep optical observations from digital stacking of multi-exposure UK Schmidt Telescope R-band films, which reach an isophotal level of 26.5 R mag arcsec^-2 (~27.5 B mag arcsec^-2). 173 HI sources have been found, 96 of which have been uniquely identified with optical counterparts in the overlap area. There is not a single source without an optical counterpart. Although we have not measured the column-densities directly, we have inferred them from the optical sizes of their counterparts. All appear to have a column-density of ...

  6. The Calan-Yale Deep Extragalactic Research (CYDER) Survey: Optical Properties and Deep Spectroscopy of Extragalactic Serendipitous X-Ray Sources

    NARCIS (Netherlands)

    P.S. Coppi; E. Treister; F.J. Castander; T.J. Maccarone; E. Gawiser; J. Maza; D. Herrera; C.M. Urry; V. Gonzalez; C. Montoya; P. Pineda

    2004-01-01

    We present the results of deep optical imaging and spectroscopy of archival Chandra sources with intermediate fluxes (>1e-15 erg/cm2/sec). 267 Chandra sources were detected in 5 archival fields, with 106 spectroscopic IDs obtained using Magellan and the VLT. The survey is designed to fill the gap be

  7. The COSMOS HI Large Extragalactic Survey (CHILES): Probing HI Across Cosmic Time

    Science.gov (United States)

    Fernandez, Ximena; van Gorkom, Jacqueline H.; Momjian, Emmanuel; Chiles Team

    2015-01-01

    Hydrogen (HI) is the most abundant element in the Universe, and surprisingly, we know very little about the neutral hydrogen beyond z~0.08. The recently upgraded VLA makes it now possible to image the HI in galaxies beyond the local Universe. We are using the broad bandwidth of the VLA to instantaneously probe HI from z=0 to z=0.5 in one pointing of the COSMOS field. Once CHILES is complete, we will have HI images of 300 galaxies across cosmic time in different environments. These images will have a spatial resolution of 0.5 kpc for nearby galaxies and 30 kpc at z~0.5, and a velocity resolution of 7 km/s. In preparation for CHILES, we carried out a pilot study that observed the same pointing out to z~0.2, and detected HI in 33 galaxies in our volume. I will describe the science goals of CHILES, what we learned from the pilot study, and present preliminary results for the first 200 hours of observations of the full survey. After 1002 hours of integration time, we will have high-resolution HI images that will help us understand galaxy evolution across cosmic time and test predictions made by cosmological simulations.

  8. LEGUS: A Legacy ExtraGalactic UV Survey of Nearby Galaxies with HST

    Science.gov (United States)

    Lee, Janice C.; Calzetti, D.; Adamo, A.; Aloisi, A.; Andrews, J. E.; Brown, T. M.; Chandar, R.; Christian, C. A.; Cignoni, M.; Clayton, G. C.; Da Silva, R. L.; de Mink, S. E.; Dobbs, C.; Elmegreen, B.; Elmegreen, D. M.; Evans, A. S.; Fumagalli, M.; Gallagher, J. S.; Gouliermis, D.; Grebel, E.; Herrero-Davo`, A.; Hilbert, B.; Hunter, D. A.; Johnson, K. E.; Kennicutt, R.; Kim, H.; Krumholz, M. R.; Lennon, D. J.; Martin, C. D.; Nair, P.; Nota, A.; Pellerin, A.; Prieto, J.; Regan, M. W.; Sabbi, E.; Schaerer, D.; Schiminovich, D.; Smith, L. J.; Thilker, D. A.; Tosi, M.; Van Dyk, S. D.; Walterbos, R. A.; Whitmore, B. C.; Wofford, A.

    2014-01-01

    We introduce LEGUS, a Hubble Space Telescope program which will provide a critical missing piece in our efforts to solve the star formation puzzle: a robust characterization of the links between star formation on two fundamental scales, those of individual young stars, stellar clusters and associations over parsec scales, and of galaxy disks over kiloparsec scales. As a 154-orbit Treasury survey, LEGUS has begun obtaining NUV,U,B,V,I imaging of 50 star-forming galaxies, at distances of 4-12 Mpc. The dataset is guaranteed to have exceptional legacy value, as the targets have been carefully selected to uniformly sample a full range of global galaxy properties, as well as have the largest suites of multi-wavelength ancillary data available. The high-resolution HST NUV and U imaging are key for deriving accurate recent (formation histories from resolved massive stars, along with the ages and masses for complete samples of star clusters and associations in each galaxy. We present an overview of the sample, the observations, and provide a first look at the science that the LEGUS team is pursuing. A companion poster presents the status of the program, and a more detailed description of the extensive data products being developed which will seed community science, and provide a foundation for studies of star formation with ALMA and JWST.

  9. Hard X-ray Luminosity Function of Tidal Disruption Events: First Results from MAXI Extragalactic Survey

    CERN Document Server

    Kawamuro, Taiki; Shidatsu, Megumi; Hori, Takafumi; Kawai, Nobuyuki; Negoro, Hitoshi; Mihara, Tatehiro

    2016-01-01

    We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of $-5/3$, a systematic search using the MAXI data in the first 37 months detected four TDEs, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is $0.0007$--$34\\%$. We confirm that at $z \\lesssim 1.5$ the...

  10. The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

    Science.gov (United States)

    Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Block, J.; Boselli, A.; Brisbin, D.; Buat, V.; Burgarella, D.; Castro-Rodriquez, N.; Cava, A.; Chanial, P.; Chapin, E.; Chapman, S.; Clements, D. L.; Conley, A.; Conversi, L.; Dowell, C. D.; Dunlop, J. S.; Dwek, E.

    2012-01-01

    We investigate the potential of submm-mm and submm-mm-radio photometric redshifts using a sample of mm-selected sources as seen at 250, 350 and 500 micron by the SPIRE instrument on Herschel. From a sample of 63 previously identified mm sources with reliable radio identifications in the Great Observatories Origins Deep Survey North and Lockman Hole North fields, 46 (73 per cent) are found to have detections in at least one SPIRE band. We explore the observed submm/mm color evolution with redshift, finding that the colors of mm sources are adequately described by a modified blackbody with constant optical depth Tau = (Nu/nu(sub 0))(exp Beta), where Beta = +1.8 and nu(sub 0) = c/100 micron. We find a tight correlation between dust temperature and IR luminosity. Using a single model of the dust temperature and IR luminosity relation, we derive photometric redshift estimates for the 46 SPIRE-detected mm sources. Testing against the 22 sources with known spectroscopic or good quality optical/near-IR photometric redshifts, we find submm/mm photometric redshifts offer a redshift accuracy of (absolute value of Delta sub (z))/(1 + z) = 0.16 (absolute value of Delta sub (z)) = 0.51). Including constraints from the radio-far-IR correlation, the accuracy is improved to (absolute value of Delta sub (z))/(1 + z) = 0.14 (((absolute value of Delta sub (z))) = 0.45). We estimate the redshift distribution of mm-selected sources finding a significant excess at Z > 3 when compared to approx 8S0 micron selected samples.

  11. SXDF-ALMA 2 Arcmin^2 Deep Survey: Resolving and Characterizing the Infrared Extragalactic Background Light Down to 0.5 mJy

    CERN Document Server

    Yamaguchi, Yuki; Kohno, Kotaro; Aretxaga, Itziar; Dunlop, James S; Hatsukade, Bunyo; Hughes, David; Ikarashi, Soh; Ishii, Shun; Ivison, Rob J; Izumi, Takuma; Kawabe, Ryohei; Kodama, Tadayuki; Lee, Minju; Makiya, Ryu; Matsuda, Yuichi; Nakanishi, Kouichiro; Ohta, Kouji; Rujopakarn, Wiphu; Tadaki, Ken-ichi; Umehata, Hideki; Wang, Wei-Hao; Wilson, Grant W; Yabe, Kiyoto; Yun, Min S

    2016-01-01

    We present a multi-wavelength analysis of five submillimeter sources (S_1.1mm = 0.54-2.02 mJy) that were detected during our 1.1-mm-deep continuum survey in the SXDF-UDS-CANDELS field (2 arcmin^2, 1sigma = 0.055 mJy beam^-1) using the Atacama Large Millimeter/submillimeter Array (ALMA). The two brightest sources correspond to a known single-dish (AzTEC) selected bright submillimeter galaxy (SMG), whereas the remaining three are faint SMGs newly uncovered by ALMA. If we exclude the two brightest sources, the contribution of the ALMA-detected faint SMGs to the infrared extragalactic background light is estimated to be ~ 4.1^{+5.4}_{-3.0} Jy deg^{-2}, which corresponds to ~ 16^{+22}_{-12}% of the infrared extragalactic background light. This suggests that their contribution to the infrared extragalactic background light is as large as that of bright SMGs. We identified multi-wavelength counterparts of the five ALMA sources. One of the sources (SXDF-ALMA3) is extremely faint in the optical to near-infrared region...

  12. The Star-Formation History of BCGs to z = 1.8 from the SpARCS/SWIRE Survey: Evidence for significant in-situ star formation at high-redshift

    CERN Document Server

    Webb, Tracy; Noble, Allison; Bonaventura, Nina; Geach, James; Hezevah, Yashar; Lidman, Chris; Wilson, Gillian; Yee, H K C; Surace, Jason; Shupe, David

    2015-01-01

    We present the results of a MIPS-24um study of the Brightest Cluster Galaxies (BCGs) of 535 high-redshift galaxy clusters. The clusters are drawn from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS), which effectively provides a sample selected on total stellar mass, over 0.2 100uJy, or 23%. The luminosity-limited detection rate of BCGs in similar richness clusters (Ngal> 12) increases rapidly with redshift. Above z ~ 1, an average of ~20\\% of the sample have 24um-inferred infrared luminosities of LIR > 10^12 Lsun, while the fraction below z ~ 1 exhibiting such luminosities is < 1 \\%. The Spitzer-IRAC colors indicate the bulk of the 24um-detected population is predominantly powered by star formation, with only 7/125 galaxies lying within the color region inhabited by Active Galactic Nuclei (AGN). Simple arguments limit the star-formation activity to several hundred million years and this may therefore be indicative of the timescale for AGN feedback to halt the star formation. Below reds...

  13. Milky Way Scattering Properties and Intrinsic Sizes of AGN Cores Probed by VLBI Surveys of Compact Extragalactic Radio Sources

    CERN Document Server

    Pushkarev, A B

    2015-01-01

    We have measured the angular sizes of radio cores of active galactic nuclei (AGN) and analyzed their sky distributions and frequency dependencies to study synchrotron opacity in AGN jets and the strength of angular broadening in the interstellar medium. We have used archival very long baseline interferometry (VLBI) data of more than 3000 compact extragalactic radio sources observed at frequencies, $\

  14. A Wideband Polarization Survey of the Extragalactic Sky at 2-4 GHz: A Science White Paper for the VLA Sky Survey

    CERN Document Server

    Mao, Sui Ann; Gaensler, Bryan; Rudnick, Lawrence; Stil, Jeroen; Purcell, Cormac; Beck, Rainer; Farnes, Jamie; O'Sullivan, Shane; Schnitzeler, Dominic; Willis, Tony; Sun, Xiaohui; Carretti, Ettore; Dolag, Klaus; Sokoloff, Dmitry; Kothes, Roland; Wolleben, Maik; Heald, George; Geisbuesch, Joern; Robishaw, Tim; Afonso, Jose; Magalhães, Antonio Mario; Lundgren, Britt; Haverkorn, Marijke; Oppermann, Niels; Taylor, Russ

    2014-01-01

    A VLA Sky Survey of the extragalactic sky at S band (2-4 GHz) with polarization information can uniquely probe the magneto-ionic medium in a wide range of astrophysical environments over cosmic time. For a shallow all-sky survey, we expect to detect over 4 million sources in total intensity $>$ 0.45 mJy beam$^{-1}$ and over 2.2$\\times$10$^5$ sources in polarized intensity. With these new observations, we expect to discover new classes of polarized radio sources in very turbulent astrophysical environments and those with extreme values of Faraday depth. Moreover, by determining reliable Faraday depths and by modeling depolarization effects, we can derive properties of the magneto-ionic medium associated with AGNs, absorption line systems and galaxies, addressing the following unresolved questions: (1) What is the covering fraction, the degree of turbulence and the origin of absorption line systems? (2) What is the thermal content in AGNs and radio galaxies? (3) How do AGNs and galaxies evolve over cosmic time?...

  15. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Ωm0 from the galaxy clustering ratio measured at z ~ 1

    Science.gov (United States)

    Bel, J.; Marinoni, C.; Granett, B. R.; Guzzo, L.; Peacock, J. A.; Branchini, E.; Cucciati, O.; de la Torre, S.; Iovino, A.; Percival, W. J.; Steigerwald, H.; Abbas, U.; Adami, C.; Arnouts, S.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Phleps, S.; Wolk, M.; Zamorani, G.

    2014-03-01

    We use a sample of about 22 000 galaxies at 0.65 Public Extragalactic Redshift Survey (VIPERS) Public Data Release 1 (PDR-1) catalogue, to constrain the cosmological model through a measurement of the galaxy clustering ratio ηg,R. This statistic has favourable properties, which is defined as the ratio of two quantities characterizing the smoothed density field in spheres of a given radius R: the value of its correlation function on a multiple of this scale, ξ(nR), and its variance σ2(R). For sufficiently large values of R, this is a universal number, which captures 2-point clustering information independently of the linear bias and linear redshift-space distortions of the specific galaxy tracers. In this paper, we discuss how to extend the application of ηg,R to quasi-linear scales and how to control and remove observational selection effects, which are typical of redshift surveys as VIPERS, in detail. We verify the accuracy and efficiency of these procedures using mock catalogues that match the survey selection process. These results show the robustness of ηg,R to non-linearities and observational effects, which is related to its very definition as a ratio of quantities that are similarly affected. At an effective redshift z = 0.93, we measured the value ηg,R(15) = 0.141 ± 0.013 at R = 5h-1 Mpc. Within a flat ΛCDM cosmology and by including the best available priors on H0, ns and baryon density, we obtain a matter density parameter at the current epoch Ωm,0 = 0.270-0.025+0.029. In addition to the great precision achieved on our estimation of Ωm using VIPERS PDR-1, this result is remarkable because it appears to be in good agreement with a recent estimate at z ≃ 0.3, which was obtained by applying the same technique to the SDSS-LRG catalogue. It, therefore, supports the robustness of the present analysis. Moreover, the combination of these two measurements at z ~ 0.3 and z ~ 0.9 provides us with a very precise estimate of Ωm,0 = 0.274 ± 0.017, which

  16. SXDF-ALMA 2 arcmin2 deep survey: Resolving and characterizing the infrared extragalactic background light down to 0.5 mJy

    Science.gov (United States)

    Yamaguchi, Yuki; Tamura, Yoichi; Kohno, Kotaro; Aretxaga, Itziar; Dunlop, James S.; Hatsukade, Bunyo; Hughes, David; Ikarashi, Soh; Ishii, Shun; Ivison, Rob J.; Izumi, Takuma; Kawabe, Ryohei; Kodama, Tadayuki; Lee, Minju; Makiya, Ryu; Matsuda, Yuichi; Nakanishi, Kouichiro; Ohta, Kouji; Rujopakarn, Wiphu; Tadaki, Ken-ichi; Umehata, Hideki; Wang, Wei-Hao; Wilson, Grant W.; Yabe, Kiyoto; Yun, Min S.

    2016-10-01

    We present a multiwavelength analysis of five submillimeter sources (S1.1mm = 0.54-2.02 mJy) that were detected during our 1.1 mm deep continuum survey in the Subaru/XMM-Newton Deep Survey Field (SXDF)-UDS-CANDELS field (2 arcmin2, 1σ = 0.055 mJy beam-1) using the Atacama Large Millimeter/submillimeter Array (ALMA). The two brightest sources correspond to a known single-dish (AzTEC) selected bright submillimeter galaxy (SMG), whereas the remaining three are faint SMGs newly uncovered by ALMA. If we exclude the two brightest sources, the contribution of the ALMA-detected faint SMGs to the infrared extragalactic background light is estimated to be ˜ 4.1^{+5.4}_{-3.0}Jy deg-2, which corresponds to ˜ 16^{+22}_{-12}% of the infrared extragalactic background light. This suggests that their contribution to the infrared extragalactic background light is as large as that of bright SMGs. We identified multiwavelength counterparts of the five ALMA sources. One of the sources (SXDF-ALMA3) is extremely faint in the optical to near-infrared region despite its infrared luminosity (L_IR˜eq 1× 10^{12} L_{⊙} or SFR ≃ 100 M⊙ yr-1). By fitting the spectral energy distributions at the optical-to-near-infrared wavelengths of the remaining four ALMA sources, we obtained the photometric redshifts (zphoto) and stellar masses (M*): zphoto ≃ 1.3-2.5, M* ≃ (3.5-9.5) × 1010 M⊙. We also derived their star formation rates (SFRs) and specific SFRs as ≃30-200 M⊙ yr-1 and ≃0.8-2 Gyr-1, respectively. These values imply that they are main sequence star-forming galaxies.

  17. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Measuring non-linear galaxy bias at z ~ 0.8

    Science.gov (United States)

    Di Porto, C.; Branchini, E.; Bel, J.; Marulli, F.; Bolzonella, M.; Cucciati, O.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Marinoni, C.; Moscardini, L.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Cappi, A.; Coupon, J.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Marchetti, A.; Martizzi, D.; Mellier, Y.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Viel, M.; Wolk, M.; Zamorani, G.

    2016-10-01

    Aims: We use the first release of the VImos Public Extragalactic Redshift Survey of galaxies (VIPERS) of ~50 000 objects to measure the biasing relation between galaxies and mass in the redshift range z = [ 0.5,1.1 ]. Methods: We estimate the 1-point distribution function [PDF] of VIPERS galaxies from counts in cells and, assuming a model for the mass PDF, we infer their mean bias relation. The reconstruction of the bias relation is performed through a novel method that accounts for Poisson noise, redshift distortions, inhomogeneous sky coverage. and other selection effects. With this procedure we constrain galaxy bias and its deviations from linearity down to scales as small as 4 h-1 Mpc and out to z = 1.1. Results: We detect small (up to 2%) but statistically significant (up to 3σ) deviations from linear bias. The mean biasing function is close to linear in regions above the mean density. The mean slope of the biasing relation is a proxy to the linear bias parameter. This slope increases with luminosity, which is in agreement with results of previous analyses. We detect a strong bias evolution only for z> 0.9, which is in agreement with some, but not all, previous studies. We also detect a significant increase of the bias with the scale, from 4 to 8 h-1 Mpc , now seen for the first time out to z = 1. The amplitude of non-linearity depends on redshift, luminosity, and scale, but no clear trend is detected. Owing to the large cosmic volume probed by VIPERS, we find that the mismatch between the previous estimates of bias at z ~ 1 from zCOSMOS and VVDS-Deep galaxy samples is fully accounted for by cosmic variance. Conclusions: The results of our work confirm the importance of going beyond the over-simplistic linear bias hypothesis showing that non-linearities can be accurately measured through the applications of the appropriate statistical tools to existing datasets like VIPERS. Based on observations collected at the European Southern Observatory, Paranal, Chile

  18. The VIMOS Public Extragalactic Redshift Survey (VIPERS). The decline of cosmic star formation: quenching, mass, and environment connections

    Science.gov (United States)

    Cucciati, O.; Davidzon, I.; Bolzonella, M.; Granett, B. R.; De Lucia, G.; Branchini, E.; Zamorani, G.; Iovino, A.; Garilli, B.; Guzzo, L.; Scodeggio, M.; de la Torre, S.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Cappi, A.; Franzetti, P.; Fritz, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Moutard, T.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Bel, J.; Blaizot, J.; Coupon, J.; Hawken, A.; Ilbert, O.; Moscardini, L.; Peacock, J. A.; Gargiulo, A.

    2017-06-01

    We use the final data of the VIMOS Public Extragalactic Redshift Survey (VIPERS) to investigate the effect of the environment on the evolution of galaxies between z = 0.5 and z = 0.9. We characterise local environment in terms of the density contrast smoothed over a cylindrical kernel, the scale of which is defined by the distance to the fifth nearest neighbour. This is performed by using a volume-limited sub-sample of galaxies complete up to z = 0.9, but allows us to attach a value of local density to all galaxies in the full VIPERS magnitude-limited sample to i reside in higher-density environments over the full redshift range explored. Defining star-forming and passive galaxies through their (NUV-r) vs. (r-K) colours, we then quantify the fraction of star-forming over passive galaxies, fap, as a function of environment at fixed stellar mass. fap is higher in low-density regions for galaxies with masses ranging from log (ℳ/ℳ⊙) = 10.38 (the lowest value explored) to at least log (ℳ/ℳ⊙) 11.3, although with decreasing significance going from lower to higher masses. This is the first time that environmental effects on high-mass galaxies are clearly detected at redshifts as high as z 0.9. We compared these results to VIPERS-like galaxy mock catalogues based on a widely used galaxy formation model. The model correctly reproduces fap in low-density environments, but underpredicts it at high densities. The discrepancy is particularly strong for the lowest-mass bins. We find that this discrepancy is driven by an excess of low-mass passive satellite galaxies in the model. In high-density regions, we obtain a better (although not perfect) agreement of the model fap with observations by studying the accretion history of these model galaxies (that is, the times when they become satellites), by assuming either that a non-negligible fraction of satellites is destroyed, or that their quenching timescale is longer than 2 Gyr. Based on observations collected at the

  19. CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics

    CERN Document Server

    Koekemoer, Anton M; Ferguson, Henry C; Grogin, Norman A; Kocevski, Dale D; Koo, David C; Lai, Kamson; Lotz, Jennifer M; Lucas, Ray A; McGrath, Elizabeth J; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G; Rodney, Steve A; Strolger, Louis; Casertano, Stefano; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Almaini, David M Alexander Omar; Ashby, Matthew L N; Barden, Marco; Bell, Eric F; Bournaud, Frédéric; Brown, Thomas M; Caputi, Karina I; Cassata, Paolo; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J; Cooray, Asantha Roshan; Croton, Darren J; Daddi, Emanuele; Davé, Romeel; de Mello, Duilia F; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L; Dunlop, James S; Dutton, Aaron A; Elbaz, David; Fazio, Giovanni G; Filippenko, Alex V; Finkelstein, Steven L; Frazer, Chris; Gardner, Jonathan P; Garnavich, Peter M; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G; Häussler, Boris; Herrington, Jessica; Hopkins, Philip F; Huang, Jia-Sheng; Jha, Saurabh; Johnson, Andrew; Kartaltepe, Jeyhan S; Khostovan, Ali Ahmad; Kirshner, Robert P; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J; McIntosh, Daniel H; McLure, Ross J; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A; Nielsen, Jennifer L; Niemi, Sami; Noeske, Kai G; Papovich, Casey J; Pentericci, Laura; Pope, Alexandra; Primack, Joel R; Ravindranath, Swara; Reddy, Naveen A; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R; Rosario, David J; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S; Spinrad, Hyron; Straughn, Amber N; Telford, Olivia; Teplitz, Harry I; Trump, Jonathan R; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R; Wandro, Pat; Wechsler, Risa H; Weiner, Benjamin J; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at $z\\sim1.5-8$, and to study Type Ia SNe beyond $z>1.5$. Five premier multi-wavelength sky regions are selected, each with extensive multiwavelength observations. The primary CANDELS data consist of imaging obtained in the Wide Field Camera 3 / infrared channel (WFC3/IR) and UVIS channel, along with the Advanced Camera for Surveys (ACS). The CANDELS/Deep survey covers \\sim125 square arcminutes within GOODS-N and GOODS-S, while the remainder consists of the CANDELS/Wide survey, achieving a total of \\sim800 square arcminutes across GOODS and three additional fields (EGS, COSMOS, and UDS). We summarize the observational aspects of the survey as motivated by the scientific goals and present a detailed description of the data reduction procedures and products from...

  20. Survey of IRAC-Selected Galaxy Cluster Candidates at z>1.3

    Science.gov (United States)

    Papovich, Casey; Brodwin, Mark; Lotz, Jennifer; Momcheva, Ivelina; Rudnick, Gregory; Tran, Kim Vy; Willmer, Christopher; McCarthy, Patrick; Khan, Sophia; Rieke, Marcia; Sivanandam, Suresh

    2008-08-01

    We request 2 nights with Magellan/IMACS to target candidate galaxy clusters at z>1.3 selected as overdensities of galaxies with red SPITZER/IRAC colors (mone - mtwo > -0.1 AB mag) from the 50 deg^2 SPITZER Wide Infrared Extragalactic (SWIRE) survey. This simple, highly efficient IRAC color selection identifies >90% of galaxies with z>1.3 and it is sensitive to red and blue galaxies nearly equally, avoiding possible biases associated with other high- redshift cluster searches. These cluster candidates show strong angular clustering consistent with expectations for the progenitors of present- day galaxy clusters, and therefore they represent real physical structures (and not projections of galaxies along the line of sight). Here, we propose a pilot program to measure the redshifts of >200 galaxies in 18 candidate galaxy clusters, which would double the known number of spectroscopically confirmed clusters at these redshifts. Our primary goal is to use the deep spectroscopy to confirm the candidate clusters in redshift space (requiring >5 galaxies per cluster) and to verify our cluster-selection algorithm, enabling further studies using the full 50 deg^2 SWIRE fields. We will also use these data to compare the properties of passively evolving versus star-forming galaxies in these clusters to those in the field, and to study estimators of cluster masses.

  1. The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds: VII. Ophiuchus Observed with MIPS

    CERN Document Server

    Padgett, Deborah L; Stapelfeldt, Karl R; Chapman, Nicholas L; Lai, Shih-Ping; Mundy, Lee G; Evans, Neal J; Brooke, Timothy Y; Cieza, Lucas A; Spiesman, William J; Noriega-Crespo, Alberto; McCabe, Caer-Eve; Allen, Lori E; Blake, Geoffrey A; Harvey, Paul M; Huard, Tracy L; Jorgensen, Jes K; Koerner, David W; Myers, Philip C; Sargent, Anneila I; Teuben, Peter; van Dishoeck, Ewine F; Wahhaj, Zahed; Young, Kaisa E

    2007-01-01

    We present maps of 14.4 deg^2 of the Ophiuchus dark clouds observed by the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS). These high quality maps depict both numerous point sources as well as extended dust emission within the star-forming and non-star-forming portions of these clouds. Using PSF-fitting photometry, we detect 5779 sources at 24 um and 81 sources at 70 um at the 10 sigma level of significance. Three hundred twenty-three candidate young stellar objects (YSOs) were identified according to their positions on the MIPS/2MASS K versus K$-$[24] color-magnitude diagrams as compared to 24 um detections in the SWIRE extragalactic survey. We find that more than half of the YSO candidates, and almost all the ones with protostellar Class I spectral energy distributions, are confined to the known cluster and aggregates.

  2. The NuSTAR Extragalactic Surveys: The Number Counts of Active Galactic Nuclei and the Resolved Fraction of the Cosmic X-ray Background

    CERN Document Server

    Harrison, F A; Civano, F; Lansbury, G; Mullaney, J R; Ballantyne, D R; Alexander, D M; Stern, D; Ajello, M; Barret, D; Bauer, F E; Balokovic, M; Brandt, W N; Brightman, M; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Del Moro, A; Forster, K; Gandhi, P; Giommi, P; Grefenstette, B W; Hailey, C J; Hickox, R C; Hornstrup, A; Kitaguchi, T; Koglin, J; Luo, B; Madsen, K K; Mao, P H; Miyasaka, H; Mori, K; Perri, M; Pivovaroff, M; Puccetti, S; Rana, V; Treister, E; Walton, D; Westergaard, N J; Wik, D; Zappacosta, L; Zhang, W W; Zoglauer, A

    2015-01-01

    We present the 3-8 keV and 8-24 keV number counts of active galactic nuclei (AGN) identified in the NuSTAR extragalactic surveys. NuSTAR has now resolved approximately 35% of the X-ray background in the 8-24 keV band, directly identifying AGN with obscuring columns up to 1e25 / cm2. In the softer 3-8 keV band the number counts are in general agreement with those measured by XMM-Newton and Chandra over the flux range 5e-15 1e-11 erg/cm2/s, for any realistic AGN spectral model. The most natural explanation for the difference is an evolution in the AGN poulation between the very local objects seen by BAT and the more distant (0.5 < z < 1) NuSTAR sample that is not accounted for in the current models.

  3. The VIMOS Public Extragalactic Redshift Survey (VIPERS). The matter density and baryon fraction from the galaxy power spectrum at redshift $0.6

    CERN Document Server

    Rota, S; Bel, J; Guzzo, L; Peacock, J A; Wilson, M J; Pezzotta, A; de la Torre, S; Garilli, B; Bolzonella, M; Scodeggio, M; Abbas, U; Adami, C; Bottini, D; Cappi, A; Cucciati, O; Davidson, I; Franzetti, P; Fritz, A; Iovino, A; Krywult, J; Brun, V Le; Fèvre, O Le; Mascagni, D; Małek, K; Marulli, F; Percival, W J; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Arnouts, S; Branchini, E; Coupon, J; De Lucia, G; Ilbert, O; Moscardini, L; Moutard, T

    2016-01-01

    We use the final catalogue of the VIMOS Public Extragalactic Redshift Survey (VIPERS) to measure the power spectrum of the galaxy distribution at high redshift, presenting results that extend beyond $z=1$ for the first time. We apply an FFT technique to four independent sub-volumes comprising a total of $51,728$ galaxies at $0.6survey). We concentrate here on the shape of the direction-averaged power spectrum in redshift space, explaining the level of modelling of redshift-space anisotropies and the anisotropic survey window function that are needed to deduce this in a robust fashion. We then use covariance matrices derived from a large ensemble of mock datasets in order to fit the spectral data. The results are well matched by a standard $\\Lambda$CDM model, with density parameter $\\Omega_M h =\\smash{0.227^{+0.063}_{-0.050}}$ and baryon fraction $\\smash{f_B=\\Omega_B/\\Omega_M=0.220^{+0.058}_{-0.072}}$. These inferences from the high-$z$ galaxy dis...

  4. Extragalactic millimeter-wave point-source catalog, number counts and statistics from 771 deg{sup 2} of the SPT-SZ survey

    Energy Technology Data Exchange (ETDEWEB)

    Mocanu, L. M.; Crawford, T. M.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Vieira, J. D. [California Institute of Technology, Pasadena, CA 91125 (United States); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Aravena, M. [European Southern Observatory, Alonso de Córdova 3107, Vitacura Santiago (Chile); Austermann, J. E.; Everett, W. B.; Halverson, N. W. [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); Béthermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CEA-Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Bothwell, M. [Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax NS B3H 3J5 (Canada); Cho, H.-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); De Haan, T.; Dobbs, M. A. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); George, E. M., E-mail: lmocanu@uchicago.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others

    2013-12-10

    We present a point-source catalog from 771 deg{sup 2} of the South Pole Telescope Sunyaev-Zel'dovich survey at 95, 150, and 220 GHz. We detect 1545 sources above 4.5σ significance in at least one band. Based on their relative brightness between survey bands, we classify the sources into two populations, one dominated by synchrotron emission from active galactic nuclei, and one dominated by thermal emission from dust-enshrouded star-forming galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all sources against external catalogs and find 189 unidentified synchrotron sources and 189 unidentified dusty sources. The dusty sources without counterparts are good candidates for high-redshift, strongly lensed submillimeter galaxies. We derive number counts for each population from 1 Jy down to roughly 11, 4, and 11 mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population models and find that none of the models we consider for either population provide a good fit to the measured counts in all three bands. The disparities imply that these measurements will be an important input to the next generation of millimeter-wave extragalactic source population models.

  5. Deep 610-MHz Giant Metrewave Radio Telescope observations of the Spitzer extragalactic First Look Survey field - III. The radio properties of Infrared-Faint Radio Sources

    CERN Document Server

    Garn, Timothy

    2008-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of source which are bright at radio frequencies, but do not appear in deep infrared images. We report the detection of 14 IFRSs within the Spitzer extragalactic First Look Survey field, eight of which are detected near to the limiting magnitude of a deep R-band image of the region, at R ~ 24.5. Sensitive Spitzer Space Telescope images are stacked in order to place upper limits on their mid-infrared flux densities, and using recent 610-MHz and 1.4-GHz observations we find that they have spectral indices which vary between alpha = 0.05 and 1.38, where we define alpha such that S = S_0 nu^(- alpha), and should not be thought of as a single source population. We place constraints on the luminosity and linear size of these sources, and through comparison with well-studied local objects in the 3CRR catalogue demonstrate that they can be modelled as being compact ( 4).

  6. Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar and Planetary Science

    CERN Document Server

    Doré, Olivier; Ashby, Matt; Banerjee, Pancha; Battaglia, Nick; Bauer, James; Benjamin, Robert A; Bleem, Lindsey E; Bock, Jamie; Boogert, Adwin; Bull, Philip; Capak, Peter; Chang, Tzu-Ching; Chiar, Jean; Cohen, Seth H; Cooray, Asantha; Crill, Brendan; Cushing, Michael; de Putter, Roland; Driver, Simon P; Eifler, Tim; Feng, Chang; Ferraro, Simone; Finkbeiner, Douglas; Gaudi, B Scott; Greene, Tom; Hillenbrand, Lynne; Höflich, Peter A; Hsiao, Eric; Huffenberger, Kevin; Jansen, Rolf A; Jeong, Woong-Seob; Joshi, Bhavin; Kim, Duho; Kim, Minjin; Kirkpatrick, J Davy; Korngut, Phil; Krause, Elisabeth; Kriek, Mariska; Leistedt, Boris; Li, Aigen; Lisse, Carey M; Mauskopf, Phil; Mechtley, Matt; Melnick, Gary; Mohr, Joseph; Murphy, Jeremiah; Neben, Abraham; Neufeld, David; Nguyen, Hien; Pierpaoli, Elena; Pyo, Jeonghyun; Rhodes, Jason; Sandstrom, Karin; Schaan, Emmanuel; Schlaufman, Kevin C; Silverman, John; Su, Kate; Stassun, Keivan; Stevens, Daniel; Strauss, Michael A; Tielens, Xander; Tsai, Chao-Wei; Tolls, Volker; Unwin, Stephen; Viero, Marco; Windhorst, Rogier A; Zemcov, Michael

    2016-01-01

    SPHEREx is a proposed SMEX mission selected for Phase A. SPHEREx will carry out the first all-sky spectral survey and provide for every 6.2" pixel a spectra between 0.75 and 4.18 $\\mu$m [with R$\\sim$41.4] and 4.18 and 5.00 $\\mu$m [with R$\\sim$135]. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light. It is readily apparent, however, that many other questions in astrophysics and planetary sciences could be addressed with the SPHEREx data. The SPHEREx team convened a community workshop in February 2016, with the intent of enlisting the aid of a larger group of scientists in defining these questions. This paper summarizes the rich and varied menu of investigations that was laid out. It includes studies of the composition of main belt and Trojan/Greek asteroids; mapping the zodiacal light with unprecedented spatial and spectral resolution; identifying and stud...

  7. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Luminosity and stellar mass dependence of galaxy clustering at 0.5

    CERN Document Server

    Marulli, F; Branchini, E; Davidzon, I; de la Torre, S; Granett, B R; Guzzo, L; Iovino, A; Moscardini, L; Pollo, A; Abbas, U; Adami, C; Arnouts, S; Bel, J; Bottini, D; Cappi, A; Coupon, J; Cucciati, O; De Lucia, G; Fritz, A; Franzetti, P; Fumana, M; Garilli, B; Ilbert, O; Krywult, J; Brun, V Le; Fevre, O Le; Maccagni, D; Malek, K; McCracken, H J; Paioro, L; Polletta, M; Schlagenhaufer, H; Scodeggio, M; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Burden, A; Di Porto, C; Marchetti, A; Marinoni, C; Mellier, Y; Nichol, R C; Peacock, J A; Percival, W J; Phleps, S; Wolk, M; Zamorani, G

    2013-01-01

    We investigate the dependence of galaxy clustering on luminosity and stellar mass, in the redshift range 0.5Extragalactic Redshift Survey (VIPERS). To characterize the spatial properties of the VIPERS galaxies, we measure the redshift-space two-point correlation functions (2PCF), and the projected correlation function, in samples covering different ranges of B-band absolute magnitudes and stellar masses. We consider both threshold and binned galaxy samples, with median B-band absolute magnitudes -21.6

  8. The Extragalactic Lens VLBI Imaging Survey (ELVIS). I. A Search for the Central Image in the Gravitational Lens PMN J1838-3427

    CERN Document Server

    Boyce, E R; Hewitt, J N; Myers, S T; Boyce, Edward R.; Winn, Joshua N.; Hewitt, Jacqueline N.; Myers, Steven T.

    2006-01-01

    The Extragalactic Lens VLBI Imaging Survey (ELVIS) searches for central images of lensed radio quasars, in order to measure the central density profiles of distant galaxies. Here we present sensitive multi-epoch Very Long Baseline Array (VLBA) observations of PMN J1838-3427 at 8 GHz, with a 1 sigma noise level of 38 microJy beam^(-1). Based on the absence of a central image of the background source at this level, we explore the possibilities for the central matter distribution in the lens galaxy. A power-law density profile, rho ~ r^(-gamma), must have gamma > 1.93. Thus the density profile is close to an isothermal profile (gamma = 2) or steeper. The upper limit on any constant-density core in an otherwise isothermal profile is ~< 5 parsecs. We also derive the constraints on models in which the density profile is isothermal on kiloparsec scales, but is allowed to have a different power law in the central ~100 parsecs. If the lens galaxy harbors a supermassive black hole, the galaxy profile is allowed to b...

  9. The Spitzer Space Telescope Extra-Galactic First Look Survey: 24 micron data reduction, catalog, and source identification

    CERN Document Server

    Fadda, D; Armus, L; Chapman, S C; Choi, P I; Fang, F; Frayer, D T; Heinrichsen, I; Helou, G; Im, M; Lacy, M; Makovoz, D; Marleau, F R; Shupe, D L; Soifer, B T; Squires, G K; Storrie-Lombardi, L J; Surace, J; Teplitz, H I; Wilson, G; Yan, L; Fadda, Dario

    2006-01-01

    We present the reduction of the 24 micron data obtained during the first cosmological survey performed by the Spitzer Space Telescope (First Look Survey, FLS). The survey consists of a shallow observation of 2.5x2 sq deg centered at 17h18m +59d30m (main survey) and a deeper observation of 1x0.5 sq deg centered at 17h17m +59d45m(verification survey). Issues with the reduction of the 24 micron MIPS data are discussed and solutions to attenuate instrumental effects are proposed and applied to the data. Approximately 17000 sources are extracted with a SNR greater than five. The photometry of the point sources is evaluated through PSF fitting using an empirical PSF derived from the data. Aperture corrections and the absolute calibration have been checked using stars in the field. Astrometric and photometric errors depend on the SNR of the source varying between 0.35-1 arcsec and 5-15%, respectively, for sources detected at 20-5 sigma. The flux of the 123 extended sources have been estimated through aperture photom...

  10. Extragalactic Jets as Probes of Distant Clusters of Galaxies and the Clusters Occupied by Bent Radio AGN (COBRA) Survey

    CERN Document Server

    Blanton, Elizabeth L; Wing, Joshua D; Ashby, M L N; Golden-Marx, Emmet; Brodwin, Mark; Douglass, E M; Randall, Scott W; Clarke, T E

    2014-01-01

    We are conducting a large survey of distant clusters of galaxies using radio sources with bent jets and lobes as tracers. These radio sources are driven by AGN and achieve their bent morphologies through interaction with the surrounding gas found in clusters of galaxies. Based on low-redshift studies, these types of sources can be used to identify clusters very efficiently. We present initial results from our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and it has revealed $\\sim$200 distant clusters or proto-clusters in the redshift range $z\\sim0.7 - 3.0$. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

  11. VizieR Online Data Catalog: GaLactic and Extragalactic All-sky MWA survey (Hurley-Walker+, 2016)

    Science.gov (United States)

    Hurley-Walker, N.; Callingham, J. R.; Hancock, P. J.; Franzen, T. M. O.; Hindson, L.; Kapinska, A. D.; Morgan, J.; Offringa, A. R.; Wayth, R. B.; Wu, C.; Zheng, Q.; Murphy, T.; Bell, M. E.; Dwarakanath, K. S.; For, B.; Gaensler, B. M.; Johnston-Hollitt, M.; Lenc, E.; Procopio, P.; Staveley-Smith, L.; Ekers, R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Greenhill, L.; Hazelton, B. J.; Kaplan, D. L.; Lonsdale, C. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Webster, R. L.; Williams, A.; Williams, C. L.

    2016-10-01

    This paper concerns only data collected in the first year, i.e. four weeks between June 2013 and July 2014. We also do not image every observation, since the survey is redundant across approximately 50% of the observed RA ranges, and some parts are adversely acted by the Galactic plane and Centaurus A. Table 1 lists the observations which have been used to create this first GLEAM catalogue. (4 data files).

  12. VIMOS Public Extragalactic Redshift Survey (VIPERS). The distinct build-up of dense and normal massive passive galaxies

    CERN Document Server

    Gargiulo, A; Scodeggio, M; Krywult, J; De Lucia, G; Guzzo, L; Garilli, B; Grannet, B R; de la Torre, S; Abbas, U; Adami, C; Arnouts, S; Bottini, D; Cappi, A; Cucciati, O; Davidzon, I; Franzetti, P; Fritz, A; Haines, C; Hawken, A; Iovino, A; Brun, V Le; Fèvre, O Le; Maccagni, D; Małek, K; Marulli, F; Moutard, T; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Zamorani, G; Bel, J; Branchini, E; Coupon, J; Ilbert, O; Moscardini, L

    2016-01-01

    We use the final data from the VIPERS redshift survey to extract an unparalleled sample of more than 2000 massive M > 10^11 M_sun passive galaxies (MPGs) at redshift 0.5 2000 M_sun pc^-2) MPGs show a constant comoving number density over this redshift range, whilst this increases by a factor ~ 4 for the least dense objects, defined as having Sigma 10^11 M_sun objects). Such systems observed at z ~ 1 in VIPERS, therefore, represent the most plausible progenitors of the subsequent emerging class of larger MPGs.

  13. The VIMOS Public Extragalactic Redshift Survey (VIPERS). The coevolution of galaxy morphology and colour to z~1

    CERN Document Server

    Krywult, J; Pollo, A; Vergani, D; Bolzonella, M; Davidzon, I; Iovino, A; Gargiulo, A; Haines, C P; Scodeggio, M; Guzzo, L; Zamorani, G; Garilli, B; Granett, B R; de la Torre, S; Abbas, U; Adami, C; Bottini, D; Cappi, A; Cucciati, O; Franzetti, P; Fritz, A; Brun, V Le; Fèvre, O Le; Maccagni, D; Małek, K; Marulli, F; Polletta, M; Tojeiro, R; Zanichelli, A; Arnouts, S; Bel, J; Branchini, E; De Lucia, G; Ilbert, O; McCracken, H J; Moscardini, L; Takeuchi, T T

    2016-01-01

    We explore the evolution of the statistical distribution of galaxy morphological properties and colours over the redshift range $0.5Survey with the large number of redshifts and extended photometry from the VIPERS survey. Galaxy structural parameters are measured by fitting S\\'ersic profiles to $i$-band images and then combined with absolute magnitudes, colours and redshifts, to trace the evolution in a multi-parameter space. We analyse, using a new method, the combination of colours and structural parameters of early- and late-type galaxies in luminosity--redshift space. We found that both the rest-frame colour distributions in the (U-B) vs. (B-V) plane and the S\\'ersic index distributions are well fitted by a sum of two Gaussians, with a remarkable consistency of red-spheroidal and blue-disky galaxy populations, over the explored redshift ($0.5

  14. The VIMOS Public Extragalactic Redshift Survey (VIPERS). The coevolution of galaxy morphology and colour to z 1

    Science.gov (United States)

    Krywult, J.; Tasca, L. A. M.; Pollo, A.; Vergani, D.; Bolzonella, M.; Davidzon, I.; Iovino, A.; Gargiulo, A.; Haines, C. P.; Scodeggio, M.; Guzzo, L.; Zamorani, G.; Garilli, B.; Granett, B. R.; de la Torre, S.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Franzetti, P.; Fritz, A.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Tojeiro, R.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; Coupon, J.; De Lucia, G.; Ilbert, O.; McCracken, H. J.; Moscardini, L.; Takeuchi, T. T.

    2017-02-01

    Context. The study of the separation of galaxy types into different classes that share the same characteristics, and of the evolution of the specific parameters used in the classification are fundamental for understanding galaxy evolution. Aims: We explore the evolution of the statistical distribution of galaxy morphological properties and colours combining high-quality imaging data from the CFHT Legacy Survey with the large number of redshifts and extended photometry from the VIPERS survey. Methods: Galaxy structural parameters were combined with absolute magnitudes, colours and redshifts in order to trace evolution in a multi-parameter space. Using a new method we analysed the combination of colours and structural parameters of early- and late-type galaxies in luminosity-redshift space. Results: We find that both the rest-frame colour distributions in the (U-B) vs. (B-V) plane and the Sérsic index distributions are well fitted by a sum of two Gaussians, with a remarkable consistency of red-spheroidal and blue-disky galaxy populations, over the explored redshift (0.5 statistical description of the structure of galaxies and their evolution. Additionally, the proposed method provides a robust way to split galaxies into early and late types. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS

  15. The NuSTAR Extragalactic Surveys: The Number Counts of Active Galactic Nuclei and the Resolved Fraction of the Cosmic X-Ray Background

    Science.gov (United States)

    Harrison, F. A.; Aird, J.; Civano, F.; Lansbury, G.; Mullaney, J. R.; Ballantyne, D. R.; Alexander, D. M.; Stern, D.; Ajello, M.; Barret, D.; Bauer, F. E.; Baloković, M.; Brandt, W. N.; Brightman, M.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Del Moro, A.; Forster, K.; Gandhi, P.; Giommi, P.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Hornstrup, A.; Kitaguchi, T.; Koglin, J.; Luo, B.; Madsen, K. K.; Mao, P. H.; Miyasaka, H.; Mori, K.; Perri, M.; Pivovaroff, M.; Puccetti, S.; Rana, V.; Treister, E.; Walton, D.; Westergaard, N. J.; Wik, D.; Zappacosta, L.; Zhang, W. W.; Zoglauer, A.

    2016-11-01

    We present the 3-8 keV and 8-24 keV number counts of active galactic nuclei (AGNs) identified in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic surveys. NuSTAR has now resolved 33%-39% of the X-ray background in the 8-24 keV band, directly identifying AGNs with obscuring columns up to ˜ {10}25 {{cm}}-2. In the softer 3-8 keV band the number counts are in general agreement with those measured by XMM-Newton and Chandra over the flux range 5× {10}-15 ≲ S(3-8 keV)/{erg} {{{s}}}-1 {{cm}}-2 ≲ {10}-12 probed by NuSTAR. In the hard 8-24 keV band NuSTAR probes fluxes over the range 2× {10}-14 ≲ S(8-24 keV)/{erg} {{{s}}}-1 {{cm}}-2 ≲ {10}-12, a factor ˜100 fainter than previous measurements. The 8-24 keV number counts match predictions from AGN population synthesis models, directly confirming the existence of a population of obscured and/or hard X-ray sources inferred from the shape of the integrated cosmic X-ray background. The measured NuSTAR counts lie significantly above simple extrapolation with a Euclidian slope to low flux of the Swift/BAT 15-55 keV number counts measured at higher fluxes (S(15-55 keV) ≳ 10-11 {erg} {{{s}}}-1 {{cm}}-2), reflecting the evolution of the AGN population between the Swift/BAT local (z\\lt 0.1) sample and NuSTAR’s z˜ 1 sample. CXB synthesis models, which account for AGN evolution, lie above the Swift/BAT measurements, suggesting that they do not fully capture the evolution of obscured AGNs at low redshifts.

  16. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    Science.gov (United States)

    Adamo, A.; Ryon, J. E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D. O.; Calzetti, D.; Lee, J. C.; Whitmore, B. C.; Elmegreen, B. G.; Ubeda, L.; Smith, L. J.; Bright, S. N.; Runnholm, A.; Andrews, J. E.; Fumagalli, M.; Gouliermis, D. A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T. M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G. C.; Dale, D. A.; de Mink, S. E.; Dobbs, C.; Elmegreen, D. M.; Evans, A. S.; Gallagher, J. S., III; Grebel, E. K.; Herrero, A.; Hunter, D. A.; Johnson, K. E.; Kennicutt, R. C.; Krumholz, M. R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M. W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S. D.; Zackrisson, E.

    2017-06-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify their genuine nature, produce multiband photometry (from NUV to NIR), and derive their physical properties via spectral energy distribution fitting analyses. We use the nearby spiral galaxy NGC 628 as a test case for demonstrating the impact that LEGUS will have on our understanding of the formation and evolution of YSCs and compact stellar associations within their host galaxy. Our analysis of the cluster luminosity function from the UV to the NIR finds a steepening at the bright end and at all wavelengths suggesting a dearth of luminous clusters. The cluster mass function of NGC 628 is consistent with a power-law distribution of slopes ˜ -2 and a truncation of a few times 105 {M}⊙ . After their formation, YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer time frame, confirming their being potentially bound systems. Associations disappear on timescales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC 628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass (≤104 {M}⊙ ) clusters, suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC 628. Based on observations obtained with the NASA/ESA Hubble Space Telescope, 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.

  17. The VIMOS Public Extragalactic Redshift Survey (VIPERS). On the recovery of the count-in-cell probability distribution function

    Science.gov (United States)

    Bel, J.; Branchini, E.; Di Porto, C.; Cucciati, O.; Granett, B. R.; Iovino, A.; de la Torre, S.; Marinoni, C.; Guzzo, L.; Moscardini, L.; Cappi, A.; Abbas, U.; Adami, C.; Arnouts, S.; Bolzonella, M.; Bottini, D.; Coupon, J.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Marchetti, A.; Mellier, Y.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.

    2016-04-01

    We compare three methods to measure the count-in-cell probability density function of galaxies in a spectroscopic redshift survey. From this comparison we found that, when the sampling is low (the average number of object per cell is around unity), it is necessary to use a parametric method to model the galaxy distribution. We used a set of mock catalogues of VIPERS to verify if we were able to reconstruct the cell-count probability distribution once the observational strategy is applied. We find that, in the simulated catalogues, the probability distribution of galaxies is better represented by a Gamma expansion than a skewed log-normal distribution. Finally, we correct the cell-count probability distribution function from the angular selection effect of the VIMOS instrument and study the redshift and absolute magnitude dependency of the underlying galaxy density function in VIPERS from redshift 0.5 to 1.1. We found a very weak evolution of the probability density distribution function and that it is well approximated by a Gamma distribution, independently of the chosen tracers. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

  18. Hard X-ray luminosity function of tidal disruption events: First results from the MAXI extragalactic survey

    Science.gov (United States)

    Kawamuro, Taiki; Ueda, Yoshihiro; Shidatsu, Megumi; Hori, Takafumi; Kawai, Nobuyuki; Negoro, Hitoshi; Mihara, Tatehiro

    2016-08-01

    We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of -5/3, a systematic search using the MAXI data detected four TDEs in the first 37 months of observations, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all-sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is 0.0007%-34%. We confirm that at z ≲ 1.5 the contamination of the hard X-ray luminosity functions of active galactic nuclei by TDEs is not significant and hence that their contribution to the growth of SMBHs is negligible at the redshifts.

  19. Radio Bursts with Extragalactic Spectral Characteristics Show Terrestrial Origins

    CERN Document Server

    Burke-Spolaor, Sarah; Ekers, Ronald; Macquart, Jean-Pierre; Crawford, Fronefield

    2010-01-01

    Three years ago, the report of a solitary radio burst was thought to be the first discovery of a rare, impulsive event of unknown extragalactic origin (Lorimer et al. 2007). The extragalactic interpretation was based on the swept-frequency nature of the event, which followed the dispersive delay expected from an extragalactic pulse. We report here on the detection of 16 pulses, the bulk of which exhibit a frequency sweep with a shape and magnitude resembling the Lorimer Burst. These new events were detected in a sidelobe of the Parkes Telescope and are of clearly terrestrial origin, with properties unlike any known sources of terrestrial broad-band radio emission. The new detections cast doubt on the extragalactic interpretation of the original burst, and call for further sophistication in radio-pulse survey techniques to identify the origin of the anomalous terrestrial signals and definitively distinguish future extragalactic pulse detections from local signals. The ambiguous origin of these seemingly disper...

  20. Matching Radio Catalogs with Realistic Geometry: Application to SWIRE and ATLAS

    CERN Document Server

    Fan, Dongwei; Norris, Ray P; Hopkins, Andrew M

    2015-01-01

    Crossmatching catalogs at different wavelengths is a difficult problem in astronomy, especially when the objects are not point-like. At radio wavelengths an object can have several components corresponding, for example, to a core and lobes. {Considering not all radio detections correspond to visible or infrared sources, matching these catalogs can be challenging.} Traditionally this is done by eye for better quality, which does not scale to the large data volumes expected from the next-generation of radio telescopes. We present a novel automated procedure, using Bayesian hypothesis testing, to achieve reliable associations by explicit modelling of a particular class of radio-source morphology. {The new algorithm not only assesses the likelihood of an association between data at two different wavelengths, but also tries to assess whether different radio sources are physically associated, are double-lobed radio galaxies, or just distinct nearby objects.} Application to the SWIRE and ATLAS CDF-S catalogs shows t...

  1. Extragalactic Gamma Ray Excess from Coma Supercluster Direction

    Indian Academy of Sciences (India)

    Pantea Davoudifar; S. Jalil Fatemi

    2011-09-01

    The origin of extragalactic diffuse gamma ray is not accurately known, especially because our suggestions are related to many models that need to be considered either to compute the galactic diffuse gamma ray intensity or to consider the contribution of other extragalactic structures while surveying a specific portion of the sky. More precise analysis of EGRET data however, makes it possible to estimate the diffuse gamma ray in Coma supercluster (i.e., Coma\\A1367 supercluster) direction with a value of ( > 30MeV) ≃ 1.9 × 10-6 cm-2 s-1, which is considered to be an upper limit for the diffuse gamma ray due to Coma supercluster. The related total intensity (on average) is calculated to be ∼ 5% of the actual diffuse extragalactic background. The calculated intensity makes it possible to estimate the origin of extragalactic diffuse gamma ray.

  2. Extragalactic Star Clusters Speculations on the Future

    CERN Document Server

    Gallagher, J S; Gallagher, John S.; Grebel, Eva K.

    2001-01-01

    We discuss the future possibilities for extragalactic star cluster research with the expected new ground-based and space-based telescopes and instrumentation. Significant gains are expected due to improved angular resolution, sensitivity, and area coverage particularly in the infrared and radio, accompanied by progress in evolutionary and dynamical modelling. Improvements in angular resolution are anticipated, especially through new adaptive optics systems (e.g., Keck, Gemini, VLT), and interferometry (e.g., Keck, VLT, LBT, ALMA, SMA, SkA), and space instrumentation (e.g., Chandra, NGST), enabling studies even of deeply embedded, forming extragalactic star clusters. Tidal disruption of Galactic clusters becomes observable through wide-area surveys such as the SDSS, VISTA, PRIME, including proper motion measurements through high-resolution imaging (e.g., HST, LBT, SIM, GAIA). Sensitive new optical and infrared spectrographs (e.g., HET, SALT, GranTeCan, Magellan, Keck, VLT, CELT, OWL, NGST) will push kinematic ...

  3. The extragalactic IR background

    CERN Document Server

    De Zotti, G; Mazzei, P; Toffolatti, L; Danese, L; De Zotti, G; Franceschini, A; Mazzei, P; Toffolatti, L; Danese, L

    1994-01-01

    Current limits on the intensity of the extragalactic infrared background are consistent with the expected contribution from evolving galaxies. Depending on the behaviour of the star formation rate and of the initial mass function, we can expect that dust extinction during early evolutionary phases ranges from moderate to strong. An example of the latter case may be the ultraluminous galaxy IRAS F10214 + 4724. The remarkable lack of high redshift galaxies in faint optically selected samples may be indirect evidence that strong extinction is common during early phases. Testable implications of different scenarios are discussed; ISO can play a key role in this context. Estimates of possible contributions of galaxies to the background under different assumptions are presented. The COBE/FIRAS limits on deviations from a blackbody spectrum at sub-mm wavelengths already set important constraints on the evolution of the far-IR emission of galaxies and on the density of obscured (``Type 2'') AGNs. A major progress in ...

  4. The NuSTAR Extragalactic Survey: First Direct Measurements of the Greater Than Or Similar To 10 Kev X-Ray Luminosity Function For Active Galactic Nuclei At z > 0.1

    DEFF Research Database (Denmark)

    Aird, J.; Alexander, D. M.; Ballantyne, D. R.;

    2015-01-01

    number of sources in our sample, leading to small, systematic differences in our binned estimates of the XLF. Adopting a model with a lower intrinsic fraction of Compton-thick sources and a larger population of sources with column densities NH ∼1023-24 cm-2 or a model with stronger Compton reflection......We present the first direct measurements of the rest-frame 10-40 keV X-ray luminosity function (XLF) of active galactic nuclei (AGNs) based on a sample of 94 sources at 0.1 sources in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic survey...... component (with a relative normalization of R ∼ 2 at all luminosities) can bring extrapolations of the XLF from 2-10 keV into agreement with our NuSTAR sample. Ultimately, X-ray spectral analysis of the NuSTAR sources is required to break this degeneracy between the distribution of absorbing column...

  5. The Chandra Survey of Extragalactic Sources in the 3CR Catalog: X-ray Emission from Nuclei, Jets, and Hotspots in the Chandra Archival Observations

    CERN Document Server

    Massaro, F; Liuzzo, E; Orienti, M; Paladino, R; Paggi, A; Tremblay, G R; Wilkes, B J; Kuraszkiewicz, J; Baum, S A; O'Dea, C P

    2016-01-01

    As part of our program to build a complete radio and X-ray database of all the 3CR extragalactic radio sources, we present an analysis of 93 sources for which Chandra archival data are available. Most of these sources have been already published. Here we provide a uniform re-analysis and present nuclear X-ray fluxes and X-ray emission associated with radio jet knots and hotspots using both publicly available radio images and new radio images that have been constructed from data available in the VLA archive. For about 1/3 of the sources in the selected sample a comparison between the Chandra and the radio observations was not reported in the literature: we find X-ray detections of 2 new radio jet knots and 17 hotspots. We also report the X-ray detection of extended emission from the intergalactic medium of 15 galaxy clusters, two of which were most likely unknown previously.

  6. THE CHANDRA SURVEY OF EXTRAGALACTIC SOURCES IN THE 3CR CATALOG: X-RAY EMISSION FROM NUCLEI, JETS, AND HOTSPOTS IN THE CHANDRA ARCHIVAL OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [Dipartimento di Fisica, Università degli Studi di Torino, via Pietro Giuria 1, I-10125 Torino (Italy); Harris, D. E.; Paggi, A.; Wilkes, B. J.; Kuraszkiewicz, J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Liuzzo, E.; Orienti, M.; Paladino, R. [Istituto di Radioastronomia, INAF, via Gobetti 101, I-40129, Bologna (Italy); Tremblay, G. R. [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, P.O. Box 208120, New Haven, CT 06520-8120 (United States); Baum, S. A.; O’Dea, C. P. [University of Manitoba, Dept of Physics and Astronomy, Winnipeg, MB R3T 2N2 (Canada)

    2015-09-15

    As part of our program to build a complete radio and X-ray database of all Third Cambridge catalog extragalactic radio sources, we present an analysis of 93 sources for which Chandra archival data are available. Most of these sources have already been published. Here we provide a uniform re-analysis and present nuclear X-ray fluxes and X-ray emission associated with radio jet knots and hotspots using both publicly available radio images and new radio images that have been constructed from data available in the Very Large Array archive. For about 1/3 of the sources in the selected sample, a comparison between the Chandra and radio observations was not reported in the literature: we find X-ray detections of 2 new radio jet knots and 17 hotspots. We also report the X-ray detection of extended emission from the intergalactic medium for 15 galaxy clusters.

  7. WFIRST Extragalactic Potential Observations (EXPO) Science Investigation Team

    Science.gov (United States)

    Robertson, Brant

    The Wide-Field InfraRed Survey Telescope (WFIRST) holds tremendous promise as a space observatory for extragalactic astrophysics beyond cosmological surveys. The WFIRST Extragalactic Potential Observations (EXPO) Science Investigation Team will identify the most pressing and scientifically compelling Guest Investigator and Guest Observer projects with WFIRST to address a range of exciting outstanding issues in galaxy formation, from the epoch of reionization to galaxy-galaxy lensing, the discovery of exotic supernovae and luminous active galaxies, and charting the chemical evolution of galaxies. The identified EXPO GI projects will help maximize the scientific return of the WFIRST cosmological surveys, and supply innovative ideas and methods for archival research that leverages the WFIRST dataset. The EXPO team will also evaluate the science payoff of translating previous successful space telescope surveys to the era of WFIRST, helping us to realize the full power of WFIRST for extragalactic astronomy through the competed GO programs. The WFIRST-EXPO team consists of world-wide experts in designing and executing space-based extragalactic programs, multi-object spectroscopic campaigns in the optical and infrared, and theoretical modeling of galaxy formation, exotic supernovae, and reionization. In support of WFIRST before Critical Design Review, WFIRST-EXPO will 1) develop and publicly release tools to generate mock catalogs for planning extragalactic astrophysics investigations with the HLS (GI) and GO community programs, 2) simulate images for modeling medium- and ultra-deep extragalactic GO programs, 3) develop and publicly release work flows for planning and evaluating the science return of potential extragalactic GI/GO programs, 4) perform case studies of medium- and ultra-deep imaging and spectroscopic GO/GI programs, 5) evaluate WFIRST design choices that influence extragalactic science return, and 6) serve as liaisons to James Webb Space Telescope, Large

  8. A Survey of Extragalactic Faraday Rotation at High Galactic Latitude: The Vertical Magnetic Field of the Milky Way towards the Galactic Poles

    CERN Document Server

    Mao, S A; Haverkorn, M; Zweibel, E G; Madsen, G J; McClure-Griffiths, N M; Shukurov, A; Kronberg, P P

    2010-01-01

    We present a study of the vertical magnetic field of the Milky Way towards the Galactic poles, determined from observations of Faraday rotation toward more than 1000 polarized extragalactic radio sources at Galactic latitudes |b| > 77 degs, using the Westerbork Radio Synthesis Telescope and the Australia Telescope Compact Array. We find median rotation measures (RMs) of 0.0 +/- 0.5 rad/m^2 and +6.3 +/- 0.7 rad/m^2 toward the north and south Galactic poles, respectively, demonstrating that there is no coherent vertical magnetic field in the Milky Way at the Sun's position. If this is a global property of the Milky Way's magnetism, then the lack of symmetry across the disk rules out pure dipole or quadrupole geometries for the Galactic magnetic field. The angular fluctuations in RM seen in our data show no preferred scale within the range ~ 0.1 to 25 degs. The observed standard deviation in RM of ~ 9 rad/m^2 then implies an upper limit of ~1microGauss on the strength of the random magnetic field in the warm ion...

  9. Probing the properties of extragalactic SNRs

    Science.gov (United States)

    Leonidaki, Ioanna

    2016-06-01

    The investigation of extragalactic SNRs gives us the advantage of surmounting the challenges we are usually confronted with when observing Galactic SNRs, most notably Galactic extinction and distance uncertainties. At the same time, by obtaining larger samples of SNRs, we are allowed to cover a wider range of environments and ISM parameters than our Galaxy, providing us a more complete and representative picture of SNR populations. I will outline the recent progress on extragalactic surveys of SNR populations focusing on the optical, radio, and X-ray bands. Multi-wavelength surveys can provide several key aspects of the physical processes taking place during the evolution of SNRs while at the same time can overcome possible selection effects that are inherent from monochromatic surveys. I will discuss the properties derived in each band (e.g. line ratios, luminosities, densities, temperatures) and their connection in order to yield information on various aspects of their behaviour and evolution. For example their interplay with the surrounding medium, their correlation with star formation activity, their luminosity distributions and their dependence on galaxy types.

  10. New Limits on Extragalactic Magnetic Fields from Rotation Measures

    Science.gov (United States)

    Pshirkov, M. S.; Tinyakov, P. G.; Urban, F. R.

    2016-05-01

    We take advantage of the wealth of rotation measures data contained in the NRAO VLA Sky Survey catalog to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic magnetic field contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-α clouds. Based on the observation that rotation measures from distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Jeans' length coherence length to be below 1.7 nG at the 2 σ level, and fields coherent across the entire observable Universe below 0.65 nG. These limits do not depend on the particular origin of these cosmological fields.

  11. Gravitational lensing statistics with extragalactic surveys - IV. Joint constraints on lambda(0) and Omega(0) from gravitational lensing statistics and CMB anisotropies

    NARCIS (Netherlands)

    Macias-Perez, JF; Helbig, P; Quast, R; Wilkinson, A; Davies, R

    2000-01-01

    We present constraints on the cosmological constant lambda(0) and the density parameter Omega(0) from joint constraints from the analyses of gravitational lensing statistics of the Jo- drell Bank-VLA Astrometric Survey (JVAS), optical gravitational lens surveys from the literature and CMB anisotropi

  12. Gravitational lensing statistics with extragalactic surveys - IV. Joint constraints on lambda(0) and Omega(0) from gravitational lensing statistics and CMB anisotropies

    NARCIS (Netherlands)

    Macias-Perez, JF; Helbig, P; Quast, R; Wilkinson, A; Davies, R

    We present constraints on the cosmological constant lambda(0) and the density parameter Omega(0) from joint constraints from the analyses of gravitational lensing statistics of the Jo- drell Bank-VLA Astrometric Survey (JVAS), optical gravitational lens surveys from the literature and CMB

  13. The NuSTAR Extragalactic Surveys: First Direct Measurements of the >10 keV X-Ray Luminosity Function for Active Galactic Nuclei at z>0.1

    CERN Document Server

    Aird, J; Ballantyne, D R; Civano, F; Del-Moro, A; Hickox, R C; Lansbury, G B; Mullaney, J R; Bauer, F E; Brandt, W N; Comastri, A; Fabian, A C; Gandhi, P; Harrison, F A; Luo, B; Stern, D; Treister, E; Zappacosta, L; Ajello, M; Assef, R; Boggs, S E; Brightman, M; Christensen, F E; Craig, W W; Elvis, M; Forster, K; Balokovic, M; Grefenstette, B W; Hailey, C J; Koss, M; LaMassa, S M; Madsen, K K; Puccetti, S; Saez, C; Urry, C M; Wik, D R; Zhang, W

    2015-01-01

    We present the first direct measurements of the rest-frame 10-40 keV X-ray luminosity function (XLF) of Active Galactic Nuclei (AGNs) based on a sample of 94 sources at 0.1 < z <3, selected at 8-24 keV energies from sources in the NuSTAR extragalactic survey program. Our results are consistent with the strong evolution of the AGN population seen in prior, lower-energy studies of the XLF. However, different models of the intrinsic distribution of absorption, which are used to correct for selection biases, give significantly different predictions for the total number of sources in our sample, leading to small, systematic differences in our binned estimates of the XLF. Adopting a model with a lower intrinsic fraction of Compton-thick sources and a larger population of sources with column densities N_H ~ 10^{23-24} /cm2 or a model with stronger Compton reflection component (with a relative normalization of R ~ 2 at all luminosities) can bring extrapolations of the XLF from 2-10 keV into agreement with our N...

  14. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Exploring the dependence of the three-point correlation function on stellar mass and luminosity at 0.5

    CERN Document Server

    Moresco, M; Moscardini, L; Branchini, E; Cappi, A; Davidzon, I; Granett, B R; de la Torre, S; Guzzo, L; Abbas, U; Adami, C; Arnouts, S; Bel, J; Bolzonella, M; Bottini, D; Coupon, J; Cucciati, O; De Lucia, G; Franzetti, P; Fritz, A; Fumana, M; Garilli, B; Ilbert, O; Iovino, A; Krywult, J; Brun, V Le; Fèvre, O Le; Małek, K; McCracken, H J; Polletta, M; Pollo, A; Scodeggio, M; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A

    2016-01-01

    The three-point correlation function (3PCF) is a powerful probe to investigate the clustering of matter in the Universe in a complementary way with respect to lower-order statistics, providing additional information with respect to two-point correlation function and allowing to shed light on biasing, nonlinear processes and deviations from Gaussian statistics. In this paper, we analyse the first data release of the VIMOS Public Extragalactic Redshift Survey (VIPERS), determining the dependence of the three-point correlation function on luminosity and stellar mass at $z=[0.5,1.1]$. We exploit the VIPERS Public Data Release 1, consisting of more than 50000 galaxies with B-band magnitudes in the range $-21.6\\lesssim M_{\\rm B}-5\\log(h)\\lesssim-19.9$ and stellar masses in the range $9.8\\lesssim\\log(M_\\star[h^{-2}\\,M_\\odot])\\lesssim 10.7$. We measure both the connected 3PCF and the reduced 3PCF in redshift space, probing different configurations and scales, in the range $2.5

  15. Extragalactic Star Clusters: Speculations on the Future

    Science.gov (United States)

    Gallagher, J. S.; Grebel, E. K.

    We discuss the future possibilities for extragalactic star cluster research with the expected new ground-based and space-based telescopes and instrumentation. Significant gains are expected due to improved angular resolution, sensitivity, and area coverage particularly in the infrared and radio, accompanied by progress in evolutionary and dynamical modelling. Improvements in angular resolution are anticipated, especially through new adaptive optics systems (e.g., Keck, Gemini, VLT), and interferometry (e.g., Keck, VLT, LBT, ALMA, SMA, SkA), and space instrumentation (e.g., Chandra, NGST), enabling studies even of deeply embedded, forming extragalactic star clusters. Tidal disruption of Galactic clusters becomes observable through wide-area surveys such as the SDSS, VISTA, PRIME, including proper motion measurements through high-resolution imaging (e.g., HST, LBT, SIM, GAIA). Sensitive new optical and infrared spectrographs (e.g., HET, SALT, GranTeCan, Magellan, Keck, VLT, CELT, OWL, NGST) will push kinematic and abundance studies to new limits, allowing us detailed comparisons with model predictions. One important wavelength range for the study of young, massive star clusters, the far UV, appears to be neglected by future planned instrumentation.

  16. 9 June 2016 - British Foreign and Commonwealth Office, Minister of State H. Swire MP signing the guest book with CERN Director-General F. Gianotti.

    CERN Multimedia

    Bennett, Sophia Elizabeth

    2016-01-01

    The Rt Hon Hugo Swire MP Minister of State Foreign and Commonwealth Office United Kingdom of Great Britain and Northern Ireland; in the LHC superconducting magnet test hall with Beams Department Head P. Collier and in ATLAS Visitor Centre with ATLAS Collaboration Spokesperson D. Charlton.

  17. ALMA spectroscopic survey in the Hubble Ultra Deep Field: Continuum number counts, resolved 1.2-mm extragalactic background, and properties of the faintest dusty star forming galaxies

    CERN Document Server

    Aravena, Manuel; Walter, Fabian; Da Cunha, Elisabete; Bauer, Franz E; Carilli, Christopher; Daddi, Emanuele; Elbaz, David; Ivison, R J; Riechers, Dominik; Smail, Ian R; Swinbank, Mark; Weiss, Axel; Anguita, Timo; Assef, Roberto J; Bell, Eric; Bertoldi, Frank; Bacon, Roland; Bouwens, Rychard; Cortes, Paulo; Cox, Pierre; Gónzalez-López, Jorge; Hodge, Jacqueline; Ibar, Eduardo; Inami, Hanae; Infante, Leopoldo; Karim, Alexander; Fèvre, Olivier Le; Magnelli, Benjamin; Ota, Kauzuaki; Popping, Gergö; Sheth, Kartik; van der Werf, Paul; Wagg, Jeffrey

    2016-01-01

    We present an analysis of a deep (1$\\sigma$=13 $\\mu$Jy) cosmological 1.2-mm continuum map based on ASPECS, the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field. In the 1 arcmin$^2$ covered by ASPECS we detect nine sources at $>3.5\\sigma$ significance at 1.2-mm. Our ALMA--selected sample has a median redshift of $z=1.6\\pm0.4$, with only one galaxy detected at z$>$2 within the survey area. This value is significantly lower than that found in millimeter samples selected at a higher flux density cut-off and similar frequencies. Most galaxies have specific star formation rates similar to that of main sequence galaxies at the same epoch, and we find median values of stellar mass and star formation rates of $4.0\\times10^{10}\\ M_\\odot$ and $\\sim40~M_\\odot$ yr$^{-1}$, respectively. Using the dust emission as a tracer for the ISM mass, we derive depletion times that are typically longer than 300 Myr, and we find molecular gas fractions ranging from $\\sim$0.1 to 1.0. As noted by previous studies, these values ar...

  18. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Downsizing of the blue cloud and the influence of galaxy size on mass quenching over the last eight billion years

    Science.gov (United States)

    Haines, C. P.; Iovino, A.; Krywult, J.; Guzzo, L.; Davidzon, I.; Bolzonella, M.; Garilli, B.; Scodeggio, M.; Granett, B. R.; de la Torre, S.; De Lucia, G.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Cappi, A.; Cucciati, O.; Franzetti, P.; Fritz, A.; Gargiulo, A.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Moutard, T.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Zamorani, G.; Bel, J.; Branchini, E.; Coupon, J.; Ilbert, O.; Moscardini, L.; Peacock, J. A.; Siudek, M.

    2017-08-01

    We use the full VIPERS redshift survey in combination with SDSS-DR7 to explore the relationships between star-formation history (using d4000), stellar mass and galaxy structure, and how these relationships have evolved since z 1. We trace the extents and evolutions of both the blue cloud and red sequence by fitting double Gaussians to the d4000 distribution of galaxies in narrow stellar mass bins, for four redshift intervals over 0 1011M⊙, d4000 change, showing higher Sérsic indices and central stellar mass densities. For these galaxies, bulge growth is required for them to reach the high-mass limit of the blue cloud and be quenched by internal mechanisms. The blue-cloud galaxies that are being quenched at z 0.8 lie along the same size-mass relation as present day quiescent galaxies and seem the likely progenitors of today's S0s. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

  19. The VIMOS Public Extragalactic Redshift Survey (VIPERS): Downsizing of the blue cloud and the influence of galaxy size on mass quenching over the last eight billion years

    CERN Document Server

    Haines, C P; Guzzo, L; Davidzon, I; Bolzonella, M; Garilli, B; Scodeggio, M; Granett, B R; de la Torre, S; De Lucia, G; Abbas, U; Adami, C; Arnouts, S; Bottini, D; Cappi, A; Cucciati, O; Franzetti, P; Fritz, A; Gargiulo, A; Brun, V Le; Fevre, O Le; Maccagni, D; Malek, K; Marulli, F; Moutard, T; Polletta, M; Pollo, A; Tasca, L A M; Tojeiro, R; Vergani, D; Zanichelli, A; Zamorani, G; Bel, J; Branchini, E; Coupon, J; Ilbert, O; Moscardini, L; Peacock, J A; Siudek, M

    2016-01-01

    We use the full VIPERS redshift survey in combination with SDSS-DR7 to explore the relationships between star-formation history (using d4000), stellar mass and galaxy structure, and how these relationships have evolved since z~1. We trace the extents and evolutions of both the blue cloud and red sequence, by fitting double Gaussians to the d4000 distribution of galaxies in narrow stellar mass bins, for four redshift intervals over 010^11Msun, d4000<1.55) drops sharply by a factor five between z~0.8 and z~0.5. These galaxies are becoming quiescent at a rate that largely matches the increase in the numbers of massive passive galaxies seen over this period. We examine the size-mass relation of blue cloud galaxies, finding that its high-mass boundary runs along lines of constant M*/r_e or equivalently inferred velocity dispersion. Larger galaxies can continue to form stars to higher stellar masses than smaller galaxies. As blue cloud galaxies approach this high-mass limit, they start to be quenched, their d400...

  20. The X-ray log N-log S relation. [background radiation in extragalactic media

    Science.gov (United States)

    Boldt, Elihu

    1989-01-01

    Results from various surveys are reviewed as regards X-ray source counts at high galactic latitudes and the luminosity functions determined for extragalactic sources. Constraints on the associated log N-log S relation provided by the extragalactic X-ray background are emphasized in terms of its spatial fluctuations and spectrum as well as absolute flux level. The large number of sources required for this background suggests that there is not a sharp boundary in the redshift distribution of visible matter.

  1. The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Continuum Number Counts, Resolved 1.2 mm Extragalactic Background, and Properties of the Faintest Dusty Star-forming Galaxies

    Science.gov (United States)

    Aravena, M.; Decarli, R.; Walter, F.; Da Cunha, E.; Bauer, F. E.; Carilli, C. L.; Daddi, E.; Elbaz, D.; Ivison, R. J.; Riechers, D. A.; Smail, I.; Swinbank, A. M.; Weiss, A.; Anguita, T.; Assef, R. J.; Bell, E.; Bertoldi, F.; Bacon, R.; Bouwens, R.; Cortes, P.; Cox, P.; Gónzalez-López, J.; Hodge, J.; Ibar, E.; Inami, H.; Infante, L.; Karim, A.; Le Le Fèvre, O.; Magnelli, B.; Ota, K.; Popping, G.; Sheth, K.; van der Werf, P.; Wagg, J.

    2016-12-01

    We present an analysis of a deep (1σ = 13 μJy) cosmological 1.2 mm continuum map based on ASPECS, the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field. In the 1 arcmin2 covered by ASPECS we detect nine sources at \\gt 3.5σ significance at 1.2 mm. Our ALMA-selected sample has a median redshift of z=1.6+/- 0.4, with only one galaxy detected at z > 2 within the survey area. This value is significantly lower than that found in millimeter samples selected at a higher flux density cutoff and similar frequencies. Most galaxies have specific star formation rates (SFRs) similar to that of main-sequence galaxies at the same epoch, and we find median values of stellar mass and SFRs of 4.0× {10}10 {M}⊙ and ˜ 40 {M}⊙ yr-1, respectively. Using the dust emission as a tracer for the interstellar medium (ISM) mass, we derive depletion times that are typically longer than 300 Myr, and we find molecular gas fractions ranging from ˜0.1 to 1.0. As noted by previous studies, these values are lower than those using CO-based ISM estimates by a factor of ˜2. The 1 mm number counts (corrected for fidelity and completeness) are in agreement with previous studies that were typically restricted to brighter sources. With our individual detections only, we recover 55% ± 4% of the extragalactic background light (EBL) at 1.2 mm measured by the Planck satellite, and we recover 80% ± 7% of this EBL if we include the bright end of the number counts and additional detections from stacking. The stacked contribution is dominated by galaxies at z˜ 1{--}2, with stellar masses of (1-3) × 1010 M {}⊙ . For the first time, we are able to characterize the population of galaxies that dominate the EBL at 1.2 mm.

  2. A search for fast optical transients in the Pan-STARRS1 medium-deep survey: M-dwarf flares, asteroids, limits on extragalactic rates, and implications for LSST

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.; Leibler, C. N.; Chornock, R.; Foley, R. J.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Metcalfe, N. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Stubbs, C. W. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States)

    2013-12-10

    We present a search for fast optical transients (τ ∼ 0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fields. Our search takes advantage of the consecutive g {sub P1} r {sub P1} observations (16.5 minutes in each filter), by requiring detections in both bands, with non-detections on preceding and subsequent nights. We identify 19 transients brighter than 22.5 AB mag (S/N ≳ 10). Of these, 11 events exhibit quiescent counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs at d ≈ 0.2-1.2 kpc. The remaining eight transients lack quiescent counterparts, exhibit mild but significant astrometric shifts between the g {sub P1} and r {sub P1} images, colors of (g – r){sub P1} ≈ 0.5-0.8 mag, non-varying light curves, and locations near the ecliptic plane with solar elongations of about 130°, which are all indicative of main-belt asteroids near the stationary point of their orbits. With identifications for all 19 transients, we place an upper limit of R {sub FOT}(τ ∼ 0.5 hr) ≲ 0.12 deg{sup –2} day{sup –1} (95% confidence level) on the sky-projected rate of extragalactic fast transients at ≲ 22.5 mag, a factor of 30-50 times lower than previous limits; the limit for a timescale of ∼1 day is R {sub FOT} ≲ 2.4 × 10{sup –3} deg{sup –2} day{sup –1}. To convert these sky-projected rates to volumetric rates, we explore the expected peak luminosities of fast optical transients powered by various mechanisms, and find that non-relativistic events are limited to M ≈ –10 to ≈ – 14 mag for a timescale of ∼0.5 hr to ∼1 day, while relativistic sources (e.g., gamma-ray bursts, magnetar-powered transients) can reach much larger luminosities. The resulting volumetric rates are ≲ 13 Mpc{sup –3} yr{sup –1} (M ≈ –10 mag), ≲ 0.05 Mpc{sup –3} yr{sup –1} (M ≈ –14 mag), and ≲ 10{sup –6} Mpc{sup –3} yr{sup –1} (M ≈ –24 mag), significantly above the nova, supernova

  3. The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Exploring the dependence of the three-point correlation function on stellar mass and luminosity at 0.5

    Science.gov (United States)

    Moresco, M.; Marulli, F.; Moscardini, L.; Branchini, E.; Cappi, A.; Davidzon, I.; Granett, B. R.; de la Torre, S.; Guzzo, L.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Carbone, C.; Coupon, J.; Cucciati, O.; De Lucia, G.; Franzetti, P.; Fritz, A.; Fumana, M.; Garilli, B.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Małek, K.; McCracken, H. J.; Polletta, M.; Pollo, A.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.

    2017-08-01

    Aims: The three-point correlation function (3PCF) is a powerful probe to investigate the clustering of matter in the Universe in a complementary way with respect to lower-order statistics, providing additional information with respect to the two-point correlation function and allowing us to shed light on biasing, non-linear processes, and deviations from Gaussian statistics. In this paper, we analyse the first data release of the VIMOS Public Extragalactic Redshift Survey (VIPERS), determining the dependence of the three-point correlation function on luminosity and stellar mass at z = [ 0.5,1.1 ]. Methods: We exploit the VIPERS Public Data Release 1, consisting of more than 50 000 galaxies with B-band magnitudes in the range - 21.6 ≲ MB - 5log (h) ≲ - 19.9 and stellar masses in the range 9.8 ≲ log (M⋆ [ h-2M⊙ ] ) ≲ 10.7. We measure both the connected 3PCF and the reduced 3PCF in redshift space, probing different configurations and scales, in the range 2.5

  4. Millisecond extragalactic radio bursts as magnetar flares

    CERN Document Server

    Popov, S B

    2013-01-01

    Properties of the population of millisecond extragalactic radio bursts discovered by Thornton et al. (2013) are in good correspondence with the hypothesis that such events are related to hyperflares of magnetars, as was proposed by us after the first observation of an extragalactic millisecond radio burst by Lorimer et al. (2007). We also point that some of multiple millisecond radio bursts from M31 discovered by Rubio-Herrera et al. (2013) also can be related to weaker magnetar bursts.

  5. Cosmic rays: extragalactic and Galactic

    CERN Document Server

    Istomin, Ya N

    2014-01-01

    From the analysis of the flux of high energy particles, $E>3\\cdot 10^{18}eV$, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ${\\bar q}(E)\\propto E^{-2.7}$, with the same index of $2.7$ that has the distribution of Galactic cosmic rays before so called 'knee', $E3\\cdot 10^{15}eV$, from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, $D\\propto E^{0.7}$. The obtained index of the density distribution of particles over energy, $N(E)\\propto E^{-2.7-0.7/2}=E^{-3.05}$, for $E>3\\cdot 10^{15}eV$ agrees well with the observed one, $N(E)\\propto E^{-3.1}$. Estimated time of termination of the jet in the Galaxy is $4.2\\cdot 10^{4}$ years ago.

  6. Egret observations of the extragalactic gamma-ray emission

    DEFF Research Database (Denmark)

    Sreekumar, P.; Bertsch, D.L.; Dingus, B.L.

    1998-01-01

    with the local interstellar gas and radiation, as well as an almost uniformly distributed component that is generally believed to originate outside the Galaxy. Through a careful study and removal of the Galactic diffuse emission, the flux, spectrum, and uniformity of the extragalactic emission are deduced......The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by EGRET aboard the Compton Gamma Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions...

  7. ARCADE Detection of an Extragalactic Radio Background

    Science.gov (United States)

    Kogut, Alan J.

    2009-01-01

    Sometimes when we look for one thing we stumble on something else. The Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) was designed to measure the blackbody spectrum of the cosmic microwave background to search for spectral distortions related to the epoch of reionization. Instead, the July 2006 flight found evidence for an extragalactic radio background with amplitude six times brighter than the expected contribution from faint radio sources. The author discusses the ARCADE instrument and the evidence for an extragalactic radio background.

  8. Surprises from extragalactic propagation of UHECRs

    CERN Document Server

    Boncioli, Denise; Grillo, Aurelio

    2015-01-01

    Ultra-high energy cosmic ray experimental data are now of very good statistical significance even in the region of the expected GZK feature. The identification of their sources requires sophisticate analysis of their propagation in the extragalactic space. When looking at the details of this propagation some unforeseen features emerge. We will discuss some of these "surprises".

  9. Extragalactic Astronomy: The Universe Beyond Our Galaxy.

    Science.gov (United States)

    Jacobs, Kenneth Charles

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The material is presented in three parts: one section provides the fundamental content of extragalactic astronomy, another section discusses modern discoveries in…

  10. The Taiwan Extragalactic Astronomical Data Center (TWEA-DC)

    CERN Document Server

    Foucaud, Sebastien

    2011-01-01

    The next generation of telescopes and instruments are facilitating our understanding of the Universe by producing data at a pace that beats all projections, and astronomers today are left in the face of an avalanche of data like never before. In order to cope with this problem and come up with a reliable and innovative solution, Data Centers were created in various locations and the concept of Virtual Observatories elaborated. Based at the National Taiwan Normal University, the Taiwan Extragalactic Astronomical Data Center plan to join in global efforts by proposing 1Pb of data storage dedicated to extragalactic astronomy by 2015. In continuation with individual efforts in Taiwan over the past few years, this is the first stepping-stone towards the building of a National Virtual Observatory. Besides the common functionalities generally provided by data centers, our goal is to propose "on-the-fly" photometry measurements from publicly available surveys: a unique way for cross-matching information. Also we will...

  11. Extragalactic astronomy and cosmology an introduction

    CERN Document Server

    Schneider, Peter

    2015-01-01

    Accounting for the astonishing developments in the field of Extragalactic Astronomy and Cosmology, this second edition has been updated and substantially expanded. Starting with the description of our home galaxy, the Milky Way, this cogently written textbook introduces the reader to the astronomy of galaxies, their structure, active galactic nuclei, evolution and large scale distribution in the Universe. After an extensive and thorough introduction to modern observational and theoretical cosmology, the focus turns to the formation of structures and astronomical objects in the early Universe. The basics of classical astronomy and stellar astrophysics needed for extragalactic astronomy are provided in the appendix. The new edition incorporates some of the most spectacular results from new observatories like the Galaxy Evolution Explorer, Herschel, ALMA, WMAP and Planck, as well as new instruments and multi-wavelength campaigns which have expanded our understanding of the Universe and the objects populating it....

  12. Proposed nomenclature for Extragalactic Planetary Nebulae

    CERN Document Server

    Parker, Q A; Parker, Quentin A

    2004-01-01

    The ability to identify and distinguish between the wide variety of celestial objects benefits from application of a systematic and logical nomenclature. This often includes value-added information within the naming convention which can aid in placing the object positionally either via an RA/DEC or l,b concatenation. All new nomenclatures should be created following IAU guidelines. However as the number density of specific object types on the sky increases, as in the case of PN in external galaxies, a useful positional identifier becomes problematic. This brief but timely paper attempts to progress the debate on this vexing issue for the case of extragalactic planetary nebulae (EPN). There is a clear need to rationalise the current ad-hoc system now that many thousands of Extragalactic PN are being discovered.

  13. Some Remarks on Extragalactic Globular Clusters

    CERN Document Server

    Richtler, T

    2005-01-01

    I comment (in a review fashion) on a few selected topics in the field of extragalactic globular clusters with strong emphasis on recent work. The topics are: bimodality in the colour distribution of cluster systems, young massive clusters, and the brightest old clusters. Globular cluster research, perhaps more than ever, has lead to important (at least to astronomers) progress and problems in galaxy structure and formation.

  14. Synergies in extragalactic and Galactic jet research

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    The discovery of relativistic jets and superluminal sources associated with accreting X-ray binaries in the Galaxy opened new ways of investigating the physics of outflows from compact objects. The short timescales and relatively large angular sizes of Galactic jets allow to probe the physics of relativistic outflows to unprecedented details. In this article I discuss results of recent modelling of Galactic jets, covering both radiative and dynamical aspects, which can shed light on different features of their extragalactic cousins.

  15. Wasilewski 72 - an extragalactic H II region

    Science.gov (United States)

    Osterbrock, Donald E.; Tran, Hien D.; Bidelman, William P.

    1992-03-01

    Was 72 is established as an extragalactic H II region. The reddening of Was 72, as judged from the H-alpha/H-beta/H-gamma ratios, is very nearly zero, and the relative intensity of H-delta suggests a nonzero reddening. It is concluded that Was 72 is either very young or is dominated by very young stars; the age of the stars which dominate its optical spectrum is estimated at not more than 3 x 10 exp yr.

  16. Far infrared and submillimetre surveys: from IRAS to Akari, Herschel and Planck

    CERN Document Server

    Rowan-Robinson, Michael

    2015-01-01

    We discuss a new IRAS Faint Source Catalog galaxy redshift catalogue (RIFSCz) which incorporates data from Galex, SDSS, 2MASS, WISE, Akari and Planck. Akari fluxes are consistent with photometry from other far infrared and submillimetre missions provided an aperture correction is applied. Results from the Hermes-SWIRE survey in Lockman are also discussed briefly, and the strong contrast between the galaxy populations selected at 60 and 500 mu is summarized.

  17. Extragalactic Water Maser Observations with VSOP-2

    Science.gov (United States)

    Hagiwara, Y.; VSOP-2 Science Working Group

    2009-08-01

    Space-VLBI is known to achieve greatly increased angular resolution compared with ground-based VLBI observations. VSOP-2 will offer 75 μarcsec angular resolution at 22 GHz. With this improved angular resolution, VSOP-2 observations of H_2O megamaser will refine the measurements of proper motions, accelerations, distances to galaxies, and other physical parameters of galactic nuclei. In this presentation, the prospects of VSOP-2 observations of extragalactic H_2O maser with strong emphasis on H_2O megamaser are presented.

  18. Extragalactic sources in Cosmic Microwave Background maps

    Science.gov (United States)

    De Zotti, G.; Castex, G.; González-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Cai, Z.-Y.; Clemens, M.; Delabrouille, J.; Herranz, D.; Bonavera, L.; Melin, J.-B.; Tucci, M.; Serjeant, S.; Bilicki, M.; Andreani, P.; Clements, D. L.; Toffolatti, L.; Roukema, B. F.

    2015-06-01

    We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the call for a Medium-size mission (M4). We consider three possible options for the telescope size: 1 m, 1.5 m and 2 m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1 m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations taking into account all the relevant foregrounds. Predictions for the various classes of extragalactic sources are based on up-to-date models. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies (by about a factor of 8 for the 1 m telescope, of 17 for 1.5 m, of 30 for 2 m), making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temperature distributions, etc.) across the Hubble sequence. Even more interestingly, COrE+ will detect, at |b| > 30°, thousands of strongly gravitationally lensed galaxies (about 2,000, 6,000 and 13,000 for the 1 m, 1.5 m and 2 m options, respectively). Such large samples are of extraordinary astrophysical and cosmological value in many fields. Moreover, COrE+ high frequency maps will be optimally suited to pick up proto-clusters of dusty galaxies, i.e. to investigate the evolution of large scale structure at larger redshifts than can be reached by other means. Thanks to its high sensitivity COrE+ will also yield a spectacular advance in the blind detection of extragalactic sources in polarization: we expect that it

  19. Extragalactic radio sources with sharply inverted spectrum at metre wavelengths

    CERN Document Server

    Gopal-Krishna,; Mhaskey, Mukul; Ranadive, Pritesh; Wiita, Paul J; Goyal, A; Kantharia, N G; Ishwara-Chandra, C H

    2014-01-01

    We present the first results of a systematic search for the rare extragalactic radio sources showing an inverted (integrated) spectrum, with spectral index $\\alpha \\ge +2.0$, a previously unexplored spectral domain. The search is expected to yield strong candidates for $\\alpha \\ge +2.5$, for which the standard synchrotron self-absorption (characterized by a single power-law energy distribution of relativistic electron population) would not be a plausible explanation, even in an ideal case of a perfectly homogeneous source of incoherent synchrotron radiation. Such sharply inverted spectra, if found, would require alternative explanations, e.g., free-free absorption, or non-standard energy distribution of relativistic electrons which differs from a power-law (e.g., Maxwellian). The search was carried out by comparing two sensitive low-frequency radio surveys made with sub-arcminute resolution, namely, the WISH survey at 352 MHz and TGSS/DR5 at 150 MHz. The overlap region between these two surveys contains 7056 ...

  20. Transition from galactic to extragalactic cosmic rays

    CERN Document Server

    Berezinsky, V

    2007-01-01

    The transition from galactic to extragalactic cosmic rays is discussed. One of critical indications for transition is given by the Standard Model of Galactic cosmic rays, according to which the maximum energy of acceleration for iron nuclei is of order of $E_{\\rm Fe}^{\\rm max} \\approx 1\\times 10^{17}$ eV. At $E > E_{\\rm Fe}^{\\rm max}$ the spectrum is predicted to be very steep and thus the Standard Model favours the transition at energy not much higher than $E_{\\rm Fe}^{\\rm max}$. As observations are concerned there are two signatures of transition: change of energy spectra and elongation rate (depth of shower maximum in the atmosphere $X_{\\rm max}$ as function of energy). Three models of transition are discussed: dip-based model, mixed composition model and ankle model. In the latter model the transition occurs at the observed spectral feature, ankle, which starts at $E_a \\approx 1\\times 10^{19}$ eV and is characterised by change of mass compostion from galactic iron to extragalactic protons. In the dip mode...

  1. Determining the extragalactic extinction law with SALT

    CERN Document Server

    Finkelman, Ido; Kniazev, Alexei Y; Buckley, David; O'Donoghue, Darragh; Hashimoto, Yas; Loaring, Nicola; Romero, Encarni; Still, Martin; Vaisanen, Petri

    2008-01-01

    We present CCD imaging observations of early-type galaxies with dark lanes obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. We derive the extinction law by the extragalactic dust in the dark lanes in the spectral range 1.11mu m^{-1} < lambda^{-1} < 2.94 mu m^{-1} by fitting model galaxies to the unextinguished parts of the image, and subtracting from these the actual images. We find that the extinction curves run parallel to the Galactic extinction curve, which implies that the properties of dust in the extragalactic enviroment are similar to those of the Milky Way. The ratio of the total V band extinction to the selective extinction between the V and B bands is derived for each galaxy with an average of 2.82+-0.38, compared to a canonical value of 3.1 for the Milky Way. The similar values imply that galaxies with well-defined dark lanes have characteristic dust grain sizes similar to those of Galactic dust.

  2. The Taiwan Extragalactic Astronomical Data Center

    CERN Document Server

    Foucaud, Sébastien; Tsai, Meng-Feng; Kamennoff, Nicolas

    2012-01-01

    Founded in 2010, the Taiwan Extragalactic Astronomical Data Center (TWEA-DC) has for goal to propose access to large amount of data for the Taiwanese and International community, focusing its efforts on Extragalactic science. In continuation with individual efforts in Taiwan over the past few years, this is the first steppingstone towards the building of a National Virtual Observatory. Taking advantage of our own fast indexing algorithm (BLINK), based on a octahedral meshing of the sky coupled with a very fast kd-tree and a clever parallelization amongst available resources, TWEA-DC will propose from spring 2013 a service of "on-the-fly" matching facility, between on-site and user-based catalogs. We will also offer access to public and private raw and reducible data available to the Taiwanese community. Finally, we are developing high-end on-line analysis tools, such as an automated photometric redshifts and SED fitting code (APz), and an automated groups and clusters finder (APFoF).

  3. A NEW METHOD FOR MEASURING EXTRAGALACTIC DISTANCES

    Energy Technology Data Exchange (ETDEWEB)

    Yoshii, Yuzuru; Minezaki, Takeo [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kobayashi, Yukiyasu [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Koshida, Shintaro [Center of Astro Engineering and Department of Electrical Engineering, Pontificia Univercsidad Catolica de Chile, Av. Vicuna Mackenna 4868 (Chile); Peterson, Bruce A., E-mail: yoshii@ioa.s.u-tokyo.ac.jp [Mount Stromlo Observatory, Research School of Astronomy and Astrophysics, Australian National University, Weston Creek P.O., ACT 2611 (Australia)

    2014-03-20

    We have pioneered a new method for the measurement of extragalactic distances. This method uses the time lag between variations in the short wavelength and long wavelength light from an active galactic nucleus (AGN), based on a quantitative physical model of dust reverberation that relates the time lag to the absolute luminosity of the AGN. We use the large homogeneous data set from intensive monitoring observations in optical and near-infrared wavelength bands with the dedicated 2 m MAGNUM telescope to obtain the distances to 17 AGNs in the redshift range z = 0.0024 to z = 0.0353. These distance measurements are compared with distances measured using Cepheid variable stars, and are used to infer that H {sub 0} = 73 ± 3 (random) km s{sup –1} Mpc{sup –1}. The systematic error in H {sub 0} is examined, and the uncertainty in the size distribution of dust grains is the largest source of the systematic error, which is much reduced for a sample of AGNs for which their parameter values in the model of dust reverberation are individually measured. This AGN time lag method can be used beyond 30 Mpc, the farthest distance reached by extragalactic Cepheids, and can be extended to high-redshift quasi-stellar objects.

  4. Extra-Galactic Diffuse Interstellar Bands

    Science.gov (United States)

    Cox, N.; Ehrenfreund, Pascale; Kaper, Lex; Spaans, Marco; Foing, Bernard

    Diffuse Interstellar Bands (DIBs) have been observed ubiquitously along many sight-lines probing the interstellar medium of the Milky Way. Despite extensive efforts, their carrier(s) have not yet been identified, although they are very likely of a carbonaceous nature and reside in the gas phase. Possible candidates include, but are not limited to, polycyclic aromatic hydro- carbons (PAHs), fullerenes and carbon chains. To advance our understanding of DIB behaviour and thus DIB carrier properties we need to study environments inherently different from those observed in the Milky Way. Only recent advances in instrumentation and telescope capabilities are providing us with new exciting possibilities for extra-galactic DIB research. We present here a selection of our recent observational results for (extra)-galactic DIBs in the Local Group and beyond. In particular, DIBs in the Magellanic Clouds and in the spiral galaxy NGC1448. These first results show surprising similarities between certain DIB profiles as well as differences in DIB behaviour. Understanding diffuse cloud chemistry, in particular with respect to complex (carbonaceous) molecules, is crucial to any DIB carrier identification. In this respect, external galaxies offer a unique window as they exhibit local interstellar conditions (such as metallicity, UV-field and gas-to-dust ratio) very different from those observed in the Milky Way. We discuss briefly the effect of metallicity and the gas-to-dust ratio on the physi-chemical properties of diffuse clouds and the subsequent effects on the PAH charge state distribution and the DIB carriers.

  5. Extragalactic sources in Cosmic Microwave Background maps

    CERN Document Server

    De Zotti, G; Gonzalez-Nuevo, J; Lopez-Caniego, M; Negrello, M; Cai, Z -Y; Clemens, M; Delabrouille, J; Herranz, D; Bonavera, L; Melin, J -B; Tucci, M; Serjeant, S; Bilicki, M; Andreani, P; Clements, D L; Toffolatti, L; Roukema, B F

    2015-01-01

    We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the M4 call. We consider three possible options for the telescope size: 1m, 1.5m and 2m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies, making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temper...

  6. A Search for Fast Optical Transients in the Pan-STARRS1 Medium-Deep Survey: M-Dwarf Flares, Asteroids, Limits on Extragalactic Rates, and Implications for LSST

    Science.gov (United States)

    Berger, E.; Leibler, C. N.; Chornock, R.; Rest, A.; Foley, R. J.; Soderberg, A. M.; Price, P. A.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Metcalfe, N.; Stubbs, C. W.; Tonry, J. L.

    2013-12-01

    We present a search for fast optical transients (τ ~ 0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fields. Our search takes advantage of the consecutive g P1 r P1 observations (16.5 minutes in each filter), by requiring detections in both bands, with non-detections on preceding and subsequent nights. We identify 19 transients brighter than 22.5 AB mag (S/N >~ 10). Of these, 11 events exhibit quiescent counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs at d ≈ 0.2-1.2 kpc. The remaining eight transients lack quiescent counterparts, exhibit mild but significant astrometric shifts between the g P1 and r P1 images, colors of (g - r)P1 ≈ 0.5-0.8 mag, non-varying light curves, and locations near the ecliptic plane with solar elongations of about 130°, which are all indicative of main-belt asteroids near the stationary point of their orbits. With identifications for all 19 transients, we place an upper limit of R FOT(τ ~ 0.5 hr) factor of 30-50 times lower than previous limits; the limit for a timescale of ~1 day is R FOT events are limited to M ≈ -10 to ≈ - 14 mag for a timescale of ~0.5 hr to ~1 day, while relativistic sources (e.g., gamma-ray bursts, magnetar-powered transients) can reach much larger luminosities. The resulting volumetric rates are Motivated by the results of our search, we discuss strategies for identifying fast optical transients in the Large Synoptic Survey Telescope main survey, and reach the optimistic conclusion that the veil of foreground contaminants can be lifted with the survey data, without the need for expensive follow-up observations.

  7. Extragalactic Background Light: Measurements and Applications

    CERN Document Server

    Cooray, Asantha

    2016-01-01

    This review covers the measurements related to the extragalactic background light (EBL) intensity from gamma-rays to radio in the electromagnetic spectrum over 20 decades in the wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centered at 1 microns, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar system. The best measurements of COB come from an indirect technique involving Gamma-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 microns established an energetically important background with an intensity comparable to the optical background. This discovery paved the path for large aperture far-infrared and sub-millimeter observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy for...

  8. A search for extragalactic methanol masers

    CERN Document Server

    Ellingsen, S P; Whiteoak, J B; Vaile, R A; McCulloch, P M; Price, M

    1994-01-01

    A sensitive search for 6.7--GHz methanol maser emission has been made towards 10 galaxies that have yielded detectable microwave molecular--line transitions. These include several which show OH megamaser or superluminous \\water\\/ maser emission. Within the Galaxy, \\methanol\\/ and OH masers often occur in the same star formation regions and, in most cases, the \\methanol\\/ masers have a greater peak flux density than their OH counterparts. Thus we might expect \\methanol\\/ masers to be associated with extragalactic OH maser sources. We failed to detect any emission or absorption above our 60--mJy detection limit. We conclude that if the physical conditions exist to produce \\methanol\\/ megamaser emission, they are incompatible with the conditions which produce OH megamaser emission.

  9. Rapid variability of extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Quirrenbach, A.; Witzel, A.; Krichbaum, T.; Hummel, C.A.; Alberdi, A.; Schalinski, C.

    1989-02-02

    Since its discovery more than 20 years ago, variability of extragalactic radio sources on timescales of weeks to years has been the subject of many investigations. We have examined the variability of these sources on timescales of hours at wavelengths of 6 and 11 cm using the 100-m telescope of the Max-Planck-Institut fuer Radioastronomie and report the results for two sources. The quasar QSO0917 + 62 showed variations with amplitudes of up to 23% in /similar to/ 24 hours, which were correlated at the two wavelengths; in the BL Lac object 0716 + 71 we found variations with amplitudes of 7-11%. We discuss intrinsic effects, gravitational lensing and scattering in the interstellar medium as possible explanations for rapid radio variability.

  10. Statistical properties of extragalactic radio sources

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiang-Shui

    2004-01-01

    In this paper, a large sample of extragalactic radio sources is analysed to show their statistical properties. The core and total radio powers are used to determine the core-dominance parameter for galaxies, BL Lacertae objects and quasars; mutual correlations between core radio power, total radio power, redshift and core dominance parameter are 0examined for different subclasses. A statistically significant correlation between the total and core radio power is confirmed. There are no obvious correlations between core-dominance parameter and the total power for our whole sample and quasars, but there is a statistically significant anti-correlation for our galaxy sample. Some discussions and comparison of the correlations with those obtained by other authors are also given.

  11. Detailed Chemical Abundances of Extragalactic Globular Clusters

    CERN Document Server

    Bernstein, R A

    2005-01-01

    We outline a method to measure the detailed chemical composition of extragalactic (unresolved) globular clusters (GCs) from echelle spectra of their integrated light. Our goal is to use this method to measure abundance patterns of GCs in distant spiral and elliptical galaxies to constrain their formation histories. To develop this technique we have obtained a ``training set'' of integrated-light spectra of resolved GCs in the Milky Way and LMC by scanning across the clusters during exposures. Our training set also include spectra of individual stars in those GCs from which abundances can be obtained in the normal way to provide a check on our integrated-light results. We present here the preliminary integrated-light analysis of one GC in our training set, NGC 104 (47 Tuc), and outline some of the techniques utilized and problems encountered in that analysis.

  12. Extragalactic background light measurements and applications.

    Science.gov (United States)

    Cooray, Asantha

    2016-03-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

  13. The H.E.S.S. Extragalactic Sky

    CERN Document Server

    Lenain, J -P

    2013-01-01

    More than fifty extragalactic very high energy (VHE; E>100 GeV) sources have been found using ground-based imaging atmospheric Cherenkov telescopes, about twenty of which have been discovered using the H.E.S.S. (High Energy Stereoscopic System) experiment based in Namibia. Even though BL Lac objects are the dominant class of VHE detected extragalactic objects, other types of sources (starburst galaxies, radio galaxies or flat spectrum radio quasars) begin to emerge. A review of the extragalactic sources studied with H.E.S.S. is given, with an emphasis on new results.

  14. An Extragalactic HI Cloud with No Optical Counterpart?

    CERN Document Server

    Kilborn, V A; Marquarding, M; Webster, R L; Malin, D F; Banks, G D; Bhathal, R; De Blok, W J G; Boyce, P J; Disney, M J; Drinkwater, M J; Ekers, R D; Freeman, K C; Gibson, B K; Henning, P A; Jerjen, H; Knezek, P M; Koribalski, B S; Minchin, R F; Mould, J R; Oosterloo, T A; Price, R M; Putman, M E; Ryder, S D; Sadler, E M; Stewart, I; Stootman, F; Wright, A E

    2000-01-01

    We report the discovery, from the HI Parkes All-Sky Survey (HIPASS), of an isolated cloud of neutral hydrogen which we believe to be extragalactic. The HI mass of the cloud (HIPASS J1712-64) is very low, 1.7 x 10^7 Msun, using an estimated distance of ~3.2 Mpc. Most significantly, we have found no optical companion to this object to very faint limits (mu(B)~ 27 mag arcsec^-2). HIPASS J1712-64 appears to be a binary system similar to, but much less massive than, HI 1225+01 (the Virgo HI Cloud) and has a size of at least 15 kpc. The mean velocity dispersion, measured with the Australia Telescope Compact Array (ATCA), is only 4 km/s for the main component and because of the weak or non-existent star-formation, possibly reflects the thermal linewidth (T<2000 K) rather than bulk motion or turbulence. The peak column density for HIPASS J1712-64, from the combined Parkes and ATCA data, is only 3.5 x 10^19 cm^-2, which is estimated to be a factor of two below the critical threshold for star formation. Apart from i...

  15. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    Science.gov (United States)

    Pare, Dylan; Wang, Q. Daniel; Kamieneski, Patrick; Sullivan, Kendall

    2017-01-01

    Extragalactic magnetic fields are a poorly understood element of galaxies that are likely to play an important role in galaxy formation and evolution. Until recently, however, there was no way to observe these fields to a high level of detail, making it difficult to map the spatial distribution of these fields to any high degree of accuracy. Fortunately, a new technique known as Faraday Rotation Measure Synthesis allows for a more precise analysis of galactic magnetism. This technique uses the observed Faraday rotation of polarized emission from background sources to map the magnetic field of a foreground galaxy. This Faraday rotation occurs when the polarized emission encounters ionized, magnetized gas within the galaxy, causing the emission to be rotated by an amount proportional the magnetic field subjected to the ionized gas. Working as part of CHANG-ES (Continuum HAlos in Nearby Galaxies - an EVLA Survey), we have applied this technique in order to learn about the distribution of magnetic fields in the disks and halos of edge-on spiral galaxies. We will present maps of the galactic magnetic fields of CHANG-ES galaxies using this technique, indicating the potential of this technique in successfully mapping these distant fields.

  16. The Extragalactic sky with the High Energy Stereoscopic System

    CERN Document Server

    ,

    2015-01-01

    The number of extragalactic sources detected at very hight energy (VHE, E$>$100GeV) has dramatically increased during the past years to reach more than fifty. The High Energy Stereoscopic System (H.E.S.S.) had observed the sky for more than 10 years now and discovered about twenty objects. With the advent of the fifth 28 meters telescope, the H.E.S.S. energy range extends down to ~30 GeV. When H.E.S.S. data are combined with the data of the Fermi Large area Telescope, the covered energy range is of several decades allowing an unprecedented description of the spectrum of extragalactic objects. In this talk, a review of the extragalactic sources studied with H.E.S.S. will be given together with first H.E.S.S. phase II results on extragalactic sources.

  17. The size--density relation of extragalactic HII regions

    CERN Document Server

    Hunt, L K

    2009-01-01

    We investigate the size--density relation in extragalactic HII regions, with the aim of understanding the role of dust and different physical conditions in the ionized medium. First, we compiled several observational data sets for Galactic and extragalactic HII regions and confirm that extragalactic HII regions follow the same size (D)--density (n) relation as Galactic ones. Motivated by the inability of static models to explain this, we then modelled the evolution of the size--density relation of HII regions by considering their star formation history, the effects of dust, and pressure-driven expansion. The results are compared with our sample data whose size and density span roughly six orders of magnitude. We find that the extragalactic size--density relation does not result from an evolutionary sequence of HII regions but rather reflects a sequence with different initial gas densities (``density hierarchy''). Moreover, the size of many HII regions is limited by dust absorption of ionizing photons, rather ...

  18. Extragalactic Cosmic Rays and Magnetic Fields: Facts and Fiction

    CERN Document Server

    Ensslin, T A

    2005-01-01

    A critical discussion of our knowledge about extragalactic cosmic rays and magnetic fields is attempted. What do we know for sure? What are our prejudices? How do we confront our models with the observations? How can we assess the uncertainties in our modeling and in our observations? Unfortunately, perfect answers to these questions can not be given. Instead, I describe efforts I am involved in to gain reliable information about relativistic particles and magnetic fields in extragalactic space.

  19. 30 Years of Extragalactic H II Region Studies

    Science.gov (United States)

    Garnett, D.

    2000-11-01

    The study of extragalactic H II regions has provided key data on ISM abundan ces in star-forming galaxies, and on the properties and physical mechanisms associated with starbursts. Manuel Peimbert and Silvia Torres-Peimbert were early pioneers in obtaining high-quality on physical conditions in extragalactic H II regions. In this review I will highlight their contributions to the field and our present-day understanding of giant H II regions and starbursts.

  20. A selection of AKARI FIS BSC extragalactic objects

    Science.gov (United States)

    Marton, G.; Tóth, L. V.; Balázs, L. G.; Zahorecz, S.; Bagoly, Z.; Horváth, I.; Rácz, I. I.; Nagy, A.

    The point sources in the Bright Source Catalogue (BSC) of the AKARI Far-Infrared Surveyor (FIS) were classified based on their far-IR and mid-IR fluxes and colours using Quadratic Discriminant Analysis method (QDA) and Support Vector Machines (SVM). The reliability of our results show that we can successfully separate galactic and extragalactic AKARI point sources in the multidimensional space of fluxes and colours. However, differentiating among the extragalactic sub-types needs further information.

  1. A New Method for Measuring Extragalactic Distances

    CERN Document Server

    Yoshii, Y; Minezaki, T; Koshida, S; Peterson, B A

    2014-01-01

    We have pioneered a new method for the measurement of extragalactic distances. This method uses the time-lag between variations in the short wavelength and long wavelength light from an active galactic nucleus (AGN), based on a quantitative physical model of dust reverberation that relates the time-lag to the absolute luminosity of the AGN. We use the large homogeneous data set from intensive monitoring observations in optical and near-infrared wavelength bands with the dedicated 2-m MAGNUM telescope to obtain the distances to 17 AGNs in the redshift range z=0.0024 to z=0.0353. These distance measurements are compared with distances measured using Cepheid variable stars, and are used to infer that H_0= 73 +- 3 (random) km/s/Mpc. The systematic error in H_0 is examined, and the uncertainty in the size distribution of dust grains is the largest source of the systematic error, which is much reduced for a sample of AGNs for which their parameter values in the model of dust reverberation are individually measured....

  2. The VIMOS Public Extragalactic Survey (VIPERS): First Release of spectra

    CERN Document Server

    Franzetti, P; Guzzo, L; Marchetti, A; Scodeggio, M

    2014-01-01

    We release the spectra for the more than 57000 objects presented in the First VIPERS Data Release. For each object we distribute the observed, wavelength and flux calibrated spectrum, as well as cleaned spectra, where artifacts due to fringing are removed. We also provide the sky and noise spectrum and the 2D spectrum. Data can be downloaded from http://vipers.inaf.it.

  3. Capabilities of the NASA/IPAC extragalactic database in the era of a global virtual observatory

    Science.gov (United States)

    Mazzarella, Joseph M.; Madore, Barry F.; Helou, George

    2001-11-01

    We review the capabilities of the NASA/IPAC Extragalactic Database (NED, http://ned.ipac.caltech.edu) for information retrieval and knowledge discovery in the context of a globally distributed virtual observatory. Since it's inception in 1990, NED has provided astronomers world-wide with the results of a systematic cross-correlation of catalogs covering all wavelengths, along with thousands of extragalactic observations culled from published journal articles. NED is continuously being expanded and revised to include new catalogs and published observations, each undergoing a process of cross-identification to capture the current state of knowledge about extragalactic sources in a panchromatic fashion. In addition to assimilating data from the literature, the team in incrementally folding in millions of observations from new large-scale sky surveys such as 2MASS, NVSS, APM, and SDSS. At the time of writing the system contains over 3.3 million unique objects with 4.2 million cross-identifications. We summarize the recent evolution of NED from its initial emphasis on object name-, position-, and literature-based queries into a research environment that also assists statistical data exploration and discovery using large samples of objects. Newer capabilities enable intelligent Web mining of entries in geographically distributed astronomical archives that are indexed by object names and positions in NED, sample building using constraints on redshifts, object types and other parameters, as well as image and spectral archives for targeted or serendipitous discoveries. A pilot study demonstrates how NED is being used in conjunction with linked survey archives to characterize the properties of galaxy classes to form a training set for machine learning algorithms; an initial goal is production of statistical likelihoods that newly discovered sources belong to known classes, represent statistical outliers, or candidates for fundamentally new types of objects. Challenges and

  4. A catalogue of AKARI FIS BSC extragalactic objects

    Science.gov (United States)

    Marton, Gabor; Toth, L. Viktor; Gyorgy Balazs, Lajos

    2015-08-01

    We combined photometric data of about 70 thousand point sources from the AKARI Far-Infrared Surveyor Bright Source Catalogue with AllWISE catalogue data to identify galaxies. We used Quadratic Discriminant Analysis (QDA) to classify our sources. The classification was based on a 6D parameter space that contained AKARI [F65/F90], [F90/F140], [F140/F160] and WISE W1-W2 colours along with WISE W1 magnitudes and AKARI [F140] flux values. Sources were classified into 3 main objects types: YSO candidates, evolved stars and galaxies. The training samples were SIMBAD entries of the input point sources wherever an associated SIMBAD object was found within a 30 arcsecond search radius. The QDA resulted more than 5000 AKARI galaxy candidate sources. The selection was tested cross-correlating our AKARI extragalactic catalogue with the Revised IRAS-FSC Redshift Catalogue (RIFSCz). A very good match was found. A further classification attempt was also made to differentiate between extragalactic subtypes using Support Vector Machines (SVMs). The results of the various methods showed that we can confidently separate cirrus dominated objects (type 1 of RIFSCz). Some of our “galaxy candidate” sources are associated with 2MASS extended objects, and listed in the NASA Extragalactic Database so far without clear proofs of their extragalactic nature. Examples will be presented in our poster. Finally other AKARI extragalactic catalogues will be also compared to our statistical selection.

  5. Locating the "missing" baryons with extragalactic dispersion measure estimates

    CERN Document Server

    McQuinn, Matthew

    2013-01-01

    Recently, Thornton and coworkers (2013) confirmed a class of millisecond radio bursts likely of extragalactic origin that is well-suited for estimating dispersion measures (DMs). In addition, Lovelace and Richards (2013) showed that DM could be measured even towards non-variable extragalactic synchrotron sources. Motivated by these exciting results, we calculate the probability distribution of DM(z) in different models for how the cosmic baryons are distributed (both analytically and with cosmological simulations). We show that the distribution of DM is quite sensitive to whether the "missing" baryons lie around the virial radius of 10^11-10^13 Msun halos or further out, which is not easily constrained with other observational techniques. The intrinsic contribution to DM from each source could complicate studies of the extragalactic contribution. This difficulty is avoided by stacking based on the impact parameter to foreground galaxies. We show that a stacking analysis using a sample of ~100 DM measurements ...

  6. New limits on extragalactic magnetic fields from rotation measures

    CERN Document Server

    Pshirkov, Maxim S; Urban, Federico R

    2015-01-01

    We take advantage of the wealth of rotation measures data contained in the NVSS catalogue to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-$\\alpha$ clouds. Based on the observation that rotation measures from low-luminosity distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Mpc coherence length to be below 1.2 nG at the $2\\sigma$ level, and fields coherent across the entire observable Universe below 0.5 nG. These limits do not depend on the particular origin of these cosmological fields.

  7. Constraining Extragalactic Background Light From TeV Blazars

    OpenAIRE

    Yang, Jianping; Wang, Jiancheng

    2010-01-01

    Our goal is to research the upper limits on the extragalactic background light (EBL). The upper limits on the extragalactic background light (EBL), using the Fermi and very high energy (VHE) spectra recently observed in TeV blazars, are presented. We use an assumption that the VHE intrinsic photon index cannot be harder than the Fermi index measured by the Fermi-LAT. Totally, these upper limits on the EBL are compatible with ones given by most of EBL models. However, the models of high EBL de...

  8. Magnetic field disorder and Faraday effects on the polarization of extragalactic radio sources

    CERN Document Server

    Lamee, Mehdi; Farnes, Jamie S; Carretti, Ettore; Gaensler, B M; Haverkorn, Marijke; Poppi, Sergio

    2016-01-01

    We present a polarization catalog of 533 extragalactic radio sources with 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied selection effects and found that fractional polarization, $\\pi$, of radio objects at both wavelengths depends on the spectral index, source magnetic field disorder, source size and depolarization. The relationship between depolarization, spectrum and size shows that depolarization occurs primarily in the source vicinity. The median $\\pi_{2.3}$ of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are $\\sim2$ times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that numbe...

  9. Capabilities of the NASA/IPAC Extragalactic Database (NED) in the Era of a Global Virtual Observatory

    CERN Document Server

    Mazzarella, J M; Helou, G; Mazzarella, Joseph M.; Madore, Barry F.; Helou, George

    2001-01-01

    We review the capabilities of the NASA/IPAC Extragalactic Database (NED, http://ned.ipac.caltech.edu) for information retrieval and knowledge discovery in the context of a globally distributed virtual observatory. Since its inception in 1990, NED has provided astronomers world-wide with the results of a systematic cross-correlation of catalogs covering all wavelengths, along with thousands of extragalactic observations culled from published journal articles. NED is continuously being expanded and revised to include new catalogs and published observations, each undergoing a process of cross-identification to capture the current state of knowledge about extragalactic sources in a panchromatic fashion. In addition to assimilating data from the literature, the team is incrementally folding in millions of observations from new large-scale sky surveys such as 2MASS, NVSS, APM, and SDSS. At the time of writing the system contains over 3.3 million unique objects with 4.2 million cross-identifications. We summarize th...

  10. EXTRAGALACTIC VERY HIGH ENERGY GAMMA-RAY BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Neronov, A. [ISDC Data Center for Astrophysics, Chemin d' Ecogia 16, CH-1290 Versoix (Switzerland); Semikoz, D. V. [APC, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France)

    2012-09-20

    We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b| > 60 Degree-Sign . Subtracting photons associated with known sources and the residual cosmic-ray and Galactic diffuse backgrounds, we estimate the extragalactic gamma-ray background (EGB) flux. We find that the spectrum of EGB in the very high energy band above 30 GeV follows the stacked spectrum of BL Lac objects. Large Area Telescope data reveal the positive (1 + z) {sup k}, 1 < k < 4 cosmological evolution of the BL Lac source population consistent with that of their parent population, Fanaroff-Riley type I radio galaxies. We show that EGB at E > 30 GeV could be completely explained by emission from unresolved BL Lac objects if k {approx_equal} 3.

  11. Extragalactic sources towards the central region of the Galaxy

    CERN Document Server

    Roy, Subhashis; Subrahmanyan, Ravi

    2005-01-01

    We have observed a sample of 64 small diameter sources towards the central -6 degree < l< 6 degree, -2 degree < b < 2 degree of the Galaxy with the aim of studying the Faraday rotation measure near the Galactic Centre (GC) region. All the sources were observed at 6 and 3.6 cm wavelengths using the ATCA and the VLA. Fifty nine of these sources are inferred to be extragalactic. The observations presented here constitute the first systematic study of the radio polarisation properties of the background sources towards this direction and increases the number of known extragalactic radio sources in this part of the sky by almost an order of magnitude. Based on the morphology, spectral indices and lack of polarised emission, we identify four Galactic HII regions in the sample.

  12. Multiwavelength and parsec-scale properties of extragalactic jets

    CERN Document Server

    Cornelia, Müller

    2016-01-01

    Extragalactic jets originating from the central supermassive black holes of active galaxies are powerful, highly relativistic plasma outflows, emitting light from the radio up to the gamma-ray regime. The details of their formation, composition and emission mechanisms are still not completely clear. The combination of high-resolution observations using very long baseline interferometry (VLBI) and multiwavelength monitoring provides the best insight into these objects. Here, such a combined study of sources of the TANAMI sample is presented, investigating the parsec-scale and high-energy properties. The TANAMI program is a multiwavelength monitoring program of a sample of the radio and gamma-ray brightest extragalactic jets in the southern sky, below -30deg declination. We obtain the first-ever VLBI images for most of the sources, providing crucial information on the jet kinematics and brightness distribution at milliarcsecond resolution. Two particular sources are discussed in detail: PMN J1603-4904, which ca...

  13. Extragalactic photon-ALP conversion at CTA energies

    Science.gov (United States)

    Kartavtsev, A.; Raffelt, G.; Vogel, H.

    2017-01-01

    Magnetic fields in extragalactic space between galaxy clusters may induce conversions between photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. For TeV gamma rays, the oscillation length (losc) of the photon-ALP system becomes inevitably of the same order as the coherence length of the magnetic field l and the length over which the field changes significantly (transition length lt) due to refraction on background photons. We derive exact statistical evolution equations for the mean and variance of the photon and ALP transfer functions in the non-adiabatic regime (losc ~ l gg lt). We also make analytical predictions for the transfer functions in the quasi-adiabatic regime (losc ll l, lt). Our results are important in light of the upcoming Cherenkov Telescope Array (CTA), and may also be applied to models with non-zero ALP masses.

  14. The Spectroscopic Properties of Bright Extragalactic Planetary Nebulae

    CERN Document Server

    Richer, M G

    2006-01-01

    The properties of bright extragalactic planetary nebulae are reviewed based upon the results of low and high resolution spectroscopy. It is argued that bright extragalactic planetary nebulae from galaxies (or subsystems) with and without star formation have different distributions of central star temperature and ionization structure. As regards the chemical compositions, oxygen and neon are generally found to be unchanged as a result of the evolution of the stellar progenitors. Nitrogen enrichment may occur as a result of the evolution of the progenitors of bright planetary nebulae in all stellar populations, though this enrichment may be (more) random in old stellar populations. Helium abundances appear to be influenced by the chemical evolution of the host galaxy, with planetary nebulae in dwarf spheroidals having systematically elevated abundances. Neither the age nor the metallicity of the progenitor stellar population has a strong effect upon the kinematics observed for nebular shells. Both the range of ...

  15. Dust and molecules in extra-galactic planetary nebulae

    CERN Document Server

    Garcia-Hernandez, D A

    2015-01-01

    Extra-galactic planetary nebulae (PNe) permit the study of dust and molecules in metallicity environments other than the Galaxy. Their known distances lower the number of free parameters in the observations vs. models comparison, providing strong constraints on the gas-phase and solid-state astrochemistry models. Observations of PNe in the Galaxy and other Local Group galaxies such as the Magellanic Clouds (MC) provide evidence that metallicity affects the production of dust as well as the formation of complex organic molecules and inorganic solid-state compounds in their circumstellar envelopes. In particular, the lower metallicity MC environments seem to be less favorable to dust production and the frequency of carbonaceous dust features and complex fullerene molecules is generally higher with decreasing metallicity. Here, I present an observational review of the dust and molecular content in extra-galactic PNe as compared to their higher metallicity Galactic counterparts. A special attention is given to th...

  16. Axion-Like particles from extragalactic High Energy sources

    Science.gov (United States)

    Conrad, J.; Meyer, M.; Montanino, D.

    2016-05-01

    Background radiation fields (such as Extragalactic Background Light, EBL, or Cosmic Microwave Background, CMB) pervade the Universe. Above a certain energy any gamma ray flux emitted by an extragalactic source should be attenuated by the process γ+ γ(bgk) → e + + e - pair production. We have considered a scenario in which the photons are partly converted into light Axion Like Particles (ALPs) in the local magnetic field of an (extragalactic) source. Then, while the unconverted fraction of photons undergo absorption, the ALP component travel to our galaxy where is converted back to photons by the galactic magnetic field resulting in a sort of cosmic light shining through wall effect. In particular, we have considered two scenarios: 1) conversion in the turbulent magnetic field inside a galaxy cluster; and 2) conversion of photons in the coherent magnetic field at parsec scales in a Blazar jet. Afterwards, we have also analyzed mock data coming from a hypothetical Imaging Air Cherenkov Telescopes (IACT) array with characteristics similar to the Cherenkov Telescope Array (CTA) and we have investigated the dependence of the sensitivity to detect a gamma ray excess on the magnetic field parameters.

  17. A study of purely astrometric selection of extragalactic point sources

    CERN Document Server

    Heintz, Kasper E; Høg, Erik

    2015-01-01

    Selection of extragalactic point sources, e.g. QSOs, is often hampered by significant selection effects causing existing samples to have rather complex selection functions. We explore whether a purely astrometric selection of extragalactic point sources, e.g. QSOs, is feasible with the ongoing Gaia mission. Such a selection would be interesting as it would be unbiased in terms of colours of the targets and hence would allow selection also with colours in the stellar sequence. We have analyzed a total of 18 representative regions of the sky by using \\textit{GUMS}, the simulator prepared for ESAs Gaia mission, both in the range of $12\\le G \\le 20$ mag and $12\\le G \\le 18$ mag. For each region we determine the density of apparently stationary stellar sources, i.e. sources for which Gaia cannot measure a significant proper motion. The density is contrasted with the density of extragalactic point sources, e.g. QSOs, in order to establish in which celestial directions a pure astrometric selection is feasible. When ...

  18. On the origin of near-infrared extragalactic background light anisotropy.

    Science.gov (United States)

    Zemcov, Michael; Smidt, Joseph; Arai, Toshiaki; Bock, James; Cooray, Asantha; Gong, Yan; Kim, Min Gyu; Korngut, Phillip; Lam, Anson; Lee, Dae Hee; Matsumoto, Toshio; Matsuura, Shuji; Nam, Uk Won; Roudier, Gael; Tsumura, Kohji; Wada, Takehiko

    2014-11-07

    Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been attributed to primordial galaxies and black holes at the epoch of reionization (EOR) or, alternately, intrahalo light (IHL) from stars tidally stripped from their parent galaxies at low redshift. We report new EBL anisotropy measurements from a specialized sounding rocket experiment at 1.1 and 1.6 micrometers. The observed fluctuations exceed the amplitude from known galaxy populations, are inconsistent with EOR galaxies and black holes, and are largely explained by IHL emission. The measured fluctuations are associated with an EBL intensity that is comparable to the background from known galaxies measured through number counts and therefore a substantial contribution to the energy contained in photons in the cosmos.

  19. The Infrared-Gamma-Ray Connection: A WISE View of the Extragalactic Gamma-Ray Sky

    CERN Document Server

    Massaro, F

    2016-01-01

    Using data from the WISE all-sky survey we discovered that the non-thermal infrared (IR) emission of blazars, the largest known population of extragalactic gamma-ray sources, has peculiar spectral properties. In this work, we confirm and strengthen our previous analyses using the latest available releases of both the WISE and the Fermi source catalogs. We also show that there is a tight correlation between the mid-IR colors and the gamma-ray spectral index of Fermi blazars. We name this correlation "the infrared--gamma-ray connection". We discuss how this connection links both the emitted powers and the spectral shapes of particles accelerated in jets arising from blazars over ten decades in energy. Based on this evidence, we argue that the infrared--gamma-ray connection is stronger than the well known radio--gamma-ray connection.

  20. GUAIX: The UCM Group of Extragalactic Astrophysics and Astronomical Instrumentation

    Science.gov (United States)

    Gallego, J.; Cardiel, N.; Zamorano, J.; Gorgas, J.; Castillo-Morales, A.; Eliche-Moral, M. C.; Gil de Paz, A.; Pascual, S.; Pérez-González, P. G.; Guzmán, R.; Barro, G.; Díaz, C.; Espino, N.; Izquierdo, J.; Mármol-Queraltó, E.; Muñoz-Mateos, J. C.; Rodriguez, L.; Sánchez de Miguel, A.; Toloba, E.; Villar, V.; Abelleira, M.

    We present a short summary of the activities developed by GUAIX, the Universidad Complutense de Madrid (UCM) Group of Extragalactic Astrophysics and Astronomical Instrumentation. At present we are focused in the development of data reduction pipelines for several future instruments for the Spanish 10m GTC (Gran Telescopio Canarias). The careful treatment of the random error propagation throughout the data reduction is one of the main improvements of those pipelines. The first hardware development leaded by the GUAIX group will be FISIR, a fully-cryogenic (optimized for the K band) tunable filter in the near-infrared, to be installed within CIRCE, a near-IR camera for GTC.

  1. The Carnegie-Spitzer-IMACS Redshift Survey of Galaxy Evolution since z=1.5: I. Description and Methodology

    CERN Document Server

    Kelson, Daniel D; Dressler, Alan; McCarthy, Patrick J; Shectman, Stephen A; Mulchaey, John S; Villanueva, Edward V; Crane, Jeffrey D; Quadri, Ryan F

    2012-01-01

    We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade. By defining a flux-limited sample of galaxies in Spitzer 3.6micron imaging of SWIRE fields, the CSI Survey efficiently traces the stellar mass of average galaxies to z~1.5. This first paper provides an overview of the survey selection, observations, processing of the photometry and spectrophotometry. We also describe the processing of the data: new methods of fitting synthetic templates of spectral energy distributions are used to derive redshifts, stellar masses, emission line luminosities, and coarse information on recent star-formation. Our unique methodology for analyzing low-dispersion spectra taken with multilayer prisms in IMACS, combined with panchromatic photometry from the ultraviolet to the IR, has yielded 37,000 high quality redshifts in our first 5.3 sq.degs of the SWIRE XMM-LSS field. We use three...

  2. Euclid Space Mission: building the sky survey

    Science.gov (United States)

    Tereno, I.; Carvalho, C. S.; Dinis, J.; Scaramella, R.; Amiaux, J.; Burigana, C.; Cuillandre, J. C.; da Silva, A.; Derosa, A.; Maiorano, E.; Maris, M.; Oliveira, D.; Franzetti, P.; Garilli, B.; Gomez-Alvarez, P.; Meneghetti, M.; Wachter, S.; Wachter

    2014-05-01

    The Euclid space mission proposes to survey 15000 square degrees of the extragalactic sky during 6 years, with a step-and-stare technique. The scheduling of observation sequences is driven by the primary scientific objectives, spacecraft constraints, calibration requirements and physical properties of the sky. We present the current reference implementation of the Euclid survey and on-going work on survey optimization.

  3. Euclid Space Mission: building the sky survey

    CERN Document Server

    Tereno, I; Dinis, J; Scaramella, R; Amiaux, J; Burigana, C; Cuillandre, J C; da Silva, A; Derosa, A; Maiorano, E; Maris, M; Oliveira, D; Franzetti, P; Garilli, B; Gomez-Alvarez, P; Meneghetti, M; Wachter, S

    2015-01-01

    The Euclid space mission proposes to survey 15000 square degrees of the extragalactic sky during 6 years, with a step-and-stare technique. The scheduling of observation sequences is driven by the primary scientific objectives, spacecraft constraints, calibration requirements and physical properties of the sky. We present the current reference implementation of the Euclid survey and on-going work on survey optimization.

  4. The Resolved Properties of Extragalactic Giant Molecular Clouds

    CERN Document Server

    Bolatto, Alberto D; Rosolowsky, Erik; Walter, Fabian; Blitz, Leo

    2008-01-01

    We use high spatial resolution observations of CO to systematically measure the resolved size-line width, luminosity-line width, luminosity-size, and the mass-luminosity relations of Giant Molecular Clouds (GMCs) in a variety of extragalactic systems. Although the data are heterogeneous we analyze them in a consistent manner to remove the biases introduced by limited sensitivity and resolution, thus obtaining reliable sizes, velocity dispersions, and luminosities. We compare the results obtained in dwarf galaxies with those from the Local Group spiral galaxies. We find that extragalactic GMC properties measured across a wide range of environments are very much compatible with those in the Galaxy. We use these results to investigate metallicity trends in the cloud average column density and virial CO-to-H2 factor. We find that these measurements do not accord with simple predictions from photoionization-regulated star formation theory, although this could be due to the fact that we do not sample small enough s...

  5. Predicted Extragalactic TeV $\\gamma$-Ray Sources

    CERN Document Server

    Stecker, F W; Salamon, M H

    1996-01-01

    We suggest that low-redshift XBLs (X-ray selected BL Lacertae objects) may be the only extragalactic gamma-ray sources observable at TeV energies. We use simple physical considerations involving synchrotron and Compton component spectra for blazars to suggest why the observed TeV sources are XBLs, whereas mostly RBLs and FSRQs are seen at GeV energies. These considerations indicate that the differences between XBLs and RBLs cannot be explained purely as relativistic jet orientation effects. We note that the only extragalactic TeV sources which have been observed are XBLs and that a nearby RBL with a very hard spectrum in the GeV range has not been seen at TeV energies. We also note that of the 14 BL Lacs observed by EGRET, 12 are RBLs, whereas only 2 are XBLs. We give a list of nearby XBLs which we consider to be good candidate TeV sources and predict estimated TeV fluxes for these objects.

  6. Are Compact High-Velocity Clouds Extragalactic Objects?

    CERN Document Server

    Maloney, P R; Maloney, Philip R.; Putman, Mary E.

    2003-01-01

    Compact high-velocity clouds (CHVCs) are the most distant of the HVCs in the Local Group model and would have HI volume densities of order 0.0003/cm^3. Clouds with these volume densities and the observed neutral hydrogen column densities will be largely ionized, even if exposed only to the extragalactic ionizing radiation field. Here we examine the implications of this process for models of CHVCs. We have modeled the ionization structure of spherical clouds (with and without dark matter halos) for a large range of densities and sizes, appropriate to CHVCs over the range of suggested distances, exposed to the extragalactic ionizing photon flux. Constant-density cloud models in which the CHVCs are at Local Group distances have total (ionized plus neutral) gas masses roughly 20-30 times larger than the neutral gas masses, implying that the gas mass alone of the observed population of CHVCs is about 40 billion solar masses. With a realistic (10:1) dark matter to gas mass ratio, the total mass in such CHVCs is a s...

  7. Extragalactic photon-ALP conversion at CTA energies

    CERN Document Server

    Kartavtsev, A; Vogel, H

    2016-01-01

    Magnetic fields in extragalactic space between galaxy clusters may induce conversions between photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. For TeV gamma rays, the oscillation length ($l_{\\rm osc}$) of the photon-ALP system becomes inevitably of the same order as the coherence length of the magnetic field ($l$) and the length over which the field changes significantly (transition length $l_{\\rm t}$) due to refraction on background photons. We derive exact statistical evolution equations for the mean and variance of the photon and ALP transfer functions in the non-adiabatic regime ($l_{\\rm osc} \\sim l \\gg l_{\\rm t}$). We also make analytical predictions for the transfer functions in the quasi-adiabatic regime ($l_{\\rm osc} \\ll l, l_{\\rm t}$). Our results are important in light of the upcoming Cherenkov Telescope Array (CTA), and may also be applied to models with non-zero ALP masses.

  8. The 60-micron extragalactic background radiation intensity, dust-enshrouded AGNs and the assembly of groups and clusters of galaxies

    CERN Document Server

    Blain, A W; Blain, Andrew W.; Phillips, Tom

    2002-01-01

    Submillimetre observations reveal a cosmologically significant population of high-redshift dust-enshrouded galaxies. The form of evolution inferred for this population can be reconciled easily with COBE FIRAS and DIRBE measurements of the cosmic background radiation (CBR) at wavelengths >100 microns. At shorter wavelengths, however, the 60-micron CBR intensity reported by Finkbeiner et al. is less easily accounted for. Lagache et al. have proposed that this excess CBR emission is a warm Galactic component, and the detection of the highest-energy gamma-rays from blazars limits the CBR intensity at these wavelengths, but here we investigate sources of this excess CBR emission, assuming that it has a genuine extragalactic origin. We propose and test three explanations, each involving additional populations not readily detected in existing submm-wave surveys. First, dust-enshrouded galaxies with hot dust temperatures, perhaps dust-enshrouded, Compton-thick AGN as suggested by recent deep Chandra surveys. Secondly...

  9. The Extragalactic Distance Database: Color-Magnitude Diagrams

    Science.gov (United States)

    Jacobs, Bradley A.; Rizzi, Luca; Tully, R. Brent; Shaya, Edward J.; Makarov, Dmitry I.; Makarova, Lidia

    2009-08-01

    The color-magnitude diagrams/tip of the red giant branch (CMDs/TRGB) section of the Extragalactic Distance Database contains a compilation of observations of nearby galaxies from the Hubble Space Telescope. Approximately 250 (and increasing) galaxies in the Local Volume have CMDs and the stellar photometry tables used to produce them available through the Web. Various stellar populations that make up a galaxy are visible in the CMDs, but our primary purpose for collecting and analyzing these galaxy images is to measure the TRGB in each. We can estimate the distance to a galaxy by using stars at the TRGB as standard candles. In this paper, we describe the process of constructing the CMDs and make the results available to the public.

  10. The Dynamic Evolution of Young Extragalactic Radio Sources

    CERN Document Server

    An, Tao; 10.1088/0004-637X/760/1/77

    2012-01-01

    The evolution of symmetric extragalactic radio sources can be characterized by four distinct growth stages of the radio luminosity versus size of the source. The interaction of the jet with the ambient medium results in the formation and evolution of sources with non-standard (flaring) morphology. In addition, cessation or restarting of the jet power and obstruction of the jet will also result in distinct morphological structures. The radio source population may thus be classified in morphological types that indicate the prevailing physical processes. Compact symmetric objects (CSOs) occupy the earliest evolutionary phase of symmetric radio sources and their dynamical behavior is fundamental for any further evolution. Analysis of CSO dynamics is presented for a sample of 24 CSOs with known redshift and hotspot separation velocity and with a large range of radio power. Observables such as radio power, separation between two hotspots, hotspot separation velocity, and kinematic age of the source are found to be ...

  11. Extragalactic jets with helical magnetic fields: relativistic MHD simulations

    CERN Document Server

    Keppens, R; van der Holst, B; Casse, F

    2008-01-01

    Extragalactic jets are inferred to harbor dynamically important, organized magnetic fields which presumably aid in the collimation of the relativistic jet flows. We here explore by means of grid-adaptive, high resolution numerical simulations the morphology of AGN jets pervaded by helical field and flow topologies. We concentrate on morphological features of the bow shock and the jet beam behind the Mach disk, for various jet Lorentz factors and magnetic field helicities. We investigate the influence of helical magnetic fields on jet beam propagation in overdense external medium. We use the AMRVAC code, employing a novel hybrid block-based AMR strategy, to compute ideal plasma dynamics in special relativity. The helicity of the beam magnetic field is effectively transported down the beam, with compression zones in between diagonal internal cross-shocks showing stronger toroidal field regions. In comparison with equivalent low-relativistic jets which get surrounded by cocoons with vortical backflows filled by ...

  12. WARPING AND PRECESSION IN EXTRAGALACTIC MASER ACCRETION DISCS

    Directory of Open Access Journals (Sweden)

    A. Caproni

    2009-01-01

    Full Text Available Interferometric maser observations have been used to probe the physical conditions of extragalactic accretion discs at sub-parsec scales. The inferred kinematic of the water maser spots presents small deviations from Keplerian motions, which have been attributed to the warping and twisting of the parsec-scale disc. However, their physical origin is still a matter of debate in the literature. Motivated by this, we analyzed the general relativistic Bardeen-Petterson e ect, driven by a Kerr black hole, as the potential physical mechanism responsible for the disc warping and precession in the nearby Seyfert 2 galaxies NGC 1068 and NGC 4258. Assuming a power-law accretion disc, whose parameters were constrained by the observational data, we derived the basic quantities concerning the Bardeen-Petterson e ect for both sources. Some consequences from this peculiar relativistic mechanism are also presented in this work.

  13. The Extragalactic Background Light and Absorption in Gamma Ray Spectra

    Science.gov (United States)

    Gilmore, Rudy C.

    2008-03-01

    Recent state-of-the-art semi-analytic models (SAMs) can now accurately model the history of galaxy formation and evolution. These SAMs utilize a 'forward evolution' approach and include all of the important processes for determining photon emission from galaxies, such as cooling and shock heating of gas, galaxy mergers, star formation and aging, supernova and AGN feedback, and the reprocessing of light by dust. I will be presenting our group's latest prediction of the extra-galactic background light based on this work and will discuss the implications for the attenuation of VHE gamma rays from distant sources due to pair-production. These results will be compared to recent limits placed on the EBL by observations of GeV and TeV blazar spectra by experiments such as H.E.S.S., MAGIC and VERITAS. The implications for reconstructing the intrinsic spectra of distant blazars will be addressed.

  14. Simulated Extragalactic Observations with a Cryogenic Imaging Spectrophotometer

    CERN Document Server

    Mazin, B A; Mazin, Ben A.; Brunner, Robert J.

    2000-01-01

    In this paper we explore the application of cryogenic imaging spectrophotometers. Prototypes of this new class of detector, such as superconducting tunnel junctions (STJs) and transition edge sensors (TESs), currently deliver low resolution imaging spectrophotometry with high quantum efficiency (70-100%) and no read noise over a wide bandpass in the visible to near-infrared. In order to demonstrate their utility and the differences in observing strategy needed to maximize their scientific return, we present simulated observations of a deep extragalactic field. Using a simple analytic technique, we can estimate both the galaxy redshift and spectral type more accurately than is possible with current broadband techniques. From our simulated observations and a subsequent discussion of the expected migration path for this new technology, we illustrate the power and promise of these devices.

  15. Dark matter powered stars: Constraints from the extragalactic background light

    CERN Document Server

    Maurer, A; Kneiske, T; Elsässer, D; Hauschildt, P H; Horns, D

    2012-01-01

    The existence of predominantly cold non-baryonic dark matter is unambiguously demonstrated by several observations (e.g., structure formation, big bang nucleosynthesis, gravitational lensing, and rotational curves of spiral galaxies). A candidate well motivated by particle physics is a weakly interacting massive particle (WIMP). Self-annihilating WIMPs would affect the stellar evolution especially in the early universe. Stars powered by self-annihilating WIMP dark matter should possess different properties compared with standard stars. While a direct detection of such dark matter powered stars seems very challenging, their cumulative emission might leave an imprint in the diffuse metagalactic radiation fields, in particular in the mid-infrared part of the electromagnetic spectrum. In this work the possible contributions of dark matter powered stars (dark stars; DSs) to the extragalactic background light (EBL) are calculated. It is shown that existing data and limits of the EBL intensity can already be used to...

  16. Modelling extragalactic extinction through gamma-ray burst afterglows

    CERN Document Server

    Zonca, Alberto; Mulas, Giacomo; Casu, Silvia; Aresu, Giambattista

    2016-01-01

    We analyze extragalactic extinction pro?les derived through gamma-ray burst afterglows, using a dust model speci?cally constructed on the assumption that dust grains are not immutable but respond time-dependently to the local physics. Such a model includes core-mantle spherical particles of mixed chemical composition (silicate core, sp2 and sp3 carbonaceous layers), and an additional molecular component, in the form of free-flying polycyclic aromatic hydrocarbons. We fit most of the observed extinction pro?les. Failures occur for lines of sight presenting remarkable rises blueward the bump. We find a tendency in the carbon chemical structure to become more aliphatic with the galactic activity, and to some extent with increasing redshifts. Moreover, the contribution of the moleclar component to the total extinction is more important in younger objects. The results of the ?tting procedure (either successes and failures) may be naturally interpreted through an evolutionary prescription based on the carbon cycle ...

  17. Cosmic Rays in Extragalactic Systems: Clusters and Beyond

    Science.gov (United States)

    Jones, Thomas

    The existence of cosmic rays (CRs) accelerated outside our galaxy is by now established fact. For instance, the angular and spectral distributions of ultra high energy CRs (UHECRs) above roughly an EeV point clearly to their extragalactic origins. Diffuse nonthermal radio emis-sions in clusters and along their perimeters reveal GeV electrons filling volumes sometimes approaching Mpc scales. The radiative lifetimes of those leptonic CRs are so short that they must be accelerated or produced as secondaries in situ. The dominant energy sources for such extragalactic CRs are not clearly established, although they are likely to be consequences of strucure formation. Large-scale shocks (including cluster accretion shocks) and turbulence in-duced by structure formation are strong candidates. There is also the possibility that CRs may be produced through structure formation process on still larger scales associated with cos-mic filaments, although current evidence for that is sketchy. The effectiveness of processes in these environments that might accelerate CRs depends sensitively on poorly understood "mi-crophysics" in very dilute and weakly magnetized plasmas. All of these CR populations have the potential to produce diagnostic gamma rays in the GeV to TeV range. Consequently, detec-tion or improved detection limits by current and coming gamma ray observatories can provide unique and crucial information about physical processes and conditions in these environments. My talk will outline the current status of these issues. This work is supported by the US NSF, NASA and by the Minnesota Supercomputing Institute.

  18. Search for gamma-rays from M31 and other extragalactic objects

    Science.gov (United States)

    Cawley, M. F.; Fegan, D. J.; Gibbs, K.; Gorham, P. W.; Lamb, R. C.; Liebing, D. F.; Porter, N. A.; Stenger, V. J.; Weeles, T. C.

    1985-01-01

    Although the existence of fluxes of gamma-rays of energies 10 to the 12th power eV is now established for galactic sources, the detection of such gamma-rays from extragalactic sources has yet to be independently confirmed in any case. The detection and confirmation of such energetic photons is of great astrophysical importance in the study of production mechanisms for cosmic rays, and other high energy processes in extragalactic objects. Observations of m31 are discussed. It is reported as a 10 to the 12th power eV gamma-ray source. Flux limits on a number of other extragalactic objects chosen for study are given.

  19. The DENIS & 2MASS Near Infrared Surveys

    CERN Document Server

    Mamon, G A

    1996-01-01

    The DENIS and 2MASS near infrared surveys are presented. Their applications in extragalactic astronomy and cosmology are listed. The prospects for a rapid spectroscopic followup survey of a near infrared selected sample of nearly $10^5$ galaxies are illustrated with Monte-Carlo simulations.

  20. The Effelsberg Bonn HI Survey EBHIS

    NARCIS (Netherlands)

    Kerp, J.; Winkle, B.; Kalberla, P.M.W.

    2009-01-01

    The Effelsberg-Bonn HI Survey (EBHIS) covers the whole sky north of Dec(2000)= −5◦ on a fully sampled angular grid. Using state-of-the-art FPGA-spectrometers we perform a MilkyWay and an extragalactic HI survey in parallel. Moreover, the high dynamic range and short dump time of the HI spectra allow

  1. The Carnegie-Spitzer-IMACS Redshift Survey of Galaxy Evolution since z=1.5: I. Description and Methodology and More!

    CERN Document Server

    Kelson, Daniel D; Dressler, Alan; McCarthy, Patrick J; Shectman, Stephen A; Mulchaey, John S; Villanueva, Edward V; Crane, Jeffrey D; Quadri, Ryan F

    2014-01-01

    We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with IMACS on Magellan-Baade. CSI uses a flux-limited sample of galaxies in Spitzer IRAC 3.6micron imaging of SWIRE fields to efficiently trace the stellar mass of average galaxies to z~1.5. This paper provides an overview of the survey selection, observations, and processing of the photometry and spectrophotometry. We also describe the analysis of the data: new methods of fitting synthetic SEDs are used to derive redshifts, stellar masses, emission line luminosities, and coarse information on recent star-formation. Our unique methodology for analyzing low-dispersion spectra taken with multilayer prisms in IMACS, combined with panchromatic photometry from the ultraviolet to the IR, has yielded high quality redshifts for 43,347 galaxies in our first 5.3 sq. degs of the SWIRE XMM-LSS field. A new approach to assessing data quality is also described, and three different approaches are used to es...

  2. Distant galaxy clusters in the XMM Large Scale Structure survey

    CERN Document Server

    Willis, J P; Bremer, M N; Pierre, M; Adami, C; Ilbert, O; Maughan, B; Maurogordato, S; Pacaud, F; Valtchanov, I; Chiappetti, L; Thanjavur, K; Gwyn, S; Stanway, E R; Winkworth, C

    2012-01-01

    (Abridged) Distant galaxy clusters provide important tests of the growth of large scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look back time. We present a sample of 22 distant (z>0.8) galaxy clusters and cluster candidates selected from the 9 deg2 footprint of the overlapping X-ray Multi Mirror (XMM) Large Scale Structure (LSS), CFHTLS Wide and Spitzer SWIRE surveys. Clusters are selected as extended X-ray sources with an accompanying overdensity of galaxies displaying optical to mid-infrared photometry consistent with z>0.8. Nine clusters have confirmed spectroscopic redshifts in the interval 0.80.8 clusters.

  3. Magnetic Field Disorder and Faraday Effects on the Polarization of Extragalactic Radio Sources

    Science.gov (United States)

    Lamee, Mehdi; Rudnick, Lawrence; Farnes, Jamie S.; Carretti, Ettore; Gaensler, B. M.; Haverkorn, Marijke; Poppi, Sergio

    2016-09-01

    We present a polarization catalog of 533 extragalactic radio sources that have a 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied the selection effects and found that fractional polarization, π, of radio objects at both wavelengths depends on the spectral index, the source magnetic field disorder, the source size, and depolarization. The relationship between depolarization, spectrum, and size shows that depolarization occurs primarily in the source vicinity. The median {π }2.3 of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are ∼2 times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that number counts from polarization surveys will be similar at 1.4 GHz and at 2.3 GHz, for fixed sensitivity, although ∼10% of all sources may currently be missing because of strong depolarization. Objects with {π }1.4≈ {π }2.3≥slant 4 % typically have simple Faraday structures, so they are most useful for background samples. Almost half of flat-spectrum (α ≥slant -0.5) and ∼25% of steep-spectrum objects are re-polarized. Steep-spectrum, depolarized sources show a weak negative correlation of depolarization with redshift in the range 0 < z < 2.3. Previous non-detections of redshift evolution are likely due the inclusion of re-polarized sources as well.

  4. Contribution from unresolved discrete sources to the extragalactic gamma-ray background (EGRB)

    Institute of Scientific and Technical Information of China (English)

    Debbijoy Bhattacharya; Parameswaran Sreekumar; Reshmi Mukherjee

    2009-01-01

    The origin of the extragalactic gamma-ray background (EGRB) is still an open question,even nearly forty years after its discovery.The emission could originate either from truly diffuse processes or from unresolved point sources.Although the majority of the 271 point sources detected by EGRET (Energetic Gamma Ray Experiment Telescope)are unidentified,of the identified sources,blazars are the dominant candidates.Therefore,unresolved blazars may be considered the main contributor to the EGRB,and many studies have been carried out to understand their distribution,evolution and contribution to the EGRB.Considering that γ-ray emission comes mostly from jets of blazars and that the jet emission decreases rapidly with increasing jet to line-of-sight angle,it is not surprising that EGRET was not able to detect many large inclination angle active galactic nuclei (AGNs).Though Fermi could only detect a few large inclination angle AGNs during the first three months of its survey,it is expected to detect many such sources in the near future.Since non-blazar AGNs are expected to have higher density as compared to blazars,these could also contribute significantly to the EGRB.In this paper,we discuss contributions from unresolved discrete sources including normal galaxies,starburst galaxies,blazars and off-axis AGNs to the EGRB.

  5. Planck intermediate results. XLV. Radio spectra of northern extragalactic radio sources

    CERN Document Server

    Ade, P A R; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartolo, N; Battaner, E; Battye, R; Benabed, K; Bendo, G J; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Burigana, C; Butler, R C; Calabrese, E; Cardoso, J -F; Catalano, A; Chamballu, A; Chary, R -R; Chen, X; Chiang, H C; Christensen, P R; Clements, D L; Colombo, L P L; Combet, C; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Ducout, A; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frejsel, A; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; Gjerløw, E; González-Nuevo, J; Górski, K M; Gregorio, A; Gruppuso, A; Hansen, F K; Hanson, D; Harrison, D L; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Israel, F P; Jaffe, A H; Jaffe, T R; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leonardi, R; Levrier, F; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Madden, S; Maffei, B; Maino, D; Mandolesi, N; Maris, M; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Mazzotta, P; Mendes, L; Mennella, A; Migliaccio, M; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Oxborrow, C A; Pagano, L; Pajot, F; Paladini, R; Paoletti, D; Partridge, B; Pasian, F; Pearson, T J; Peel, M; Perdereau, O; Perrotta, F; Pettorino, V; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Popa, L; Pratt, G W; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Ristorcelli, I; Rocha, G; Rosset, C; Rossetti, M; Roudier, G; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Savini, G; Scott, D; Spencer, L D; Stolyarov, V; Sudiwala, R; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Wade, L A; Wandelt, B D; Watson, R; Wehus, I K; Yvon, D; Zacchei, A; Zonca, A

    2016-01-01

    Continuum spectra covering centimetre to submillimetre wavelengths are presented for a northern sample of 104 extragalactic radio sources, mainly active galactic nuclei, based on four-epoch Planck data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous ground-based radio observations between 1.1 and 37 GHz. The single-survey Planck data confirm that the flattest high-frequency radio spectral indices are close to zero, indicating that the original accelerated electron energy spectrum is much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The radio spectra peak at high frequencies and exhibit a variety of shapes. For a small set of low-z sources, we find a spectral upturn at high frequencies, indicating the presence of intrinsic cold dust. Variability can generally be approximated by achromatic variations, while sources with clear signatures of evolving shocks appear to be limited to the strongest outbursts.

  6. Evolution of the NASA/IPAC Extragalactic Database (NED) into a Data Mining Discovery Engine

    Science.gov (United States)

    Mazzarella, Joseph M.; NED Team

    2017-06-01

    We review recent advances and ongoing work in evolving the NASA/IPAC Extragalactic Database (NED) beyond an object reference database into a data mining discovery engine. Updates to the infrastructure and data integration techniques are enabling more than a 10-fold expansion; NED will soon contain over a billion objects with their fundamental attributes fused across the spectrum via cross-identifications among the largest sky surveys (e.g., GALEX, SDSS, 2MASS, AllWISE, EMU), and over 100,000 smaller but scientifically important catalogs and journal articles. The recent discovery of super-luminous spiral galaxies exemplifies the opportunities for data mining and science discovery directly from NED's rich data synthesis. Enhancements to the user interface, including new APIs, VO protocols, and queries involving derived physical quantities, are opening new pathways for panchromatic studies of large galaxy samples. Examples are shown of graphics characterizing the content of NED, as well as initial steps in exploring the database via interactive statistical visualizations.

  7. Deriving global structure of the Galactic Magnetic Field from Faraday Rotation Measures of extragalactic sources

    CERN Document Server

    Pshirkov, M S; Kronberg, P P; Newton-McGee, K J

    2011-01-01

    We made use of the two latest sets of Rotational Measures (RMs) of extra-galactic radio sources, namely the NRAO VLA Sky Survey otation Measures Catalogue, and a compilation by Kronberg&Newton-McGee(2011), to infer the global structure of the Galactic Magnetic Field (GMF). We have checked that these two data sets are consistent with each other. Motivated by clear patterns in the observed distribution of RMs over the sky, we considered GMF models consisting of the two components: disk (spiral or ring) and halo. The parameters of these components were determined by fitting different model field geometries to the observed RMs. We found that the model consisting of a symmetric (with respect to the Galactic plane) spiral disk and anti-symmetric halo fits the data best, and reproduces the observed distribution of RMs over the sky very well. We confirm that ring disk models are disfavored. Our results favor small pitch angles around -5 degrees and an increased vertical scale of electron distribution, in agreemen...

  8. Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

    Science.gov (United States)

    Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arisaka, K.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; Berat, C.; Bergmann, T.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Colombo, E.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; del Peral, L.; Deligny, O.; Della Selva, A.; Dembinski, H.; Denkiewicz, A.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fleck, I.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fuchs, B.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Gascon, A.; Gelmini, G.; Gemmeke, H.; Gesterling, K.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kadija, K.; Kaducak, M.; Kampert, K. H.; Karhan, P.; Karova, T.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meurer, C.; Mičanović, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Mueller, S.; Muller, M. A.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Parrisius, J.; Parsons, R. D.; Pastor, S.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Peķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Phan, N.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rivière, C.; Rizi, V.; Robledo, C.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schroeder, F.; Schulte, S.; Schüssler, F.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Stapleton, J.; Stasielak, J.; Stephan, M.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Tamashiro, A.; Tapia, A.; Tarutina, T.; Taşcău, O.; Tcaciuc, R.; Tcherniakhovski, D.; Tegolo, D.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tiwari, D. K.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Vargas Cárdenas, B.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Weidenhaupt, K.; Weindl, A.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Winders, L.; Winnick, M. G.; Wommer, M.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.; Pierre Auger Collaboration

    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, 6 × 10 19 eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1° from the position of an active galactic nucleus within 75 Mpc (using the Véron-Cetty and Véron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is 38-6+7%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of 69-13+11%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.

  9. Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, P.; /Lisbon, IST; Aglietta, M.; /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche; Allen, J.; /New York U.; Alvarez Castillo, J.; /Mexico U., ICN; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /INFN, Naples /Naples U.; Aminaei, A.; /Nijmegen U., IMAPP; Anchordoqui, L.; /Wisconsin U., Milwaukee /Lisbon, IST

    2010-06-01

    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuzmin energy threshold, 6 x 10{sup 19} eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1{sup o} from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38{sub -6}{sup +7})%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (69{sub -13}{sup +11})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.

  10. Planck early results. XIII. Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue

    DEFF Research Database (Denmark)

    Bucher, M.; Delabrouille, J.; Giraud-Héraud, Y.;

    2011-01-01

    and ACT surveys over small fractions of the sky. An analysis of source spectra, exploiting Planck's uniquely broad spectral coverage, finds clear evidence of a steepening of the mean spectral index above about 70 GHz. This implies that, at these frequencies, the contamination of the CMB power spectrum......The data reported in Planck's Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest...... sources in the sky. At lower frequencies (30, 44, and 70 GHz) our counts are in very good agreement with estimates based on WMAP data, being somewhat deeper at 30 and 70 GHz, and somewhat shallower at 44 GHz. Planck's source counts at 143 and 217 GHz join smoothly with the fainter ones provided by the SPT...

  11. BL Lacertae Objects and the Extragalactic Gamma-Ray Background

    CERN Document Server

    Li, Fan

    2011-01-01

    A tight correlation between gamma-ray and radio emission is found for a sample of BL Lacertae (BL Lac) objects detected by Fermi Gamma-ray Space Telescope (Fermi) and the Energetic Gamma-Ray Experiment Telescope (EGRET). The gamma-ray emission of BL Lac objects exhibits strong variability, and the detection rate of gamma-ray BL Lac objects is low, which may be related to the gamma-ray duty cycle of BL Lac objects. We estimate the gamma-ray duty cycle ~ 0.11, for BL Lac objects detected by EGRET and Fermi. Using the empirical relation of gamma-ray emission with radio emission and the estimated gamma-ray duty cycle, we derive the gamma-ray luminosity function (LF) of BL Lac objects from their radio LF. Our derived gamma-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei (AGN) sample. We find that about 45% of the extragalactic diffuse gamma-ray background (EGRB) is contributed by BL Lac objects. Combining the estimate of the quasar contri...

  12. Investigation of some galactic and extragalactic gravitational phenomena

    Directory of Open Access Journals (Sweden)

    Jovanović P.

    2012-01-01

    Full Text Available Here we present a short overview of the most important results of our investigations of the following galactic and extragalactic gravitational phenomena: supermassive black holes in centers of galaxies and quasars, supermassive black hole binaries, gravitational lenses and dark matter. For the purpose of these investigations, we developed a model of a relativistic accretion disk around a supermassive black hole, based on the ray-tracing method in the Kerr metric, a model of a bright spot in an accretion disk and three different models of gravitational microlenses. All these models enabled us to study physics, spacetime geometry and effects of strong gravity in the vicinity of supermassive black holes, variability of some active galaxies and quasars, different effects in the lensed quasars with multiple images, as well as the dark matter fraction in the Universe. We also found an observational evidence for the first spectroscopically resolved sub-parsec orbit of a supermassive black hole binary system in the core of active galaxy NGC 4151. Besides, we studied applications of one potential alternative to dark matter in the form of a modified theory of gravity on Galactic scales, to explain the recently observed orbital precession of some S-stars, which are orbiting around a massive black hole at the Galactic center. [Projekat Ministarstva nauke Republike Srbije, br. 176003: Gravitation and the Large Scale Structure of the Universe

  13. Determining the extragalactic extinction law with SALT. II. Additional sample

    CERN Document Server

    Finkelman, Ido; Kniazev, Alexei Y; Vaisanen, Petri; Buckley, David A H; O'Donoghue, Darragh; Gulbis, Amanda; Hashimoto, Yas; Loaring, Nicola; Romero-Colmenero, Encarni; Sefako, Ramotholo

    2010-01-01

    We present new results from an on-going programme to study the dust extragalactic extinction law in E/S0 galaxies with dust lanes with the Southern African Large Telescope (SALT) during its performance-verification phase. The wavelength dependence of the dust extinction for seven galaxies is derived in six spectral bands ranging from the near-ultraviolet atmospheric cutoff to the near-infrared. The derivation of an extinction law is performed by fitting model galaxies to the unextinguished parts of the image in each spectral band, and subtracting from these the actual images. We compare our results with the derived extinction law in the Galaxy and find them to run parallel to the Galactic extinction curve with a mean total-to-selective extinction value of 2.71+-0.43. We use total optical extinction values to estimate the dust mass for each galaxy, compare these with dust masses derived from IRAS measurements, and find them to range from 10^4 to 10^7 Solar masses. We study the case of the well-known dust-lane ...

  14. Extragalactic Absorption of High Energy $\\gamma$-Rays

    CERN Document Server

    Stecker, F W

    1999-01-01

    The pair-production absorption of high-energy gamma-rays by intergalactic low-energy photons is expected to produce a high-energy cutoff in the spectra of extragalactic sources which is a sensitive function of redshift. We first discuss the expected absorption coefficient as a function of energy and redshift derived by Stecker and De Jager by making use of a new empirically based calculation of the spectral energy distribution of the intergalactic infrared radiation field as given by Malkan and Stecker. We then discuss the fact that new data on the high energy gamma-ray source Mrk 501 appear to show the amount of intergalactic absorption predicted. The implications of this new HEGRA data, should they be confirmed, are significant for the astrophysics of this source, implying that (1) there is no significant intrinsic absorption inside the source, and (2) the physics of the emission produces a power-law spectrum to energies above 20 TeV. As a further test for intergalactic absorption, we give a predicted spect...

  15. Effective temperature of ionizing stars of extragalactic HII regions

    CERN Document Server

    Dors, O L; Cardaci, M V; Krabbe, A C

    2016-01-01

    The effective temperature (Teff) of the radiation field of the ionizing star(s) of a large sample of extragalactic HII regions was estimated using the R= log([OII](3727)/[OIII]5007) index. We used a grid of photoionization models to calibrate the Teff-R relation finding that it has a strong dependence with the ionizing parameter while it shows a weak direct dependence with the metallicity (variations in Z imply variations in U) of both the stellar atmosphere of the ionizing star and the gas phase of the HII region. Since the R index varies slightly with the Teff for values larger than 40 kK, the R index can be used to derive the Teff in 30-40 kK range. A large fraction of the ionization parameter variation is due to differences in the temperature of the ionizing stars and then the use of the (relatively) low Teff dependent S2=[S II](6717+31)/Ha emission-line ratio to derive the ionization parameter is preferable over others in the literature. We propose linear metallicity dependent relationships between S2 an...

  16. Extragalactic circuits, transmission lines, and CR particle acceleration

    CERN Document Server

    Kronberg, Philipp P

    2014-01-01

    A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as $\\sim 10^{20}$ eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a $10^{18} - 10^{19}$ Amp\\`eres current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be $I \\sim 10^{18}$ Amp\\`eres at $\\sim 40$ kpc away from the AGN. This indicates that organized current flow remains intact over multi-kpc distances. The electric current $...

  17. Silicate features in Galactic and extragalactic post-AGB discs

    CERN Document Server

    Gielen, C; Van Winckel, H; Evans, T Lloyd; Woods, P M; Kemper, F; Marengo, M; Meixner, M; Sloan, G C; Tielens, A G G M

    2011-01-01

    Aims. In this paper we study the Spitzer and TIMMI2 infrared spectra of post-AGB disc sources, both in the Galaxy and the LMC. Using the observed infrared spectra we determine the mineralogy and dust parameters of the discs, and look for possible differences between the Galactic and extragalactic sources. Methods. Modelling the full spectral range observed allows us to determine the dust species present in the disc and different physical parameters such as grain sizes, dust abundance ratios, and the dust and continuum temperatures. Results. We find that all the discs are dominated by emission features of crystalline and amorphous silicate dust. Only a few sample sources show features due to CO2 gas or carbonaceous molecules such as PAHs and C60 fullerenes. Our analysis shows that dust grain processing in these discs is strong, resulting in large average grain sizes and a very high crystallinity fraction. However, we do not find any correlations between the derived dust parameters and properties of the central...

  18. Characterizing Extragalactic Anomalous Microwave Emission in NGC 6946 with CARMA

    CERN Document Server

    Hensley, Brandon; Staguhn, Johannes

    2014-01-01

    Using 1 cm and 3 mm CARMA and 2 mm GISMO observations, we follow up the first extragalactic detection of anomalous microwave emission (AME) reported by Murphy et al. 2010 in an extranuclear region (Enuc. 4) of the nearby face-on spiral galaxy NGC 6946. We find the spectral shape and peak frequency of AME in this region to be consistent with models of spinning dust emission. However, the strength of the emission far exceeds the Galactic AME emissivity given the abundance of polycyclic aromatic hydrocarbons (PAHs) in that region. Using our galaxy-wide 1 cm map (21" resolution), we identify a total of eight 21"x21" regions in NGC 6946 that harbour AME at >95% significance at levels comparable to that observed in Enuc. 4. The remainder of the galaxy has 1 cm emission consistent with or below the observed Galactic AME emissivity per PAH surface density. We probe relationships between the detected AME and dust surface density, PAH emission, and radiation field, though no environmental property emerges to delineate ...

  19. Short-duration Radio Bursts with Apparent Extragalactic Dispersion

    Science.gov (United States)

    Saint-Hilaire, P.; Benz, A. O.; Monstein, C.

    2014-11-01

    We present the results of the longest yet undertaken search for apparently extragalactic radio bursts at the Bleien Radio Observatory covering 21,000 hr (898 days). The data were searched for events of less than 50 ms FWHM duration showing a ν-2 drift in the spectrogram characteristic of the delay of radio waves in plasma. We have found five cases suggesting dispersion measures between 350 and 400 cm-3 pc while searching in the range of 75-2000 cm-3 pc. Four of the five events occurred between 10:27 and 11:24 a.m. local civil time. The only exception occurred at night with the full Moon in the beam. It was an event that poorly fits plasma dispersion, but had the characteristics of a solar Type III burst. However, we were not able to confirm that it was a lunar reflection. All events were observed with a log-periodic dipole within 6800 hr, but none with a more directional horn antenna observing the rest of the time. These properties suggest a terrestrial origin of the "peryton" type reported before. However, the cause of these events remains ambiguous.

  20. Short-duration radio bursts with apparent extragalactic dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Hilaire, P. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Benz, A. O.; Monstein, C., E-mail: shilaire@ssl.berkeley.edu [Institute for Astronomy, ETH Zurich, 8093 Zurich (Switzerland)

    2014-11-01

    We present the results of the longest yet undertaken search for apparently extragalactic radio bursts at the Bleien Radio Observatory covering 21,000 hr (898 days). The data were searched for events of less than 50 ms FWHM duration showing a ν{sup –2} drift in the spectrogram characteristic of the delay of radio waves in plasma. We have found five cases suggesting dispersion measures between 350 and 400 cm{sup –3} pc while searching in the range of 75-2000 cm{sup –3} pc. Four of the five events occurred between 10:27 and 11:24 a.m. local civil time. The only exception occurred at night with the full Moon in the beam. It was an event that poorly fits plasma dispersion, but had the characteristics of a solar Type III burst. However, we were not able to confirm that it was a lunar reflection. All events were observed with a log-periodic dipole within 6800 hr, but none with a more directional horn antenna observing the rest of the time. These properties suggest a terrestrial origin of the 'peryton' type reported before. However, the cause of these events remains ambiguous.

  1. Astroparticle yield and transport from extragalactic jet terminal shocks

    CERN Document Server

    Casse, F; Casse, Fabien

    2005-01-01

    The present paper deals with the yield and transport of high-energy particle within extragalactic jet terminal shocks, also known as hotspots. We investigate in some details the cosmic ray, neutrinos and high-energy photons yield in hotspots of powerful FRII radio-galaxies by scanning all known spatial transport regimes, adiabatic and radiative losses as well as Fermi acceleration process. Since both electrons and cosmic rays are prone to the same type of acceleration, we derive analytical estimates of the maximal cosmic ray energy attainable in both toroidal and poloidal magnetic field dominated shock structures by using observational data on synchrotron emission coming from various hot-spots. One of our main conclusions is that the best hot-spot candidates for high energy astroparticle production is the extended ($L_{HS}\\geq 1kpc$), strongly magnetized ($B> 0.1mG$) terminal shock displaying synchrotron emission cut-off lying at least in the optical band. We found only one object (3C273A) over the six object...

  2. Extragalactic Background Light and Gamma-Ray Attenuation

    CERN Document Server

    Primack, Joel R; Gilmore, Rudy C; Somerville, Rachel S

    2011-01-01

    Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxies and also based on semi-analytic models, and show that they are consistent with these lower limits from observed galaxies and with the gamma-ray upper limit constraints. Such comparisons "close the loop" on cosmological galaxy formation models, since they account for all the light, including that from galaxies too faint to see. We compare our results with those of other recent works, and discuss the implications of these new EBL calculations for gamma ray attenuation. Catching a few GRBs with groundbased atmospheric Cher...

  3. The extragalactic background light revisited and the cosmic photon-photon opacity

    Science.gov (United States)

    Franceschini, Alberto; Rodighiero, Giulia

    2017-07-01

    Context. In addition to its relevant astrophysical and cosmological significance, the extragalactic background light (EBL) is a fundamental source of opacity for cosmic high energy photons, as well as a limitation for the propagation of high-energy particles in the Universe. Aims: We review our previously published determinations of the EBL photon density in the Universe and its evolution with cosmic time, in the light of recent surveys of IR sources at long wavelengths. Methods: We exploit deep survey observations by the Herschel Space Observatory and the Spitzer telescope, matched to optical and near-IR photometric and spectroscopic data, to re-estimate number counts and luminosity functions longwards of a few microns, and the contribution of resolved sources to the EBL. Results: These new data indicate slightly lower photon densities in the mid- and far-infrared and sub-millimeter compared to previous determinations. This implies slightly lower cosmic opacity for photon-photon interactions. Conclusions: The new data do not modify previously published EBL modeling in the UV-optical and near-IR up to several microns, while reducing the photon density at longer wavelengths. This improved model of the EBL alleviates some tension that had emerged in the interpretation of the highest-energy TeV observations of local blazars, reducing the case for new physics beyond the standard model (like violations of the Lorenz Invariance, LIV, at the highest particle energies), or for exotic astrophysics, that had sometimes been called for to explain it. Applications of this improved EBL model on current data are considered, as well as perspectives for future instrumentation, the Cherenkov Telescope Array (CTA) in particular.

  4. Planet from another galaxy discovered - Galactic cannibalism brings an exoplanet of extragalactic origin within astronomers' reach

    Science.gov (United States)

    2010-11-01

    An exoplanet orbiting a star that entered our Milky Way from another galaxy has been detected by a European team of astronomers using the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. The Jupiter-like planet is particularly unusual, as it is orbiting a star nearing the end of its life and could be about to be engulfed by it, giving tantalising clues about the fate of our own planetary system in the distant future. Over the last 15 years, astronomers have detected nearly 500 planets orbiting stars in our cosmic neighbourhood, but none outside our Milky Way has been confirmed [1]. Now, however, a planet with a minimum mass 1.25 times that of Jupiter [2] has been discovered orbiting a star of extragalactic origin, even though the star now finds itself within our own galaxy. It is part of the so-called Helmi stream [3] - a group of stars that originally belonged to a dwarf galaxy that was devoured by our galaxy, the Milky Way, in an act of galactic cannibalism about six to nine billion years ago. The results are published today in Science Express. "This discovery is very exciting," says Rainer Klement of the Max-Planck-Institut für Astronomie (MPIA), who was responsible for the selection of the target stars for this study. "For the first time, astronomers have detected a planetary system in a stellar stream of extragalactic origin. Because of the great distances involved, there are no confirmed detections of planets in other galaxies. But this cosmic merger has brought an extragalactic planet within our reach." The star is known as HIP 13044, and it lies about 2000 light-years from Earth in the southern constellation of Fornax (the Furnace). The astronomers detected the planet, called HIP 13044 b, by looking for the tiny telltale wobbles of the star caused by the gravitational tug of an orbiting companion. For these precise observations, the team used the high-resolution spectrograph FEROS [4] attached to the 2.2-metre MPG/ESO telescope [5] at

  5. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...... med surveys. Denne bog gennemgår alle surveyarbejdets faser og giver en praktisk indføring i: • design af undersøgelsen og udvælgelse af stikprøver, • formulering af spørgeskemaer samt indsamling og kodning af data, • metoder til at analysere resultaterne...

  6. Submillimetric study of nearby galaxies: A tool for new extragalactic molecules

    Science.gov (United States)

    Villicana Pedraza, Ilhuiyolitzin; Guesten, Rolf; Armijos Abendaño, Jairo; Carreto, Francisco; Martin, Sergio; Martin-Pintado, Jesus; Requena-Torres, Miguel; Perez-Beaupuits, Juan Pablo

    2016-07-01

    We present the first submillimetre line survey of extragalactic sources carried out by APEX, the results were presented inside of Villicana-Pedraza phd thesis in 2015. The surveys cover the 0.8 mm atmospheric window toward NGC253, NGC4945 and Arp220. We found HCN, C2H, CN, CS, C34S, HCO+, HNC, CO, N2H+, CH3OH are presents in all the sources, while 13CO,C18O and C17O, HNCO, H2CO, H2CS, SO, NO, SO2 were detected toward NGC253 and NGC4945, 13CN, *CO+, OCS, H2S in Arp220, 13CS, NH2CN, SiO in NGC253, and c-C3H2 in NGC4945 were detected. Column densities and rotation temperatures have been determinate using the Local Thermodinamical Equilibrium(LTE) line profile simulation and fitting in the MADCUBA IJ software. The differences found in the 32S/34S and 18O/17O ratios between the GC and the starburst galaxies NGC 4945 and NGC 253 suggest that the gas is less processed in the latter than in the GC. The high 18O/17O ratios in the galaxies NGC 4945 and NGC 253 suggest also material less processed in the nuclei of these galaxies than in the GC. This is consistent with the claim that 17O is a more representative primary product than 18O in stellar nucleosynthesis (Wilson and Rood 1994); Also, we did a Multitransitions study of H3O+ at 307GHz, 364GHz, 388GHz and 396GHz. From our non-LTE analysis of H3O+ in NGC253 with RADEX we found that the collisional excitation cannot explain the observed intensity of the ortho 396 GHz line. Excitation by radiation from the dust in the Far-IR can roughly explain the observations if the H2 densities are relatively low. From the derived H3O+ column densities we conclude that the chemistry of this molecule is dominated by ionization produce by the starburst in NGC253 (UV radiation from the O stars) and Arp 220 (cosmic rays from the supernovae) and likely from the AGN in NGC4549 (X-rays ); We report, for the first time, the tentative detection of the molecular ion HCNH+ (precursor of HCN and HNC) toward a galaxy, NGC4945, the abundance is much

  7. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    Science.gov (United States)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  8. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    Science.gov (United States)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  9. Evidence for Infrared-Faint Radio Sources as z > 1 Radio-Loud AGN

    CERN Document Server

    Huynh, M T; Siana, B; Middelberg, E

    2010-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift (z > 1) AGN.

  10. Extragalactic circuits, transmission lines, and CR particle acceleration

    Science.gov (United States)

    Kronberg, Philipp P.; Lovelace, Richard V. E.

    2015-08-01

    A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as ˜ 1020 eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a 1018 - 1019 Ampères current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be I ˜ 1018 Ampères at ˜ 40 kpc away from the AGN. This indicates that organised current flow remains intact over multi-kpc distances. The electric current I transports electromagnetic power into free space, P = I2Z, where Z ˜ 30 Ohms is related to the impedance of free space, and this points to the existence of cosmic electric circuit. The associated electric potential drop, V = IZ, is of the order of that required to generate Ultra High Energy Cosmic Rays (UHECR). We also explore further implications, including disruption/deflection of the power flow and also why such measurements, exemplified by those on 3C303, are currently very difficult to make and to unambiguously interpret. This naturally leads to the topic of how such measurements can be extended and improved in the future. We describe the analogy of electromagnetically dominated jets with transmission lines. High powered jets in vacuo can be understood by approximate analogy with a waveguide. The importance of inductance, impedance, and other laboratory electrical concepts are discussed in this context.

  11. BL Lacertae objects and the extragalactic γ-ray background

    Institute of Scientific and Technical Information of China (English)

    Fan Li; Xin-Wu Cao

    2011-01-01

    A tight correlation between γ-ray and radio emission is found for a sample of BL Lacertae (BL Lac) objects detected by the Fermi Gamma-ray Space Telescope (Fermi) and the Energetic Gamma-Ray Experiment Telescope (EGRET).The γ-ray emission of BL Lac objects exhibits strong variability,and the detection rate of γ-ray BL Lac objects is low,which may be related to the γ-ray duty cycle of BL Lac objects.We estimate the γ-ray duty cycle,δγ (≌)0.11,for BL Lac objects detected by EGRET and Fermi.Using the empirical relation ofγ-ray emission with radio emission and the estimated γ-ray duty cycle δγ,we derive the γ-ray luminosity function (LF) of BL Lac objects from their radio LF.Our derived γ-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei (AGN) sample.Comparison of the derived LF of the γ-ray BL Lac objects in this work with that derived by Abdo et al.(2009a) requires the γ-ray duty cycle of BL Lac objects to be almost luminosity-independent.We find that ~ 45% of the extragalactic diffuse γ-ray background (EGRB) is contributed by BL Lac objects.Combining the estimate of the quasar contribution to the EGRB in the previous work,we find that ~ 77% of the EGRB is contributed by BL Lac objects and radio quasars.

  12. Extragalactic circuits, transmission lines, and CR particle acceleration

    Directory of Open Access Journals (Sweden)

    Kronberg Philipp P.

    2015-01-01

    Full Text Available A non-negligible fraction of a Supermassive Black Hole's (SMBH rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as ∼ 1020 eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a 1018 − 1019 Ampères current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be I ∼ 1018 Ampères at ∼ 40 kpc away from the AGN. This indicates that organised current flow remains intact over multi-kpc distances. The electric current I transports electromagnetic power into free space, P = I2Z, where Z ∼ 30 Ohms is related to the impedance of free space, and this points to the existence of cosmic electric circuit. The associated electric potential drop, V = IZ, is of the order of that required to generate Ultra High Energy Cosmic Rays (UHECR. We also explore further implications, including disruption/deflection of the power flow and also why such measurements, exemplified by those on 3C303, are currently very difficult to make and to unambiguously interpret. This naturally leads to the topic of how such measurements can be extended and improved in the future. We describe the analogy of electromagnetically dominated jets with transmission lines. High powered jets in vacuo can be understood by approximate analogy with a waveguide. The importance of inductance, impedance, and other laboratory electrical concepts are discussed in this context.

  13. Effective temperature of ionizing stars of extragalactic H II regions

    Science.gov (United States)

    Dors, O. L.; Hägele, G. F.; Cardaci, M. V.; Krabbe, A. C.

    2017-04-01

    The effective temperature (Teff) of the radiation field of the ionizing star(s) of a large sample of extragalactic H II regions was estimated using the R = log([O II] (λλ3726 + 29)/[O III] λ5007) index. We used a grid of photoionization models to calibrate the Teff-R relation finding that it has a strong dependence with the ionizing parameter, while it shows a weak direct dependence with the metallicity (variations in Z imply variations in U) of both the stellar atmosphere of the ionizing star and the gas phase of the H II region. Since the R index varies slightly with the Teff for values larger than 40 kK, the R index can be used to derive the Teff in the 30-40 kK range. A large fraction of the ionization parameter variation is due to differences in the temperature of the ionizing stars and then the use of the (relatively) low Teff dependent S2 = [S II] (λλ6717 + 31)/Hα emission-line ratio to derive the ionization parameter is preferable over others in the literature. We propose linear metallicity dependent relationships between S2 and U. Teff and metallicity estimations for a sample of 865 H II regions, whose emission-line intensities were compiled from the literature, do not show any Teff-Z correlation. On the other hand, it seems to be hints of the presence of an anticorrelation between Teff-U. We found that the majority of the studied H II regions (∼87 per cent) present Teff values in the range between 37 and 40 kK, with an average value of 38.5(±1) kK. We also studied the variation of Teff as a function of the galactocentric distance for 14 spiral galaxies. Our results are in agreement with the idea of the existence of positive Teff gradients along the disc of spiral galaxies.

  14. Extra-galactic magnetic fields and the second knee in the cosmic-ray spectrum

    CERN Document Server

    Lemoine, M

    2004-01-01

    Recent work suggests that the cosmic ray spectrum may be dominated by Galactic sources up to ~10^{17.5} eV, and by an extra-Galactic component beyond, provided this latter cuts off below the transition energy. Here it is shown that this cut-off could be interpreted as a signature of extra-galactic magnetic fields with equivalent average strength B and coherence length l_c such that B\\sqrt{l_c}~2.10^{-10} G.Mpc^{1/2}, assuming l_c < r_L (Larmor radius at 10^{17} eV) and continuously emitting sources with density 10^{-5}/Mpc^3. The extra-Galactic flux is suppressed below 10^{17} eV as the diffusive propagation time from the source to the detector becomes larger than the age of the Universe.

  15. Quasar-driven outflows account for the missing extragalactic gamma-ray background

    CERN Document Server

    Wang, Xiawei

    2016-01-01

    The origin of the extragalactic $\\gamma$-ray background permeating throughout the Universe remains a mystery forty years after its discovery. The extrapolated population of blazars can account for only half of the background radiation at the energy range of ~ 0.1-10 GeV. Here we show that quasar-driven outflows generate relativistic protons that produce the missing component of the extragalactic $\\gamma$-ray background and naturally match its spectral fingerprint, with a generic break above ~ 1 GeV. The associated $\\gamma$-ray sources are too faint to be detected individually, explaining why they had not been identified so far. However, future radio observations may image their shock fronts directly. Our best fit to the Fermi-LAT observations of extragalactic $\\gamma$-ray background spectrum provides constraints on the outflow parameters that agree with observations of these outflows and theoretical predictions.

  16. Contribution of quasar-driven outflows to the extragalactic gamma-ray background

    Science.gov (United States)

    Wang, Xiawei; Loeb, Abraham

    2016-12-01

    The origin of the extragalactic γ-ray background permeating throughout the Universe remains a mystery forty years after its discovery. The extrapolated population of blazars can account for only half of the background radiation in the energy range of ~0.1-10 GeV (refs ,). Here we show that quasar-driven outflows generate relativistic protons that produce the missing component of the extragalactic γ-ray background and naturally match its spectral fingerprint, with a generic break above ~1 GeV. The associated γ-ray sources are too faint to be detected individually, explaining why they had not been identified so far. However, future radio observations may image their shock fronts directly. Our best fit to the Fermi-LAT observations of the extragalactic γ-ray background spectrum provides constraints on the outflow parameters that agree with observations of these outflows and theoretical predictions. Although our model explains the data, there might be additional contributing sources.

  17. Explosive Growth and Advancement of the NASA/IPAC Extragalactic Database (NED)

    Science.gov (United States)

    Mazzarella, Joseph M.; Ogle, P. M.; Fadda, D.; Madore, B. F.; Ebert, R.; Baker, K.; Chan, H.; Chen, X.; Frayer, C.; Helou, G.; Jacobson, J. D.; LaGue, C.; Lo, T. M.; Pevunova, O.; Schmitz, M.; Terek, S.; Steer, I.

    2014-01-01

    The NASA/IPAC Extragalactic Database (NED) is continuing to evolve in lock-step with the explosive growth of astronomical data and advancements in information technology. A new methodology is being used to fuse data from very large surveys. Selected parameters are first loaded into a new database layer and made available in areal searches before they are cross-matched with prior NED objects. Then a programmed, rule-based statistical approach is used to identify new objects and compute cross-identifications with existing objects where possible; otherwise associations between objects are derived based on positional uncertainties or spatial resolution differences. Approximately 62 million UV sources from the GALEX All-Sky Survey and Medium Imaging Survey catalogs have been integrated into NED using this new process. The December 2013 release also contains nearly half a billion sources from the 2MASS Point Source Catalog accessible in cone searches, while the large scale cross-matching is in progress. Forthcoming updates will fuse data from All-WISE, SDSS DR12, and other very large catalogs. This work is progressing in parallel with the equally important integration of data from the literature, which is also growing rapidly. Recent updates have also included H I and CO channel maps (data cubes), as well as substantial growth in redshifts, classifications, photometry, spectra and redshift-independent distances. The By Parameters search engine now incorporates a simplified form for entry of constraints, and support for long-running queries with machine-readable output. A new tool for exploring the environments of galaxies with measured radial velocities includes informative graphics and a method to assess the incompleteness of redshift measurements. The NED user interface is also undergoing a major transformation, providing more streamlined navigation and searching, and a modern development framework for future enhancements. For further information, please visit our

  18. VLBI Surveys of Active Galactic Nuclei

    Science.gov (United States)

    Kovalev, Y. Y.

    2009-08-01

    A review is given on the current status and selected results from large VLBI surveys of compact extragalactic radio sources made between 13 cm and 3 mm wavelengths and covering the entire sky. More than 4200 objects are observed and imaged with dynamic ranges from a hundred to several thousand at (sub)parsec scales. Implications to the VSOP-2 project are discussed.

  19. Constraints on the photon charge based on observations of extragalactic sources

    CERN Document Server

    Kobychev, V V

    2004-01-01

    Using modern high-resolution observations of extragalactic compact radio sources we obtain an estimate of the upper bound on a photon electric charge at the level $e_{\\gamma} \\lesssim 3 \\cdot 10^{-33}$ of elementary charge (assuming the photon charge to be energy independent). This is three orders of magnitude better than the limit obtained with radio pulsar timing. Also we set a limit on a photon charge in the gamma-ray band (energies about 0.1 MeV). In future the estimate made for extragalactic sources can be significantly improved.

  20. The Gamma Ray Opacity of the Universe -- Indirect Measurements of the Extragalactic Background Light

    CERN Document Server

    Krennrich, F

    2014-01-01

    Indirect constraints on the intensity of the Extragalactic Background Light (EBL) were provided by recent studies of extragalactic sources emitting sub-TeV to multi-TeV photons. These constraints are provided thanks to the absorption of gamma rays by soft photons from the EBL (UV/optical/IR) via pair production by gamma - gamma interactions. This paper provides an overview of recent results that have led to substantially reduced uncertainties on the EBL intensity over a wide range of wavelengths from 0.1 to 15 micron.

  1. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lavonen, N.; León-Tavares, J.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are co...

  2. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lavonen, N.; León-Tavares, J.;

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are co...

  3. Placing Limits on Extragalactic Substructure with Gravitational Lenses and Adaptive Optics

    NARCIS (Netherlands)

    Lagattuta, David J.; Vegetti, S.; Auger, M. W.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P.

    2011-01-01

    We present the first results from a systematic search for extragalactic substructure, using high resolution Adaptive Optics (AO) images of known strong gravitational lenses. In particular we focus on two lens systems, B0128+437 and B1939+666, placing limits on both luminous and dark matter substruct

  4. Constraints on decaying dark matter from the extragalactic gamma-ray background

    NARCIS (Netherlands)

    Ando, S.; Ishiwata, K.

    2015-01-01

    If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We constrain dark matter decay by analyzing the 50-month EGRB data measured with Fermi satellite, for di ff erent decay ch

  5. Planck intermediate results: XLV. Radio spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Aller, H. D.;

    2016-01-01

    Continuum spectra covering centimetre to submillimetre wavelengths are presented for a northern sample of 104 extragalactic radio sources, mainly active galactic nuclei, based on four-epoch Planck data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous gro...

  6. The contribution of blazars to the extragalactic diffuse gamma-ray background

    DEFF Research Database (Denmark)

    Mücke, A.; Pohl, M.; Dermer, C.D.

    1997-01-01

    We present results of a calculation of the blazar contribution to the extragalactic diffuse gamma-ray background (EGRB) in the EGRET-energy range. Our model is based on the non-thermal emission processes known to be important in blazar jets, and on the unification scheme of radio-loud AGN...

  7. Experimental constraints on the astrophysical interpretation of the cosmic ray Galactic-extragalactic transition region

    CERN Document Server

    De Donato, C

    2008-01-01

    The energy region spanning from $\\sim 10^{17}$ to $\\lesssim 10^{19}$ eV is critical for understanding both, the Galactic and the extragalactic cosmic ray fluxes. This is the region where the propagation regime of nuclei inside the Galactic magnetic environment changes from diffusive to ballistic, as well as the region where, very likely, the most powerful Galactic accelerators reach their maximum output energies. In this work, a diffusion Galactic model is used to analyze the end of the Galactic cosmic ray spectrum and its mixing with the extragalactic cosmic ray flux. In particular, we study the conditions that must be met, from the spectral and composition points of view, by the Galactic and the extragalactic fluxes in order to reproduce simultaneously the total spectrum and elongation rate measured over the transition region by HiRes and Auger. Our analysis favors a mixed extragalactic spectrum in combination with a Galactic spectrum enhanced by additional high energy components, i.e., extending beyond the...

  8. On the detectability of extragalactic fast radio transients

    CERN Document Server

    Lorimer, D R; McLaughlin, M A; Johnston, S

    2013-01-01

    Recent discoveries of highly dispersed millisecond radio bursts by Thornton et al. in a survey with the Parkes radio telescope at 1.4 GHz point towards an emerging population of sources at cosmological distances whose origin is currently unclear. Here we demonstrate that the scattering effects at lower radio frequencies are less than previously thought, and that the bursts could be detectable at redshifts out to about $z=0.5$ in surveys below 1 GHz. Using a source model in which the bursts are standard candles with bolometric luminosities $\\sim 4 \\times 10^{44}$ ergs/s uniformly distributed per unit comoving volume, we derive an expression for the observed peak flux density as a function of redshift and use this, together with the rate estimates found by Thornton et al. to find an empirical relationship between event rate and redshift probed by a given survey. The non-detection of any such events in Arecibo 1.4 GHz survey data by Deneva et al., and the Allen Telescope Array survey by Simeon et al. is consiste...

  9. The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

    Science.gov (United States)

    Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Bock, J.; hide

    2011-01-01

    We investigate the potential of submm-mm and submm-mm-radio photometric red-shifts using a sample of mm-selected sources as seen at 250, 350 and 500 micrometers by the SPIRE instrument on Herschel. From a sample of 63 previously identified mm-sources with reliable radio identifications in the GOODS-N and Lockman Hole North fields 46 (73 per cent) are found to have detections in at least one SPIRE band. We explore the observed submm/mm colour evolution with redshift, finding that the colours of mm-sources are adequately described by a modified blackbody with constant optical depth Tau = (nu/nu(0))beta where beta = +1.8 and nu(0) = c/100 micrometers. We find a tight correlation between dust temperature and IR luminosity. Using a single model of the dust temperature and IR luminosity relation we derive photometric redshift estimates for the 46 SPIRE detected mm-sources. Testing against the 22 sources with known spectroscopic, or good quality optical/near-IR photometric, redshifts we find submm/mm photometric redshifts offer a redshift accuracy of |delta z|/(1+z) = 0.16 (less than |delta z| greater than = 0.51). Including constraints from the radio-far IR correlation the accuracy is improved to |delta z|/(1 + z) = 0.15 (less than |delta z| greater than = 0.45). We estimate the redshift distribution of mm-selected sources finding a significant excess at z greater than 3 when compared to 850 micrometer selected samples.

  10. A Survey of Variable Extragalactic Sources with XTE's All Sky Monitor (ASM)

    Science.gov (United States)

    Jernigan, Garrett

    1998-01-01

    The original goal of the project was the near real-time detection of AGN utilizing the SSC 3 of the ASM on XTE which does a deep integration on one 100 square degree region of the sky. While the SSC never performed sufficiently well to allow the success of this goal, the work on the project has led to the development of a new analysis method for coded aperture systems which has now been applied to ASM data for mapping regions near clusters of galaxies such as the Perseus Cluster and the Coma Cluster. Publications are in preparation that describe both the new method and the results from mapping clusters of galaxies.

  11. VizieR Online Data Catalog: Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)

    Science.gov (United States)

    Oliver, S. J.; Bock, J.; Altieri, B.; Amblard, A.; Arumugam, V.; Aussel, H.; Babbedge, T.; Beelen, A.; Bethermin, M.; Blain, A.; Boselli, A.; Bridge, C.; Brisbin, D.; Buat, V.; Burgarella, D.; Castro-Rodriguez, N.; Cava, A.; Chanial, P.; Cirasuolo, M.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dubois, E. N.; Dwek, E.; Dye, S.; Eales, S.; Elbaz, D.; Farrah, D.; Feltre, A.; Ferrero, P.; Fiolet, N.; Fox, M.; Franceschini, A.; Gear, W.; Giovannoli, E.; Glenn, J.; Gong, Y.; Gonzalez Solares, E. A.; Griffin, M.; Halpern, M.; Harwit, M.; Hatziminaoglou, E.; Heinis, S.; Hurley, P.; Hwang, H. S.; Hyde, A.; Ibar, E.; Ilbert, O.; Isaak, K.; Ivison, R. J.; Lagache, G.; Le Floc'h, E.; Levenson, L.; Faro, B. L.; Lu, N.; Madden, S.; Maffei, B.; Magdis, G.; Mainetti, G.; Marchetti, L.; Marsden, G.; Marshall, J.; Mortier, A. M. J.; Nguyen, H. T.; O'Halloran, B.; Omont, A.; Page, M. J.; Panuzzo, P.; Papageorgiou, A.; Patel, H.; Pearson, C. P.; Perez-Fournon, I.; Pohlen, M.; Rawlings, J. I.; Raymond, G.; Rigopoulou, D.; Riguccini, L.; Rizzo, D.; Rodighier!, O. G.; Ros Eboom, I. G.; Rowan-Robinson, M.; Sanchez Portal, M.; Schulz, B.; Scott, D.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vaccari, M.; Valtchanov, I.; Vieira, J. D.; Viero, M.; Vigroux, L.; Wang, L.; Ward, R.; Wardlow, J.; Wright, G.; Xu, C. K.; Zemcov, M.

    2017-03-01

    SPIRE maps (250, 350 and 500 microns) and PACS maps (100 and 160 microns) covering an area of more than 385 square degrees in the sky resulting from observations taken as part of HerMES (KPGTsoliver1), a Herschel Key Project whose main objective was to chart the formation and evolution of infrared galaxies throughout cosmic history, measuring the bolometric emission of infrared galaxies and their clustering properties. The associated catalogues extracted from these maps include over 1,200,000 entries representing over 340,000 galaxies. They consist of 'blind extraction' catalogues containing photometric information derived directly from these maps, 'band merged' catalogues extracted at SPIRE 250 micron positions plus 'cross-identification' catalogues based on prior Spitzer MIPS 24 micron source positions. The latest data releases contain also information derived from the complementary Herschel programmes HeLMS (GT2mviero1) and HeRS (OT2mviero2). (4 data files).

  12. The SWIRE-VVDS-CFHTLS surveys: stellar mass assembly over the last 10 Gyears. Evidence for a major build up of the red sequence between z=2 and z=1

    CERN Document Server

    Arnouts, S; Le Fèvre, O; Zamorani, G; Ilbert, O; Pozzetti, L; Bardelli, S; Tresse, L; Zucca, E; Le Brun, V; Charlot, S; Lamareille, F; McCracken, H J; Bolzonella, M; Iovino, A; Lonsdale, C; Polletta, M; Surace, J; Bottini, D; Garilli, B; MacCagni, D; Picat, J P; Scaramella, R; Scodeggio, M; Vettolani, G; Zanichelli, A; Adami, C; Cappi, A; Ciliegi, P; Contini, T; De la Torre, S; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Radovich, M; Temporin, S; Vergani, D

    2007-01-01

    (abridged abstract) We present an analysis of the stellar mass growth over the last 10 Gyrs using a large 3.6$\\mu$ selected sample. We split our sample into active (blue) and quiescent (red) galaxies. Our measurements of the K-LFs and LD evolution support the idea that a large fraction of galaxies is already assembled at $z\\sim 1.2$. Based on the analysis of the evolution of the stellar mass-to-light ratio (in K-band) for the spectroscopic sub-sample, we derive the stellar mass density for the entire sample. We find that the global evolution of the stellar mass density is well reproduced by the star formation rate derived from UV dust corrected measurements. Over the last 8Gyrs, we observe that the stellar mass density of the active population remains approximately constant while it gradually increases for the quiescent population over the same timescale. As a consequence, the growth of the stellar mass in the quiescent population must be due to the shutoff of star formation in active galaxies that migrate in...

  13. The NSF Undergraduate ALFALFA Team: Partnering with Arecibo Observatory to Offer Undergraduate and Faculty Extragalactic Radio Astronomy Research Opportunities

    Science.gov (United States)

    Ribaudo, Joseph; Koopmann, Rebecca A.; Haynes, Martha P.; Balonek, Thomas J.; Cannon, John M.; Coble, Kimberly A.; Craig, David W.; Denn, Grant R.; Durbala, Adriana; Finn, Rose; Hallenbeck, Gregory L.; Hoffman, G. Lyle; Lebron, Mayra E.; Miller, Brendan P.; Crone-Odekon, Mary; O'Donoghue, Aileen A.; Olowin, Ronald Paul; Pantoja, Carmen; Pisano, Daniel J.; Rosenberg, Jessica L.; Troischt, Parker; Venkatesan, Aparna; Wilcots, Eric M.; ALFALFA Team

    2017-01-01

    The NSF-sponsored Undergraduate ALFALFA (Arecibo Legacy Fast ALFA) Team (UAT) is a consortium of 20 institutions across the US and Puerto Rico, founded to promote undergraduate research and faculty development within the extragalactic ALFALFA HI blind survey project and follow-up programs. The objective of the UAT is to provide opportunities for its members to develop expertise in the technical aspects of observational radio spectroscopy, its associated data analysis, and the motivating science. Partnering with Arecibo Observatory, the UAT has worked with more than 280 undergraduates and 26 faculty to date, offering 8 workshops onsite at Arecibo (148 undergraduates), observing runs at Arecibo (69 undergraduates), remote observing runs on campus, undergraduate research projects based on Arecibo science (120 academic year and 185 summer projects), and presentation of results at national meetings such as the AAS (at AAS229: Ball et al., Collova et al., Davis et al., Miazzo et al., Ruvolo et al, Singer et al., Cannon et al., Craig et al., Koopmann et al., O'Donoghue et al.). 40% of the students and 45% of the faculty participants have been women and members of underrepresented groups. More than 90% of student alumni are attending graduate school and/or pursuing a career in STEM. 42% of those pursuing graduate degrees in Physics or Astronomy are women.In this presentation, we summarize the UAT program and the current research efforts of UAT members based on Arecibo science, including multiwavelength followup observations of ALFALFA sources, the UAT Collaborative Groups Project, the Survey of HI in Extremely Low-mass Dwarfs (SHIELD), and the Arecibo Pisces-Perseus Supercluster Survey (APPSS). This work has been supported by NSF grants AST-0724918/0902211, AST-075267/0903394, AST-0725380, AST-121105, and AST-1637339.

  14. DARK MATTER SEARCHES IN THE GAMMA-RAY EXTRAGALACTIC BACKGROUND VIA CROSS-CORRELATIONS WITH GALAXY CATALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Cuoco, Alessandro; Regis, Marco; Fornengo, Nicolao [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, I-10125 Torino (Italy); Xia, Jun-Qing [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Branchini, Enzo [Dipartimento di Matematica e Fisica, Università degli Studi “Roma Tre,” via della Vasca Navale 84, I-00146 Roma (Italy); Viel, Matteo, E-mail: cuoco@to.infn.it, E-mail: regis@to.infn.it, E-mail: fornengo@to.infn.it, E-mail: xiajq@bnu.edu.cn, E-mail: branchin@fis.uniroma3.it, E-mail: viel@oats.inaf.it [INAF Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34141, Trieste (Italy)

    2015-12-15

    We compare the measured angular cross-correlation between the Fermi-Large Area Telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (WIMP) dark matter (DM). We include a detailed description of the contribution of astrophysical γ-ray emitters such as blazars, misaligned active galactic nucleus (AGN), and star-forming galaxies, and perform a global fit to the measured cross-correlation. Five catalogs are considered: Sloan Digital Sky Survey (SDSS)-DR6 quasars, Two Micron All Sky Survey galaxies, NRAO VLA Sky Survey radio galaxies, SDSS-DR8 Luminous Red Galaxies, and the SDSS-DR8 main galaxy sample. To model the cross-correlation signal, we use the halo occupation distribution formalism to estimate the number of galaxies of a given catalog in DM halos and their spatial correlation properties. We discuss uncertainties in the predicted cross-correlation signal arising from the DM clustering and WIMP microscopic properties, which set the DM γ-ray emission. The use of different catalogs probing objects at different redshifts significantly reduces, though not completely, the degeneracy among the different γ-ray components. We find that the presence of a significant WIMP DM signal is allowed by the data but not significantly preferred by the fit, although this is mainly due to a degeneracy with the misaligned AGN component. With modest substructure boost, the sensitivity of this method excludes thermal annihilation cross sections at 95% level for WIMP masses up to few tens of GeV. Constraining the low-redshift properties of astrophysical populations with future data will further improve the sensitivity to DM.

  15. Sharp edges to neutral hydrogen disks in galaxies and the extragalactic radiation field

    Science.gov (United States)

    Maloney, Philip

    1993-01-01

    It is shown that the very sharp truncation of the neutral hydrogen distribution seen in NGC 3198 (and probably M33) is well modeled as the result of ionization of the atomic gas by the extragalactic radiation field. Below a critical column density of about a few times 10 exp 19/sq cm the gas is dominantly ionized and undetectable in the 21-cm line. It is inferred from the photoionization models that the total disk gas distribution in NGC 3198 is actually fairly axisymmetric. The critical column density for ionization is not a strong function of galaxy mass or mass distribution; thus, all galaxies should show a cutoff at approximately the same column density. Specific models of 3198 suggest that the extragalactic ionizing photon flux is 5000-10,000 photons/sq cm s.

  16. Sharp edges to neutral hydrogen disks in galaxies and the extragalactic radiation field

    Science.gov (United States)

    Maloney, Philip

    1993-09-01

    It is shown that the very sharp truncation of the neutral hydrogen distribution seen in NGC 3198 (and probably M33) is well modeled as the result of ionization of the atomic gas by the extragalactic radiation field. Below a critical column density of about a few times 10 exp 19/sq cm the gas is dominantly ionized and undetectable in the 21-cm line. It is inferred from the photoionization models that the total disk gas distribution in NGC 3198 is actually fairly axisymmetric. The critical column density for ionization is not a strong function of galaxy mass or mass distribution; thus, all galaxies should show a cutoff at approximately the same column density. Specific models of 3198 suggest that the extragalactic ionizing photon flux is 5000-10,000 photons/sq cm s.

  17. Fixing the Reference Frame for PPMXL Proper Motions Using Extragalactic Sources

    CERN Document Server

    Grabowski, Kathleen; Newberg, Heidi Jo; Beers, Timothy C; Chen, Li; Deng, Licai; Grillmair, Carl J; Guhathakurta, Puragra; Hou, Jinliang; Lepine, Sebastien; Liu, Chao; Liu, Xiaowei; Luo, A-Li; Smith, Martin C; Yanny, Brian; Zhang, Haotong; Zheng, Zheng

    2014-01-01

    We quantify and correct systematic errors in PPMXL proper motions using extragalactic sources from the first two LAMOST data releases and the Veron-Cetty & Veron Catalog of Quasars. Although the majority of the sources are from the Veron catalog, LAMOST makes important contributions in regions that are not well-sampled by previous catalogs, particularly at low Galactic latitudes and in the south Galactic cap. We show that quasars in PPMXL have measureable and significant proper motions, which reflect the systematic zero-point offsets present in the catalog. We confirm the global proper motion shifts seen by Wu, Ma, & Zhou (2011), and additionally find smaller-scale fluctuations of the QSO-derived corrections to an absolute frame. We average the proper motions of 158,106 extragalactic objects in bins of 3x3 degrees and present a table of proper motion corrections.

  18. Effects of uncertainties in simulations of extragalactic UHECR propagation, using CRPropa and SimProp

    CERN Document Server

    Batista, Rafael Alves; di Matteo, Armando; van Vliet, Arjen; Walz, David

    2015-01-01

    The results of simulations of the extragalactic propagation of ultra-high energy cosmic rays (UHECRs) have intrinsic uncertainties due to poorly known physical quantities and approximations used in the codes. We quantify the uncertainties in the simulated UHECR spectrum and composition due to different models for the extragalactic background light (EBL), different photodisintegration setups, approximations concerning photopion production and the use of different simulation codes. We discuss the results for several representative source scenarios with proton, nitrogen or iron at injection. For this purpose we used SimProp and CRPropa, two publicly available codes for Monte Carlo simulations of UHECR propagation. CRPropa is a detailed and extensive simulation code, while SimProp aims to achieve acceptable results using a simpler code. We show that especially the choices for the EBL model and the photodisintegration setup can have a considerable impact on the simulated UHECR spectrum and composition.

  19. Confusing the extragalactic neutrino flux limit with a neutrino propagation limit

    Energy Technology Data Exchange (ETDEWEB)

    Barranco, Juan [Instituto de Astronomía, Universidad Nacional Autonoma de México, Mexico, DF 04510 (Mexico); Miranda, Omar G. [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740 07000 México, D.F. (Mexico); Moura, Celio A. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, 09210-170 Santo André, SP (Brazil); Rashba, Timur I. [Max-Planck-Institute for Solar System Research, Katlenburg-Lindau, 37191 (Germany); Rossi-Torres, Fernando, E-mail: barranco@astroscu.unam.mx, E-mail: Omar.Miranda@fis.cinvestav.mx, E-mail: celio.moura@ufabc.edu.br, E-mail: timur@mppmu.mpg.de, E-mail: ftorres@ifi.unicamp.br [Instituto de Física Teórica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271 - Bl. II, 01140-070, São Paulo, SP (Brazil)

    2011-10-01

    We study the possible suppression of the extragalactic neutrino flux due to a nonstandard interaction during its propagation. In particular, we study neutrino interaction with an ultra-light scalar field dark matter. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a new mechanism to reduce the ultra-high energy neutrino flux. We study both the cases of non-self-conjugate as well as self-conjugate dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms for the reduction of the neutrino flux.

  20. Planck early results: Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    CERN Document Server

    Aatrokoski, J; Aghanim, N; Aller, H D; Aller, M F; Angelakis, E; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Balbi, A; Banday, A J; Barreiro, R B; Bartlett, J G; Battaner, E; Benabed, K; Benoît, A; Berdyugin, A; Bernard, J -P; Bersanelli, M; Bhatia, R; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Bucher, M; Burigana, C; Burrows, D N; Cabella, P; Capalbi, M; Cappellini, B; Cardoso, J -F; Catalano, A; Cavazzuti, E; Cayón, L; Challinor, A; Chamballu, A; Chary, R -R; Chiang, L -Y; Christensen, P R; Clements, D L; Colafrancesco, S; Colombi, S; Couchot, F; Coulais, A; Cutini, S; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Gasperis, G; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Dickinson, C; Dole, H; Donzelli, S; Doré, O; Dörl, U; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Fuhrmann, L; Galeotta, S; Ganga, K; Gargano, F; Gasparrini, D; Gehrels, N; Giard, M; Giardino, G; Giglietto, N; Giommi, P; Giordano, F; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Harrison, D; Henrot-Versillé, S; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hoyland, R J; Huffenberger, K M; Jaffe, A H; Juvela, M; Keihänen, E; Keskitalo, R; King, O; Kisner, T S; Kneissl, R; Knox, L; Krichbaum, T P; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lavonen, N; Lawrence, C R; Leach, S; Leonardi, R; León-Tavares, J; Linden-V\\ornle, M; Lindfors, E; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Mann, R; Maris, M; Martínez-González, E; Masi, S; Massardi, M; Matarrese, S; Matthai, F; Max-Moerbeck, W; Mazziotta, M N; Mazzotta, P; Melchiorri, A; Mendes, L; Mennella, A; Michelson, P F; Mingaliev, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Monte, C; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Natoli, P; Nestoras, I; Netterfield, C B; Nieppola, E; Nilsson, K; N\\orgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; O'Dwyer, I J; Osborne, S; Pajot, F; Partridge, B; Pasian, F; Patanchon, G; Pavlidou, V; Pearson, T J; Perdereau, O; Perotto, L; Perri, M; Perrotta, F; Piacentini, F; Piat, M; Plaszczynski, S; Platania, P; Pointecouteau, E; Polenta, G; Ponthieu, N; Poutanen, T; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Rainó, S; Reach, W T; Readhead, A; Rebolo, R; Reeves, R; Reinecke, M; Reinthal, R; Renault, C; Ricciardi, S; Richards, J; Riller, T; Riquelme, D; Ristorcelli, I; Rocha, G; Rosset, C; Rowan-Robinson, M; Rubi\; Rusholme, B; Saarinen, J; Sandri, M; Savolainen, P; Scott, D; Seiffert, M D; Sievers, A; Sillanpää, A; Smoot, G F; Sotnikova, Y; Starck, J -L; Stevenson, M; Stivoli, F; Stolyarov, V; Sudiwala, R; Sygnet, J -F; Takalo, L; Tammi, J; Tauber, J A; Terenzi, L; Thompson, D J; Toffolatti, L; Tomasi, M; Tornikoski, M; Torre, J -P; Tosti, G; Tramacere, A; Tristram, M; Tuovinen, J; Türler, M; Turunen, M; Umana, G; Ungerechts, H; Valenziano, L; Valtaoja, E; Varis, J; Verrecchia, F; Vielva, P; Villa, F; Vittorio, N; Wandelt, B D; Wu, J; Yvon, D; Zacchei, A; Zensus, J A; Zhou, X; Zonca, A

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalog (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, moving in the relativistic jet, shape the radio spectra. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelli...

  1. The fields of reference stars for optical positional observations of astrometric extragalactic radio sources

    Science.gov (United States)

    Dement'eva, A. A.; Ryl'Kov, V. P.

    The Pulkovo programme (Pul ERS) and the techniques used to create a catalogue of coordinates and magnitudes for more than 7000 faint stars in 73 small fields around extragalactic radiosources (ERS) are described. Accurate positions of stars in the fields around ERS 2200+420 and ERS 2021+614 are given. The catalogue containing 223 stars is presented. The errors of coordinate reductions in the system of reference stars from the CMC catalogue are found to be 1.5-2.0 times smaller than for those in the system of the PPM catalogue. This programme (Pul ERS) is required for quick identification of the extragalactic radio sources and for obtaining their characteristics from observations with large telescopes and CCD detectors.

  2. Contribution from normal and starburst galaxies to the extragalactic gamma-ray background (EGRB)

    Institute of Scientific and Technical Information of China (English)

    Debbijoy Bhattacharya; Parameswaran Sreekumar

    2009-01-01

    The extragalactic diffuse emission at γ-ray energies has interesting cosmo-logical implications since these photons suffer little or no attenuation during their prop-agation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar mat-ter and radiation (~90%) along with a small contribution from discrete point sources (~10%). Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous at γ-ray energies to be detected by the current γ-ray mission (Fermi Gamma-ray Space Telescope).

  3. Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

    Science.gov (United States)

    Venters, T. M.; Pavlidou, V.

    2013-01-01

    The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer nonnegligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

  4. Extragalactic radio sources with hybrid morphology: implications for the Fanaroff-Riley dichotomy

    OpenAIRE

    Gopal-Krishna; Wiita, Paul J.

    2000-01-01

    We provide observational and theoretical perspectives on the currently much debated issue of the Fanaroff-Riley (FR) morphological dichotomy of extragalactic radio sources. In this context we introduce a new, albeit rare, class of double radio sources in which the two lobes exhibit clearly different FR morphologies. It is argued that such `HYbrid MOrphology Radio Sources', or HYMORS, could be used to effectively constrain the theoretical mechanisms proposed for the FR dichotomy. Basically, th...

  5. An empirical approach to the extragalactic background light from AEGIS galaxy SED-type fractions

    OpenAIRE

    Domínguez, Alberto

    2011-01-01

    The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy. However, the overall spectrum of the EBL between 0.1 and 1000 microns has never been determined directly neither from observed luminosity functions (LFs), over a wide redshift range, nor from any multiwavelength observation of galaxy spectral energy distributions (SEDs). The evolving, overall spectrum of the EBL is derived here utiliz...

  6. Inhomogeneous extragalactic magnetic fields and the second knee in the cosmic ray spectrum

    CERN Document Server

    Kotera, Kumiko

    2007-01-01

    Various experiments indicate the existence of a second knee around energy E=3 10^{17} eV in the cosmic ray spectrum. This feature could be the signature of the end of the galactic component and of the emergence of the extragalactic one, provided that the latter cuts off at low energies. Recent analytical calculations have shown that this cut-off could be a consequence of the existence of extragalactic magnetic fields: low energy protons diffuse on extragalactic magnetic fields and cannot reach the observer within a given time. We study the influence of inhomogeneous magnetic fields on the magnetic horizon, using a newly written original semi-analytical propagation code. Our results indicate that, at a fixed value of the volume averaged magnetic field , the amplitude of the low energy cut-off is mainly controled by the strength of magnetic fields in the voids of the large scale structure distribution. Our simulations also enable us to constrain some crucial parameters: should be greater than 0.3 nG and not ex...

  7. The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation

    CERN Document Server

    Ajello, M; Sanchez-Conde, M; Zaharijas, G; Gustafsson, M; Cohen-Tanugi, J; Dermer, C D; Inoue, Y; Hartmann, D; Ackermann, M; Bechtol, K; Franckowiak, A; Reimer, A; Romani, R W; Strong, A W

    2015-01-01

    The origin of the extragalactic $\\gamma$-ray background (EGB) has been debated for some time. { The EGB comprises the $\\gamma$-ray emission from resolved and unresolved extragalactic sources, such as blazars, star-forming galaxies and radio galaxies, as well as radiation from truly diffuse processes.} This letter focuses on the blazar source class, the most numerous detected population, and presents an updated luminosity function and spectral energy distribution model consistent with the blazar observations performed by the {\\it Fermi} Large Area Telescope (LAT). We show that blazars account for 50$^{+12}_{-11}$\\,\\% of the EGB photons ($>$0.1\\,GeV), and that {\\it Fermi}-LAT has already resolved $\\sim$70\\,\\% of this contribution. Blazars, and in particular low-luminosity hard-spectrum nearby sources like BL Lacs, are responsible for most of the EGB emission above 100\\,GeV. We find that the extragalactic background light, which attenuates blazars' high-energy emission, is responsible for the high-energy cut-off...

  8. Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

    CERN Document Server

    Moliné, Ángeles; Palomares-Ruiz, Sergio; Boehm, Celine; Baugh, Carlton M

    2016-01-01

    The extragalactic gamma-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (LambdaCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the gamma-ray and neutrino emission in these models may differ from LambdaCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in LambdaCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond LambdaCDM as being due to CD...

  9. Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

    Science.gov (United States)

    Moliné, Ángeles; Schewtschenko, Jascha A.; Palomares-Ruiz, Sergio; Bœhm, Céline; Baugh, Carlton M.

    2016-08-01

    The extragalactic γ-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (ΛCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the γ-ray and neutrino emission in these models may differ from ΛCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in ΛCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond ΛCDM as being due to CDM particles annihilating with a much weaker cross section than expected.

  10. Effects of the galactic magnetic field upon large scale anisotropies of extragalactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Harari, D.; Mollerach, S.; Roulet, E., E-mail: harari@cab.cnea.gov.ar, E-mail: mollerach@cab.cnea.gov.ar, E-mail: roulet@cab.cnea.gov.ar [CONICET, Centro Atómico Bariloche, Bustillo 9500, 8400 Bariloche (Argentina)

    2010-11-01

    The large scale pattern in the arrival directions of extragalactic cosmic rays that reach the Earth is different from that of the flux arriving to the halo of the Galaxy as a result of the propagation through the galactic magnetic field. Two different effects are relevant in this process: deflections of trajectories and (de)acceleration by the electric field component due to the galactic rotation. The deflection of the cosmic ray trajectories makes the flux intensity arriving to the halo from some direction to appear reaching the Earth from another direction. This applies to any intrinsic anisotropy in the extragalactic distribution or, even in the absence of intrinsic anisotropies, to the dipolar Compton-Getting anisotropy induced when the observer is moving with respect to the cosmic rays rest frame. For an observer moving with the solar system, cosmic rays traveling through far away regions of the Galaxy also experience an electric force coming from the relative motion (due to the rotation of the Galaxy) of the local system in which the field can be considered as being purely magnetic. This produces small changes in the particles momentum that can originate large scale anisotropies even for an isotropic extragalactic flux.

  11. MIGHTEE: The MeerKAT International GHz Tiered Extragalactic Exploration

    Science.gov (United States)

    Taylor, A. Russ; Jarvis, Matt

    2017-05-01

    The MeerKAT telescope is the precursor of the Square Kilometre Array mid-frequency dish array to be deployed later this decade on the African continent. MIGHTEE is one of the MeerKAT large survey projects designed to pathfind SKA key science in cosmology and galaxy evolution. Through a tiered radio continuum deep imaging project including several fields totaling 20 square degrees to microJy sensitivities and an ultra-deep image of a single 1 square degree field of view, MIGHTEE will explore dark matter and large scale structure, the evolution of galaxies, including AGN activity and star formation as a function of cosmic time and environment, the emergence and evolution of magnetic fields in galaxies, and the magnetic counter part to large scale structure of the universe.

  12. Planck intermediate results: VII. Statistical properties of infrared and radio extragalactic sources from the Planck Early Release Compact Source Catalogue at frequencies between 100 and 857 GHz

    DEFF Research Database (Denmark)

    Delabrouille, J.; Ganga, K.; Giraud-Héraud, Y.

    2013-01-01

    of the Planck High Frequency Instrument, all the sources have been classified as either dust-dominated (infrared galaxies) or synchrotron-dominated (radio galaxies) on the basis of their spectral energy distributions (SED). Our sample is thus complete, flux-limited and color-selected to differentiate between......We make use of the Planck all-sky survey to derive number counts and spectral indices of extragalactic sources-infrared and radio sources-from the Planck Early Release Compact Source Catalogue (ERCSC) at 100 to 857 GHz (3 mm to 350 μm). Three zones (deep, medium and shallow) of approximately...... the two populations. We find an approximately equal number of synchrotron and dusty sources between 217 and 353 GHz; at 353 GHz or higher (or 217 GHz and lower) frequencies, the number is dominated by dusty (synchrotron) sources, as expected. For most of the sources, the spectral indices are also derived...

  13. The CfA Einstein Observatory extended deep X-ray survey

    Science.gov (United States)

    Primini, F. A.; Murray, S. S.; Huchra, J.; Schild, R.; Burg, R.

    1991-01-01

    All IPC exposures in the Einstein Extended Deep X-ray Survey program have been reanalyzed. The current survey covers about 2.3 sq deg with a typical limiting sensitivity of about 5 x 10 to the -14th ergs/sq cm/s in the energy range from 0.8-3.5 keV. A total of 25 IPC sources are detected above a threshold of 4.5 sigma. A total of 18 are detected independently in the HRI, leading to the identification of six with stars and 11 with extragalactic objects. The remaining sources are classified as extragalactic. The population of identified extragalactic objects is dominated by QSOs, with one or two possible clusters. The basic conclusions of the original survey remain unchanged.

  14. Plasma effects on extragalactic ultra-high-energy cosmic ray hadron beams in cosmic voids

    Energy Technology Data Exchange (ETDEWEB)

    Krakau, Steffen; Schlickeiser, Reinhard [Institut fur Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum (Germany)

    2015-05-01

    The linear instability of an ultrarelativistic hadron beam (Γ{sub b} ∼ 10{sup 6}) in the unmagnetized intergalactic medium is investigated with respect to the excitation of collective electrostatic and aperiodic electromagnetic fluctuations. This analysis is important for the propagation of extragalactic ultrarelativistic cosmic rays (E > 10{sup 15} eV) from their distant sources to Earth. We calculate minimum instability growth times which are orders of magnitude shorter than the cosmic ray propagation time in the IGM. Due to nonlinear effects, especially the modulation instability, the cosmic ray beam stabilize and can propagate with nearly no energy loss through the intergalactic medium.

  15. Initial analysis of extragalactic fields using a new AKARI/IRC analysis pipeline

    CERN Document Server

    Davidge, H R; Pearson, C P

    2016-01-01

    We present the first results of a new data analysis pipeline for processing extragalactic AKARI/IRC images. The main improvements of the pipeline over the standard analysis are the removal of Earth shine and image distortion correction. We present the differential number counts of the AKARI/IRC S11 filter IRAC validation field. The differential number counts are consistent with S11 AKARI NEP deep and 12 microns WISE NEP number counts, and with a phenomenological backward evolution galaxy model, at brighter fluxes densities. There is a detection of deeper galaxies in the IRAC validation field.

  16. A search for extragalactic sources of Ultrahigh-Energy Cosmic Rays

    Energy Technology Data Exchange (ETDEWEB)

    Knurenko, S.P.; Ivanov, A.A.; Sabourov, A.V. [Yu. G. Shafer Institute for Cosmophysical Research and Aeronomy, Yakutsk, 677980 (Russian Federation)

    2009-12-15

    Possible extragalactic sources of cosmic rays at energies above 4x10{sup 19} eV detected with the Yakutsk array are sought. Correlation of the shower arrival directions with objects from Veron's catalog that are located closer than 100 Mpc from the Earth confirms the observations at the Pierre Auger observatory, as well as the Greisen-Zatsepin-Kuzmin effect on ultrahigh-energy cosmic rays. The detailed analysis of the data reveals the classes of objects belonging to the active galactic nuclei that are probable sources of ultrahigh-energy cosmic rays.

  17. Detection of extragalactic CF+ toward PKS1830-211 -- Chemical differentiation in the absorbing gas

    CERN Document Server

    Muller, S; Black, J H; Amano, T

    2016-01-01

    We report the first extragalactic detection of CF+, the fluoromethylidynium ion, in the z=0.89 absorber toward PKS1830-211. We estimate an abundance of ~3E-10 relative to H2 and that ~1% of fluorine is captured in CF+. The absorption line profile of CF+ is found to be markedly different from that of other species observed within the same tuning, and is notably anti-correlated with CH3OH. On the other hand, the CF+ profile resembles that of [C I]. Our results are consistent with expected fluorine chemistry and point to chemical differentiation in the column of absorbing gas.

  18. Constraints on the Extragalactic Background Light from Very High Energy Gamma-Ray Observations of Blazars

    OpenAIRE

    Finke, Justin D.; Razzaque, Soebur

    2009-01-01

    The extragalactic background light (EBL) from the infrared to the ultraviolet is difficult to measure directly, but can be constrained with a variety of methods. EBL photons absorb gamma-rays from distant blazars, allowing one to use blazar spectra from atmospheric Cherenkov telescopes (ACTs) to put upper limits on the EBL by assuming a blazar source spectrum. Here we apply a simple technique, similar to the one developed by Schroedter (2005), to the most recent very-high energy (VHE) gamma-r...

  19. Cosmological constraints on dark matter annihilation and decay: Cross-correlation analysis of the extragalactic $\\gamma$-ray background and cosmic shear

    CERN Document Server

    Shirasaki, Masato; Horiuchi, Shunsaku; Shirai, Satoshi; Yoshida, Naoki

    2016-01-01

    We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of $\\sim660$ squared degrees in total. We improve upon our previous analyses by using an updated extragalactic $\\gamma$-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological $N$-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of $\\sim100$ in the mass range of O(1) TeV when including contributions from secondary $\\gamma...

  20. Propagation of high-energy cosmic rays in extragalactic turbulent magnetic fields: resulting energy spectrum and composition

    CERN Document Server

    Globus, N; Parizot, E

    2007-01-01

    We extend previous studies of mixed-composition extragalactic cosmic-ray source models, by investigating the influence of a non-negligible extragalactic magnetic field on the propagated cosmic-ray spectrum and composition. We study the transport of charged particles in turbulent fields and the transition from a ballistic to a diffusive propagation regime. We introduce a method allowing a fast integration of the particle trajectories, which allows us to calculate extragalactic cosmic-ray spectra in the general case, without using either the diffusive or the rectilinear approximation. We find that the main features of the mixed-composition models -- regarding the interpretation of the ankle and the non-monotonous evolution of the average cosmic-ray mass -- remain essentially unchanged as long as the magnetic field intensity does not exceed a few nG.

  1. First data from the ISOPHOT FIR Serendipity survey.

    Science.gov (United States)

    Bogun, S.; Lemke, D.; Klaas, U.; Herbstmeier, U.; Assendorp, R.; Richter, G.; Laureijs, R.; Kessler, M. F.; Burgdorf, M.; Schulz, B.; Pelz, G.; Beichman, C. A.; Rowan-Robinson, M.

    1996-11-01

    The ISOPHOT Serendipity Survey fills the otherwise unused slew time between ISO's fine pointings with measurements in an unexplored wavelength regime near 200μm. First results of the Serendipity Survey demonstrate its capabilities in the detection of extragalactic point sources as well as in investigations of the galactic infrared cirrus. With the detection limit for point sources of ~1Jy more than 3000 galaxies will be observed.

  2. Studying extragalactic background fluctuations with the Cosmic Infrared Background ExpeRiment 2 (CIBER-2)

    Science.gov (United States)

    Lanz, Alicia; Arai, Toshiaki; Battle, John; Bock, James; Cooray, Asantha; Hristov, Viktor; Korngut, Phillip; Lee, Dae Hee; Mason, Peter; Matsumoto, Toshio; Matsuura, Shuji; Morford, Tracy; Onishi, Yosuke; Shirahata, Mai; Tsumura, Kohji; Wada, Takehiko; Zemcov, Michael

    2014-08-01

    Fluctuations in the extragalactic background light trace emission from the history of galaxy formation, including the emission from the earliest sources from the epoch of reionization. A number of recent near-infrared measure- ments show excess spatial power at large angular scales inconsistent with models of z CIBER-2) will measure spatial anisotropies in the extra- galactic infrared background caused by cosmological structure using six broad spectral bands. The experiment uses three 2048 x 2048 Hawaii-2RG near-infrared arrays in three cameras coupled to a single 28.5 cm telescope housed in a reusable sounding rocket-borne payload. A small portion of each array will also be combined with a linear-variable filter to make absolute measurements of the spectrum of the extragalactic background with high spatial resolution for deep subtraction of Galactic starlight. The large field of view and multiple spectral bands make CIBER-2 unique in its sensitivity to fluctuations predicted by models of lower limits on the luminosity of the first stars and galaxies and in its ability to distinguish between primordial and foreground anisotropies. In this paper the scientific motivation for CIBER-2 and details of its first flight instrumentation will be discussed, including detailed designs of the mechanical, cryogenic, and electrical systems. Plans for the future will also be presented.

  3. Measuring X-ray Binary Accretion State Distributions in Extragalactic Environments using XMM-Newton

    Science.gov (United States)

    West, Lacey; Lehmer, Bret; Yukita, Mihoko; Hornschemeier, Ann E.; Ptak, Andrew; Wik, Daniel R.; Zezas, Andreas

    2017-01-01

    X-ray binary systems (XRBs) in the MW can exist in several different accretion states, and many have been found to vary along specific tracks on intensity-color diagrams. Observationally measuring the distributions of these accretion states in a variety of environments can aid in population synthesis modeling and ultimately help us understand the formation and evolution of XRBs and their compact object components (i.e., black holes and neutron stars). Recent innovative studies with NuSTAR have demonstrated the utility of color-color and intensity-color diagrams in differentiating between XRB accretion states in extragalactic environments (NGC 253, M83, and M31). The key to NuSTAR’s success is its sensitivity above »10keV, where spectral differences between accretion states are most pronounced. However, due to the relatively low spatial resolution and large background of NuSTAR, the constraints from these diagrams is limited to only bright sources in nearby galaxies. In this poster, we present evidence that XMM-Newton observations of M83 in the 4.0-12.0 keV range can be used to create similar color-intensity and color-color diagrams and therefore differentiate between these accretion states. We will further discuss plans to leverage XMM-Newton’s vast archive and 17-year baseline to dramatically expand studies of accretion state distributions and state transitions for XRB populations in extragalactic environments.

  4. VizieR Online Data Catalog: Optically Bright extragalactic Radio Sources II (Petrov, 2013)

    Science.gov (United States)

    Petrov, L.

    2014-06-01

    The first VLBI (Very Long Baseline Interferometry) observing campaign in 2007 resulted in the detection of 398 targets with the European VLBI Network (EVN; Bourda et al., 2010, cat. J/A+A/520/A113). During the second observing campaign, a subset of 105 sources detected in the previous campaign was observed (Bourda et al., 2011, cat. J/A+A/526/A102). Their positions were derived by Petrov (2011, cat. J/AJ/142/105) and formed the OBRS-1 (Optically Bright extragalactic Radio Sources) catalog. The remaining sources were observed in the third campaign, called OBRS-2. During the OBRS-2 campaign, there were three observing sessions with 10 VLBA (Very Long Baseline Array) stations and 5-6 EVN stations from this list: EFLSBERG, MEDICINA, ONSALA60, YEBES40M, DSS63, HARTRAO, and NOTO. Observations were made on 2010 Mar 23 (session ID gc034a), on 2011 Nov 8 (gc034bcd), and on 2011 Mar 15 (gc034ef). The OBRS-2 catalog presents precise positions of the 295 extragalactic radio sources as well as median correlated flux densities at 8.4 and 2.2GHz at baseline lengths shorter than 900km and at baseline lengths longer than 5000km. (1 data file).

  5. What can we learn about the kinematics of bright extragalactic planetary nebulae

    CERN Document Server

    Richer, M G; López, J A; Riesgo, H; Garcia-Diaz, Ma T

    2009-01-01

    We present high resolution spectroscopy in the [\\ion{O}{3}]$\\lambda$5007 and H$\\alpha$ lines of bright planetary nebulae in the Milky Way bulge and the dwarf galaxies M32, Fornax, Sagittarius, and NGC 6822 obtained at the Observatorio Astronomico Nacional in the Sierra San Pedro Martir using the Manchester Echelle Spectrograph. We use the high signal-to-noise (S/N) observations of Milky Way bulge planetary nebulae to explore what kinematic information can be determined reliably when observing extragalactic planetary nebulae in the [\\ion{O}{3}]$\\lambda$5007 line at modest S/N. We find that the intrinsic line widths measured in [\\ion{O}{3}]$\\lambda$5007 and H$\\alpha$ are very similar. Over the range of S/N available in this sample, the line width we measure is independent of the S/N. Finally, deviations from a Gaussian line shape are small. Thus, the line width of the [\\ion{O}{3}]$\\lambda$5007 line in bright extragalactic planetary nebulae should reflect the kinematics of most of the mass in the ionized nebular...

  6. ANATOMY OF HELICAL EXTRAGALACTIC JETS: THE CASE OF S5 0836+710

    Energy Technology Data Exchange (ETDEWEB)

    Perucho, M.; Kovalev, Y. Y. [Departament d' Astronomia i Astrofisica, Universitat de Valencia, 46100 Burjassot (Valencia) (Spain); Lobanov, A. P. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Hardee, P. E. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL 35487 (United States); Agudo, I., E-mail: manel.perucho@uv.es [Instituto de Astrofisica de Andalucia, Apartado 3004, 18080 Granada (Spain)

    2012-04-10

    Helical structures are common in extragalactic jets. They are usually attributed in the literature to periodical phenomena in the source (e.g., precession). In this work, we use very long baseline interferometry data of the radio jet in the quasar S5 0836+710 and hypothesize that the ridgeline of helical jets like this corresponds to a pressure maximum in the jet and assume that the helically twisted pressure maximum is the result of a helical wave pattern. For our study, we use observations of the jet in S5 0836+710 at different frequencies and epochs. The results show that the structures observed are physical and not generated artificially by the observing arrays. Our hypothesis that the observed intensity ridgeline can correspond to a helically twisted pressure maximum is confirmed by our observational tests. This interpretation allows us to explain jet misalignment between parsec and kiloparsec scales when the viewing angle is small, and also brings us to the conclusion that high-frequency observations may show only a small region of the jet flow concentrated around the maximum pressure ridgeline observed at low frequencies. Our work provides a potential explanation for the apparent transversal superluminal speeds observed in several extragalactic jets by means of transversal shift of an apparent core position with time.

  7. First hints of pressure waves in a helical extragalactic jet: S5~0836+710

    CERN Document Server

    Perucho, Manel

    2013-01-01

    One of the open questions in extragalactic jet Astrophysics is related to the nature of the observed radio jet, namely whether it traces a pattern or the flow structure itself. In this paper I summarize the evidence collected for the presence of waves in extragalactic jets. The evidence points towards the peak of emission in helical jets corresponding to pressure-maxima of a wave that is generated within the core region and propagates downstream. Making use of a number of very long baseline interferometry (VLBI) observations of the radio jet in the quasar S5~0836+710 at different frequencies and epochs, Perucho et al. (2012) were able to observe wave-like behavior within the observed radio-jet. The ridge-line of the emission in the jet coincides within the errors at all frequencies. Moreover, small differences between epochs at 15 GHz reveal wave-like motion of the ridge-line transversal to the jet propagation axis. The authors conclude that the helicity is a real, physical structure. I report here on those r...

  8. Extragalactic Inverse Compton Light from Dark Matter annihilation and the Pamela positron excess

    Energy Technology Data Exchange (ETDEWEB)

    Profumo, Stefano [Department of Physics, University of California, 1156 High St, Santa Cruz, CA 95064 (United States); Jeltema, Tesla E., E-mail: profumo@scipp.ucsc.edu, E-mail: tesla@ucolick.org [UCO/Lick Observatories, 1156 High St, Santa Cruz, CA 95064 (United States)

    2009-07-01

    We calculate the extragalactic diffuse emission originating from the up-scattering of cosmic microwave photons by energetic electrons and positrons produced in particle dark matter annihilation events at all redshifts and in all halos. We outline the observational constraints on this emission and we study its dependence on both the particle dark matter model (including the particle mass and its dominant annihilation final state) and on assumptions on structure formation and on the density profile of halos. We find that for low-mass dark matter models, data in the X-ray band provide the most stringent constraints, while the gamma-ray energy range probes models featuring large masses and pair-annihilation rates, and a hard spectrum for the injected electrons and positrons. Specifically, we point out that the all-redshift, all-halo inverse Compton emission from many dark matter models that might provide an explanation to the anomalous positron fraction measured by the Pamela payload severely overproduces the observed extragalactic gamma-ray background.

  9. Transition from Galactic to extragalactic cosmic rays and cosmic ray anisotropy

    Directory of Open Access Journals (Sweden)

    Sigl G.

    2013-06-01

    Full Text Available This talk based on results of ref. [1], where we constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z ≳ 10(16−17 eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. If the primary composition is mostly light or intermediate around E ∼ 1018 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >10 μG. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 1017 eV and 1018 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E > 1018 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.

  10. Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

    Science.gov (United States)

    Hackstein, S.; Vazza, F.; Brüggen, M.; Sigl, G.; Dundovic, A.

    2016-11-01

    We use the CRPROPA code to simulate the propagation of ultrahigh energy cosmic rays (with energy ≥1018eV and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code. We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky Way-like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within an ˜50 Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at ˜EeV energies, the average magnetic fields in cosmic voids must be ˜ 0.1 nG, providing limits on the strength of primordial seed fields.

  11. Propagation of Ultra High Energy Cosmic Rays in Extragalactic Magnetic Fields: A view from cosmological simulations

    CERN Document Server

    Hackstein, Stefan; Brueggen, Marcus; Sigl, Guenter; Dundovic, Andrej

    2016-01-01

    We use the CRPropa code to simulate the propagation of ultra high energy cosmic rays (with energy $\\geq 10^{18} \\rm eV$ and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code.We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky-Way like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within a $\\sim 50$ Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at $\\sim $ EeV energies, the average magnetic fields in cosmic voids must...

  12. The Catalog of Positions of Optically Bright Extragalactic Radio Sources OBRS-1

    Science.gov (United States)

    Petrov, L.

    2011-01-01

    It is expected that the European Space Agency mission Gaia will make it possible to determine coordinates in the optical domain of more than 500,000 quasars. In 2006, a radio astrometry project was launched with the overall goal of making comparisons between coordinate systems derived from future space-born astrometry instruments and the coordinate system constructed from analysis of global very long baseline interferometry (VLBI) more robust. Investigation of the rotation, zonal errors, and non-alignment of the radio and optical positions caused by both radio and optical structures is needed to validate both techniques. In order to support these studies, the densification of the list of compact extragalactic objects that are bright in both radio and optical ranges is desirable. A set of 105 objects from the list of 398 compact extragalactic radio sources with decl. > -10deg was observed with the Very Long Baseline Array and European VLBI Network (EVN) with the primary goal of producing images with milliarcsecond resolution. These sources are brighter than 18 mag in the V band, and they were previously detected by the EVN. In this paper, coordinates of observed sources have been derived with milliarcsecond accuracies from analysis of these VLBI observations using an absolute astrometry method. The catalog of positions for 105 target sources is presented. The accuracies of source coordinates are in the range of 0.3.7 mas, with a median of 1.1 mas.

  13. An X-Ray-selected Active Galactic Nucleus at z=4.6 Discovered by the CYDER Survey

    NARCIS (Netherlands)

    Treister, E.; Castander, F.J.; Maccarone, T.J.; Herrera, D.; Gawiser, E.; Maza, J.; Coppi, P.S.

    2004-01-01

    We present the discovery of a high-redshift, X-ray-selected active galactic nucleus (AGN) by the Calan-Yale Deep Extragalactic Research (CYDER) survey: CXOCY J033716.7-050153, located at z=4.61, the second high-redshift AGN discovered by this survey. Here we present its optical, near-IR, and X-ray

  14. Extragalactic Large-Scale Structures behind the Southern Milky Way. IV. Redshifts Obtained with MEFOS A Galactic O-Star Catalog

    CERN Document Server

    Woudt, P A; Cayatte, V; Balkowski, C; Felenbok, P; Maíz-Appelániz, J; Walborn, N R; Galué, H A; Wei, L H; Woudt, Patrick A.; Kraan-Korteweg, Renee C.; Cayatte, Veronique; Balkowski, Chantal; Felenbok, Paul

    2004-01-01

    Abbreviated: As part of our efforts to unveil extragalactic large-scale structures behind the southern Milky Way, we here present redshifts for 764 galaxies in the Hydra/Antlia, Crux and Great Attractor region (266deg < l < 338deg, |b| < 10deg), obtained with the Meudon-ESO Fibre Object Spectrograph (MEFOS) at the 3.6-m telescope of ESO. The observations are part of a redshift survey of partially obscured galaxies recorded in the course of a deep optical galaxy search behind the southern Milky Way. A total of 947 galaxies have been observed, a small percentage of the spectra (N=109, 11.5%) were contaminated by foreground stars, and 74 galaxies (7.8%) were too faint to allow a reliable redshift determination. With MEFOS we obtained spectra down to the faintest galaxies of our optical galaxy survey, and hence probe large-scale structures out to larger distances (v <~ 30000 km/s) than our other redshift follow-ups. The most distinct large-scale structures revealed in the southern Zone of Avoidance ar...

  15. Planck early results. XIII. Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue

    DEFF Research Database (Denmark)

    Bucher, M.; Delabrouille, J.; Giraud-Héraud, Y.

    2011-01-01

    The data reported in Planck's Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest sou...

  16. A semianalytical method for calculating the parameters of the electromagnetic halos around extragalactic gamma-ray sources

    NARCIS (Netherlands)

    Kel'ner, [No Value; Khangulyan, DV; Aharonian, FA

    2004-01-01

    The ultrahigh-energy (>20 TeV) gamma rays emitted by active galactic nuclei can be absorbed in intergalactic space through the production of electron-positron pairs during their interaction with extragalactic background photon fields. The electrons and positrons produced by this interaction form an

  17. The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars

    CERN Document Server

    ,

    2012-01-01

    The light emitted by stars and accreting compact objects through the history of the Universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are lim- ited by Galactic and other foreground emissions. Here we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z$\\sim$1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to UV frequencies, and allowed us to measure the EBL flux density in this frequency band.

  18. Variability of Extragalactic Objects in Relation to Redshift, Color, Radio Spectral Index and Absorption Lines

    Indian Academy of Sciences (India)

    D. Basu

    2001-12-01

    Optical variability of extragalactic objects, viz., QSOs, BL Lacs and Seyfert galaxies has been monitored systematically over an appreciable period of time and a large amount of data have accumulated. The present work reports results of investigations involving statistical analysis of updated data on relationships between variability and various observed properties of the objects, viz., redshift, color indices, radio spectral index and absorption lines. It is found that at high frequencies (rest frame) radio spectral index does not change significantly with the degree of variability. However, the degree of variability depends on redshifts. On the other hand, presence or absence of absorption lines is significantly associated with variability for QSOs with larger redshifts ( > 1.0), while no such relationship exists for QSOs at smaller redshifts ( < 1.0 or other objects. Correlation between color indices and redshifts depends on the degree of variability and the sample chosen for the color index.

  19. Problems and Prospects from a Flood of Extragalactic TeV Neutrinos in IceCube

    CERN Document Server

    Kistler, Matthew D

    2015-01-01

    The steep spectrum of neutrinos measured by IceCube extending from >1 PeV down to ~10 TeV has an energy flux now encroaching on the Fermi isotropic GeV background. We examine several implications starting from source energetics requirements for neutrino production. We show how the environment of extragalactic nuclei can extinguish ~10-100 TeV gamma rays and convert their energy to X-rays for plausible conditions of infrared luminosity and magnetic field, so that the Fermi background is not overwhelmed by cascades. We address a variety of scenarios, such as for acceleration by supermassive black holes and hadronic scenarios, and observations that may help elucidate the neutrinos' shadowy origins.

  20. Search for extragalactic astrophysical counterparts of IceCube neutrino events

    CERN Document Server

    Moharana, Reetanjali; Razzaque, Soebur

    2016-01-01

    Detection of 54 very high-energy (VHE) neutrinos by the IceCube Neutrino Observatory has opened a new chapter in multi-messenger astronomy. However due to large errors in measuring the directions of the neutrino shower-type events, which dominate the current event list, it is difficult to identify their astrophysical sources. We perform cross-correlation study of IceCube neutrino events with extragalactic candidate sources using X-ray and gamma-ray selected source catalogues such as Swift-BAT, 3LAC and TeV-Cat. We apply different cuts on the X-ray and gamma-ray fluxes of the sources in these catalogs, and use different source classes in order to study correlation. We use invariant statistic and Monte Carlo simulations to evaluate statistical significance of any correlation.

  1. Relativistic particle transport in extragalactic jets: I. Coupling MHD and kinetic theory

    CERN Document Server

    Casse, F

    2003-01-01

    Multidimensional magneto-hydrodynamical (MHD) simulations coupled with stochastic differential equations (SDEs) adapted to test particle acceleration and transport in complex astrophysical flows are presented. The numerical scheme allows the investigation of shock acceleration, adiabatic and radiative losses as well as diffusive spatial transport in various diffusion regimes. The applicability of SDEs to astrophysics is first discussed in regards to the different regimes and the MHD code spatial resolution. The procedure is then applied to 2.5D MHD-SDE simulations of kilo-parsec scale extragalactic jets. The ability of SDE to reproduce analytical solutions of the diffusion-convection equation for electrons is tested through the incorporation of an increasing number of effects: shock acceleration, spatially dependent diffusion coefficients and synchrotron losses. The SDEs prove to be efficient in various shock configuration occurring in the inner jet during the development of the Kelvin-Helmholtz instability. ...

  2. Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects

    Science.gov (United States)

    Pierre Auger Collaboration; Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez, C.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anzalone, A.; Aramo, C.; Argirò, S.; Arisaka, K.; Armengaud, E.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Atulugama, B. S.; Aublin, J.; Ave, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Barbosa, A. F.; Barnhill, D.; Barroso, S. L. C.; Bauleo, P.; Beatty, J.; Beau, T.; Becker, B. R.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bergmann, T.; Bernardini, P.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blasi, P.; Bleve, C.; Blümer, H.; Bohácová, M.; Bonifazi, C.; Bonino, R.; Boratav, M.; Brack, J.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Busca, N. G.; Caballero-Mora, K. S.; Cai, B.; Camin, D. V.; Caruso, R.; Carvalho, W.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazón-Boado, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chye, J.; Clark, P. D. J.; Clay, R. W.; Colombo, E.; Conceição, R.; Connolly, B.; Contreras, F.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Cronin, J.; Dagoret-Campagne, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; Di Giulio, C.; Diaz, J. C.; Dobrigkeit, C.; D'Olivo, J. C.; Dornic, D.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; DuVernois, M. A.; Engel, R.; Epele, L.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fernández, A.; Ferrer, F.; Ferry, S.; Fick, B.; Filevich, A.; Filipcic, A.; Fleck, I.; Fonte, R.; Fracchiolla, C. E.; Fulgione, W.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Geenen, H.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Herrero, R.; Gonçalves, P.; Gonçalves do Amaral, M.; Gonzalez, D.; Gonzalez, J. G.; González, M.; Góra, D.; Gorgi, A.; Gouffon, P.; Grassi, V.; Grillo, A.; Grunfeld, C.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Gutiérrez, J.; Hague, J. D.; Hamilton, J. C.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hauschildt, T.; Healy, M. D.; Hebbeker, T.; Heck, D.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J.; Horneffer, A.; Horvat, M.; Hrabovsky, M.; Huege, T.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Kaducak, M.; Kampert, K. H.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Kopmann, A.; Krieger, A.; Krömer, O.; Kümpel, D.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lebrun, D.; Le Brun, P.; Lee, J.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Leuthold, M.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Lozano Bahilo, J.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Malek, M.; Mancarella, G.; Manceñido, M. E.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Maris, I. C.; Martello, D.; Martínez, J.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McCauley, T.; McEwen, M.; McNeil, R. R.; Medina, M. C.; Medina-Tanco, G.; Meli, A.; Melo, D.; Menichetti, E.; Menschikov, A.; Meurer, Chr.; Meyhandan, R.; Micheletti, M. I.; Miele, G.; Miller, W.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Nellen, L.; Newman-Holmes, C.; Newton, D.; Nguyen Thi, T.; Nierstenhöfer, N.; Nitz, D.; Nosek, D.; Nozka, L.; Oehlschläger, J.; Ohnuki, T.; Olinto, A.; Olmos-Gilbaja, V. M.; Ortiz, M.; Ostapchenko, S.; Otero, L.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Parente, G.; Parizot, E.; Parlati, S.; Pastor, S.; Patel, M.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Pçkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petrera, S.; Petrinca, P.; Petrov, Y.; Ngoc, DiepPham; Ngoc, DongPham; Pham Thi, T. N.; Pichel, A.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pinto, T.; Pirronello, V.; Pisanti, O.; Platino, M.; Pochon, J.; Porter, T. A.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Reucroft, S.; Revenu, B.; Rezende, F. A. S.; Rídky, J.; Riggi, S.; Risse, M.; Rivière, C.; Rizi, V.; Roberts, M.; Robledo, C.; Rodriguez, G.; Rodríguez Frías, D.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Ros, G.; Rosado, J.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scherini, V.; Schieler, H.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schovánek, P.; Schüssler, F.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Sigl, G.; Smetniansky De Grande, N.; Smialkowski, A.; Smída, R.; Smith, A. G. K.; Smith, B. E.; Snow, G. R.; Sokolsky, P.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Takahashi, J.; Tamashiro, A.; Tamburro, A.; Tascau, O.; Tcaciuc, R.; Thomas, D.; Ticona, R.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Torresi, D.; Travnicek, P.; Tripathi, A.; Tristram, G.; Tscherniakhovski, D.; Tueros, M.; Tunnicliffe, V.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; van Elewyck, V.; Vázquez, R. A.; Veberic, D.; Veiga, A.; Velarde, A.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Waldenmaier, T.; Walker, P.; Warner, D.; Watson, A. A.; Westerhoff, S.; Wieczorek, G.; Wiencke, L.; Wilczynska, B.; Wilczynski, H.; Wileman, C.; Winnick, M. G.; Wu, H.; Wundheiler, B.; Xu, J.; Yamamoto, T.; Younk, P.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zech, A.; Zepeda, A.; Ziolkowski, M.

    2007-11-01

    Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above 6 × 1019 electron volts and the positions of active galactic nuclei (AGN) lying within ~75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest-energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

  3. HELP : The Herschel Extragalactic Legacy Project & The Coming of Age of Multi-Wavelength Astrophysics

    CERN Document Server

    Vaccari, Mattia

    2015-01-01

    How did galaxies form and evolve? This is one of the most challenging questions in astronomy today. Answering it requires a careful combination of observational and theoretical work to reliably determine the observed properties of cosmic bodies over large portions of the distant Universe on the one hand, and accurately model the physical processes driving their evolution on the other. Most importantly, it requires bringing together disparate multi-wavelength and multi-resolution spectro-photometric datasets in an homogeneous and well-characterized manner so that they are suitable for a rigorous statistical analysis. The Herschel Extragalactic Legacy Project (HELP) funded by the EC FP7 SPACE program aims to achieve this goal by combining the expertise of optical, infrared and radio astronomers to provide a multi-wavelength database for the distant Universe as an accessible value-added resource for the astronomical community. It will do so by bringing together multi-wavelength datasets covering the 1000 deg$^2$...

  4. Extragalactic Globular Clusters: Old Spectroscopic Ages and New Views on Their Formation

    CERN Document Server

    Strader, J; Cenarro, A J; Beasley, M A; Forbes, D A; Strader, Jay; Brodie, Jean P.; Beasley, Michael A.; Forbes, Duncan A.

    2005-01-01

    We present the results of a meta-analysis of Keck spectra of extragalactic globular clusters (GCs) in a sample of eight galaxies, ranging from dwarfs to massive ellipticals. We infer ages for the metal-poor and metal-rich GCs in these galaxies through comparisons to Galactic GCs. Both subpopulations appear to be no younger than their Galactic counterparts, with ages ~> 10 Gyr. This is the largest sample of galaxies for which ages have been constrained spectroscopically. Our results support the formation of most GCs in massive galaxies at high redshift. We propose a scenario for the formation of GC subpopulations that synthesizes aspects of both accretion and in situ approaches in the context of galaxy formation through hierarchical merging.

  5. Extragalactic Ultracompact HII Regions: Probing the Birth Environments of Super Star Clusters

    CERN Document Server

    Johnson, K E

    2004-01-01

    In recent years, a number of extragalactic massive star clusters that are still deeply embedded in their birth material have been discovered. These objects represent the youngest stage of massive star cluster evolution yet observed, and the most massive and dense of these may be proto globular clusters. Their properties appear to be similar to those of ultracompact HII regions in the Galaxy, but scaled up in total mass and luminosity. In many cases, these clusters are only visible at mid-IR to radio wavelengths, and they have typically been detected as ``inverted'' spectrum radio sources. However, the set of existing observations is anemic, and our current physical model for these natal clusters in simplistic. This article will overview what we think we know about these objects based on existing observations and outline some of the most significant gaps in our current understanding.

  6. The shape of the extragalactic cosmic ray spectrum from galaxy clusters

    Science.gov (United States)

    Harari, Diego; Mollerach, Silvia; Roulet, Esteban

    2016-08-01

    We study the diffusive escape of cosmic rays from a central source inside a galaxy cluster to obtain the suppression in the outgoing flux appearing when the confinement times get comparable or larger than the age of the sources. We also discuss the attenuation of the flux due to the interactions of the cosmic rays with the cluster medium, which can be sizeable for heavy nuclei. The overall suppression in the total cosmic ray flux expected on Earth is important to understand the shape of the extragalactic contribution to the cosmic ray spectrum for E/Z < 1 EeV . This suppression can also be relevant to interpret the results of fits to composition-sensitive observables measured at ultra-high energies.

  7. The shape of the extragalactic cosmic ray spectrum from Galaxy Clusters

    CERN Document Server

    Harari, Diego; Roulet, Esteban

    2016-01-01

    We study the diffusive escape of cosmic rays from a central source inside a galaxy cluster to obtain the suppression in the outgoing flux appearing when the confinement times get comparable or larger than the age of the sources. We also discuss the attenuation of the flux due to the interactions of the cosmic rays with the cluster medium, which can be sizeable for heavy nuclei. The overall suppression in the total cosmic ray flux expected on Earth is important to understand the shape of the extragalactic contribution to the cosmic ray spectrum for $E/Z<1$ EeV. This suppression can also be relevant to interpret the results of fits to composition-sensitive observables measured at ultra-high energies.

  8. An Infrared Photometric Study of Galaxies with Extragalactic H2O Maser Sources

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    All galaxies with extragalactic H2O maser sources observed so far are collected. With the 2MASS and the IRAS photometric data an infrared study is performed on those galaxies. By a comparison between the H2O maser detected sources and non-detected sources in the infrared it is indicated that infrared properties in the IRAS 12-25/μm and 60-100/μm are important for producing H2O masers in galaxies. It is also found that the H2O maser galaxies with different nuclear activity types have rather different infrared properties mainly in the IRAS 12-60/μm region.

  9. Magnetic Bubble Expansion as an Experimental Model for Extra-Galactic Radio Lobes

    Science.gov (United States)

    Lynn, Alan; Zhang, Yue; Hsu, Scott

    2010-11-01

    The Plasma Bubble Expansion Experiment (PBEX) is conducting laboratory experiments to address outstanding nonlinear plasma physics issues related to how magnetic energy and helicity carried by extra-galactic jets interacts with the intergalactic medium to form radio lobe structures. Experiments are being conducted in the 4 meter long, 50 cm diameter HELCAT linear plasma device at UNM. A pulsed magnetized coaxial gun (˜10 kV, ˜100 kA, ˜2 mWb) forms and injects magnetized plasma bubbles perpendicularly into a lower pressure weakly magnetized background plasma formed by a helicon and/or hot cathode source in HELCAT. Ideal MHD simulations show that an MHD shock develops ahead of the bubble as it propagates, and that the bubble develops asymmetries due to the background field [1]. Experimental data from plasma bubble injection into a background plasma, particularly magnetic probe measurements, will be discussed. [4pt] [1] W. Liu et al., Phys. Plasmas 15, 072905 (2008).

  10. Correlation of the highest-energy cosmic rays with nearby extragalactic objects.

    Science.gov (United States)

    Abraham, J; Abreu, P; Aglietta, M; Aguirre, C; Allard, D; Allekotte, I; Allen, J; Allison, P; Alvarez, C; Alvarez-Muñiz, J; Ambrosio, M; Anchordoqui, L; Andringa, S; Anzalone, A; Aramo, C; Argirò, S; Arisaka, K; Armengaud, E; Arneodo, F; Arqueros, F; Asch, T; Asorey, H; Assis, P; Atulugama, B S; Aublin, J; Ave, M; Avila, G; Bäcker, T; Badagnani, D; Barbosa, A F; Barnhill, D; Barroso, S L C; Bauleo, P; Beatty, J; Beau, T; Becker, B R; Becker, K H; Bellido, J A; Benzvi, S; Berat, C; Bergmann, T; Bernardini, P; Bertou, X; Biermann, P L; Billoir, P; Blanch-Bigas, O; Blanco, F; Blasi, P; Bleve, C; Blümer, H; Bohácová, M; Bonifazi, C; Bonino, R; Boratav, M; Brack, J; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Busca, N G; Caballero-Mora, K S; Cai, B; Camin, D V; Caruso, R; Carvalho, W; Castellina, A; Catalano, O; Cataldi, G; Cazón-Boado, L; Cester, R; Chauvin, J; Chiavassa, A; Chinellato, J A; Chou, A; Chye, J; Clark, P D J; Clay, R W; Colombo, E; Conceição, R; Connolly, B; Contreras, F; Coppens, J; Cordier, A; Cotti, U; Coutu, S; Covault, C E; Creusot, A; Cronin, J; Dagoret-Campagne, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Donato, C; de Jong, S J; De La Vega, G; de Mello Junior, W J M; de Mello Neto, J R T; De Mitri, I; de Souza, V; Del Peral, L; Deligny, O; Selva, A Della; Fratte, C Delle; Dembinski, H; Di Giulio, C; Diaz, J C; Dobrigkeit, C; D'Olivo, J C; Dornic, D; Dorofeev, A; Dos Anjos, J C; Dova, M T; D'Urso, D; Duvernois, M A; Engel, R; Epele, L; Erdmann, M; Escobar, C O; Etchegoyen, A; Facal San Luis, P; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Fernández, A; Ferrer, F; Ferry, S; Fick, B; Filevich, A; Filipcic, A; Fleck, I; Fonte, R; Fracchiolla, C E; Fulgione, W; García, B; García Gámez, D; Garcia-Pinto, D; Garrido, X; Geenen, H; Gelmini, G; Gemmeke, H; Ghia, P L; Giller, M; Glass, H; Gold, M S; Golup, G; Albarracin, F Gomez; Berisso, M Gómez; Herrero, R Gómez; Gonçalves, P; Gonçalves do Amaral, M; Gonzalez, D; Gonzalez, J G; González, M; Góra, D; Gorgi, A; Gouffon, P; Grassi, V; Grillo, A; Grunfeld, C; Guardincerri, Y; Guarino, F; Guedes, G P; Gutiérrez, J; Hague, J D; Hamilton, J C; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Hauschildt, T; Healy, M D; Hebbeker, T; Heck, D; Hojvat, C; Holmes, V C; Homola, P; Hörandel, J; Horneffer, A; Horvat, M; Hrabovsky, M; Huege, T; Iarlori, M; Insolia, A; Ionita, F; Italiano, A; Kaducak, M; Kampert, K H; Keilhauer, B; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Knapik, R; Knapp, J; Koang, D-H; Kopmann, A; Krieger, A; Krömer, O; Kümpel, D; Kunka, N; Kusenko, A; La Rosa, G; Lachaud, C; Lago, B L; Lebrun, D; Lebrun, P; Lee, J; Leigui de Oliveira, M A; Letessier-Selvon, A; Leuthold, M; Lhenry-Yvon, I; López, R; Lopez Agüera, A; Lozano Bahilo, J; Maccarone, M C; Macolino, C; Maldera, S; Malek, M; Mancarella, G; Manceñido, M E; Mandat, D; Mantsch, P; Mariazzi, A G; Maris, I C; Martello, D; Martínez, J; Martínez Bravo, O; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mazur, P O; McCauley, T; McEwen, M; McNeil, R R; Medina, M C; Medina-Tanco, G; Meli, A; Melo, D; Menichetti, E; Menschikov, A; Meurer, Chr; Meyhandan, R; Micheletti, M I; Miele, G; Miller, W; Mollerach, S; Monasor, M; Monnier Ragaigne, D; Montanet, F; Morales, B; Morello, C; Moreno, E; Moreno, J C; Morris, C; Mostafá, M; Muller, M A; Mussa, R; Navarra, G; Navarro, J L; Navas, S; Nellen, L; Newman-Holmes, C; Newton, D; Thi, T Nguyen; Nierstenhöfer, N; Nitz, D; Nosek, D; Nozka, L; Oehlschläger, J; Ohnuki, T; Olinto, A; Olmos-Gilbaja, V M; Ortiz, M; Ostapchenko, S; Otero, L; Pakk Selmi-Dei, D; Palatka, M; Pallotta, J; Parente, G; Parizot, E; Parlati, S; Pastor, S; Patel, M; Paul, T; Pavlidou, V; Payet, K; Pech, M; Pekala, J; Pelayo, R; Pepe, I M; Perrone, L; Petrera, S; Petrinca, P; Petrov, Y; Ngoc, Dieppham; Ngoc, Dongpham; Pham Thi, T N; Pichel, A; Piegaia, R; Pierog, T; Pimenta, M; Pinto, T; Pirronello, V; Pisanti, O; Platino, M; Pochon, J; Porter, T A; Privitera, P; Prouza, M; Quel, E J; Rautenberg, J; Reucroft, S; Revenu, B; Rezende, F A S; Rídky, J; Riggi, S; Risse, M; Rivière, C; Rizi, V; Roberts, M; Robledo, C; Rodriguez, G; Rodríguez Frías, D; Rodriguez Martino, J; Rodriguez Rojo, J; Rodriguez-Cabo, I; Ros, G; Rosado, J; Roth, M; Rouillé-d'Orfeuil, B; Roulet, E; Rovero, A C; Salamida, F; Salazar, H; Salina, G; Sánchez, F; Santander, M; Santo, C E; Santos, E M; Sarazin, F; Sarkar, S; Sato, R; Scherini, V; Schieler, H; Schmidt, F; Schmidt, T; Scholten, O; Schovánek, P; Schüssler, F; Sciutto, S J; Scuderi, M; Segreto, A; Semikoz, D; Settimo, M; Shellard, R C; Sidelnik, I; Siffert, B B; Sigl, G; De Grande, N Smetniansky; Smialkowski, A; Smída, R; Smith, A G K; Smith, B E; Snow, G R; Sokolsky, P; Sommers, P; Sorokin, J; Spinka, H

    2007-11-01

    Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above 6 x 10(19) electron volts and the positions of active galactic nuclei (AGN) lying within approximately 75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest-energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

  11. Search for correlated radio and optical events in long-term studies of extragalactic sources

    Science.gov (United States)

    Pomphrey, R. B.; Smith, A. G.; Leacock, R. J.; Olsson, C. N.; Scott, R. L.; Pollock, J. T.; Edwards, P.; Dent, W. A.

    1976-01-01

    For the first time, long-term records of radio and optical fluxes of a large sample of variable extragalactic sources have been assembled and compared, with linear cross-correlation analysis being used to reinforce the visual comparisons. Only in the case of the BL Lac object OJ 287 is the correlation between radio and optical records strong. In the majority of cases there is no evidence of significant correlation, although nine sources show limited or weak evidence of correlation. The results do not support naive extrapolation of the expanding source model. The general absence of strong correlation between the radio and optical regions has important implications for the energetics of events occurring in such sources.

  12. A compiled catalogue of reference stars around 227 ICRF extragalactic radio sources.

    Science.gov (United States)

    Ryl'kov, V. P.; Narizhnaya, N. V.; Dement'eva, A. A.; Pinigin, G. I.; Maigurova, N. V.; Martinov, M. V.

    A compiled catalogue of21440 stars with magnitudes from 10 to 17 is prepared on the basis of original observations made from the end of the 20th to the beginning of the 21th century. The catalogue con tains 227 fields of the cetes tial sphere around extragalactic radio sources in a declination zone from -17 to +89°. The field size is 40' for both right ascension and declination. The internal accuracy of positions for both coordinates is not worse than 0.1". The comparison of stellar positions with the use of the UCAC2 and CMC13 catalogues shows that the average external accuracy is about 0.05-0.15" for the majority ofchosenfields of the compiled catalogue. The positions of 10795 stars up to +50° in declination are given at epoch J2000.0, whereas the positions of other stars are given at the epoch of an observation.

  13. Correlation of the highest energy cosmic rays with nearby extragalactic objects

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez, C.; Alvarez-Muniz, J.; Ambrosio, M.; /Balseiro Inst., San Carlos de Bariloche /Buenos Aires, CONICET /CNEA, Buenos Aires /Pierre Auger Observ. /La Plata U. /Natl. Tech. U., San Rafael /Adelaide U. /Catholic U. of Bolivia, La Paz /Bolivia U. /Rio de Janeiro, CBPF /Sao Paulo U.

    2007-11-01

    Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrate that there is a correlation between the arrival directions of cosmic rays with energy above {approx} 6 x 10{sup 19} eV and the positions of active galactic nuclei (AGN) lying within {approx} 75 Mpc. We reject the hypothesis of an isotropic distribution of these cosmic rays at over 99% confidence level from a prescribed a priori test. The correlation we observe is compatible with the hypothesis that the highest energy particles originate from nearby extragalactic sources whose flux has not been significantly reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

  14. Near-IR Extragalactic Background Results from the Cosmic Infrared Background Experiment (CIBER)

    Science.gov (United States)

    Zemcov, Michael B.; CIBER

    2016-01-01

    The near IR extragalactic background light (EBL) encodes the integrated light production over cosmic history, so represents the total emission from all galaxies along the line of sight up to ancient first-light objects present during the epoch of reionization (EOR). This EOR emission necessarily comprises part of the background, and indeed a minimum level is required to supply enough photons to ionize the intergalactic medium, corresponding to an EBL brightness less than 1 nW m^-2 sr^-1, about one tenth of the integrated galactic light (IGL). In addition to emission from these IGL and EOR populations, low surface brightness tidal streams of stars stripped by gravitational interactions during galaxy formation at low redshifts, called intrahalo light (IHL), may also contribute a significant fraction of the EBL. Models for these components can be constrained both through direct photometric measurements, as well as the new technique of EBL anisotropy intensity mapping that takes advantage of the fact that the Zodiacal Light is spatially smooth while distant populations produce anisotropies with distinct spatial and spectral characteristics. This talk will present recent results from the Cosmic Infrared Background Experiment (CIBER), a sounding rocket borne payload designed to measure both the fluctuations and direct photometric emission of the extra-galactic background light. The anisotropy of the near-IR EBL suggests the presence of a bright component approximately as bright as the IGL component near 1 micron which we interpret as the aggregate emission from low-redshift IHL. New direct photometric measurements from CIBER's low resolution spectrometer will also be discussed.

  15. Optical counterpart positions of extragalactic radio sources and connecting optical and radio reference frames

    Science.gov (United States)

    Aslan, Z.; Gumerov, R.; Jin, W.; Khamitov, I.; Maigurova, N.; Pinigin, G.; Tang, Z.; Wang, S.

    2010-01-01

    We discuss the results of an investigation of astrometric positions of extragalactic radio sources from a list for the International Celestial Reference Frame. About 300 fields around extragalactic radio sources were observed during the years 2000-2003. The observations were performed mainly using two telescopes equipped with CCD cameras at TUG, Turkey (Russian-Turkish Telescope - RTT150) and at YAO (1 m telescope), (Kunming, China). The mean accuracies of the measured positions are 38 mas in right ascension and 35 mas in declination. A comparison between the measured optical positions determined using the UCAC2 catalog and the radio positions from the current ICRF shows that the overall optical-minus- radio offsets are -4 and +15 mas for right ascension and declination, respectively. The formal internal errors of these mean offsets are 4 mas. The results of optical positions with respect to the reference catalogue 2MASS are also given. A search for a relation between optical and radio reference frames indicates that the orientation angles are near zero within their accuracy of about 5 mas. The link accuracy becomes 3 mas when our observations are combined with other studies. Tables 2 and 3 giving the positions are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A10Present address: İstanbul Kültür University, Ataköy Yerleşkesi, 34156 Istanbul, Turkey

  16. The Extragalactic Background Light and the Gamma-ray Opacity of the Universe

    Science.gov (United States)

    Dwek, Eli; Krennrich, Frank

    2012-01-01

    The extragalactic background light (EBL) is one of the fundamental observational quantities in cosmology. All energy releases from resolved and unresolved extragalactic sources, and the light from any truly diffuse background, excluding the cosmic microwave background (CMB), contribute to its intensity and spectral energy distribution. It therefore plays a crucial role in cosmological tests for the formation and evolution of stellar objects and galaxies, and for setting limits on exotic energy releases in the universe. The EBL also plays an important role in the propagation of very high energy gamma-rays which are attenuated en route to Earth by pair producing gamma-gamma interactions with the EBL and CMB. The EBL affects the spectrum of the sources, predominantly blazars, in the approx 10 GeV to 10 TeV energy regime. Knowledge of the EBL intensity and spectrum will allow the determination of the intrinsic blazar spectrum in a crucial energy regime that can be used to test particle acceleration mechanisms and VHE gamma-ray production models. Conversely, knowledge of the intrinsic gamma-ray spectrum and the detection of blazars at increasingly higher redshifts will set strong limits on the EBL and its evolution. This paper reviews the latest developments in the determination of the EBL and its impact on the current understanding of the origin and production mechanisms of gamma-rays in blazars, and on energy releases in the universe. The review concludes with a summary and future directions in Cherenkov Telescope Array techniques and in infrared ground-based and space observatories that will greatly improve our knowledge of the EBL and the origin and production of very high energy gamma-rays.

  17. Cosmological constraints on dark matter annihilation and decay: Cross-correlation analysis of the extragalactic γ -ray background and cosmic shear

    Science.gov (United States)

    Shirasaki, Masato; Macias, Oscar; Horiuchi, Shunsaku; Shirai, Satoshi; Yoshida, Naoki

    2016-09-01

    We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of ˜660 squared degrees in total. We improve upon our previous analyses by using an updated extragalactic γ -ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological N -body simulations and use them to estimate statistical errors accurately. The measured cross-correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of ˜100 in the mass range of O (1 ) TeV when including contributions from secondary γ rays due to the inverse-Compton upscattering of background photons. Annihilation cross sections of ⟨σ v ⟩˜10-23 cm3/s are excluded for TeV-scale DM depending on channel. Lifetimes of ˜1 025 sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.

  18. First results from MASIV : The microarcsecond scintillation-induced variability survey

    NARCIS (Netherlands)

    Lovell, JEJ; Jauncey, DL; Bignall, HE; Kedziora-Chudczer, L; Macquart, JP; Rickett, BJ; Tzioumis, AK

    2003-01-01

    We are undertaking a large-scale, microarcsecond scintillation-induced variability survey, MASIV, of the northern sky (decl. > 0degrees) at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic sources with which to examine both the microarcsecond

  19. The Carnegie-Spitzer-IMACS redshift survey of galaxy evolution since z = 1.5. I. Description and methodology

    Energy Technology Data Exchange (ETDEWEB)

    Kelson, Daniel D.; Williams, Rik J.; Dressler, Alan; McCarthy, Patrick J.; Shectman, Stephen A.; Mulchaey, John S.; Villanueva, Edward V.; Crane, Jeffrey D.; Quadri, Ryan F. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2014-03-10

    We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade. By defining a flux-limited sample of galaxies in Spitzer Infrared Array Camera 3.6 μm imaging of SWIRE fields, the CSI Survey efficiently traces the stellar mass of average galaxies to z ∼ 1.5. This first paper provides an overview of the survey selection, observations, processing of the photometry and spectrophotometry. We also describe the processing of the data: new methods of fitting synthetic templates of spectral energy distributions are used to derive redshifts, stellar masses, emission line luminosities, and coarse information on recent star formation. Our unique methodology for analyzing low-dispersion spectra taken with multilayer prisms in IMACS, combined with panchromatic photometry from the ultraviolet to the IR, has yielded high-quality redshifts for 43,347 galaxies in our first 5.3 deg{sup 2} of the SWIRE XMM-LSS field. We use three different approaches to estimate our redshift errors and find robust agreement. Over the full range of 3.6 μm fluxes of our selection, we find typical redshift uncertainties of σ {sub z}/(1 + z) ≲ 0.015. In comparisons with previously published spectroscopic redshifts we find scatters of σ {sub z}/(1 + z) = 0.011 for galaxies at 0.7 ≤ z ≤ 0.9, and σ {sub z}/(1 + z) = 0.014 for galaxies at 0.9 ≤ z ≤ 1.2. For galaxies brighter and fainter than i = 23 mag, we find σ {sub z}/(1 + z) = 0.008 and σ {sub z}/(1 + z) = 0.022, respectively. Notably, our low-dispersion spectroscopy and analysis yields comparable redshift uncertainties and success rates for both red and blue galaxies, largely eliminating color-based systematics that can seriously bias observed dependencies of galaxy evolution on environment.

  20. Radio Galaxy Zoo: host galaxies and radio morphologies for large surveys from visual inspection

    CERN Document Server

    Willett, Kyle W

    2016-01-01

    We present early results from Radio Galaxy Zoo, a web-based citizen science project for visual inspection and classification of images from all-sky radio surveys. The goals of the project are to classify individual radio sources (particularly galaxies with multiple lobes and/or complex morphologies) as well as matching the continuum radio emission to the host galaxy. Radio images come from the FIRST and ATLAS surveys, while matches to potential hosts are performed with infrared imaging from WISE and SWIRE. The first twelve months of classification yielded more than 1 million classifications of more than 60,000 sources. For images with at least 75% consensus by the volunteer classifiers, the accuracy is comparable to visual inspection by the expert science team. Based on mid-infrared colors, the hosts associated with radio emission are primarily a mixture of elliptical galaxies, QSOs, and LIRGs, which are in good agreement with previous studies. The full catalog of radio lobes and their host galaxies will meas...

  1. Extragalactic H2O Megamaser Sources:Central Black Holes,Nuclear X-ray and Maser Emissions

    Institute of Scientific and Technical Information of China (English)

    Jiang-Bo Su; Jiang-Shui Zhang; Jun-Hui Fan

    2008-01-01

    Extragalactic H2O megamasers are typically found within the innermost few parsecs of active galaxy nuclei (AGN) and the maser emission is considered to be excited most likely by the X-ray irradiation of the AGN.We investigate a comprehensive sample of extragalactic H2O masers in a sample of 38 maser host AGN to check potential correlations of the megamaser emission with parameters of the AGN,such as X-ray luminosity and black hole (BH) masses.We find a relation between the maser luminosities and BH masses,LH2O∝ M3.64-0.4 BH,which supports basically the theoretical prediction.The relation between the maser emission and X-ray emission is also confirmed.

  2. The Cosmic Infrared Background Experiment (CIBER): A Sounding Rocket Payload to Study the Near Infrared Extragalactic Background Light

    CERN Document Server

    Zemcov, M; Battle, J; Bock, J; Cooray, A; Hristov, V; Keating, B; Kim, M G; Lee, D H; Levenson, L R; Mason, P; Matsumoto, T; Matsuura, S; Nam, U W; Renbarger, T; Sullivan, I; Suzuki, K; Tsumura, K; Wada, T

    2011-01-01

    The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the Zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recover...

  3. On the radiative and thermodynamic properties of the extragalactic far infrared background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the explicit form of the function to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15 - 2.4 THz frequency interval, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density are calculated. The calculated value of the total intensity received in the 0.15 - 2.4 THz frequency interval is 13.6 nW m^-2 sr^-1, and comprises about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z = 1.5.

  4. Non-thermal emission from extragalactic radio sources a high resolution broad band (radio to X-rays) approach

    CERN Document Server

    Brunetti, G

    2002-01-01

    In the framework of the study of extragalactic radio sources, we will focus on the importance of the spatial resolution at different wavelengths, and of the combination of observations at different frequency bands. In particular, a substantial step forward in this field is now provided by the new generation X-ray telescopes which are able to image radio sources in between 0.1--10 keV with a spatial resolution comparable with that of the radio telescopes (VLA) and of the optical telescopes. After a brief description of some basic aspects of acceleration mechanisms and of the radiative processes at work in the extragalactic radio sources, we will focus on a number of recent radio, optical and X-ray observations with arcsec resolution, and discuss the deriving constraints on the physics of these sources.

  5. Origin of the ankle in the ultra-high energy cosmic ray spectrum and of the extragalactic protons below it

    CERN Document Server

    Farrar, Glennys R; Anchordoqui, Luis A

    2015-01-01

    The sharp change in slope of the ultra-high energy cosmic ray (UHECR) spectrum around 10^{18.6} eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle which evolves to intermediate composition above, has proved exceedingly challenging to understand theoretically. We show that for a range of source conditions, photo-disintegration of ultra-high energy nuclei in the region surrounding a UHECR accelerator naturally accounts for the observed spectrum and composition of the entire extragalactic component, which dominates above about 10^{17.5} eV. The mechanism has a clear signature in the spectrum and flavors of neutrinos.

  6. Perturbations to aquatic photosynthesis due to high-energy cosmic ray induced muon flux in the extragalactic shock model

    CERN Document Server

    Rodriguez, Lien; Rodriguez, Oscar

    2013-01-01

    We modify a mathematical model of photosynthesis to quantify the perturbations that high energy muons could make on aquatic primary productivity. Then we apply this in the context of the extragalactic shock model, according to which Earth receives an enhanced dose of high-energy cosmic rays when it is at the galactic north. We obtain considerable reduction in the photosynthesis rates, consistent with potential drops in biodiversity.

  7. Kinematics in the Galactic Bulge with APOGEE. II. High-Order Kinematic Moments and Comparison to Extragalactic Bar Diagnostics

    Science.gov (United States)

    Zasowski, G.; Ness, M. K.; García Pérez, A. E.; Martinez-Valpuesta, I.; Johnson, J. A.; Majewski, S. R.

    2016-12-01

    Much of the inner Milky Way’s (MW) global rotation and velocity dispersion patterns can be reproduced by models of secularly evolved, bar-dominated bulges. More sophisticated constraints, including the higher moments of the line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical substructure, are critical for interpreting observations of the unresolved inner regions of extragalactic systems and for placing the MW in context with other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by presenting the first maps of the skewness and kurtosis of the LOSVDs of metal-rich and metal-poor inner MW stars (divided at [Fe/H] = -0.4), and comparing the observed patterns to those that are seen both in N-body models and in extragalactic bars. Despite closely matching the mean velocity and dispersion, the models do not reproduce the observed skewness patterns of the LOSVDs in different ways, which demonstrates that our understanding of the detailed orbital structure of the inner MW remains an important regime for improvement. We find evidence in the MW of the skewness-velocity correlation that is used as a diagnostic of extragalactic bars/bulges. This correlation appears in metal-rich stars only, providing further evidence for different evolutionary histories of chemically differentiated populations. We connect these skewness measurements to previous work on high-velocity “peaks” in the inner Galaxy, confirming the presence of that phenomenon, and we quantify the cylindrical rotation of the inner Galaxy, finding that the latitude-independent rotation vanishes outside l ˜ 7°. Finally, we evaluate the MW data in the light of selected extragalactic bar diagnostics and discuss the progress and challenges in using the MW as a resolved analog of unresolved stellar populations.

  8. EleCa: A Monte Carlo code for the propagation of extragalactic photons at ultra-high energy

    Energy Technology Data Exchange (ETDEWEB)

    Settimo, Mariangela [University of Siegen (Germany); De Domenico, Manlio [Laboratory of Complex Systems, Scuola Superiore di Catania and INFN (Italy); Lyberis, Haris [Federal University of Rio de Janeiro (Brazil)

    2013-06-15

    Ultra high energy photons, above 10{sup 17}–10{sup 18}eV, can interact with the extragalactic background radiation leading to the development of electromagnetic cascades. A Monte Carlo code to simulate the electromagnetic cascades initiated by high-energy photons and electrons is presented. Results from simulations and their impact on the predicted flux at Earth are discussed in different astrophysical scenarios.

  9. Redshift-independent Distances in the NASA/IPAC Extragalactic Database: Methodology, Content, and Use of NED-D

    Science.gov (United States)

    Steer, Ian; Madore, Barry F.; Mazzarella, Joseph M.; Schmitz, Marion; Corwin, Harold G.; Chan, Ben H. P.; Ebert, Rick; Helou, George; Baker, Kay; Chen, Xi; Frayer, Cren; Jacobson, Jeff; Lo, Tak; Ogle, Patrick; Pevunova, Olga; Terek, Scott

    2017-01-01

    Estimates of galaxy distances based on indicators that are independent of cosmological redshift are fundamental to astrophysics. Researchers use them to establish the extragalactic distance scale, to underpin estimates of the Hubble constant, and to study peculiar velocities induced by gravitational attractions that perturb the motions of galaxies with respect to the “Hubble flow” of universal expansion. In 2006 the NASA/IPAC Extragalactic Database (NED) began making available a comprehensive compilation of redshift-independent extragalactic distance estimates. A decade later, this compendium of distances (NED-D) now contains more than 100,000 individual estimates based on primary and secondary indicators, available for more than 28,000 galaxies, and compiled from over 2000 references in the refereed astronomical literature. This paper describes the methodology, content, and use of NED-D, and addresses challenges to be overcome in compiling such distances. Currently, 75 different distance indicators are in use. We include a figure that facilitates comparison of the indicators with significant numbers of estimates in terms of the minimum, 25th percentile, median, 75th percentile, and maximum distances spanned. Brief descriptions of the indicators, including examples of their use in the database, are given in an appendix.

  10. High-energy electromagnetic cascades in extragalactic space: Physics and features

    Science.gov (United States)

    Berezinsky, V.; Kalashev, O.

    2016-07-01

    Using the analytic modeling of the electromagnetic cascades compared with more precise numerical simulations, we describe the physical properties of electromagnetic cascades developing in the universe on cosmic microwave background and extragalactic background light radiations. A cascade is initiated by very-high-energy photon or electron, and the remnant photons at large distance have two-component energy spectrum, ∝E-2 (∝E-1.9 in numerical simulations) produced at the cascade multiplication stage and ∝E-3 /2 from Inverse Compton electron cooling at low energies. The most noticeable property of the cascade spectrum in analytic modeling is "strong universality," which includes the standard energy spectrum and the energy density of the cascade ωcas as its only numerical parameter. Using numerical simulations of the cascade spectrum and comparing it with recent Fermi LAT spectrum, we obtained the upper limit on ωcas stronger than in previous works. The new feature of the analysis is the "Emax rule." We investigate the dependence of ωcas on the distribution of sources, distinguishing two cases of universality: the strong and weak ones.

  11. Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae

    CERN Document Server

    Patat, F; Cox, N L J; Baade, D; Clocchiatti, A; Hoeflich, P; Maund, J R; Reilly, E; Spyromilio, J; Wang, L; Wheeler, J C; Zelaya, P

    2014-01-01

    Aims: The aim of this paper is twofold: i. investigate the properties of extragalactic dust and compare them to what is seen in the Galaxy; ii. address in an independent way the problem of the anomalous extinction curves reported for reddened Type Ia Supernovae (SN) in connection to the environments in which they explode. Methods: The properties of the dust are derived from the wavelength dependence of the continuum polarization observed in four reddened Type Ia SN: 1986G, 2006X, 2008fp and 2014J. [...] Results: All four objects are characterized by exceptionally low total-to-selective absorption ratios (R_V) and display an anomalous interstellar polarization law, characterized by very blue polarization peaks. In all cases the polarization position angle is well aligned with the local spiral structure. While SN1986G is compatible with the most extreme cases of interstellar polarization known in the Galaxy, SN2006X, 2008fp and 2014J show unprecedented behaviors. The observed deviations do not appear to be conn...

  12. Variability along the Blazar-Sequence - Hints for extragalactic Cosmic Rays?

    CERN Document Server

    Weidinger, Matthias

    2011-01-01

    The spectral energy distribution and variability of several blazars (Mkn 501, 1 ES 2344+51.4, PKS 2155-30.4, 1 ES 1218+30.4, 3C 454.3) along the blazar sequence is investigated using a selfconsistent and timedependent lepto-hadronic hybrid emission model. The BL Lac objects in the list are successfully modelled with purely leptonic radiation processes (essentially Synchrotron Self-Compton emission), while the Flat Spectrum Radio Quasar requires highly relativistic hadrons to be present within the jet. Variability is exploited as well with our model to distinguish between Self-Compton and hadronic gamma radiation making use of their different signatures in lightcurves. As a consequence active galactic nuclei with z > 0.5 are the best candidates as sources of extragalactic consmic rays, since High-Peaked BL Lac objects do not seem to accelerate protons to energies above thermal. Furthermore the parameters found during the modelling of the objects agree very well with obervations of e.g. superluminal motion or t...

  13. Inverse Compton Contribution to the Star-Forming Extragalactic Gamma-Ray Background

    CERN Document Server

    Chakraborty, Nachiketa

    2012-01-01

    Fermi has resolved several star-forming galaxies, but the vast majority of the star-forming universe is unresolved and thus contributes to the extragalactic gamma ray background (EGB). Here, we calculate the contribution from star-forming galaxies to the EGB in the Fermi range from 100 MeV to 100 GeV, due to inverse-Compton (IC) scattering of the interstellar photon field by cosmic-ray electrons. We first construct a one-zone model for a single star-forming galaxy, assuming supernovae power the acceleration of cosmic rays. The same IC interactions leading to gamma rays also substantially contribute to the energy loss of the high-energy cosmic-ray electrons. Consequently, a galaxy's IC emission is determined by the relative importance of IC losses in the cosmic-ray electron energy budget ("partial calorimetry"). We use our template for galactic IC luminosity to find the cosmological contribution of star-forming galaxies to the EGB. For all of our models, we find the IC EGB contribution is almost an order of ma...

  14. Axion decay and anisotropy of near-IR extragalactic background light

    CERN Document Server

    Gong, Yan; Mitchell-Wynne, Ketron; Chen, Xuelei; Zemcov, Michael; Smidt, Joseph

    2015-01-01

    The extragalactic background light is expected to be comprised of the cumulative radiation from all galaxies and active galactic nuclei over the cosmic history. In addition to point sources, EBL also contains information from diffuse sources of radiation. An example is the intra-halo light, associated with diffuse stars in dark matter halos resulting from galaxy mergers and tidal interactions, identified based on measurements involving the angular power spectrum of infrared background anisotropies. The angular power spectra of the near-infrared intensities could still contain additional signals and a complete understanding of the nature of the IR background is still lacking in the literature. Here we explore the constraints that can be placed on the decay products associated with particle decays, especially candidate dark matter models involving axions that trace dark matter halos of galaxies. Axions with a mass around a few eV will decay via two photons with wavelengths in the near-IR band, and will leave a ...

  15. First extragalactic detection of submillimeter CH rotational lines from the Herschel space observatory

    Energy Technology Data Exchange (ETDEWEB)

    Rangwala, Naseem; Maloney, Philip R.; Glenn, Jason; Kamenetzky, Julia [Center for Astrophysics and Space Astronomy, University of Colorado, 1255 38th street, Boulder, CO 80303 (United States); Wilson, Christine D.; Schirm, Maximilien R. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Spinoglio, Luigi; Pereira Santaella, Miguel [Istituto di Fisica dello Spazio Interplanetario, INAF, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)

    2014-06-20

    We present the first extragalactic detections of several CH rotational transitions in the far-infrared in four nearby galaxies, NGC 1068, Arp 220, M82, and NGC 253, using the Herschel Space Observatory. The CH lines in all four galaxies are a factor of 2-4 brighter than the adjacent HCN and HCO{sup +} J = 6-5 lines (also detected in the same spectra). In the star-formation-dominated galaxies, M82, NGC 253, and Arp 220, the CH/CO abundance ratio is low (∼10{sup –5}), implying that the CH is primarily arising in diffuse and translucent gas where the chemistry is driven by UV radiation as found in the Milky Way interstellar matter. In NGC 1068, which has a luminous active galactic nucleus (AGN), the CH/CO ratio is an order of magnitude higher, suggesting that CH formation is driven by an X-ray-dominated region (XDR). Our XDR models show that both the CH and CO abundances in NGC 1068 can be explained by an XDR-driven chemistry for gas densities and molecular hydrogen column densities that are well constrained by the CO observations. We conclude that the CH/CO ratio may a good indicator of the presence of AGN in galaxies. We also discuss the feasibility of detecting CH in intermediate- to high-z galaxies with ALMA.

  16. Probing the peak of the star formation rate density with the extragalactic background light

    CERN Document Server

    Raue, Martin

    2012-01-01

    The extragalactic background light (EBL), i.e., the diffuse meta-galactic photon field in the ultraviolet to infrared, is dominated by the emission from stars in galaxies. It is, therefore, intimately connected with the integrated star formation rate density (SFRD). In this paper, the SFRD is constrained using recent limits on the EBL density derived from observations of distant sources of high and very-high energy gamma-rays. The stellar EBL contribution is modeled utilizing simple stellar population spectra including dust attenuation and emission. A wide range of values for the different model parameters (SFRD(z), metallicity, dust absorption) is investigated and their impact on the resulting EBL is studied. The calculated EBL densities are compared with the specific EBL density limits and constraints on the SFRD are derived. For the fiducial model, adopting a Chabrier initial mass function (IMF), the SFRD is constrained to ~< 0.1 M_solar yr^-1 Mpc^-3 and < 0.2 M_solar yr^-1 Mpc^-3 for a redshift of z...

  17. The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

    CERN Document Server

    Perucho, Manel

    2015-01-01

    Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of helical radio-jets do not correspond to observational artifacts. This conclusion was reached by studying a number of VLBI observations of the radio jet in the quasar S5~0836+710 at different frequencies and epochs. The ridge-line of the emission in the jet coincides at all frequencies within the errors. Moreover, small differences between the ridge-lines as observed at different epochs reveal wave-like motion transversal to the jet propagation axis. I also discuss similar results, albeit with different interpretations, obta...

  18. Long-term variability of extragalactic radio sources in the Planck Early Release Compact Source Catalogue

    CERN Document Server

    Chen, X; Lopez-Caniego, M; Dickinson, C; Pearson, T J; Fuhrmann, L; Krichbaum, T P; Partridge, B

    2013-01-01

    Combining measurements taken using the Wilkinson Microwave Anisotropy Probe (WMAP) from 2001 to 2008 with measurements taken using Planck from 2009 to 2010, we investigate the long-term flux density variability of extragalactic radio sources selected from the Planck Early Release Compact Source Catalogue. The single-year, single-frequency WMAP maps are used to estimate yearly-averaged flux densities of the sources in the four WMAP bands: Ka (33 GHz), Q (41 GHz), V (61 GHz), and W (94 GHz). We identify 82, 67, 32, and 15 sources respectively as variable at greater than 99% confidence level in these four bands. The amplitudes of variation are comparable between bands, and are not correlated with either the flux densities or the spectral indices of the sources. The number counts of WMAP Ka-band sources are stable from year to year despite the fluctuation caused by individual source variability. Most of our sources show strong correlation in variability between bands. Almost all the sources that show variability ...

  19. Extragalactic cosmic-ray source composition and the interpretation of the ankle

    CERN Document Server

    Allard, D; Olinto, A V; Khan, E; Goriely, S

    2005-01-01

    We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray (EGCR) component if the source spectrum is $\\propto E^{-2.6}$. In this case the ankle in the cosmic ray (CR) spectrum may be interpreted as a pair-production dip associated with the propagation. We show that when heavier nuclei are included in the source with a composition similar to that of Galactic cosmic-rays (GCRs), the pair-production dip is not present unless the proton fraction is higher than 85%. In the mixed composition case, the ankle recovers the past interpretation as the transition from GCRs to EGCRs and the highest energy data can be explained by a harder source spectrum $\\propto E^{-2.2}$-- $E^{-2.3}$, reminiscent of relativistic shock accel...

  20. Centaurus A: The Extragalactic Source of Cosmic Rays with Energies above the Knee

    Science.gov (United States)

    Biermann, Peter L.; de Souza, Vitor

    2012-02-01

    The origin of cosmic rays at all energies is still uncertain. In this paper, we present and explore an astrophysical scenario to produce cosmic rays with energy ranging from below 1015 to 3 × 1020 eV. We show here that just our Galaxy and the radio galaxy Cen A, each with their own galactic cosmic-ray particles but with those from the radio galaxy pushed up in energy by a relativistic shock in the jet emanating from the active black hole, are sufficient to describe the most recent data in the PeV to near ZeV energy range. Data are available over this entire energy range from the KASCADE, KASCADE-Grande, and Pierre Auger Observatory experiments. The energy spectrum calculated here correctly reproduces the measured spectrum beyond the knee and, contrary to widely held expectations, no other extragalactic source population is required to explain the data even at energies far below the general cutoff expected at 6 × 1019 eV, the Greisen-Zatsepin-Kuz'min turnoff due to interaction with the cosmological microwave background. We present several predictions for the source population, the cosmic-ray composition, and the propagation to Earth which can be tested in the near future.

  1. CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations

    Science.gov (United States)

    Indriolo, Nick; Bergin, E. A.; Goicoechea, J. R.; Cernicharo, J.; Gerin, M.; Gusdorf, A.; Lis, D. C.; Schilke, P.

    2017-02-01

    The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel/HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these observations are combined with those from Herschel/PACS observations of the same sources to construct CO spectral line energy distributions (SLEDs) from 5 ≤ J u ≤ 48. These CO SLEDs are compared to those reported in other galaxies, with the intention of empirically determining which mechanisms dominate excitation in such systems. We find that CO SLEDs in Galactic star-forming cores cannot be used to reproduce those observed in other galaxies, although the discrepancies arise primarily as a result of beam filling factors. The much larger regions sampled by the Herschel beams at distances of several megaparsecs contain significant amounts of cooler gas, which dominate the extragalactic CO SLEDs, in contrast to observations of Galactic star-forming regions, which are focused specifically on cores containing primarily hot molecular gas. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  2. Safeguarding Old and New Journal Tables for the VO: Status for Extragalactic and Radio Data

    Directory of Open Access Journals (Sweden)

    Heinz Andernach

    2009-03-01

    Full Text Available Independent of established data centers, and partly for my own research, since 1989 I have been collecting the tabular data from over 2600 articles concerned with radio sources and extragalactic objects in general. Optical character recognition (OCR was used to recover tables from 740 papers. Tables from only 41 percent of the 2600 articles are available in the CDS or CATS catalog collections, and only slightly better coverage is estimated for the NED database. This fraction is not better for articles published electronically since 2001. Both object databases (NED, SIMBAD, LEDA as well as catalog browsers (VizieR, CATS need to be consulted to obtain the most complete information on astronomical objects. More human resources at the data centers and better collaboration between authors, referees, editors, publishers, and data centers are required to improve data coverage and accessibility. The current efforts within the Virtual Observatory (VO project, to provide retrieval and analysis tools for different types of published and archival data stored at various sites, should be balanced by an equal effort to recover and include large amounts of published data not currently available in this way.

  3. Extragalactic Inverse Compton Light from Dark Matter Annihilation and the Pamela Positron Excess

    CERN Document Server

    Profumo, Stefano

    2009-01-01

    We calculate the extragalactic diffuse emission originating from the up-scattering of cosmic microwave photons by energetic electrons and positrons produced in particle dark matter annihilation events at all redshifts and in all halos. We outline the observational constraints on this emission and we study its dependence on both the particle dark matter model (including the particle mass and its dominant annihilation final state) and on assumptions on structure formation and on the density profile of halos. We find that for low-mass dark matter models, data in the X-ray band provide the most stringent constraints, while the gamma-ray energy range probes models featuring large masses and pair-annihilation rates, and a hard spectrum for the injected electrons and positrons. Specifically, we point out that the all-redshift, all-halo inverse Compton emission from many dark matter models that might provide an explanation to the anomalous positron fraction measured by the Pamela payload severely overproduces the obs...

  4. Ideal magnetohydrodynamic simulation of magnetic bubble expansion as a model for extragalactic radio lobes

    CERN Document Server

    Liu, Wei; Li, Hui; Li, Shengtai; Lynn, Alan G

    2008-01-01

    Nonlinear ideal magnetohydrodynamic (MHD) simulations of the propagation and expansion of a magnetic "bubble" plasma into a lower density, weakly-magnetized background plasma are presented. These simulations mimic the geometry and parameters of the Plasma Bubble Expansion Experiment (PBEX) [A. G. Lynn, Y. Zhang, S. C. Hsu, H. Li, W. Liu, M. Gilmore, and C. Watts, Bull. Amer. Phys. Soc. {\\bf 52}, 53 (2007)], which is studying magnetic bubble expansion as a model for extra-galactic radio lobes. The simulations predict several key features of the bubble evolution. First, the direction of bubble expansion depends on the ratio of the bubble toroidal to poloidal magnetic field, with a higher ratio leading to expansion predominantly in the direction of propagation and a lower ratio leading to expansion predominantly normal to the direction of propagation. Second, an MHD shock and a trailing slow-mode compressible MHD wavefront are formed ahead of the bubble as it propagates into the background plasma. Third, the bub...

  5. High energy cosmic ray self-confinement close to extragalactic sources

    CERN Document Server

    Blasi, P; D'Angelo, M

    2015-01-01

    The ultra-high energy cosmic rays observed at the Earth are most likely accelerated in extra-galactic sources. For the typical luminosities invoked for such sources, the electric current associated to the flux of cosmic rays that leave them is large. The associated plasma instabilities create magnetic fluctuations that can efficiently scatter particles. We argue that this phenomenon forces cosmic rays to be self-confined in the source proximity for energies $E

  6. SCP06F6: A carbon-rich extragalactic transient at redshift z~0.14

    CERN Document Server

    Gänsicke, B T; Marsh, T R; Wheatley, P J

    2008-01-01

    We show that the spectrum of the unusual transient SCP06F6 is consistent with emission from a cool, carbon-rich atmosphere at a redshift of z~0.14. The extragalactic nature of the transient rules out novae, shell flashes, and V838 Mon-like events as cause of the observed brightening. The distance to SCP 06F6 implies a peak magnitude of M_I~-18, in the regime of supernovae. The morphology of the light curve of SCP 06F6 around the peak in brightness resembles the slowly evolving TypeII supernovae SN 1994Y and SN 2006 gy. We further report the detection of an X-ray source co-incident with SCP 06F6 in a target of opportunity XMM-Newton observation made during the declining phase of the transient. The X-ray luminosity of L_X~(5+-1)x10^42 erg/s is two orders of magnitude higher than observed to date from supernovae. If related to a supernova event, SCP 06F6 would define a new class. An alternative, though less likely, scenario is the tidal disruption of a carbon-rich star.

  7. Exploring Cosmic Origins with CORE: Extragalactic sources in Cosmic Microwave Background maps

    CERN Document Server

    De Zotti, G; Lopez-Caniego, M; Negrello, M; Greenslade, J; Hernandez-Monteagudo, C; Delabrouille, J; Cai, Z -Y; Biesiada, M; Bilicki, M; Bonaldi, A; Bonato, M; Burigana, C; Clements, D L; Colafrancesco, S; Diego, J M; Brun, A Le; Massardi, M; Melin, J B; Pollo, A; Roukema, B; Serjeant, S; Toffolatti, L; Tucci, M

    2016-01-01

    We update and extend our earlier discussion of the potential of a next generation space-borne CMB experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of a future space project, CORE, that will be submitted in response to ESA's call for a Medium-size mission opportunity (M5) as the successor of the Planck satellite. Even though the effective telescope size will be similar or somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, at variance with Planck, it will be diffraction limited. The better resolution implies a substantial decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect several thousands of strongly lensed high-z galaxies distributed over the full sky. These are the brightest (sub-)mm sources in the sky and, as such, will allow studies of high-z star forming galaxies in exquisite detail. Also, the CORE resolution matches...

  8. Tracing molecular gas mass in extreme extragalactic environments: an observational study

    CERN Document Server

    Zhu, Ming; Xilouris, Emmanuel M; Kuno, Nario; Lisenfeld, Ute

    2009-01-01

    We present a new observational study of the CO(1-0) line emission as an H2 gas mass tracer under extreme conditions in extragalactic environments. Our approach is to study the full neutral interstellar medium (H2, HI and dust) of two galaxies whose bulk interstellar medium (ISM) resides in environments that mark (and bracket) the excitation extremes of the ISM conditions found in infrared luminous galaxies, the starburst NGC3310 and the quiescent spiral NGC157. Our study maintains a robust statistical notion of the so-called X factor (i.e. a large ensemble of clouds is involved) while exploring its dependency on the very different average ISM conditions prevailing within these two systems. These are constrained by fully-sampled CO(3-2) and CO(1-0) observations, at a matched beam resolution of Half Power Beam Width 15'', obtained with the JCMT the Nobeyama 45-m telescope, combined with sensitive 850 and 450 micron dust emission and HI interferometric images which allow a complete view of all the neutral ISM co...

  9. The Starburst Contribution to the Extra-Galactic Gamma-Ray Background

    CERN Document Server

    Thompson, T A; Waxman, E; Thompson, Todd A.; Quataert, Eliot; Waxman, Eli

    2006-01-01

    Cosmic ray protons interacting with gas at the mean density of the interstellar medium in starburst galaxies lose energy rapidly via inelastic collisions with ambient nuclei. The resulting pions produce secondary electrons and positrons, high-energy neutrinos, and gamma-ray photons. We estimate the cumulative gamma-ray emission from starburst galaxies and find a specific intensity at GeV energies of (nu I_nu) ~ 3 times 10^{-7} GeV cm^{-2} s^{-1} sr^{-1}. Starbursts may thus account for a significant fraction of the extra-galactic gamma-ray background. We show that the FIR-radio correlation provides a strong constraint on the gamma-ray emission from starburst galaxies because pions decay into both gamma-rays and radio-emitting electron/positron pairs. We identify several nearby systems where the potential for observing gamma-ray emission is the most favorable (M82, NGC 253, & IC 342), predict their fluxes, and predict a linear FIR-gamma-ray correlation for the densest starbursts. If established, the FIR-ga...

  10. Propagation of extragalactic photons at ultra-high energy with the EleCa code

    CERN Document Server

    Settimo, Mariangela

    2013-01-01

    Ultra-high energy (UHE) photons play an important role as an independent probe of the photo-pion production mechanism by UHE cosmic rays. Their observation, or non-observation, may constrain astrophysical scenarios for the origin of UHECRs and help to understand the nature of the flux suppression observed by several experiments at energies above $10^{19.5}$ eV. Whereas the interaction length of UHE photons above $10^{17}$ eV ranges from a few hundred kpc up to tenths of Mpc, photons can interact with the extragalactic background radiation initiating the development of electromagnetic cascades which affect the fluxes of photons observed at Earth. The interpretation of the current experimental results rely on the simulations of the UHE photon propagation. In this paper, we present the novel Monte Carlo code EleCa to simulate the $Ele$ctromagnetic $Ca$scading initiated by high-energy photons and electrons. We provide an estimation of the surviving probability for photons inducing electromagnetic cascades as a fu...

  11. The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

    Science.gov (United States)

    Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.; hide

    2013-01-01

    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like active galactic nuclei (AGN), galaxies and the intergalactic medium (IGM). The power of unresolved cosmic source fluctuations accounts for approximately 12 per cent of the 0.5-2 keV extragalactic CXB. Overall, our modelling predicts that approximately 20 per cent of the unresolved CXB flux is produced by low-luminosity AGN, approximately 25 per cent by galaxies and approximately 55 per cent by the IGM. We do not find any direct evidence of the so-called 'warm hot intergalactic medium' (i.e. matter with 10(exp 5) less than T less than 10(exp 7) K and density contrast delta less than 1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit on the space density of postulated X-ray-emitting early black holes at z greater than 7.5 and compared it with supermassive black hole evolution models.

  12. Effects of spatial fluctuations in the extragalactic background light on hard gamma-ray spectra

    Science.gov (United States)

    Kudoda, A. M.; Faltenbacher, A.

    2017-05-01

    This study investigates the impact of the fluctuations in the extragalactic background light (EBL) on the attenuation of the hard γ-ray spectra of distant blazars. EBL fluctuations occur on the scales up to 100 Mpc and are caused by the clustering of galaxies. The EBL photons interact with high-energy γ-rays via the electron-positron pair production mechanism: γ + γ΄ → e+ + e-. The attenuation of γ-rays depends on their energy and the density of the intervening EBL photon field. Using a simple model for the evolution of the mean EBL photon density, we implement an analytical description of the EBL fluctuations. We find that the amplitudes of the EBL energy density can vary by ±1 per cent as a function of environment. The EBL fluctuations lead to mild alterations of the optical depth or equivalently the transmissivity for γ-rays from distant blazars. Our model predicts maximum changes of ±10 per cent in the γ-ray transmissivity. However, this translates into marginal differences in the power-law slopes of currently observed γ-ray spectra. The slopes of deabsorbed γ-ray spectra differ by not more than ±1 per cent if EBL fluctuations are included.

  13. Fermi-LAT high-z active galactic nuclei and the extragalactic background light

    Science.gov (United States)

    Armstrong, Thomas; Brown, Anthony M.; Chadwick, Paula M.

    2017-10-01

    Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good understanding of the EBL is included. In this work, an investigation into the imprint of the EBL on the observed spectra of high-redshift Fermi-LAT active galactic nuclei is presented. By fitting the spectrum below ˜10 GeV, an estimation of the unabsorbed intrinsic source spectrum is obtained; by applying this spectrum to data up to 300 GeV, it is then possible to derive a scaling factor for different EBL models. A second approach uses five sources (PKS 0426-380, 4C +55.17, Ton 116, PG 1246+586 and RBS 1432) that were found to exhibit very high energy (VHE) emission (Eγ > 100 GeV). Through Monte Carlo simulations, it is shown that the observation of VHE photons, despite the large distances of these objects, is consistent with current EBL models. Many of these sources would be observable with the upcoming ground-based observatory, the Cherenkov Telescope Array, leading to a better understanding of the EBL.

  14. Estimation of the extragalactic background light using TeV observations of BL Lac objects

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Atreyee; Acharya, B. S. [Department of High Energy Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Sahayanathan, S.; Godambe, S. [Astrophysical Sciences Division, Bhabha Atomic Research Center, Mumbai (India); Misra, R., E-mail: atreyee@tifr.res.in, E-mail: acharya@tifr.res.in, E-mail: sunder@barc.ernet.in, E-mail: gsagar@barc.ernet.in, E-mail: rmisra@iucaa.ernet.in [Inter-University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India)

    2014-11-01

    The very high-energy (VHE) gamma-ray spectral index of high-energy peaked blazars correlates strongly with its corresponding redshift, whereas no such correlation is observed in the X-ray or GeV bands. We attribute this correlation to photon-photon absorption of TeV photons with the extragalactic background light (EBL), and utilizing this we compute the allowed flux range for the EBL, which is independent of previous estimates. The observed VHE spectrum of the sources in our sample can be well approximated by a power law, and if the de-absorbed spectrum is also assumed to be a power law, then we show that the spectral shape of EBL will be εn(ε) ∼ klog (ε/ε {sub p}). We estimate the range of values for the parameters defining the EBL spectrum, k and ε {sub p}, such that the correlation of the intrinsic VHE spectrum with redshift is nullified. The estimated EBL depends only on the observed correlation and the assumption of a power-law source spectrum. Specifically, it does not depend on the spectral modeling or radiative mechanism of the sources or on any theoretical shape of the EBL spectrum obtained through cosmological calculations. The estimated EBL spectrum is consistent with the upper and lower limits imposed by different observations. Moreover, it also agrees closely with the theoretical estimates obtained through cosmological evolution models.

  15. Optical Recombination Lines of Heavy-elements in Giant Extragalactic HII Regions

    CERN Document Server

    Esteban, C; Torres-Peimbert, S; Rodríguez, M

    2002-01-01

    We present high resolution observations of the giant extragalactic H II regions NGC 604, NGC 2363, NGC 5461 and NGC 5471, based on observations taken with the ISIS spectrograph on the William Herschel Telescope. We have detected -by the first time- C II and O II recombination lines in these objects. We find that recombination lines give larger C^{++} and O^{++} abundances than collisionallly excited lines, suggesting that temperature variations can be present in the objects. We detect [Fe IV] lines in NGC 2363 and NGC 5471, the most confident detection of optical lines of this kind in H II regions. Considering the temperature structure we derive their H, He, C, N, O, Ne, S, Ar, and Fe abundances. From the recombination lines of NGC 5461 and NGC 5471 we determine the presence of C/H and O/H gradients in M101. We calculate the Delta Y/Delta O and Delta Y/Delta Z values considering the presence of temperature variations and under the assumption of constant temperature. We obtain a better agreement with models of...

  16. The Unresolved Star-Forming Galaxy Component of the Extragalactic Gamma Ray Background

    Science.gov (United States)

    Venters, Tonia M.; Stecker, F. W.

    2011-01-01

    We present new theoretical estimates of the contribution of unresolved star-forming galaxies to the extragalactic gamma-ray background (EGB) as measured by EGRET and the Fermi-LAT. We employ several methods for determining the star-forming galaxy contribution the the EGB, including a method positing a correlation between the gamma-ray luminosity of a galaxy and its rate of star formation as calculated from the total infrared luminosity, and a method that makes use of a model of the evolution of the galaxy gas mass with cosmic time. We find that depending on the model, unresolved star-forming galaxies could contribute significantly to the EGB as measured by the Fermi-LAT at energies between approx. 300 MeV and approx. few GeV. However, the overall spectrum of unresolved star-forming galaxies can explain neither the EGRET EGB spectrum at energies between 50 and 200 MeV nor the Fermi-LAT EGB spectrum at energies above approx. few GeV.

  17. Supermassive Black-Hole Growth Over Cosmic Time: Active Galaxy Demography, Physics, and Ecology from Chandra Surveys

    CERN Document Server

    Brandt, W N

    2010-01-01

    Extragalactic X-ray surveys over the past decade have dramatically improved understanding of the majority populations of active galactic nuclei (AGNs) over most of the history of the Universe. Here we briefly highlight some of the exciting discoveries about AGN demography, physics, and ecology with a focus on results from Chandra. We also discuss some key unresolved questions and future prospects.

  18. Extragalactic archeology with the GHOSTS Survey I. - Age-resolved disk structure of nearby low-mass galaxies

    CERN Document Server

    Streich, David; Bailin, Jeremy; Bell, Eric F; Holwerda, Benne W; Minchev, Ivan; Monachesi, Antonela; Radburn-Smith, David J

    2016-01-01

    We study the individual evolution histories of three nearby low-mass edge-on galaxies (IC 5052, NGC4244, and NGC5023). Using resolved stellar populations, we constructed star count density maps for populations of different ages and analyzed the change of structural parameters with stellar age within each galaxy. We do not detect a separate thick disk in any of the three galaxies, even though our observations cover a wider range in equivalent surface brightness than any integrated light study. While scale heights increase with age, each population can be well described by a single disk. Two of the galaxies contain a very weak additional component, which we identify as the faint halo. The mass of these faint halos is lower than 1% of the mass of the disk. The three galaxies show low vertical heating rates, which are much lower than the heating rate of the Milky Way. This indicates that heating agents, such as giant molecular clouds and spiral structure, are weak in low-mass galaxies. All populations in the thre...

  19. The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds VIII. Serpens Observed with MIPS

    CERN Document Server

    Harvey, Paul M; Brooke, Tim; Spiesman, William J; Chapman, Nicholas; Huard, Tracy L; Evans, Neal J; Cieza, Lucas; Lai, Shih-Ping; Allen, Lori E; Mundy, Lee G; Padgett, Deborah L; Sargent, Anneila I; Stapelfeldt, Karl R; Myers, Philip C; van Dishoeck, Ewine F; Blake, Geoffrey A; Koerner, David W

    2007-01-01

    We present maps of 1.5 square degrees of the Serpens dark cloud at 24, 70, and 160\\micron observed with the Spitzer Space Telescope MIPS Camera. More than 2400 compact sources have been extracted at 24um, nearly 100 at 70um, and 4 at 160um. We estimate completeness limits for our 24um survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.50 deg^2 set on a low-extinction region near the dark cloud, and a 5.3 deg^2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens Cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two, and find that the most embedded YSO candidates are located in the areas of highest visual extinct...

  20. Influence of the Galactic Gravitational Field on the Positional Accuracy of Extragalactic Sources

    Science.gov (United States)

    Larchenkova, Tatiana I.; Lutovinov, Alexander A.; Lyskova, Natalya S.

    2017-01-01

    We investigate the influence of random variations of the Galactic gravitational field on the apparent celestial positions of extragalactic sources. The basic statistical characteristics of a stochastic process (first-order moments, an autocorrelation function and a power spectral density) are used to describe a light ray deflection in a gravitational field of randomly moving point masses as a function of the source coordinates. We map a 2D distribution of the standard deviation of the angular shifts in positions of distant sources (including reference sources of the International Celestial Reference Frame) with respect to their true positions. For different Galactic matter distributions the standard deviation of the offset angle can reach several tens of μas (microarcsecond) toward the Galactic center, decreasing down to 4–6 μas at high galactic latitudes. The conditional standard deviation (“jitter”) of 2.5 μas is reached within 10 years at high galactic latitudes and within a few months toward the inner part of the Galaxy. The photometric microlensing events are not expected to be disturbed by astrometric random variations anywhere except the inner part of the Galaxy as the Einstein–Chvolson times are typically much shorter than the jittering timescale. While a jitter of a single reference source can be up to dozens of μas over some reasonable observational time, using a sample of reference sources would reduce the error in relative astrometry. The obtained results can be used for estimating the physical upper limits on the time-dependent accuracy of astrometric measurements.

  1. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Ke; Olinto, Angela V. [Department of Astronomy and Astrophysics, Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, Illinois 60637 (United States); Kotera, Kumiko, E-mail: kefang@uchicago.edu, E-mail: kotera@iap.fr, E-mail: olinto@kicp.uchicago.edu [Institut d' Astrophysique de Paris, UMR 7095 - CNRS, Université Pierre and Marie Curie, 98 bis boulevard Arago, 75014, Paris (France)

    2013-03-01

    The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10{sup 19} eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ∼ E{sup −1}) due to pulsar spin down and a maximum energy E{sub max} ∼ Z 10{sup 19} eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10{sup 16} and 10{sup 18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.

  2. Redshift-Independent Distances in the NASA/IPAC Extragalactic Database Surpass 166,000 Estimates for 77,000 Galaxies

    Science.gov (United States)

    Steer, Ian

    2017-01-01

    Redshift-independent extragalactic distance estimates are used by researchers to establish the extragalactic distance scale, to underpin estimates of the Hubble constant, and to study peculiar velocities induced by gravitational attractions that perturb the motions of galaxies with respect to the “Hubble flow” of universal expansion. In 2006, the NASA/IPAC Extragalactic Database (NED) began providing users with a comprehensive tabulation of the redshift-independent extragalactic distance estimates published in the astronomical literature since 1980. A decade later, this compendium of distances (NED-D) surpassed 100,000 estimates for 28,000 galaxies, as reported in our recent journal article (Steer et al. 2016). Here, we are pleased to report NED-D has surpassed 166,000 distance estimates for 77,000 galaxies. Visualizations of the growth in data and of the statistical distributions of the most used distance indicators will be presented, along with an overview of the new data responsible for the most recent growth. We conclude with an outline of NED’s current plans to facilitate extragalactic research further by making greater use of redshift-independent distances. Additional information about other extensive updates to NED is presented at this meeting by Mazzarella et al. (2017). NED is operated by and this research is funded by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  3. A study of the 15 micron quasars in the ELAIS N1 and N2 fields

    CERN Document Server

    Afonso-Luis, A; González-Solares, E A; Hatziminaoglou, E; Montenegro-Montes, F M; Hernan-Caballero, A; Serjeant,; Rowan-Robinson, M; Lari, C; Vaccari, M; Oliver, S

    2004-01-01

    This paper discusses properties of the European Large Area ISO Survey 15 micron quasars and tries to establish a robust method of quasar selection for future use within the Spitzer Wide-Area Infrared Extragalactic Survey (SWIRE) framework. The importance of good quality ground-based optical data is stressed, both for the candidates selection and for the photometric redshifts estimates. Colour-colour plots and template fitting are used for these purposes. The properties of the 15 micron quasars sample are studied, including variability and black hole masses and compared to the properties of other quasars that lie within the same fields but have no mid-infrared counterparts. The two subsamples do not present substantial differences and are believed to come from the same parent population.

  4. Follow-up observations at 16 and 33 GHz of extragalactic sources from WMAP 3-year data: I - Spectral properties

    OpenAIRE

    2009-01-01

    We present follow-up observations of 97 point sources from the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data, contained within the New Extragalactic WMAP Point Source (NEWPS) catalogue between declinations of -4 and +60 degrees; the sources form a flux-density-limited sample complete to 1.1 Jy (approximately 5 sigma) at 33 GHz. Our observations were made at 16 GHz using the Arcminute Microkelvin Imager (AMI) and at 33 GHz with the Very Small Array (VSA). 94 of the sources have relia...

  5. On the Nature of the Gamma-ray Source 2FGL J1823.8 4312: The Discovery of a New Class of Extragalactic X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, Francesco

    2012-08-03

    One of the unsolved mysteries of gamma-ray astronomy concerns the nature of the unidentified gamma-ray sources. Recently, using the Second Fermi LAT source catalog (2FGL) and the Wide-field Infrared Survey Explorer (WISE) archive, we discovered that the WISE counterparts of gamma-ray blazars, a class of active galactic nuclei, delineate a region (the WISE Gamma-ray Strip) in the 3-dimensional infrared color space well separated from the locus of the other astronomical objects. Based on this result, we built an association procedure to recognize if there areWISE blazar candidates within the positional uncertainty region of the unidentified gamma-ray sources. Here we report on our analysis of 2FGL J1823.8+4312, a gamma-ray active galactic nucleus of uncertain type associated with the X-ray source 1RXS J182418.7+430954 according to the 2FGL, to verify whether it is a blazar. Applying our association method we found two sources with IR colors typical of gamma-ray blazars, located within the 99.9% confidence region of 2FGL J1823.8+4312: WISE J182352.33+431452.5 and WISE J182409.25+431404.7. Then we searched in the Chandra, NVSS and SDSS archival observations for their counterparts. We discovered that WISE J182352.33+431452.5, our preferred gamma-ray blazar candidate according to our WISE association procedure, is detected in the optical and in the X-rays but not in the radio, making it extremely unusual if it is a blazar. Given its enigmatic spectral energy distribution, we considered the possibility that it is a 'radio faint blazar' or the prototype of a new class of extragalactic sources, our conclusion is independent of whether WISE J182352.33+431452.5 is the actual counterpart of 2FGL J1823.8+4312.

  6. AzTEC half square degree survey of the SHADES fields : II. Identifications, redshifts, and evidence for large-scale structure

    NARCIS (Netherlands)

    Michalowski, Michal J.; Dunlop, J.S.; Ivison, R.J.; Cirasuolo, M.; Caputi, K.I.

    2012-01-01

    The AzTEC 1.1mm survey of the two SCUBA HAlf Degree Extragalactic Survey (SHADES) fields is the largest (0.7 deg2) blank-field millimetre-wavelength survey un- dertaken to date at a resolution of ≃ 18 arcsec and a depth of ≃ 1mJy. We have used the deep optical-to-radio multi-wavelength data in the S

  7. Recent Advances and Coming Attractions in the NASA/IPAC Extragalactic Database

    Science.gov (United States)

    Mazzarella, Joseph M.; Baker, Kay; Pan Chan, Hiu; Chen, Xi; Ebert, Rick; Frayer, Cren; Helou, George; Jacobson, Jeffery D.; Lo, Tak M.; Madore, Barry; Ogle, Patrick M.; Pevunova, Olga; Steer, Ian; Schmitz, Marion; Terek, Scott

    2017-01-01

    We review highlights of recent advances and developments underway at the NASA/IPAC Extragalactic Database (NED). Extensive updates have been made to the infrastructure and processes essential for scaling NED for the next steps in its evolution. A major overhaul of the data integration pipeline provides greater modularity and parallelization to increase the rate of source cross-matching and data integration. The new pipeline was used recently to fold in data for nearly 300,000 sources published in over 900 recent journal articles, as well as fundamental parameters for 42 million sources in the Spitzer Enhanced Imaging Products Source List. The latter has added over 360 million photometric measurements at 3.6, 4.5, 5.8. 8.0 (IRAC) and 24 microns (MIPS) to the spectral energy distributions of affected objects in NED. The recent discovery of super-luminous spiral galaxies (Ogle et al. 2016) exemplifies the opportunities for science discovery and data mining available directly from NED’s unique data synthesis, spanning the spectrum from gamma ray through radio frequencies. The number of references in NED has surpassed 103,000. In the coming year, cross-identifications of sources in the 2MASS Point Source Catalog and in the AllWISE Source Catalog with prior objects in the database (including GALEX) will increase the holdings to over a billion distinct objects, providing a rich resource for multi-wavelength analysis. Information about a recent surge in growth of redshift-independent distances in NED is presented at this meeting by Steer et al. (2017). Website updates include a ’simple search’ to perform common queries in a single entry field, an interface to query the image repository with options to sort and filter the initial results, connectivity to the IRSA Finder Chart service, as well as a program interface to query images using the international virtual observatory Simple Image Access protocol. Graphical characterizations of NED content and completeness are

  8. Kinetic Alfven Waves and the Depletion of the Thermal Population in Extragalactic Jets

    Science.gov (United States)

    Jafelice, L. C.; Opher, R.

    1990-11-01

    RESUMEN. Chorros Extragalacticos (CE) y Fuentes Radio Extendidas (FRE) son locales de ricos y complejos procesos de plasma magnetizado. Recien tes observaciones indican que esas fuentes son estructuradas en filamen tos. Nos concentramos aqui en el analisis de dos problemas: 1) el prob[e ma de injecci6n,queespropuesto porlas teorias de aceleraci6n de p ? las en plasmas de CE e FRE, que necesitan partfculas que ya tengan ener gfas moderadamente relativisticas para que los procesos de Fermi sean efectivos; y 2) la reciente evidencia observacional de la ausencia de partfculas termicas en CE. El presente modelo pone en evidencia que ambos problemas estan 1ntimamente relacionados uno con el otro. Jafelice y Opher (1987a) (Astrophys. Space Sci. 137, 303) muestram que es espera da una abundante generaci6n de olas Alf cineticas (OAC) en CE y FRE. En el presente trabajo estudiamos Ia cadena de procesos: a) OAC aceleran electrons termicos al largo del campo magnetico de fondo producien- do electrones supratermicos fugitivos; b) que generan olas Langmuir; y c) las cuales por su vez aceleran una fraccion de los electrones fugi- tivos hasta energias moderadamente relativfsticas. Mostramos que supo - niendo que no haya otra fuente de poblaci6n termica a no ser la , la secuencia de procesos arriba puede encargarse delconsumo de los elec- trones termicos en una escala de tiempo %< que el tiempo de vida de la fuente. ABSTRACT: Extragalactic Jets (EJ) and Extended Radio Sources (ERS) are sites of rich and complex magnetized plasma processes.Recent observa - tions indicate that these sources are filamentary structured. We concentrate here on the analysis of two problems:i) the injection problem, faced by theories of particle acceleration in EJ and ERS plasmas, which need particles with already moderately relativistic energies for the Fer mi processes `to be effective; and 2) the recent observational evidence of the abscence of thermal particles within EJ. The present model makes

  9. The FLAMINGOS-2 Early Science Surveys

    Science.gov (United States)

    Eikenberry, Stephen S.; FLAMINGOS-2 Early Science Survey Teams

    2010-01-01

    The FLAMINGOS-2 instrument achieved high-quality first-light observations on the Gemini South telescope in September 2009 and is undergoing further testing and scientific commissioning into early 2010. Based on the results so far, FLAMINGOS-2 (F2) on the Gemini 8-meter telescope is an extremely powerful wide-field near-infrared imager and multi-object spectrograph. In order to take best advantage of the strengths of F2 early in its life cycle, we propose to use 21 nights of Gemini guaranteed time in 3 surveys - the FLAMINGOS-2 Early Science Surveys (F2ESS). The F2ESS will encompass 3 corresponding scientific themes - the Galactic Center, extragalactic astronomy, and star formation. In this poster, I review the plans for carrying out these surveys with F2, data analysis plans and software, and the expected scientific impact from this powerful new observational tool.

  10. The Cosmic Infrared Background Experiment (CIBER): A Sounding Rocket Payload to Study the near Infrared Extragalactic Background Light

    Science.gov (United States)

    Zemcov, M.; Arai, T.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Tsumura, K.; Wada, T.

    2013-08-01

    The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

  11. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

    Energy Technology Data Exchange (ETDEWEB)

    Zemcov, M.; Bock, J.; Hristov, V.; Levenson, L. R.; Mason, P. [Department of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Sullivan, I. [Department of Physics, The University of Washington, Seattle, WA 98195 (United States); Suzuki, K., E-mail: zemcov@caltech.edu [Instrument Development Group of Technical Center, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

    2013-08-15

    The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

  12. Kinematics in the Galactic Bulge with APOGEE: II. High-Order Kinematical Moments and Comparison to Extragalactic Bar Diagnostics

    CERN Document Server

    Zasowski, G; Pérez, A E García; Martinez-Valpuesta, I; Johnson, J A; Majewski, S R

    2016-01-01

    Much of the inner Milky Way's (MW) global rotation and velocity dispersion patterns can be reproduced by models of secularly-evolved, bar-dominated bulges. More sophisticated constraints, including the higher moments of the line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical substructure, are critical for interpreting observations of the unresolved inner regions of extragalactic systems and for placing the MW in context with other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by presenting the first maps of the LOSVD skewness and kurtosis of metal-rich and metal-poor inner MW stars (divided at [Fe/H] = -0.4), and comparing the observed patterns to those that are seen both in N-body models and in extragalactic bars. Despite closely matching the mean velocity and dispersion, the models do not reproduce the observed LOSVD skewness patterns in different ways, which demonstrates that our understanding of the detailed orbital structure of the inner MW remains an im...

  13. Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

    Directory of Open Access Journals (Sweden)

    Marinelli Antonio

    2016-01-01

    Full Text Available The last IceCube catalog of High Energy Starting Events (HESE obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1 and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than 5σ. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model a extra-Galactic component derived from the astrophysical muonic neutrinos reconstructed in the Northern hemisphere. A good agreement between the expected astrophysical neutrino flux and the IceCube data is found for the full sky as well as for the Galactic plane region.

  14. Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

    Science.gov (United States)

    Marinelli, Antonio; Gaggero, Daniele; Grasso, Dario; Urbano, Alfredo; Valli, Mauro

    2016-04-01

    The last IceCube catalog of High Energy Starting Events (HESE) obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1) and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than 5σ. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR) transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model) a extra-Galactic component derived from the astrophysical muonic neutrinos reconstructed in the Northern hemisphere. A good agreement between the expected astrophysical neutrino flux and the IceCube data is found for the full sky as well as for the Galactic plane region.

  15. Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

    CERN Document Server

    Marinelli, Antonio; Grasso, Dario; Urbano, Alfredo; Valli, Mauro

    2016-01-01

    The last IceCube catalog of High Energy Starting Events (HESE) obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1) and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than $5\\sigma$. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR) transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model) a extra-Galactic component derived from the as...

  16. The VLBA Calibrator Search for the BeSSeL Survey

    CERN Document Server

    Immer, K; Reid, M J; Bartkiewicz, A; Choi, Y K; Menten, K M; Moscadelli, L; Sanna, A; Wu, Y W; Xu, Y; Zhang, B; Zheng, X W

    2011-01-01

    We present the results of a survey of radio continuum sources near the Galactic plane using the Very Long Baseline Array (VLBA). Our observations are designed to identify compact extragalactic sources of milliarcsecond size that can be used for parallax measurements in the Bar and Spiral Structure Legacy Survey. We selected point sources from the NVSS and CORNISH catalogs with flux densities above 30 mJy and within $1.5\\degr$ of known maser targets. Of the 1529 sources observed, 199 were detected. For sources detected on 3 or more baselines, we determined accurate positions and evaluated their quality as potential calibrators. Most of the 1330 sources that were not detected with the VLBA are probably of extragalactic origin.

  17. Accurate extragalactic distances and dark energy: anchoring the distance scale with rotational parallaxes

    Science.gov (United States)

    Olling, Rob P.

    2007-07-01

    We investigate how the current and future uncertainty on the Hubble constant affects the uncertainty in the equation of state (EOS) of dark energy (DE) (w) and the total density of the Universe (Ωtot). We start with the approximate linear relations between the cosmological parameters as presented by Spergel et al., and use the s.e. propagation relations to estimate the effects of improving the cosmic microwave background (CMB) parameters as well as the Hubble constant (H0) on our knowledge of the EOS of DE. Because we do not assume a flat universe, we also estimate the attainable accuracy on Ωtot and the spatial curvature of the Universe. In one limiting case, we assume that the constraints provided by additional data (galaxy clustering, weak lensing and so forth) do not improve significantly, while the error on the Hubble constant is decreased by a factor of up to 10. The other limiting case of significantly improved additional data with current H0 errors has been investigated by the Dark Energy Task Force (DETF). For the former scenario, we find that future improvements of the determination of the CMB hardly changes the accuracy with which the EOS and Ωtot are known, unless the Hubble constant can be measured with an accuracy of several per cent. The conclusion of the DETF is that the Hubble constant hardly matters if the additional data are sufficiently accurate. We find that a combination of moderate H0 improvements with moderately improved `other' data might significantly constrain the evolution of DE, but at a reduced cost. We review in some detail several methods that might yield extragalactic distances with errors of the order of several per cent, where we focus on the current and future strengths and weaknesses of the methods. Specifically we review the following: the velocity field method, two maser methods, four light echo techniques, two binary star methods and the `rotational parallax' (RP) technique. Because these methods substantially rely on

  18. Infrared Constraints on AGN Tori Models

    CERN Document Server

    Hatziminaoglou, E; Pérez-Fournon, I; Franceschini, A; Hernan-Caballero, A; Afonso-Luis, A; Lonsdale, C; Fang, F; Oliver, S; Rowan-Robinson, M; Shupe, D; Smith, H; Surace, J; Gonzales-Solares, E

    2006-01-01

    This work focuses on the properties of dusty tori in active galactic nuclei (AGN) derived from the comparison of SDSS type 1 quasars with mid-Infrared (MIR) counterparts and a new, detailed torus model. The infrared data were taken by the Spitzer Wide-area InfraRed Extragalactic (SWIRE) Survey. Basic model parameters are constraint, such as the density law of the graphite and silicate grains, the torus size and its opening angle. A whole variety of optical depths is supported. The favoured models are those with decreasing density with distance from the centre, while there is no clear tendency as to the covering factor, ie small, medium and large covering factors are almost equally distributed. Based on the models that better describe the observed SEDs, properties such as the accretion luminosity, the mass of dust, the inner to outer radius ratio and the hydrogen column density are computed.

  19. Multi-Color Anisotropy Measurements of the Cosmic Near-Infrared Extragalactic Background Light with CIBER2

    Science.gov (United States)

    Bock, James

    We propose to carry out a program of observations with the Cosmic Infrared Background Experiment (CIBER-2), a sounding rocket instrument designed to measure anisotropy in the extragalactic background light in multiple optical to near-infrared spectral bands. Scientifically, CIBER-2 follows on the results of CIBER-1, which has detected near-infrared background anisotropy. CIBER-1 has also produced leading results on the absolute brightness of the background, the spectrum of diffuse galactic light, the spectrum of Zodiacal light, and constraints on the Zodiacal light foreground from Fraunhofer line observations. CIBER-2 builds on the measurement techniques developed and successfully demonstrated by CIBER-1. With high-sensitivity, multi-color anisotropy measurements, CIBER-2 will elucidate the history of interhalo light production and carry out a deep search for extragalactic background fluctuations associated with the epoch of reionization. A plausible interpretation of the infrared background anisotropy detected by CIBER-1, Spitzer and AKARI is interhalo light from stars tidally stripped from their parent galaxies during galaxy mergers. Based on the rms amplitude of the anisotropy, interhalo light produces approximately half of the background, representing a major branch of light production. Probing the history of interhalo light through improved anisotropy measurements using multiple bands and correlating with tracers of large-scale structure is essential to understand its role in the cosmic history of star formation. The first generation of stars and their remnants are likely responsible for the reionization of the intergalactic medium, observed to be ionized out to distant quasars at a redshift of 6. The total luminosity produced by first stars is uncertain, but a lower limit can be placed assuming a minimal number of photons to produce and sustain reionization. This 'minimal' extragalactic background component associated with reionization is detectable in

  20. Assembling the Infrared Extragalactic Background Light with CIBER-2: Probing Inter-Halo Light and the Epoch of Reionization.

    Science.gov (United States)

    Bock, James

    We propose to carry out a program of observations with the Cosmic Infrared Background Experiment (CIBER-2). CIBER-2 is a near-infrared sounding rocket experiment designed to measure spatial fluctuations in the extragalactic background light. CIBER-2 scientifically follows on the detection of fluctuations with the CIBER-1 imaging instrument, and will use measurement techniques developed and successfully demonstrated by CIBER-1. With high-sensitivity, multi-band imaging measurements, CIBER-2 will elucidate the history of interhalo light (IHL) production and carry out a deep search for extragalactic background fluctuations associated with the epoch of reionization (EOR). CIBER-1 has made high-quality detections of large-scale fluctuations over 4 sounding rocket flights. CIBER-1 measured the amplitude and spatial power spectrum of fluctuations, and observed an electromagnetic spectrum that is close to Rayleigh-Jeans, but with a statistically significant turnover at 1.1 um. The fluctuations cross-correlate with Spitzer images and are significantly bluer than the spectrum of the integrated background derived from galaxy counts. We interpret the CIBER-1 fluctuations as arising from IHL, low-mass stars tidally stripped from their parent galaxies during galaxy mergers. The first generation of stars and their remnants are likely responsible for the for the reionization of the intergalactic medium, observed to be ionized out to the most distant quasars at a redshift of 6. The total luminosity produced by first stars is uncertain, but a lower limit can be placed assuming a minimal number of photons to produce and sustain reionization. This 'minimal' extragalactic background component associated with reionization is detectable in fluctuations at the design sensitivity of CIBER-2. The CIBER-2 instrument is optimized for sensitivity to surface brightness in a short sounding rocket flight. The instrument consists of a 28 cm wide-field telescope operating in 6 spectral bands

  1. The energy spectrum, time history, and IPN error ellipse of GRB051103, a possible extragalactic SGR giant flare

    CERN Document Server

    Hurley, K; Perley, D; Mitrofanov, I G; Golovin, D V; Kozyrev, A S; Litvak, M L; Sanin, A B; Boynton, W; Fellows, C; Harshmann, K; Ohno, M; Yamaoka, K; Nakagawa, Y E; Smith, D M; Cline, T; Gehrels, N; Krimm, H; Palmer, D M; Duncan, R C; Wigger, C; Hajdas, W; Atteia, J -L; Ricker, G; Vanderspek, R; Rau, A; Von Kienlin, A

    2009-01-01

    GRB051103 is considered to be a candidate soft gamma repeater (SGR) extragalactic giant magnetar flare by virtue of its time history, localization, and energy spectrum. We have derived a refined interplanetary network localization for this burst which reduces the size of the error box by over a factor of two. We examine its time history for evidence of a periodic component, which would be one signature of an SGR giant flare, and conclude that this component is neither detected nor detectable under reasonable assumptions. We analyze the time-resolved energy spectra of this event with improved time- and energy resolution, and conclude that although the spectrum is very hard, its temporal evolution at late times cannot be determined, which further complicates the giant flare association.

  2. Can periodicity in low altitude cloud cover be induced by cosmic ray variability in the extragalactic shock model?

    CERN Document Server

    Atri, Dimitra; Melott, Adrian L; Kansas, University of; University, Washburn

    2010-01-01

    Variation in high energy cosmic rays (HECRs) has been proposed to explain a 62 My periodicity in terrestrial fossil biodiversity. It has been suggested that the infall of our galaxy toward the Virgo cluster could generate an extragalactic shock, accelerating charged particles and exposing the earth to a flux of high energy cosmic rays (HECRs). The oscillation of the Sun perpendicular to the galactic plane could induce 62 My periodicity in the HECR flux on the Earth, with a magnitude much higher than the Galactic cosmic ray change we see in a solar cycle. This mechanism could potentially explain the observed 62 My periodicity in terrestrial biodiversity over the past 500 My. In addition to direct effects on life from secondaries, HECRs induced air showers ionize the atmosphere leading to changes in atmospheric chemistry and microphysical processes that can lead to cloud formation including low altitude cloud cover. An increase in ionization changes the global electric circuit which could enhance the formation ...

  3. Detecting the cosmic web with radio surveys

    CERN Document Server

    Vazza, F; Gheller, C; Ferrari, C; Bonafede, A

    2016-01-01

    We study the challenges to detect the cosmic web at radio wavelengths with state-of-the-art cosmological simulations of extragalactic magnetic fields. The incoming generation of radio surveys operating at low frequency, like LOFAR, SKA-LOW and MWA will have the best chance to detect the large-scale, low surface brightness emission from the shocked cosmic web. The detected radio emission will enable to constrain the average magnetisation level of the gas in filaments and the acceleration efficiency of electrons by strong shocks. In case of detections, through statistical modelling (e.g. correlation functions) it will be possible to discriminate among competing scenarios for the magnetisation of large-scale structures (i.e. astrophysical versus primordial scenarios), making radio surveys an important probe of cosmic magnetogenesis.

  4. Limits of noise and confusion in the MWA GLEAM year 1 survey

    CERN Document Server

    Franzen, T M O; Callingham, J R; Ekers, R D; Hancock, P J; Hurley-Walker, N; Morgan, J; Seymour, N; Wayth, R B; White, S V; Bell, M E; Dwarakanath, K S; For, B; Gaensler, B M; Hindson, L; Johnston-Hollitt, M; Kapinska, A D; Lenc, E; McKinley, B; Offringa, A R; Procopio, P; Staveley-Smith, L; Wu, C; Zheng, Q

    2016-01-01

    The GaLactic and Extragalactic All-sky MWA survey (GLEAM) is a new relatively low resolution, contiguous 72-231 MHz survey of the entire sky south of declination +25 deg. In this paper, we outline one approach to determine the relative contribution of system noise, classical confusion and sidelobe confusion in GLEAM images. An understanding of the noise and confusion properties of GLEAM is essential if we are to fully exploit GLEAM data and improve the design of future low-frequency surveys. Our early results indicate that sidelobe confusion dominates over the entire frequency range, implying that enhancements in data processing have the potential to further reduce the noise.

  5. A WISE Measurement of the 2:4 mum Galaxy Luminosity Function and its Implications for the Extragalactic Background Light at 3:4 mum

    Science.gov (United States)

    Lake, Sean Earl

    2017-05-01

    The measurement of the the Extragalactic Background Light (EBL) has seen some controversy in recent works, with direct and indirect measures conflicting. Specifi- cally, upper limits based on analyzing the plausible opacity obscuring TeV spectra of blazars suggests that the density of radiation with wavelengths near 3.4 mum is onethirdtoonehalfasintenseasdirectmeasuresofthesame(forexample: Aharonian et al., 2006; Levenson et al., 2007; Matsumoto et al., 2005). The dominant contributor of the EBL at 3.4mum is expected to be ordinary starlight from relatively local, z EBL. While analyses of this sort have been done by others (Dominguez et al., 2011; Helgason et al., 2012), the full sky coverage of the AllWISE database has made it possible for us to improve the measurement of both the LF at 2.4 mum and the EBL using the large public spectroscopic redshift surveys. In order to do so, we had to develop a mathematical model for the measurement of a generalization of the LF, which is the density of galaxies per unit comoving volume per unit luminosity, to the Spectro-Luminosity Functional (SLF), which replaces the density per unit single luminosity, dL, with the density per luminosi- ii ties at all frequencies, DL nu. Our best combined analysis of the data yields present day Shechter Function LF parameters of: L⋆ = 6.4+/-[0.1 stat, 0.3sys]x1010 L2.4mum [solar mass](M⋆ = -21.67+/-[0.02 stat, 0.05sys] AB mag), φ⋆ = 5.8+/-[0.3stat, 0.3sys]x10 -3 Mpc-3, and alpha = -1.050 +/- [0.004stat, 0.03sys]; this implies a present day density of galaxies of 0.08 Mpc-3 brighter that 106 L2.4mum [solar mass] (10-3 Mpc-3 brighter than L⋆) and a luminosity density equivalent to 3.8 x 108 L2.4mum [solar mass] Mpc-3. The net EBL at 3.4mum that our synthesis model produces from galaxies closer than z = 5 is Inu = 9.0 +/- 0.5 kJy sr-1 (nuInu = 8.0 +/- 0.4 nW m-2 sr -1), largely in agreement with similar LF based estimates of the EBL.

  6. The extragalactic background and its fluctuations in the far-infrared wavelengths

    CERN Document Server

    Lagache, G; Abergel, A; Bouchet, F R; Boulanger, F; Ciliegi, P; Clements, D L; Césarsky, C J; Désert, F X; Dole, H; Elbaz, D; Franceschini, A; Gispert, R; Guiderdoni, B; Haffner, L M; Harwit, M; Laureijs, R J; Lemke, D; Moorwood, A F M; Oliver, S; Reach, W T; Reynolds, R J; Rowan-Robinson, M; Stickel, M; Tufte, S L

    2000-01-01

    A Cosmic Far-InfraRed Background (CFIRB) has long been predicted that wouldtraces the intial phases of galaxy formation. It has been first detected byPuget et al.(1996) using COBE data and has been later confirmed by severalrecent studies (Fixsen et al. 1998, Hauser et al. 1998, Lagache et al. 1999).We will present a new determination of the CFIRB that uses for the first time,in addition to COBE data, two independent gas tracers: the HI survey ofLeiden/Dwingeloo (hartmann, 1998) and the WHAM H$_{\\alpha}$ survey (Reynolds etal 1998). We will see that the CFIRB above 100 micron is now very wellconstrained. The next step is to see if we can detect its fluctuations. Tosearch for the CFIRB fluctuations, we have used the FIRBACK observations.FIRBACK is a deep cosmological survey conducted at 170 micron with ISOPHOT(Dole et al., 2000). We show that the emission of unresolved extra-galacticsources clearly dominates, at arcminute scales, the background fluctuations inthe lowest galactic emission regions. This is the f...

  7. The Spitzer Survey of Interstellar Clouds in the Gould Belt. VI. The Auriga-California Molecular Cloud observed with IRAC and MIPS

    CERN Document Server

    Broekhoven-Fiene, Hannah; Harvey, Paul M; Gutermuth, Robert A; Huard, Tracy L; Tothill, Nicholas F H; Nutter, David; Bourke, Tyler L; DiFrancesco, James; Jørgensen, Jes K; Allen, Lori E; Chapman, Nicholas L; Dunham, Michael M; Merın, Bruno; Miller, Jennifer F; Terebey, Susan; Peterson, Dawn E; Stapelfeldt, Karl R

    2014-01-01

    We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70 and 160 micron observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 sq-deg with IRAC and 10.47 sq-deg with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkHalpha 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the fraction of YSOs in the region with disks relative to an estimate of the diskless YS...

  8. The Spitzer Survey of Interstellar Clouds in the Gould Belt. VI. The Auriga-California Molecular Cloud Observed with IRAC and MIPS

    Science.gov (United States)

    Broekhoven-Fiene, Hannah; Matthews, Brenda C.; Harvey, Paul M.; Gutermuth, Robert A.; Huard, Tracy L.; Tothill, Nicholas F. H.; Nutter, David; Bourke, Tyler L.; DiFrancesco, James; Jorgensen, Jes K.; Allen, Lori E.; Chapman, Nicholas L.; Dunham, Michael M.; Merin, Bruno; Miller, Jennifer F.; Terebey, Susan; Peterson, Dawn E.; Stapelfeldt, Karl R.

    2014-01-01

    We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70 and 160 micrometers observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg(exp 2) with IRAC and 10.47 deg2 with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkH(alpha) 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the fraction of YSOs in the region with disks relative to an estimate of the diskless YSO population. Although the AMC is similar in mass, size and distance to the OMC, it is forming about 15 - 20 times fewer stars.

  9. The Spitzer survey of interstellar clouds in the gould belt. VI. The Auriga-California molecular cloud observed with IRAC and MIPS

    Energy Technology Data Exchange (ETDEWEB)

    Broekhoven-Fiene, Hannah; Matthews, Brenda C. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada); Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Huard, Tracy L.; Miller, Jennifer F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Tothill, Nicholas F. H. [School of Computing, Engineering and Mathematics, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Nutter, David [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); DiFrancesco, James [National Research Council Herzberg Astronomy and Astrophysics, Victoria, BC, V9E 2E7 (Canada); Jørgensen, Jes K. [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-DK-2100 Copenhagen Ø. (Denmark); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Chapman, Nicholas L. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Dunham, Michael M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Merín, Bruno [Herschel Science Centre, ESAC-ESA, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); and others

    2014-05-01

    We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg{sup 2} with IRAC and 10.47 deg{sup 2} with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkHα 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the relative fraction of YSOs in earlier (Class I and F) and later (Class II) classes compared to other clouds. We perform simple SED modeling of the YSOs with disks to compare the mid-IR properties to disks in other clouds and identify 14 classical transition disk candidates. Although the AMC is similar in mass, size, and distance to the OMC, it is forming about 15-20 times fewer stars.

  10. Recent Developments in Astrophysical and Cosmological Exploitation of Microwave Surveys

    DEFF Research Database (Denmark)

    Burigana, Carlo; Davies, Rodney D.; De Bernardis, Paolo

    2013-01-01

    In this paper, we focus on the astrophysical results and the related cosmological implications derived from recent microwave surveys, with emphasis to those coming from the Planck mission. We critically discuss the impact of systematic effects and the role of methods to separate the cosmic...... microwave background (CMB) signal from the astrophysical emissions and each different astrophysical component from the others. We then review the state-of-the-art diffuse emissions, extragalactic sources, cosmic infrared background and galaxy clusters, addressing the information they provide to our global...

  11. The KPNO International Spectroscopic Survey. V. H-alpha-selected Survey List 3

    CERN Document Server

    Jangren, A; Sarajedini, V L; Gronwall, C; Werk, J K; Chomiuk, L; Moody, J W; Boroson, T A; Jangren, Anna; Salzer, John J.; Sarajedini, Vicki L.; Gronwall, Caryl; Werk, Jessica K.; Chomiuk, Laura; Boroson, Todd A.

    2005-01-01

    The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey designed to detect extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is the first purely digital objective-prism survey for emission-line galaxies (ELGs). Here we present the third list of ELG candidates selected from our red spectral data, which cover the wavelength range 6400 to 7200 A. In most cases, the detected emission line is H-alpha. The current survey list covers the region of the NOAO Deep Wide-Field Survey (NDWFS). This survey covers two fields; the first is 3 x 3 degrees square and located at RA = 14h 30m, DEC = 34.5 deg (B1950), the second is 2.3 x 4.0 degrees and centered at RA = 2h 7.5m, DEC = -4.75 deg. A total area of 19.65 deg^2 is covered by the KISS data. A total of 261 candidate emission-line objects have been selected for inclusion in the survey list (13.3 per deg^2). We tabulate accurate coordinate...

  12. (Almost) Dark HI Sources in the ALFALFA Survey: The Intriguing Case of HI1232+20

    CERN Document Server

    Janowiecki, Steven; Jozsa, Gyula; Salzer, John J; Haynes, Martha P; Giovanelli, Riccardo; Rhode, Katherine L; Cannon, John M; Adams, Elizabeth A K; Janesh, William F

    2015-01-01

    We report the discovery and follow-up observations of a system of three objects identified by the ALFALFA extragalactic HI survey, cataloged as (almost) dark extragalactic sources, i.e., extragalactic HI detections with no discernible counterpart in publicly available, wide-field, imaging surveys. We have obtained deep optical imaging with WIYN pODI and HI synthesis maps with WSRT of the HI1232+20 system. The source with the highest HI flux has a newly discovered ultra-low surface brightness (LSB) optical counterpart associated with it, while the other two sources have no detected optical counterparts in our images. Our optical observations show that the detected LSB optical counterpart has a peak surface brightness of ~26.4 mag/arcsec^2 in g', which is exceptionally faint. This source (AGC 229385) has the largest accurately measured HI mass-to-light ratio of an isolated object: MHI/Lg'=46 Msun/Lsun, and has an HI mass of 7.2*10^8 Msun. The other two HI sources (with HI masses 2.0*10^8 and 1.2*10^8 Msun) with...

  13. Planck intermediate results: XLV. Radio spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Aller, H. D.

    2016-01-01

    ground-based radio observations between 1.1 and 37 GHz. The single-survey Planck data confirm that the flattest high-frequency radio spectral indices are close to zero, indicating that the original accelerated electron energy spectrum is much harder than commonly thought, with power-law index around 1.......5 instead of the canonical 2.5. The radio spectra peak at high frequencies and exhibit a variety of shapes. For a small set of low-z sources, we find a spectral upturn at high frequencies, indicating the presence of intrinsic cold dust. Variability can generally be approximated by achromatic variations...

  14. Extragalactic large-scale structures in the northern Zone of Avoidance

    CERN Document Server

    Ramatsoku, M; Schröder, A C; van Driel, W

    2014-01-01

    We used the Nan\\c{c}ay Radio Telescope (NRT) to measure the 21 cm line emission of near-infrared bright galaxies in the northern Zone of Avoidance (ZoA) without previous redshift determinations. We selected galaxies with extinction-corrected magnitudes $K_s^o \\leq 11\\hbox{$.\\!\\!^{\\rm m}$}25$ from the 2MASS Extended Source Catalog. These data will complement the existing 2MASS Redshift Survey (2MRS; first data release) as well as the ongoing 2MASS Tully-Fisher survey, both of which exclude the inner ZoA ($|b|< 5^{\\circ}$), where the identification of galaxy candidates is the hardest. Of the $\\sim$1000 identified 2MASX galaxy candidates we have so far detected 252 to our 3.0 mJy rms sensitivity limit and the velocity limit of 10500 km/s. The resulting redshift distribution reveals various new structures that were hitherto uncharted. They seem to form part of the larger Perseus-Pisces Supercluster (PPS). The most conspicuous is a ridge at about $\\ell\\approx 160^{\\circ}$,$v \\approx 6500$ km/s. Within this wall...

  15. Extragalactic Science and Cosmology with the Subaru Prime Focus Spectrograph (PFS)

    CERN Document Server

    Ellis, Richard; Aihara, Hiroaki; Arimoto, Nobuo; Bundy, Kevin; Chiba, Masashi; Cohen, Judith; Dore, Olivier; Greene, Jenny E; Gunn, James; Heckman, Timothy; Hirata, Chris; Ho, Paul; Kneib, Jean-Paul; Fevre, Olivier Le; Murayama, Hitoshi; Nagao, Tohru; Ouchi, Masami; Seiffert, Michael; Silverman, John; Sodre, Laerte; Spergel, David; Strauss, Michael A; Sugai, Hajime; Suto, Yasushi; Takami, Hideki; Wyse, Rosemary

    2012-01-01

    The Subaru Prime Focus Spectrograph (PFS) is a massively-multiplexed fiber-fed optical and near-infrared spectrograph (N=2400, 380survey astronomy. Following a successful CoDR, the instrument is now under construction with first light predicted in late 2017. Here we summarize the science case for this unique instrument anticipating a Subaru Strategic Program of about 300 nights. We describe plans to constrain the nature of dark energy via a survey of emission line galaxies spanning a comoving volume of 9.3(Gpc/h)^3 for 0.8

  16. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: II. Extragalactic far infrared background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using formula to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15-2.4 THz frequency interval at mean temperature T=18.5 K, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure are calculated. The value for the total intensity received in the 0.15-2.4 THz frequency interval is equal to 13.6 nW m-2 sr-1. This value is about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z=1.5.

  17. The cosmic infrared background experiment-2 (CIBER-2) for studying the near-infrared extragalactic background light

    Science.gov (United States)

    Shirahata, Mai; Arai, Toshiaki; Battle, John; Bock, James; Cooray, Asantha; Enokuchi, Akito; Hristov, Viktor; Kanai, Yoshikazu; Kim, Min Gyu; Korngut, Phillip; Lanz, Alicia; Lee, Dae-Hee; Mason, Peter; Matsumoto, Toshio; Matsuura, Shuji; Morford, Tracy; Ohnishi, Yosuke; Park, Won-Kee; Sano, Kei; Takeyama, Norihide; Tsumura, Kohji; Wada, Takehiko; Wang, Shiang-Yu; Zemcov, Michael

    2016-07-01

    We present the current status of the Cosmic Infrared Background ExpeRiment-2 (CIBER-2) project, whose goal is to make a rocket-borne measurement of the near-infrared Extragalactic Background Light (EBL), under a collaboration with U.S.A., Japan, South Korea, and Taiwan. The EBL is the integrated light of all extragalactic sources of emission back to the early Universe. At near-infrared wavelengths, measurement of the EBL is a promising way to detect the diffuse light from the first collapsed structures at redshift z˜10, which are impossible to detect as individual sources. However, recently, the intra-halo light (IHL) model is advocated as the main contribution to the EBL, and our new result of the EBL fluctuation from CIBER-1 experiment is also supporting this model. In this model, EBL is contributed by accumulated light from stars in the dark halo regions of low- redshift (zCIBER- 1 experiment, we are now developing a new instrument CIBER-2, which is comprised of a 28.5-cm aluminum telescope and three broad-band, wide-field imaging cameras. The three wide-field (2.3×2.3 degrees) imaging cameras use the 2K×2K HgCdTe HAWAII-2RG arrays, and cover the optical and near-infrared wavelength range of 0.5-0.9 μm, 1.0-1.4 μm and 1.5-2.0 μm, respectively. Combining a large area telescope with the high sensitivity detectors, CIBER-2 will be able to measure the spatial fluctuations in the EBL at much fainter levels than those detected in previous CIBER-1 experiment. Additionally, we will use a linear variable filter installed just above the detectors so that a measurement of the absolute spectrum of the EBL is also possible. In this paper, the scientific motivation and the expected performance for CIBER-2 will be presented. The detailed designs of the telescope and imaging cameras will also be discussed, including the designs of the mechanical, cryogenic, and electrical systems.

  18. THE NEXT GENERATION VIRGO CLUSTER SURVEY (NGVS). I. INTRODUCTION TO THE SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Ferrarese, Laura; Cote, Patrick; Gwyn, S. D. J.; MacArthur, Lauren A.; McConnachie, Alan W.; Blakeslee, John P. [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC, V9E 2E7 (Canada); Cuillandre, Jean-Charles [Canada-France-Hawaii Telescope Corporation, Kamuela, HI 96743 (United States); Peng, Eric W. [Department of Astronomy, Peking University, Beijing 100871 (China); Duc, Pierre-Alain [AIM Paris Saclay, CNRS/INSU, CEA/Irfu, Universite Paris Diderot, Orme des Merisiers, F-91191 Gif sur Yvette cedex (France); Boselli, A. [Laboratoire d' Astrophysique de Marseille, UMR 6110 CNRS, 38 rue F. Joliot-Curie, F-13388 Marseille (France); Mei, Simona [GEPI, Observatoire de Paris, CNRS, 5 Place Jules Jannssen, F-92195 Meudon (France); Erben, Thomas [Argelander-Institut fuer Astronomie, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Durrell, Patrick R. [Department of Physics and Astronomy, Youngstown State University, Youngstown, OH (United States); Christopher Mihos, J. [Department of Astronomy, Case Western Reserve University, Cleveland, OH (United States); Jordan, Andres; Puzia, Thomas H. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, 7820436 Macul, Santiago (Chile); Lancon, Ariane [Observatoire Astronomique, Universite de Strasbourg and CNRS UMR 7550, 11 rue de l' Universite, F-67000 Strasbourg (France); Emsellem, Eric [Universite de Lyon 1, CRAL, Observatoire de Lyon, 9 av. Charles Andre, F-69230 Saint-Genis Laval (France); CNRS, UMR 5574, ENS de Lyon (France); Balogh, Michael L. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Van Waerbeke, Ludovic [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C., V6T 1Z1 (Canada); and others

    2012-05-01

    The Next Generation Virgo Cluster Survey (NGVS) is a program that uses the 1 deg{sup 2} MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical imaging survey of the Virgo cluster, from its core to its virial radius-covering a total area of 104 deg{sup 2}-in the u*griz bandpasses. Thanks to a dedicated data acquisition strategy and processing pipeline, the NGVS reaches a point-source depth of g Almost-Equal-To 25.9 mag (10{sigma}) and a surface brightness limit of {mu}{sub g} {approx} 29 mag arcsec{sup -2} (2{sigma} above the mean sky level), thus superseding all previous optical studies of this benchmark galaxy cluster. In this paper, we give an overview of the technical aspects of the survey, such as areal coverage, field placement, choice of filters, limiting magnitudes, observing strategies, data processing and calibration pipelines, survey timeline, and data products. We also describe the primary scientific topics of the NGVS, which include: the galaxy luminosity and mass functions; the color-magnitude relation; galaxy scaling relations; compact stellar systems; galactic nuclei; the extragalactic distance scale; the large-scale environment of the cluster and its relationship to the Local Supercluster; diffuse light and the intracluster medium; galaxy interactions and evolutionary processes; and extragalactic star clusters. In addition, we describe a number of ancillary programs dealing with 'foreground' and 'background' science topics, including the study of high-inclination trans-Neptunian objects; the structure of the Galactic halo in the direction of the Virgo Overdensity and Sagittarius Stream; the measurement of cosmic shear, galaxy-galaxy, and cluster lensing; and the identification of distant galaxy clusters, and strong-lensing events.

  19. Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources

    CERN Document Server

    Anderson, C S; Feain, I J; Franzen, T M O

    2015-01-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 \\& 2.0 GHz using data taken with the Australia Telescope Compact Array (ATCA). We have used rotation measure synthesis to identify Faraday complex polarized sources --- i.e. objects whose frequency-dependent polarization behaviour indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday simple polarized sources (i.e. sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12\\% of polarized sources at $\\sim1'$ resolution, but demonstrate that underlying signal-to-noise limitations...

  20. The Angstrom Project Alert System: real-time detection of extragalactic microlensing

    CERN Document Server

    Darnley, M J; Newsam, A; Duke, J P; Gould, A; Han, C; Ibrahimov, M A; Im, M; Jeon, Y B; Karimov, R G; Lee, C U; Park, B G

    2006-01-01

    The Angstrom Project is undertaking an optical survey of stellar microlensing events across the bulge region of the Andromeda Galaxy (M31) using a distributed network of two-meter class telescopes. The Angstrom Project Alert System (APAS) has been developed to identify in real time candidate microlensing and transient events using data from the Liverpool and Faulkes North robotic telescopes. This is the first time that real-time microlensing discovery has been attempted outside of the Milky Way and its satellite galaxies. The APAS is designed to enable follow-up studies of M31 microlensing systems, including searches for gas giant planets in M31. Here we describe the APAS and we present a few example light curves obtained during its commissioning phase which clearly demonstrate its real-time capability to identify microlensing candidates as well as other transient sources.

  1. Deriving Metallicities From the Integrated Spectra of Extragalactic Globular Clusters Using the Near-Infrared Calcium Triplet

    CERN Document Server

    Foster, Caroline; Proctor, Robert N; Strader, Jay; Brodie, Jean P; Spitler, Lee R

    2010-01-01

    The Ca triplet (CaT) feature in the near-infrared has been employed as a metallicity indicator for individual stars as well as integrated light of Galactic globular clusters (GCs) and galaxies with varying degrees of success, and sometimes puzzling results. Using the DEIMOS multi-object spectrograph on Keck we obtain a sample of 144 integrated light spectra of GCs around the brightest group galaxy NGC 1407 to test whether the CaT index can be used as a metallicity indicator for extragalactic GCs. Different sets of single stellar population models make different predictions for the behavior of the CaT as a function of metallicity. In this work, the metallicities of the GCs around NGC 1407 are obtained from CaT index values using an empirical conversion. The measured CaT/metallicity distributions show unexpected features, the most remarkable being that the brightest red and blue GCs have similar CaT values despite their large difference in mean color. Suggested explanations for this behavior in the NGC 1407 GC ...

  2. Galactic HI on the 50-AU scale in the direction of three extra-galactic sources observed with MERLIN

    CERN Document Server

    Goss, W M; Muxlow, T W B; Thomasson, P

    2008-01-01

    We present MERLIN observations of Galactic 21-cm HI absorption at an angular resolution of c. 0.1-0.2 arcsec and a velocity resolution of 0.5 km/s, in the direction of three moderately low latitude (-8< b <-12 deg) extragalactic radio sources, 3C111, 3C123 and 3C161, all of which are heavily reddened. HI absorption is observed against resolved background emission sources up to c. 2 arcsec in extent and we distinguish details of the opacity distribution within 1-1.5 arcsec regions towards 3C~123 and 3C~161. This study is the second MERLIN investigation of small scale structure in interstellar HI (earlier work probed Galactic HI in the directions of the compact sources 3C138 and 3C147). The 0.1-arcsec scale is intermediate between HI absorption studies made with other fixed element interferometers with resolution of 1 to 10 arcsec and VLBI studies with resolutions of 10-20 milli-arcsec. At a scale of 1 arcsec (about 500 AU), prominent changes in Galactic HI opacity in excess of 1-1.5 are determined in the...

  3. Extragalactic background light absorption signal in the 0.26-10 TeV spectra of blazars

    CERN Document Server

    Vasilev, V

    1999-01-01

    Recent observations of the TeV gamma-ray spectra of the two closest active galactic nuclei (AGNs), Markarian 501 (Mrk 501) and Markarian 421 (Mrk 421), by the Whipple and HEGRA collaborations have stimulated efforts to estimate or limit the spectral energy density (SED) of extragalactic background light (EBL) which causes attenuation of TeV photons via pair-production when they travel cosmological distances. In spite of the lack of any distinct cutoff-like feature in the spectra of Mrk 501 and Mrk 421 (in the interval 0.26-10 TeV) which could clearly indicate the presence of such a photon absorption mechanism, we demonstrate that strong EBL attenuation signal (survival probability of 10 TeV photon (~10^{-2}) may still be present in the spectra of these AGNs. This attenuation could escape detection due to a special form of SED of EBL and unknown intrinsic spectra of these blazars. Here we show how the proposed and existing experiments, VERITAS, HESS, MAGIC, STACEE and CELESTE may be able to detect or severely ...

  4. EleCa: a Monte Carlo code for the propagation of extragalactic photons at ultra-high energy

    CERN Document Server

    Settimo, Mariangela

    2013-01-01

    Ultra high energy photons play an important role as an independent probe of the photo-pion production mechanism by UHE cosmic rays. Their observation, or non-observation, may constrain astrophysical scenarios for the origin of UHECRs and help to understand the nature of the flux suppression observed by several experiments at energies above 10$^{19.5}$ eV. Whereas the interaction length of UHE photons above 10$^{17}$ eV is only of a few hundred kpc up to tenths of Mpc, photons can interact with the extragalactic background radiation leading to the development of electromagnetic cascades which affect the fluxes of photons observed at Earth. The interpretation of the current experimental results rely on the simulations of the UHE photon propagation. In this contribution, we present the novel Monte Carlo code "EleCa" to simulate the \\emph{Ele}ctromagnetic \\emph{Ca}scading initiated by high-energy photons and electrons. The distance within which we expect to observe UHE photons is discussed and the flux of GZK pho...

  5. Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of their Matter Content

    CERN Document Server

    Georganopoulos, M; Perlman, E; Stecker, F; Georganopoulos, {Markos; Kazanas, Demosthenes; Perlman, Eric; Stecker, Floyd

    2005-01-01

    We propose a method for estimating the composition, i.e. the relative amounts of leptons and protons, of extragalactic jets which exhibit X-ray bright knots in their kpc scale jets. The method relies on measuring, or setting upper limits on, the component of the Cosmic Microwave Background (CMB) radiation that is bulk-Comptonized by cold electrons in the relativistically flowing jet. These measurements, along with modeling of the broadband knot emission that constrain the bulk Lorentz factor of the jets, can yield estimates of the jet power carried by protons and leptons. We provide an explicit calculation of the spectrum of the bulk-Comptonized (BC) CMB component and apply these results to PKS 0637--752 and 3C 273, two superluminal quasars with Chandra-detected large scale jets. What makes these sources particularly suited for such a procedure is the absence of significant non-thermal jet emission in the `bridge', the region between the core and the first bright jet knot, which guarantees that most of the el...

  6. Early Phase Detection and Coverage of Extragalactic and Galactic Black Hole X-ray Transients with the SKA

    CERN Document Server

    Yu, Wenfei; Yan, Zhen; Zhang, Wenda

    2015-01-01

    SKA's large field of view and high sensitivity at low frequencies will provide almost a complete coverage of the very early rising phase of extragalactic and Galactic transients which undergo a flare or outburst due to an abrupt accretion onto either supermassive (such as tidal disruption events, TDEs) or stellar mass black hole transients (such as black hole LMXB) , when their broadband emission is supposed to be jet-dominated at low luminosities, allowing SKA to be the first facility to make source discoveries and to send out alerts for follow-up ground or space observations as compared with the sensitivity of future X-ray wide-field-view monitoring. On the other hand, due to extremely large rate-of-change in the mass accretion rate during the rising phase of TDE flares or transient outbursts, SKA will be able to cover an extremely large range of the mass accretion rate as well as its rate-of-change not accessible with observations in persistent black hole systems, which will shape our understanding of disk...

  7. Spectroscopic Confirmation of Two Massive Red-sequence-selected Galaxy Clusters at Z Approximately Equal to 1.2 in the Sparcs-North Cluster Survey

    Science.gov (United States)

    Muzzin, Adam; Wilson, Gillian; Yee, H.K.C.; Hoekstra, Henk; Gilbank, David; Surace, Jason; Lacy, Mark; Blindert, Kris; Majumdar, Subhabrata; Demarco, Ricardo; Gardner, Jonathan P.; Gladders, Mike; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z -band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large homogeneously-selected sample of massive clusters at z > 1 using an infrared adaptation of the cluster red-sequence method. We present an overview of the northern component of the survey which has been observed with CFHT/MegaCam and covers 28.3 deg(sup 2). The southern component of the survey was observed with CTIO/MOSAICII, covers 13.6 deg(sup 2), and is summarized in a companion paper by Wilson et al. (2008). We also present spectroscopic confirmation of two rich cluster candidates at z approx. 1.2. Based on Nod-and- Shuffle spectroscopy from GMOS-N on Gemini there are 17 and 28 confirmed cluster members in SpARCS J163435+402151 and SpARCS J163852+403843 which have spectroscopic redshifts of 1.1798 and 1.1963, respectively. The clusters have velocity dispersions of 490 +/- 140 km/s and 650 +/- 160 km/s, respectively which imply masses (M(sub 200)) of (1.0 +/- 0.9) x 10(exp 14) Stellar Mass and (2.4 +/- 1.8) x 10(exp 14) Stellar Mass. Confirmation of these candidates as bonafide massive clusters demonstrates that two-filter imaging is an effective, yet observationally efficient, method for selecting clusters at z > 1.

  8. SPHEREx: An All-Sky Spectral Survey

    CERN Document Server

    Doré, Olivier; Capak, Peter; de Putter, Roland; Eifler, Tim; Hirata, Chris; Korngut, Phil; Krause, Elisabeth; Masters, Daniel; Raccanelli, Alvise; Zemcov, Mike; Cooray, Asantha; Flagey, Nicolas; Gong, Yan; Katti, Raj; Melnick, Gary; Mennesson, Bertrand; Unwin, Steve; Viero, Marco; Werner, Mike; Ashby, Matthew; Habib, Salman; Heitmann, Katrin; Lee, Dae-Hee; Jeong, Woong-Seob; Mauskopf, Phil; Nguyen, Hien; Öberg, Karin; Smith, Roger; Song, Yong-Seon; Tolls, Volker; Venumadhav, Tejaswi

    2014-01-01

    SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) is a proposed all-sky spectroscopic survey satellite designed to address all three science goals in NASA's Astrophysics Division: probe the origin and destiny of our Universe; explore whether planets around other stars could harbor life; and explore the origin and evolution of galaxies. SPHEREx will scan a series of Linear Variable Filters systematically across the entire sky. The SPHEREx data-set will contain R=40 spectra spanning the near infrared (0.75$\\mu$m$<\\lambda<$ 4.83$\\mu$m) for every 6.2 arcsecond pixel over the the entire-sky. In this paper, we detail the extra-galactic and cosmological studies SPHEREx will enable and present detailed systematic effect evaluations.

  9. The FLAMINGOS-2 Galactic Center Survey

    Science.gov (United States)

    Raines, Steven N.; Flamingos-2 Galactic Center Survey Team

    2010-03-01

    The FLAMINGOS-2 instrument achieved high-quality first-light observations on the Gemini South telescope in September 2009 and is undergoing further testing and scientific commissioning into early 2010. Based on the results so far, FLAMINGOS-2 (F2) on the Gemini 8-meter telescope is an extremely powerful wide-field near-infrared imager and multi-object spectrograph. In order to take best advantage of the strengths of F2 early in its life cycle, we propose to use 21 nights of Gemini guaranteed time in 3 surveys - the FLAMINGOS-2 Early Science Surveys (F2ESS). The F2ESS will encompass 3 corresponding scientific themes - the Galactic Center, extragalactic astronomy, and star formation. In particular, the Galactic Center Survey will identify the IR couterparts to several hundred new X-ray binaries in the Galactic Center. This will allow us to identify the nature of the mysterious Chandra source population in the Galactic Center and provide tremendous opportunities for multi-wavelength follow-up observations. In addition, the "by-catch" of this survey will be a catalog of several thousand red giant branch stars with accurate spectroscopy -- these can be used to measure the star formation history of the Galactic Center and thus constrain the mass evolution history of the supermassive black hole in Sgr A*. In this poster, I review the plans for carrying out this survey with F2, data analysis plans and software, and the expected scientific impact from this powerful new observational tool.

  10. Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources

    Science.gov (United States)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-12-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1‧ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  11. First Extragalactic Direct Detection of Large-Scale Molecular Hydrogen in the Disk of NGC 891

    Science.gov (United States)

    Valentijn, Edwin A.; van der Werf, Paul P.

    1999-09-01

    We present direct observations of molecular hydrogen in the disk of the nearby edge-on spiral galaxy NGC 891. With Infrared Space Observatory's Short-Wavelength Spectrometer (SWS) it has been possible, for the first time, to observe the lowest pure rotational lines of H2 [S(0) at 28.2 μm and S(1) at 17.0 μm] at eight positions throughout the stellar disk of NGC 891. Both lines have been detected at all the surveyed positions out to 11 kpc north of the center of the galaxy. An H2 rotation curve is derived, and we compare H2 radial profiles with CO and H I data. The observed line ratios indicate relatively warm (T=150-230 K) molecular clouds scattered throughout the disk in addition to a massive cooler (T=80-90 K) component which dominates the signal in the outer regions. For H2 ortho/para ratios of 2-3, the cool gas has typical edge-on column densities (1-3)×1023 cm-2 (or ~3000 Msolar pc-2), in which case it outweighs the H I by a factor of 5-15. This factor matches well the mass required to resolve the problem of the missing matter of spiral galaxies within at least the optical disk. The newly discovered cool H2 component would be less massive in the case in which its dominant ortho/para ratio is near unity. We address the thermal balance of this component by a comparison with [C II] 158 μm data. When combining the new coolish molecular gas results with recent SCUBA cold dust observations of NGC 891, the total gas-to-dust ratio at rISO, an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) and with the participation of ISAS and NASA.

  12. BROADBAND RADIO POLARIMETRY AND FARADAY ROTATION OF 563 EXTRAGALACTIC RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Franzen, T. M. O., E-mail: craiga@physics.usyd.edu.au [CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia)

    2015-12-10

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1′ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  13. The KPNO International Spectroscopic Survey. III. [O III]-selected Survey List

    CERN Document Server

    Salzer, J J; Sarajedini, V L; Lipovetsky, V A; Kniazev, A Yu; Moody, J W; Boroson, T A; Thuan, T X; Izotov, Yu I; Herrero, J L; Frattare, L M; Salzer, John J.; Gronwall, Caryl; Sarajedini, Vicki L.; Lipovetsky, Valentin A.; Kniazev, Alexei; Boroson, Todd A.; Thuan, Trinh X.; Izotov, Yuri I.; Herrero, Jose L.; Frattare, Lisa M.

    2002-01-01

    The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey for extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is the first purely digital objective-prism survey for emission-line galaxies. Here we present the first list of emission-line galaxy candidates selected from our blue spectral data, which cover the wavelength range 4800 -- 5500 A. In most cases, the detected emission line is [O III]5007. The current survey list covers a one-degree-wide strip located at Dec = 29 deg 30' (B1950.0) and spanning the right ascension range 8h 30m to 17h 0m. An area of 116.6 deg^2 is covered. A total of 223 candidate emission-line objects have been selected for inclusion in the survey list (1.91 deg^-2). We tabulate accurate coordinates and photometry for each source, as well as estimates of the redshift, emission-line flux, and equivalent width based on measurements of the digital objectiv...

  14. Understanding nature's particle accelerators using high energy gamma-ray survey instruments

    Science.gov (United States)

    Abeysekara, Anushka Udara

    Nature's particle accelerators, such as Pulsars, Pulsar Wind Nebulae, Active Galactic Nuclei and Supernova Remnants accelerate charged particles to very high energies that then produce high energy photons. The particle acceleration mechanisms and the high energy photon emission mechanisms are poorly understood phenomena. These mechanisms can be understood either by studying individual sources in detail or, alternatively, using the collective properties of a sample of sources. Recent development of GeV survey instruments, such as Fermi-LAT, and TeV survey instruments, such as Milagro, provides a large sample of high energy gamma-ray flux measurements from galactic and extra-galactic sources. In this thesis I provide constraints on GeV and TeV radiation mechanisms using the X-ray-TeV correlations and GeV-TeV correlations. My data sample was obtained from three targeted searches for extragalactic sources and two targeted search for galactic sources, using the existing Milagro sky maps. The first extragalactic candidate list consists of Fermi-LAT GeV extragalactic sources, and the second extragalactic candidate list consists of TeVCat extragalactic sources that have been detected by Imaging Atmospheric Cerenkov Telescopes (IACTs). In both extragalactic candidate lists Markarian 421 was the only source detected by Milagro. A comparison between the Markarian 421 time-averaged flux, measured by Milagro, and the flux measurements of transient states, measured by IACTs, is discussed. The third extragalactic candidate list is a list of potential TeV emitting BL Lac candidates that was synthesized using X-ray observations of BL Lac objects and a Synchrotron Self-Compton model. Milagro's sensitivity was not sufficient to detect any of those candidates. However, the 95% confidence flux upper limits of those sources were above the predicted flux. Therefore, these results provide evidence to conclude that the Synchrotron Self-Compton model for BL Lac objects is still a viable

  15. Digital Sky Surveys from the ground: Status and Perspectives

    CERN Document Server

    Shanks, T

    2015-01-01

    I first review the status of Digital Sky Surveys. The focus will be on extragalactic surveys with an area of more than 100 sq.deg. The Sloan Digital Sky Survey is the archetype of such imaging surveys and it is its great success that has prompted great activity in this field. The latest surveys explore wider, fainter and higher resolution and also a longer wavelength range than SDSS. Many of these surveys overlap particularly in the S Hemisphere where we now have Pan-STARRS, DES and the ESO VST surveys, and our aim here is to compare their properties. Since there is no dedicated article on the VST ATLAS in this symposium, we shall especially review the properties of this particular survey. This easily fits onto our other main focus which is to compare overlapping Southern Surveys and see how they best fit with the available NIR imaging data. We conclude that the Southern Hemisphere will soon overtake the North in terms of multiwavelength imaging. However we note that the South has more limited opportunities f...

  16. VizieR Online Data Catalog: VISTA Deep Extragalactic Observations (VIDEO) (Jarvis+, 2013)

    Science.gov (United States)

    Jarvis, M. J.; Bonfield, D. G.; Bruce, V. A.; Geach, J. E.; McAlpine, K.; McLure, R. J.; Gonzalez-Solares, E.; Irwin, M.; Lewis, J.; Kupcu Yoldas, A.; Andreon, S.; Cross, N. J. G.; Emerson, J. P.; Dalton, G.; Dunlop, J. S.; Hodgkin, S. T.; Le, F. O.; Karouzos, M.; Meisenheimer, K.; Oliver, S.; Rawlings, S.; Simpson, C.; Smail, I.; Smith, D. J. B.; Sullivan, M.; Sutherland, W.; White, S. V.; Zwart, J. T. L.

    2014-11-01

    The released VIDEO data reach a 5σ AB-magnitude depth of Z=25.7, Y=24.5, J=24.4, H=24.1 and Ks=23.8 in 2 arcsec diameter apertures (the full depth of Y=24.6 will be reached within the full integration time in future releases). To the 5σ limit, the Ks catalog contains 198718 sources over 1.8 square degrees. The Ks-selected catalog provides band-merged photometry using the Ks-band as the detection image and extracting photometry from the shorter wavelength imaging data. The authors recommend using only those sources with KsJarvis et al., 2013MNRAS.428.1281J). In the Ks-selected band-merged catalog, columns where the value is "NaN" denote that the object was detected at the position of the Ks-band source with negative flux, this occurs over all apertures and filters for different objects, but is mostly a problem for the larger aperture. The VIDEO survey was specifically designed to enable the evolution of galaxies and large structures to be traced as a function of both epoch and environment from the pre sent day out to z=4, and active galactic nuclei (AGNs) and the most massive galaxies up to and into the epoch of reionization. With its depth and area, VIDEO is able to fully explore the period in the Universe where AGN and starburst activity were at their peak and the first galaxy clusters were beginning to virialize. VIDEO therefore offers a unique data set with which to investigate the interplay between AGN, starbursts and environment, and the role of feedback at a time when it was potentially most crucial. Acknowledging VIDEO in publications: Please use the following statement in any publication using these data: "Based on data products from observations made with ESO telescopes at the Las Silla Paranal Observatory under programme ID 179.A-2006." (1 data file).

  17. Bridging the Gap from Galactic to Extragalactic: Star Formation and Giant Molecular Clouds within the Nearby Spiral Galaxy NGC 300

    Science.gov (United States)

    Faesi, Christopher

    2017-01-01

    The questions surrounding the origins of stars are of key importance in astrophysics across a huge range in physical scales. However, until recently, investigations have been restricted to either detailed studies targeting a few nearby regions in the Milky Way, or kpc- or larger-scale studies of entire galaxies. Between these two scales lies a crucial gap in understanding. In this thesis work, I have taken steps in bridging this gap between Galactic and extragalactic star formation. I will present the results of a campaign of observations and modeling targeting the nearby spiral galaxy NGC 300. Using an extensive suite of multi-wavelength data I have characterized the star formation activity and molecular gas in a large sample of star-forming regions within this galaxy. Additionally, I have assembled an extensive (300 clouds) and high resolution (10 pc) catalog of Giant Molecular Clouds (GMCs) based on ALMA CO observations. This unprecedented look at the population of GMCs in a nearby spiral galaxy reveals an astonishing range of morphologies and properties in the Molecular Gas as well as providing a key testbed for comparison with GMCs in the Milky Way and other nearby galaxies. The GMCs in NGC 300 appear to have similar global properties and show scaling relations consistent with those seen in the Milky Way. Furthermore, the star formation rate appears to correlate with the mass of molecular gas with approximately 250 Gyr depletion time, extending the relation discovered in the Milky Way linearly to larger scales. These results suggest a level of universality in the star formation process within spiral galaxy disks like our own Milky Way.

  18. Globular clusters in the far-ultraviolet: evidence for He-enriched second populations in extragalactic globular clusters?

    Science.gov (United States)

    Peacock, Mark B.; Zepf, Stephen E.; Kundu, Arunav; Chael, Julia

    2017-01-01

    We investigate the integrated far-ultraviolet (FUV) emission from globular clusters. We present new FUV photometry of M87's clusters based on archival Hubble Space Telescope (HST) Wide Field Planetary Camera 2 F170W observations. We use these data to test the reliability of published photometry based on HST space telescope imaging spectrograph FUV-MAMA observations, which are now known to suffer from significant red-leak. We generally confirm these previous FUV detections, but suggest they may be somewhat fainter. We compare the FUV emission from bright (MV populations models. Metal-rich globular clusters show a large spread in FUV - V, with some clusters in M31, M81 and M87 being much bluer than standard predictions. This requires that some metal-rich clusters host a significant population of blue/extreme horizontal branch (HB) stars. These hot HB stars are not traditionally expected in metal-rich environments, but are a natural consequence of multiple populations in clusters - since the enriched population is observed to be He enhanced and will therefore produce bluer HB stars, even at high metallicity. We conclude that the observed FUV emission from metal-rich clusters in M31, M81 and M87 provides evidence that He-enhanced second populations, similar to those observed directly in the Milky Way, may be a ubiquitous feature of globular clusters in the local Universe. Future HST FUV photometry is required to both confirm our interpretation of these archival data and provide constraints on He-enriched second populations of stars in extragalactic globular clusters.

  19. New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

    Science.gov (United States)

    Matsuura, Shuji; Arai, Toshiaki; Bock, James J.; Cooray, Asantha; Korngut, Phillip M.; Kim, Min Gyu; Lee, Hyung Mok; Lee, Dae Hee; Levenson, Louis R.; Matsumoto, Toshio; Onishi, Yosuke; Shirahata, Mai; Tsumura, Kohji; Wada, Takehiko; Zemcov, Michael

    2017-04-01

    The extragalactic background light (EBL) captures the total integrated emission from stars and galaxies throughout the cosmic history. The amplitude of the near-infrared EBL from space absolute photometry observations has been controversial and depends strongly on the modeling and subtraction of the zodiacal light (ZL) foreground. We report the first measurement of the diffuse background spectrum at 0.8-1.7 μm from the CIBER experiment. The observations were obtained with an absolute spectrometer over two flights in multiple sky fields to enable the subtraction of ZL, stars, terrestrial emission, and diffuse Galactic light. After subtracting foregrounds and accounting for systematic errors, we find the nominal EBL brightness, assuming the Kelsall ZL model, is {42.7}-10.6+11.9 nW m-2 sr-1 at 1.4 μm. We also analyzed the data using the Wright ZL model, which results in a worse statistical fit to the data and an unphysical EBL, falling below the known background light from galaxies at λ EBL brightness, we find an EBL brightness of {28.7}-3.3+5.1 nWm-2 sr-1 at 1.4 μm. While the derived EBL amplitude strongly depends on the ZL model, we find that we cannot fit the spectral data to ZL, Galactic emission, and EBL from solely integrated galactic light from galaxy counts. The results require a new diffuse component, such as an additional foreground or an excess EBL with a redder spectrum than that of ZL.

  20. Planck intermediate results. VII. Statistical properties of infrared and radio extragalactic sources from the Planck Early Release Compact Source Catalogue at frequencies between 100 and 857 GHz

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Argüeso, F.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bethermin, M.; Bhatia, R.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Cabella, P.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, L.-Y.; Christensen, P. R.; Clements, D. L.; Colafrancesco, S.; Colombi, S.; Colombo, L. P. L.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Fosalba, P.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Jaffe, T. R.; Jaffe, A. H.; Jagemann, T.; Jones, W. C.; Juvela, M.; Keihänen, E.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurinsky, N.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lawrence, C. R.; Leonardi, R.; Lilje, P. B.; López-Caniego, M.; Macías-Pérez, J. F.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Mitra, S.; Miville-Deschènes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sajina, A.; Sandri, M.; Savini, G.; Scott, D.; Smoot, G. F.; Starck, J.-L.; Sudiwala, R.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Türler, M.; Valenziano, L.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; White, M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2013-02-01

    We make use of the Planck all-sky survey to derive number counts and spectral indices of extragalactic sources - infrared and radio sources - from the Planck Early Release Compact Source Catalogue (ERCSC) at 100 to 857 GHz (3 mm to 350 μm). Three zones (deep, medium and shallow) of approximately homogeneous coverage are used to permit a clean and controlled correction for incompleteness, which was explicitly not done for the ERCSC, as it was aimed at providing lists of sources to be followed up. Our sample, prior to the 80% completeness cut, contains between 217 sources at 100 GHz and 1058 sources at 857 GHz over about 12 800 to 16 550 deg2 (31 to 40% of the sky). After the 80% completeness cut, between 122 and 452 and sources remain, with flux densities above 0.3 and 1.9 Jy at 100 and 857 GHz. The sample so defined can be used for statistical analysis. Using the multi-frequency coverage of the Planck High Frequency Instrument, all the sources have been classified as either dust-dominated (infrared galaxies) or synchrotron-dominated (radio galaxies) on the basis of their spectral energy distributions (SED). Our sample is thus complete, flux-limited and color-selected to differentiate between the two populations. We find an approximately equal number of synchrotron and dusty sources between 217 and 353 GHz; at 353 GHz or higher (or 217 GHz and lower) frequencies, the number is dominated by dusty (synchrotron) sources, as expected. For most of the sources, the spectral indices are also derived. We provide for the first time counts of bright sources from 353 to 857 GHz and the contributions from dusty and synchrotron sources at all HFI frequencies in the key spectral range where these spectra are crossing. The observed counts are in the Euclidean regime. The number counts are compared to previously published data (from earlier Planck results, Herschel, BLAST, SCUBA, LABOCA, SPT, and ACT) and models taking into account both radio or infrared galaxies, and covering a

  1. Predictions for ASKAP Neutral Hydrogen Surveys

    CERN Document Server

    Duffy, Alan R; Staveley-Smith, Lister; Bernyk, Maksym; Croton, Darren J; Koribalski, Barbel S; Gerstmann, Derek; Westerlund, Stefan

    2012-01-01

    The Australian Square Kilometer Array Pathfinder (ASKAP) will revolutionise our knowledge of gas-rich galaxies in the Universe. Here we present predictions for two proposed extragalactic ASKAP neutral hydrogen (HI) emission-line surveys, based on semi-analytic models applied to cosmological N-body simulations. The ASKAP HI All-Sky Survey, known as WALLABY, is a shallow 3 Pi survey (z = 0 - 0.26) which will probe the mass and dynamics of over 600,000 galaxies. A much deeper small-area HI survey, called DINGO, aims to trace the evolution of HI from z = 0 - 0.43, a cosmological volume of 40 million Mpc^3, detecting potentially 100,000 galaxies. The high-sensitivity 30 antenna ASKAP core (diameter ~2 km) will provide an angular resolution of 30 arcsec (at z=0). Our simulations show that the majority of galaxies detected in WALLABY (87.5%) will be resolved. About 5000 galaxies will be well resolved, i.e. more than five beams (2.5 arcmin) across the major axis, enabling kinematic studies of their gaseous disks. Thi...

  2. The Spitzer-South Pole Telescope Deep Field: Survey Design and IRAC Catalogs

    CERN Document Server

    Ashby, M L N; Brodwin, M; Gonzalez, A H; Martinez, J; Bartlett, J G; Benson, B A; Bleem, L E; Crawford, T M; Dey, A; Dressler, A; Eisenhardt, P R M; Galametz, A; Jannuzi, B T; Marrone, D P; Mei, S; Muzzin, A; Pacaud, F; Pierre, M; Stern, D; Vieira, J D

    2013-01-01

    The Spitzer-South Pole Telescope Deep Field (SSDF) is a wide-area survey using Spitzer's Infrared Array Camera (IRAC) to cover 94 square degrees of extragalactic sky, making it the largest IRAC survey completed to date outside the Milky Way midplane. The SSDF is centered at 23:30,-55:00, in a region that combines observations spanning a broad wavelength range from numerous facilities. These include millimeter imaging from the South Pole Telescope, far-infrared observations from Herschel/SPIRE, X-ray observations from the XMM XXL survey, near-infrared observations from the VISTA Hemisphere Survey, and radio-wavelength imaging from the Australia Telescope Compact Array, in a panchromatic project designed to address major outstanding questions surrounding galaxy clusters and the baryon budget. Here we describe the Spitzer/IRAC observations of the SSDF, including the survey design, observations, processing, source extraction, and publicly available data products. In particular, we present two band-merged catalogs...

  3. THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. I. IMPLICATIONS OF PLASMA INSTABILITIES FOR THE INTERGALACTIC MAGNETIC FIELD AND EXTRAGALACTIC GAMMA-RAY BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E.; Chang, Philip; Pfrommer, Christoph, E-mail: aeb@cita.utoronto.ca, E-mail: pchang@cita.utoronto.ca, E-mail: christoph.pfrommer@h-its.org [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2012-06-10

    Inverse Compton cascades (ICCs) initiated by energetic gamma rays (E {approx}> 100 GeV) enhance the GeV emission from bright, extragalactic TeV sources. The absence of this emission from bright TeV blazars has been used to constrain the intergalactic magnetic field (IGMF), and the stringent limits placed on the unresolved extragalactic gamma-ray background (EGRB) by Fermi have been used to argue against a large number of such objects at high redshifts. However, these are predicated on the assumption that inverse Compton scattering is the primary energy-loss mechanism for the ultrarelativistic pairs produced by the annihilation of the energetic gamma rays on extragalactic background light photons. Here, we show that for sufficiently bright TeV sources (isotropic-equivalent luminosities {approx}> 10{sup 42} erg s{sup -1}) plasma beam instabilities, specifically the 'oblique' instability, present a plausible mechanism by which the energy of these pairs can be dissipated locally, heating the intergalactic medium. Since these instabilities typically grow on timescales short in comparison to the inverse Compton cooling rate, they necessarily suppress the ICCs. As a consequence, this places a severe constraint on efforts to limit the IGMF from the lack of a discernible GeV bump in TeV sources. Similarly, it considerably weakens the Fermi limits on the evolution of blazar populations. Specifically, we construct a TeV-blazar luminosity function from those objects currently observed and find that it is very well described by the quasar luminosity function at z {approx} 0.1, shifted to lower luminosities and number densities, suggesting that both classes of sources are regulated by similar processes. Extending this relationship to higher redshifts, we show that the magnitude and shape of the EGRB above {approx}10 GeV are naturally reproduced with this particular example of a rapidly evolving TeV-blazar luminosity function.

  4. CHILES Con Pol: An ultra-deep JVLA survey probing galaxy evolution and cosmic magnetism

    Science.gov (United States)

    Hales, Christopher A.; Momjian, Emmanuel; van Gorkom, Jacqueline; Rupen, Michael P.; Greiner, Maksim; Ensslin, Torsten A.; Bonzini, Margherita; Padovani, Paolo; Harrison, Ian; Brown, Michael L.; Gim, Hansung; Yun, Min S.; Maddox, Natasha; Stewart, Adam; Fender, Rob P.; Tremou, Evangelia; Chomiuk, Laura; Peters, Charee; Wilcots, Eric M.; Lazio, Joseph

    2015-08-01

    We are undertaking a 1000 hour campaign with the Karl G. Jansky VLA to survey 0.2 square degrees of the COSMOS field in full polarization continuum at 1.4 GHz. Our observations are part of a joint program with the spectral line COSMOS HI Large Extragalactic Survey (CHILES). When complete, we expect our CHILES Continuum Polarization (CHILES Con Pol) survey to reach an SKA-era sensitivity of 500 nJy per 4 arcsecond resolving beam, the deepest view of the radio sky yet. CHILES Con Pol will open new and fertile parameter space, with sensitivity to star formation rates of 10 Msun per year out to an unprecedented redshift of z=2, and ultra-luminous infrared galaxies and sub-millimeter galaxies out to redshifts of z=8 and beyond. This rich resource will extend the utility of radio band studies beyond the usual radio quasar and radio galaxy populations, opening sensitivity to the starforming and radio-quiet AGN populations that form the bulk of extragalactic sources detected in the optical, X-ray, and infrared bands. In this talk I will outline the key science of CHILES Con Pol, including galaxy evolution and novel measurements of intergalactic magnetic fields. I will present initial results from the first 180 hours of the survey and describe our forthcoming Data Release 1. I invite the astronomical community to consider unique science that can be pursued with CHILES Con Pol radio data.

  5. A JVLA 10~degree^2 deep survey

    CERN Document Server

    Jarvis, Matt J; Bruggen, Marcus; Ferrari, Chiara; Heywood, Ian; Hardcastle, Martin; Murphy, Eric; Taylor, Russ; Smirnov, Oleg; Simpson, Chris; Smolcic, Vernesa; Stil, Jeroen; van der Heyden, Kurt

    2014-01-01

    (Abridged)One of the fundamental challenges for astrophysics in the 21st century is finding a way to untangle the physical processes that govern galaxy formation and evolution. Given the importance and scope of this problem, the multi-wavelength astronomical community has used the past decade to build up a wealth of information over specific extragalactic deep fields to address key questions in galaxy formation and evolution. These fields generally cover at least 10square degrees to facilitate the investigation of the rarest, typically most massive, galaxies and AGN. Furthermore, such areal coverage allows the environments to be fully accounted for, thereby linking the single halo to the two-halo terms in the halo occupation distribution. Surveys at radio wavelengths have begun to lag behind those at other wavelengths, especially in this medium-deep survey tier. However, the survey speed offered by the JVLA means that we can now reach a point where we can begin to obtain commensurate data at radio wavelengths...

  6. The Parkes HI Zone of Avoidance Survey

    CERN Document Server

    Staveley-Smith, L; Schröder, A C; Henning, P A; Koribalski, B S; Stewart, I M; Heald, G

    2016-01-01

    A blind HI survey of the extragalactic sky behind the southern Milky Way has been conducted with the multibeam receiver on the 64-m Parkes radio telescope. The survey covers the Galactic longitude range 212 < l < 36 and Galactic latitudes |b| < 5, and yields 883 galaxies to a recessional velocity of 12,000 km/s. The survey covers the sky within the HIPASS area to greater sensitivity, finding lower HI-mass galaxies at all distances, and probing more completely the large-scale structures at and beyond the distance of the Great Attractor. Fifty-one percent of the HI detections have an optical/NIR counterpart in the literature. A further 27% have new counterparts found in existing, or newly obtained, optical/NIR images. The counterpart rate drops in regions of high foreground stellar crowding and extinction, and for low-HI mass objects. Only 8% of all counterparts have a previous optical redshift measurement. A notable new galaxy is HIZOA J1353-58, a possible companion to the Circinus galaxy. Merging thi...

  7. Euclid mission: building of a reference survey

    Science.gov (United States)

    Amiaux, J.; Scaramella, R.; Mellier, Y.; Altieri, B.; Burigana, C.; Da Silva, Antonio; Gomez, P.; Hoar, J.; Laureijs, R.; Maiorano, E.; Magalhães Oliveira, D.; Renk, F.; Saavedra Criado, G.; Tereno, I.; Auguères, J. L.; Brinchmann, J.; Cropper, M.; Duvet, L.; Ealet, A.; Franzetti, P.; Garilli, B.; Gondoin, P.; Guzzo, L.; Hoekstra, H.; Holmes, R.; Jahnke, K.; Kitching, T.; Meneghetti, M.; Percival, W.; Warren, S.

    2012-09-01

    Euclid is an ESA Cosmic-Vision wide-field-space mission which is designed to explain the origin of the acceleration of Universe expansion. The mission will investigate at the same time two primary cosmological probes: Weak gravitational Lensing (WL) and Galaxy Clustering (in particular Baryon Acoustic Oscillations, BAO). The extreme precision requested on primary science objectives can only be achieved by observing a large number of galaxies distributed over the whole sky in order to probe the distribution of dark matter and galaxies at all scales. The extreme accuracy needed requires observation from space to limit all observational biases in the measurements. The definition of the Euclid survey, aiming at detecting billions of galaxies over 15 000 square degrees of the extragalactic sky, is a key parameter of the mission. It drives its scientific potential, its duration and the mass of the spacecraft. The construction of a Reference Survey derives from the high level science requirements for a Wide and a Deep survey. The definition of a main sequence of observations and the associated calibrations were indeed a major achievement of the Definition Phase. Implementation of this sequence demonstrated the feasibility of covering the requested area in less than 6 years while taking into account the overheads of space segment observing and maneuvering sequence. This reference mission will be used for sizing the spacecraft consumables needed for primary science. It will also set the framework for optimizing the time on the sky to fulfill the primary science and maximize the Euclid legacy.

  8. SACS: Spitzer Archival Cluster Survey

    Science.gov (United States)

    Stern, Daniel

    Emerging from the cosmic web, galaxy clusters are the most massive gravitationally bound structures in the universe. Thought to have begun their assembly at z > 2, clusters provide insights into the growth of large-scale structure as well as the physics that drives galaxy evolution. Understanding how and when the most massive galaxies assemble their stellar mass, stop forming stars, and acquire their observed morphologies in these environments remain outstanding questions. The redshift range 1.3 galaxies start to become the dominant population in cluster cores, and star formation in spiral galaxies is being quenched. Until recently, however, this redshift range was essentially unreachable with available instrumentation, with clusters at these redshifts exceedingly challenging to identify from either ground-based optical/nearinfrared imaging or from X-ray surveys. Mid-infrared (MIR) imaging with the IRAC camera on board of the Spitzer Space Telescope has changed the landscape. High-redshift clusters are easily identified in the MIR due to a combination of the unique colors of distant galaxies and a negative k-correction in the 3-5 μm range which makes such galaxies bright. Even 90-sec observations with Spitzer/IRAC, a depth which essentially all extragalactic observations in the archive achieve, is sufficient to robustly detect overdensities of L* galaxies out to z~2. Here we request funding to embark on a ambitious scientific program, the “SACS: Spitzer Archival Cluster Survey”, a comprehensive search for the most distant galaxy clusters in all Spitzer/IRAC extragalactic pointings available in the archive. With the SACS we aim to discover ~2000 of 1.3 star formation and AGN activity out to z~2, and to study the effect of star-forming galaxies and AGNs on cosmological results from ongoing Sunyaev-Zel'dovich (SZ) and X-ray cluster surveys. The identified clusters will be valuable for both astrophysics and cosmology. In terms of astrophysics, the redshift probed

  9. Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S.

    Science.gov (United States)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker Tjus, J.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Cologna, G.; Conrad, J.; Couturier, C.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; deWilt, P.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Gast, H.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Grondin, M.-H.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Menzler, U.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nguyen, N.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Wouters, D.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2013-02-01

    The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the EBL opacity to γ-rays on the spectra of the brightest extragalactic sources detected with the High Energy Stereoscopic System (H.E.S.S.). The originality of the method lies in the joint fit of the EBL optical depth and of the intrinsic spectra of the sources, assuming intrinsic smoothness. Analysis of a total of ~105γ-ray events enables the detection of an EBL signature at the 8.8σ level and constitutes the first measurement of the EBL optical depth using very-high energy (E > 100 GeV) γ-rays. The EBL flux density is constrained over almost two decades of wavelengths [0.30 μm, 17 μm] and the peak value at 1.4 μm is derived as λFλ = 15 ± 2stat ± 3sys nW m-2 sr-1. Appendix A is available in electronic form at http://www.aanda.org

  10. Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S

    CERN Document Server

    :,; Acero, F; Aharonian, F; Akhperjanian, A G; Anton, G; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Tjus, J Becker; Bernlöhr, K; Birsin, E; Biteau, J; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Cologna, G; Conrad, J; Couturier, C; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; deWilt, P; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gajdus, M; Gallant, Y A; Garrigoux, T; Gast, H; Giebels, B; Glicenstein, J F; Glück, B; Göring, D; Grondin, M -H; Häffner, S; Hague, J D; Hahn, J; Hampf, D; Harris, J; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Khélifi, B; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Krayzel, F; Laffon, H; Lamanna, G; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Menzler, U; Moderski, R; Mohamed, M; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nguyen, N; Niemiec, J; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sheidaei, F; Skilton, J L; Sol, H; Spengler, G; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; White, R; Wierzcholska, A; Wouters, D; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S

    2012-01-01

    The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the EBL opacity to gamma-rays on the spectra of the brightest extragalactic sources detected with the High Energy Stereoscopic System (H.E.S.S.). The originality of the method lies in the joint fit of the EBL optical depth and of the intrinsic spectra of the sources, assuming intrinsic smoothness. Analysis of a total of ~10^5 gamma-ray events enables the detection of an EBL signature at the 8.8 std dev level and constitutes the first measurement of the EBL optical depth using very-high energy (E>100 GeV) gamma-rays. The EBL flux density is constrained over almost two decades of wavelengths (0.30-17 microns) and the peak value at 1.4 micron is derived as 15 +/- 2 (stat) +/- 3 (sys) nW / m^2 sr.

  11. The NuSTAR Extragalactic Survey: A First Sensitive Look at the High-Energy Cosmic X-Ray Background Population

    Science.gov (United States)

    Alexander, D. M.; Stern, D.; DelMoro, A.; Lansbury, G. B.; Assef, R. J.; Aird, J.; Ajello, M.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; hide

    2013-01-01

    We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array (NuSTAR) to provide the first sensitive census of the cosmic X-ray background source population at approximately greater than 10 keV. We find that these NuSTAR-detected sources are approximately 100 times fainter than those previously detected at approximately greater than 10 keV and have a broad range in redshift and luminosity (z = 0.020-2.923 and L(sub 10-40 keV) approximately equals 4 × 10(exp 41) - 5 × 10(exp 45) erg per second; the median redshift and luminosity are z approximately equal to 0.7 and L(sub 10-40 keV) approximately equal to 3 × 10(exp 44) erg per second, respectively. We characterize these sources on the basis of broad-band approximately equal to 0.5 - 32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L(sub 10-40 keV) greater than 10(exp 44) erg per second, of which approximately 50% are obscured with N(sub H) approximately greater than 10(exp 22) per square centimeters. However, none of the 10 NuSTAR sources are Compton thick (N(sub H) approximately greater than 10(exp 24) per square centimeters) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L(sub 10-40 keV) greater than 10(exp 44) erg per second) selected at approximately greater than 10 keV of approximately less than 33% over the redshift range z = 0.5 - 1.1. We jointly fitted the rest-frame approximately equal to 10-40 keV data for all of the non-beamed sources with L(sub 10-40 keV) greater than 10(exp 43) erg per second to constrain the average strength of reflection; we find R less than 1.4 for gamma = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at approximately greater than 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of approximately 10(exp 11) solar mass, a factor approximately 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

  12. The Nustar Extragalactic Surveys: The Number Counts of Active Galactic Nuclei and the Resolved Fraction of the Cosmic X-Ray Background

    DEFF Research Database (Denmark)

    Harrison, F. A.; Aird, J.; Civano, F.;

    2016-01-01

    cm-2 ≤ 10-12, a factor ∼100 fainter than previous measurements. The 8–24 keV number counts match predictions from AGN populationsynthesis models, directly confirming the existence of a population of obscured and/or hard X-ray sources inferredfrom the shape of the integrated cosmic X-ray background...

  13. The Nustar Extragalactic Surveys: The Number Counts of Active Galactic Nuclei and the Resolved Fraction of the Cosmic X-Ray Background

    DEFF Research Database (Denmark)

    Harrison, F. A.; Aird, J.; Civano, F.

    2016-01-01

    . The measured NuSTAR counts lie significantly abovesimple extrapolation with a Euclidian slope to low flux of the Swift/BAT 15–55 keV number counts measured at higher fluxes (S(15–55 keV) ≤ 10−11 erg s-1 cm-2), reflecting the evolution of the AGN population between the Swift/BAT local (z ...STAR’s z ~ 1 sample. CXB synthesis models, which account for AGNevolution, lie above the Swift/BAT measurements, suggesting that they do not fully capture the evolution of obscured AGNs at low redshifts....

  14. The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population

    DEFF Research Database (Denmark)

    Alexander, D. M.; Stern, D.; Del Moro, A.;

    2013-01-01

    of broad-band ≈ 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L10-40 keV > 1044 erg s-1, of which ≈ 50% are obscured with NH ≳ 1022 cm-2. However, none of the 10 NuSTAR......We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) to provide the first sensitive census of the cosmic X-ray background source population at ≳ 10 keV. We find that these NuSTAR -detected sources are ≈ 100 times...... times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties...

  15. The NuSTAR Extragalactic Surveys: Initial Results and Catalog from the Extended Chandra Deep Field South

    DEFF Research Database (Denmark)

    Mullaney, J. R.; Del-Moro, A.; Aird, J.

    2015-01-01

    that are detected in both bands span the range 0.39–1.7, corresponding to a photon index range of G » 0.5-2.3, with a median photon index of G = 1.70 ± 0.52. Theredshifts of the 49 sources in our main sample span the range z = 0.21-2.7, and their rest-frame 10–40 keVluminosities (derived from the observed 8–24 ke...

  16. Gravitational lensing statistics with extragalactic surveys; 3, Joint constraints on $lambda_{0}$ and $Omega_{0}$ from lensing statistics and the m-z relation for type Ia supernovae

    NARCIS (Netherlands)

    Helbig, P.

    1999-01-01

    Published in: Astron. Astrophys. 350 (1999) 1-8 citations recorded in [Science Citation Index] Abstract: I present constraints on cosmological parameters in the lambda_0-Omega_0 plane from a joint analysis of gravitational lensing statistics (astro-ph/9904175) and the magnitude-redshift relation for

  17. Gravitational lensing statistics with extragalactic surveys III. Joint constraints on lambda(0) and Omega(0) from lensing statistics and the m-z relation for type Ia supernovae

    NARCIS (Netherlands)

    Helbig, P

    1999-01-01

    I present constraints on cosmological parameters in the lambda(0)-Omega(0) plane from a joint analysis of gravitational lensing statistics (Helbig et al. 1999b) and the magnitude-redshift relation for Type Ia supernovae (Perlmutter et al. 1999; Riess et al. 1998). I discuss reasons why this

  18. Cosmology with AGN dust time lags-simulating the new VEILS survey

    Science.gov (United States)

    Hönig, S. F.; Watson, D.; Kishimoto, M.; Gandhi, P.; Goad, M.; Horne, K.; Shankar, F.; Banerji, M.; Boulderstone, B.; Jarvis, M.; Smith, M.; Sullivan, M.

    2017-01-01

    The time lag between optical and near-infrared continuum emission in active galactic nuclei (AGN) shows a tight correlation with luminosity and has been proposed as a standardizable candle for cosmology. In this paper, we explore the use of these AGN hot-dust time lags for cosmological model fitting under the constraints of the new VISTA Extragalactic Infrared Legacy Survey (VEILS). This new survey will target a 9 deg2 field observed in J and Ks band with a 14-d cadence and will run for 3 yr. The same area will be covered simultaneously in the optical griz bands by the Dark Energy Survey, providing complementary time-domain optical data. We perform realistic simulations of the survey setup, showing that we expect to recover dust time lags for about 450 objects out of a total of 1350 optical type 1 AGN, spanning a redshift range of 0.1 4.

  19. Cosmology with AGN dust time lags -- Simulating the new VEILS survey

    CERN Document Server

    Hönig, S F; Kishimoto, M; Gandhi, P; Goad, M; Horne, K; Shankar, F; Banerji, M; Boulderstone, B; Jarvis, M; Smith, M; Sullivan, M

    2016-01-01

    The time lag between optical and near-infrared continuum emission in active galactic nuclei (AGN) shows a tight correlation with luminosity and has been proposed as a standardisable candle for cosmology. In this paper, we explore the use of these AGN hot-dust time lags for cosmological model fitting under the constraints of the new VISTA Extragalactic Infrared Legacy Survey VEILS. This new survey will target a 9 deg^2 field observed in J- and Ks-band with a 14-day cadence and will run for three years. The same area will be covered simultaneously in the optical griz bands by the Dark Energy Survey, providing complementary time-domain optical data. We perform realistic simulations of the survey setup, showing that we expect to recover dust time lags for about 450 objects out of a total of 1350 optical type 1 AGN, spanning a redshift range of 0.1 4.

  20. "Suntelligence" Survey

    Science.gov (United States)

    ... to the American Academy of Dermatology's "Suntelligence" sun-smart survey. Please answer the following questions to measure ... be able to view a ranking of major cities suntelligence based on residents' responses to this survey. ...

  1. Survey Says

    Science.gov (United States)

    McCarthy, Susan K.

    2005-01-01

    Survey Says is a lesson plan designed to teach college students how to access Internet resources for valid data related to the sexual health of young people. Discussion questions based on the most recent available data from two national surveys, the Youth Risk Behavior Surveillance-United States, 2003 (CDC, 2004) and the National Survey of…

  2. Astronomical Surveys, Catalogs, Databases, and Archives

    Science.gov (United States)

    Mickaelian, A. M.

    2016-06-01

    All-sky and large-area astronomical surveys and their cataloged data over the whole range of electromagnetic spectrum are reviewed, from γ-ray to radio, such as Fermi-GLAST and INTEGRAL in γ-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). Most important astronomical databases and archives are reviewed as well, including Wide-Field Plate DataBase (WFPDB), ESO, HEASARC, IRSA and MAST archives, CDS SIMBAD, VizieR and Aladin, NED and HyperLEDA extragalactic databases, ADS and astro-ph services. They are powerful sources for many-sided efficient research using Virtual Observatory tools. Using and analysis of Big Data accumulated in astronomy lead to many new discoveries.

  3. Euclid Mission: building of a Reference Survey

    CERN Document Server

    Amiaux, J; Mellier, Y; Altieri, B; Burigana, C; Da Silva, A; Gomez, P; Hoar, J; Laureijs, R; Maiorano, E; Oliveira, D Magalhaes; Renk, F; Criado, G Saavedra; Tereno, I; Augueres, J L; Brinchmann, J; Cropper, M; Duvet, L; Ealet, A; Franzetti, P; Garilli, B; Gondoin, P; Guzzo, L; Hoekstra, H; Holmes, R; Jahnke, K; Kitching, T; Meneghetti, M; Percival, W; Warren, S

    2012-01-01

    Euclid is an ESA Cosmic-Vision wide-field-space mission which is designed to explain the origin of the acceleration of Universe expansion. The mission will investigate at the same time two primary cosmological probes: Weak gravitational Lensing (WL) and Galaxy Clustering (in particular Baryon Acoustic Oscillations, BAO). The extreme precision requested on primary science objectives can only be achieved by observing a large number of galaxies distributed over the whole sky in order to probe the distribution of dark matter and galaxies at all scales. The extreme accuracy needed requires observation from space to limit all observational biases in the measurements. The definition of the Euclid survey, aiming at detecting billions of galaxies over 15 000 square degrees of the extragalactic sky, is a key parameter of the mission. It drives its scientific potential, its duration and the mass of the spacecraft. The construction of a Reference Survey derives from the high level science requirements for a Wide and a De...

  4. Cosmology with all-sky surveys

    CERN Document Server

    Bilicki, Maciej

    2015-01-01

    Various aspects of cosmology require comprehensive all-sky mapping of the cosmic web to considerable depths. In order to probe the whole extragalactic sky beyond 100 Mpc, one must draw on multiwavelength datasets and state-of-the-art photometric redshift techniques. Here I summarize our dedicated program that employs the largest photometric all-sky surveys -- 2MASS, WISE and SuperCOSMOS -- to obtain accurate redshift estimates of millions of galaxies. The first outcome of these efforts -- the 2MASS Photometric Redshift catalog (2MPZ) -- was publicly released in 2013 and includes almost 1 million galaxies with a median redshift of z~0.1. I discuss how this catalog was constructed and how it is being used for various cosmological tests. I also present how combining the WISE mid-infrared survey with SuperCOSMOS optical data allowed us to push to depths over 1 Gpc on unprecedented angular scales. These photometric redshift samples, with about 20 million sources in total, provide access to volumes large enough to ...

  5. Cosmology with all-sky surveys

    Science.gov (United States)

    Bilicki, Maciej

    2016-06-01

    Various aspects of cosmology require comprehensive all-sky mapping of the cosmic web to considerable depths. In order to probe the whole extragalactic sky beyond 100 Mpc, one must draw on multiwavelength datasets and state-of-the-art photometric redshift techniques. Here I summarize our dedicated program that employs the largest photometric all-sky surveys - 2MASS, WISE and SuperCOSMOS - to obtain accurate redshift estimates of millions of galaxies. The first outcome of these efforts - the 2MASS Photometric Redshift catalog (2MPZ) - was publicly released in 2013 and includes almost 1 million galaxies with a median redshift of z˜0.1. I discuss how this catalog was constructed and how it is being used for various cosmological tests. I also present how combining the WISE mid-infrared survey with SuperCOSMOS optical data allowed us to push to depths over 1 Gpc on unprecedented angular scales. These photometric redshift samples, with about 20 million sources in total, provide access to volumes large enough to study observationally the Copernican Principle of universal homogeneity and isotropy, as well as to probe various aspects of dark energy and dark matter through cross-correlations with other data such as the cosmic microwave or gamma-ray backgrounds. Last but not least, they constitute a test-bed for forthcoming wide-angle multi-million galaxy samples expected from such instruments as the SKA, Euclid, or LSST.

  6. PLASMA EFFECTS ON EXTRAGALACTIC ULTRAHIGH-ENERGY COSMIC-RAY HADRON BEAMS IN COSMIC VOIDS. II. KINETIC INSTABILITY OF PARALLEL ELECTROSTATIC WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Krakau, S.; Schlickeiser, R., E-mail: steffen.krakau@rub.de, E-mail: rsch@tp4.rub.de [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2016-02-20

    The linear instability of an ultrarelativistic hadron beam in the unmagnetized intergalactic medium (IGM) is investigated with respect to the excitation of parallel electrostatic and electromagnetic fluctuations. This analysis is important for the propagation of extragalactic ultrarelativistic cosmic rays from their distant sources to Earth. As opposed to the previous paper, we calculate the minimum instability growth time for Lorentz-distributed cosmic rays which traverse the hot IGM. The growth times are orders of magnitude higher than the cosmic-ray propagation time in the IGM. Since the backreaction of the generated plasma fluctuations (plateauing) lasts longer than the propagation time, the cosmic-ray hadron beam can propagate to the Earth without losing a significant amount of energy to electrostatic turbulence.

  7. Search for correlations of the arrival directions of ultra-high energy cosmic ray with extragalactic objects as observed by the telescope array experiment

    CERN Document Server

    Abu-Zayyad, T; Allen, M; Anderson, R; Azuma, R; Barcikowski, E; Belz, J W; Bergman, D R; Blake, S A; Cady, R; Cheon, B G; Chiba, J; Chikawa, M; Cho, E J; Cho, W R; Fujii, H; Fujii, T; Fukuda, T; Fukushima, M; Hanlon, W; Hayashi, K; Hayashi, Y; Hayashida, N; Hibino, K; Hiyama, K; Honda, K; Iguchi, T; Ikeda, D; Ikuta, K; Inoue, N; Ishii, T; Ishimori, R; Ito, H; Ivanov, D; Iwamoto, S; Jui, C C H; Kadota, K; Kakimoto, F; Kalashev, O; Kanbe, T; Kasahara, K; Kawai, H; Kawakami, S; Kawana, S; Kido, E; Kim, H B; Kim, H K; Kim, J H; Kitamoto, K; Kitamura, S; Kitamura, Y; Kobayashi, K; Kobayashi, Y; Kondo, Y; Kuramoto, K; Kuzmin, V; Kwon, Y J; Lan, J; Lim, S I; Lundquist, J P; Machida, S; Martens, K; Matsuda, T; Matsuura, T; Matsuyama, T; Matthews, J N; Minamino, M; Miyata, K; Murano, Y; Myers, I; Nagasawa, K; Nagataki, S; Nakamura, T; Nam, S W; Nonaka, T; Ogio, S; Ohnishi, M; Ohoka, H; Oki, K; Oku, D; Okuda, T; Ono, M; Oshima, A; Ozawa, S; Park, I H; Pshirkov, M S; Rodriguez, D C; Roh, S Y; Rubtsov, G; Ryu, D; Sagawa, H; Sakurai, N; Sampson, A L; Scott, L M; Shah, P D; Shibata, F; Shibata, T; Shimodaira, H; Shin, B K; Shin, J I; Shirahama, T; Smith, J D; Sokolsky, P; Springer, R W; Stokes, B T; Stratton, S R; Stroman, T; Suzuki, S; Takahashi, Y; Takeda, M; Taketa, A; Takita, M; Tameda, Y; Tanaka, H; Tanaka, K; Tanaka, M; Thomas, S B; Thomson, G B; Tinyakov, P; Tkachev, I; Tokuno, H; Tomida, T; Troitsky, S; Tsunesada, Y; Tsutsumi, K; Tsuyuguchi, Y; Uchihori, Y; Udo, S; Ukai, H; Urban, F; Vasiloff, G; Wada, Y; Wong, T; Yamakawa, Y; Yamane, R; Yamaoka, H; Yamazaki, K; Yang, J; Yoneda, Y; Yoshida, S; Yoshii, H; Zhou, X; Zollinger, R; Zundel, Z

    2013-01-01

    We search for correlations between positions of extragalactic objects and arrival directions of Ultra-High Energy Cosmic Rays (UHECRs) with primary energy $E \\ge 40$ EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examined several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We counted the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine combinations of these parameters which maximize the correlations, and calculate the chance probabilities of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several...

  8. Observations of 1ES 1101-232 with H.E.S.S. and at lower frequencies: A hard spectrum blazar and constraints on the extragalactic background light

    Science.gov (United States)

    Pühlhofer, Gerd; Benbow, Wystan; Costamante, Luigi; Sol, Helene; Boisson, Catherine; Emmanoulopoulos, Dimitrios; Wagner, Stefan; Horns, Dieter; Giebels, Berrie

    VHE observations of the distant (z=0.186) blazar 1ES 1101-232 with H.E.S.S. are used to constrain the extragalactic background light (EBL) in the optical to near infrared band. As the EBL traces the galaxy formation history of the universe, galaxy evolution models can therefore be tested with the data. In order to measure the EBL absorption effect on a blazar spectrum, we assume that usual constraints on the hardness of the intrinsic blazar spectrum are not violated. We present an update of the VHE spectrum obtained with H.E.S.S. and the multifrequency data that were taken simultaneously with the H.E.S.S. measurements. The data verify that the broadband characteristics of 1ES 1101-232 are similar to those of other, more nearby blazars, and strengthen the assumptions that were used to derive the EBL upper limit.

  9. Discovery of an unusual new radio source in the star-forming galaxy M82: Faint supernova, supermassive blackhole, or an extra-galactic microquasar?

    CERN Document Server

    Muxlow, T W B; Garrington, S T; Pedlar, A; Fenech, D M; Argo, M K; van Eymeren, J; Ward, M; Zezas, A; Brunthaler, A

    2010-01-01

    A faint new radio source has been detected in the nuclear region of the starburst galaxy M82 using MERLIN radio observations designed to monitor the flux density evolution of the recent bright supernova SN2008iz. This new source was initially identified in observations made between 1-5th May 2009 but had not been present in observations made one week earlier, or in any previous observations of M82. In this paper we report the discovery of this new source and monitoring of its evolution over its first 9 months of existence. The true nature of this new source remains unclear, and we discuss whether this source may be an unusual and faint supernova, a supermassive blackhole associated with the nucleus of M82, or intriguingly the first detection of radio emission from an extragalactic microquasar.

  10. FAST Maser Surveys

    Indian Academy of Sciences (India)

    J. S. Zhang

    2014-09-01

    FAST, the Five-hundred meter Aperture Spherical radio Telescope, will become the largest operating single-dish telescope in the coming years. It has many advantages: much better sensitivity for its largest collecting area; large sky coverage due to its innovative design of the active primary surface; extremely radio quiet from its unique location, etc. In this work, I will highlight the future capabilities of FAST to discover and observe both galactic and extragalactic masers.

  11. GALFACTS: The G-ALFA Continuum Transit Survey

    CERN Document Server

    Taylor, Russ

    2010-01-01

    The GALFACTS project is using the L-band seven feed array receiver system on the Arecibo telescope to carry out an imaging spectro-polarimetric survey of the 30% of the sky visible from Arecibo. GALFACTS observations will create full-Stokes image cubes at an angular resolution of 3.5', with several thousand spectral channels covering 1225 - 1525 MHz, and band-averaged sensitivity of 90 uJy, allowing sensitive imaging of polarized radiation and Faraday Rotation Measure from both diffuse emission and against a high density grid of extragalactic sources. GALFACTS will be a major observational advance in imaging of the polarized radiation from the Milky Way and will provide a rich new database for exploration of the magnetic field of the Galaxy and the properties of the magneto-ionic medium.

  12. The Commensal Real-time ASKAP Fast Transients (CRAFT) survey

    CERN Document Server

    Macquart, Jean-Pierre; Bower, G C; Bunton, J D; Chatterjee, S; Colegate, T; Cordes, J M; D'Addario, L; Deller, A; Dodson, R; Fender, R; Haines, K; Hall, P; Harris, C; Hotan, A; Johnston, S; Jones, D L; Keith, M; Koay, J Y; Lazio, T J W; Majid, W; Murphy, T; Navarro, R; Phillips, C; Quinn, P; Preston, R A; Stansby, B; Stairs, I; Stappers, B; Staveley-Smith, L; Tingay, S; Thompson, D; van Straten, W; Wagstaff, K; Warren, M; Wayth, R; Wen, L

    2010-01-01

    We are developing a purely commensal survey experiment for fast (<5s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest single events in the Universe. Our objective is to cover the enormous volume of transients parameter space made available by ASKAP, with an unprecedented combination of sensitivity and field of view. Fast timescale transients open new vistas on the physics of high brightness temperature emission, extreme states of matter and the physics of strong gravitational fields. In addition, the detection of extragalactic objects affords us an entirely new and extremely sensitive probe on the huge reservoir of baryons present in the IGM. We outline here our approach to the considerable challenge involved in detecting fast transients, particularly the development of hardware fast enough to dedisperse and search the ASKAP data stream at or near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of the key technologies and surve...

  13. The Molonglo Galactic Plane Survey, 1 Overview and Images

    CERN Document Server

    Green, A J; Large, M I; Ye, T; Ye, Taisheng

    1998-01-01

    The first epoch Molonglo Galactic Plane Survey (MGPS1) is a radio continuum survey made using the Molonglo Observatory Synthesis Telescope (MOST) at 843 MHz with a resolution of 43" X 43" cosec |delta|. The region surveyed is 245 deg < l < 355 deg, |b| < 1.5 deg. The thirteen 9 deg X 3 deg mosaic images presented here are the superposition of over 450 complete synthesis observations, each taking 12 h and covering 70' X 70' cosec |delta|. The root-mean-square sensitivity over much of the mosaiced survey is 1-2 mJy/beam (1 sigma), and the positional accuracy is approximately 1" X 1" cosec |delta| for sources brighter than 20 mJy. The dynamic range is no better than 250:1, and this also constrains the sensitivity in some parts of the images. The survey area of 330 sq deg contains well over 12,000 unresolved or barely resolved objects, almost all of which are extra-galactic sources lying in the Zone of Avoidance. In addition a significant fraction of this area is covered by extended, diffuse emission ass...

  14. Data reduction strategy of the Effelsberg-Bonn HI Survey (EBHIS)

    CERN Document Server

    Winkel, B; Kalberla, P M W

    2009-01-01

    Since autumn 2008 a new L-band 7-Feed-Array receiver is used for an HI 21-cm line survey performed with the 100-m Effelsberg telescope. The survey will cover the whole northern hemisphere comprising both, the galactic and extragalactic sky in parallel. Using state-of-the-art FPGA based digital Fast Fourier Transform spectrometers, superior in dynamic range and temporal resolution, allows to apply sophisticated radio frequency interferences (RFI) mitigation schemes to the survey data. The EBHIS data reduction software includes the RFI mitigation, gain-curve correction, intensity calibration, stray-radiation correction, gridding, and source detection. We discuss the severe degradation of radio astronomical HI data by RFI signals and the gain in scientific yield when applying modern RFI mitigation schemes. For this aim simulations of the galaxy distribution within the local volume (z<0.07) with and without RFI degradation were performed. These simulations, allow us to investigate potential biases and selectio...

  15. The Millimeter Astronomy Legacy Team 90 GHz Survey (MALT90) and ALMA

    CERN Document Server

    Foster, Jonathan B; Jackson, James M; Longmore, Steve N; Whitaker, Scott; Hoq, Sadia

    2013-01-01

    ALMA will revolutionize our understanding of star formation within our galaxy, but before we can use ALMA we need to know where to look. The Millimeter Astronomy Legacy Team 90 GHz (MALT90) Survey is a large international project to map the molecular line emission of over 2,000 dense clumps in the Galactic plane. MALT90 serves as a pathfinder for ALMA, providing a large public database of dense molecular clumps associated with high-mass star formation. In this proceedings, we describe the survey parameters and share early science highlights from the survey, including (1) a comparison between galactic and extragalactic star formation relations, (2) chemical trends in MALT90 clumps, (3) the distribution of high-mass star formation in the Milky Way, and (4) a discussion of the Brick, the target of successful ALMA Cycle 0 and Cycle 1 proposals.

  16. The Millimeter Astronomy Legacy Team 90 GHz Survey (MALT90) and ALMA

    Science.gov (United States)

    Foster, J.; Rathborne, J.; Jackson, J.; Longmore, S.; Whitaker, S.; Hoq, S.

    2013-10-01

    ALMA will revolutionize our understanding of star formation within our galaxy, but before we can use ALMA we need to know where to look. The Millimeter Astronomy Legacy Team 90 GHz (MALT90) Survey is a large international project to map the molecular line emission of over 2,000 dense clumps in the Galactic plane. MALT90 serves as a pathfinder mission for ALMA, providing a large public database of dense molecular clumps associated with high-mass star formation. In this proceedings, we describe the survey parameters and share early science highlights from the survey, including (1) a comparison between galactic and extragalactic star formation relations, (2) chemical trends in MALT90 clumps, (3) the distribution of high-mass star formation in the Milky Way, and (4) a discussion of the “Brick”, the target of successful ALMA Cycle 0 and Cycle 1 proposals.

  17. ESO Public Surveys at VISTA: Lessons learned from Cycle 1 Surveys and the start of Cycle 2

    Science.gov (United States)

    Arnaboldi, M.; Delmotte, N.; Gadotti, D.; Hilker, M.; Hussain, G.; Mascetti, L.; Micol, A.; Petr-Gotzens, M.; Rejkuba, M.; Retzlaff, J.; Ivison, R.; Leibundgut, B.; Romaniello, M.

    2017-06-01

    The ESO Public Surveys on VISTA serve the science goals of the survey teams while increasing the legacy value of ESO programmes, thanks to their homogeneity and the breadth of their sky coverage in multiple bands. These projects address a variety of research areas: from the detection of planets via microlensing, to stars, the Milky Way and Local Group galaxies, to extragalactic astronomy, galaxy evolution, the high-redshift Universe and cosmology. In 2015, as the first generation of imaging surveys was nearing completion, a second call for Public Surveys was opened to define a coherent scientific programme for VISTA until the commissioning of the wide-field multi-fibre spectrograph, 4MOST, in 2020. This article presents the status of the Cycle 1 surveys as well as an overview of the seven new programmes in Cycle 2, including their science goals, coverage on the sky and observing strategies. We conclude with a forward look at the Cycle 2 data releases and the timelines for their release.

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

    Energy Technology Data Exchange (ETDEWEB)

    Spitler, L. G.; Freire, P. C. C.; Lazarus, P.; Lee, K. J. [Max-Planck-Institut für Radioastronomie, D-53121 Bonn (Germany); Cordes, J. M.; Chatterjee, S.; Wharton, R. S.; Brazier, A. [Department of Astronomy and Space Sciences, Cornell University, Ithaca, NY 14853 (United States); Hessels, J. W. T. [ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); Lorimer, D. R.; McLaughlin, M. A. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Crawford, F. [Department of Physics and Astronomy, Franklin and Marshall College, Lancaster, PA 17604-3003 (United States); Deneva, J. S. [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Kaspi, V. M.; Karako-Argaman, C. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Allen, B. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Bogdanov, S.; Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Jenet, F. A. [Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Knispel, B., E-mail: lspitler@mpifr-bonn.mpg.de [Leibniz Universität, Hannover, D-30167 Hannover (Germany); and others

    2014-08-01

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

  19. A Deep Proper-Motion Survey in Kapteyn Selected Areas: I. Survey Description and First Results for Stars in the Tidal Tail of Sagittarius and in the Monoceros Ring

    CERN Document Server

    Casetti-Dinescu, D I; Girard, T M; Carlin, J L; Van Altena, W F; Patterson, R J; Law, D R; Casetti-Dinescu, Dana I.; Majewski, Steven R.; Girard, Terrence M.; Carlin, Jefferey L.; Altena, William F. van; Patterson, Richard J.; Law, David R.

    2006-01-01

    We describe a high-precision, deep (to V ~ 19-21) absolute proper-motion survey that samples ~50 lines of sight in the Kapteyn Selected Areas along declination zones -15, 0 and 15 degrees. In many fields the astrometric baseline reaches nearly a century. We demonstrate that these data provide typical per star precisions between ~ 1 and 3 mas/yr to the above magnitude limits, with the absolute reference frame established by numerous extragalactic sources in each survey field. Combined with existing and ongoing photometric and radial velocity surveys in these fields, these astrometric data will enable, among other things, accurate, detailed dynamical modeling of satellite interactions with our Galaxy. In this contribution we describe the astrometric part of our survey and show preliminary results along the trailing tail of the Sagittarius dwarf galaxy, and in the Monoceros ring region.

  20. A deep ROSAT survey 10, X-ray luminous narrow emission line galaxies

    CERN Document Server

    Griffiths, R E; Georgantopoulos, I; Boyle, B J; Stewart, G C; Shanks, T; Fruscione, A; Griffiths, Richard E; Della Ceca, Roberto; Georgantopoulos, Ioannis; Boyle, Brian J; Stewart, Gordon C; Shanks, Tom; Fruscione, Antonella

    1996-01-01

    X-ray luminous narrow emision-line galaxies (NELG) have been previously identified and proposed as an important class of extragalactic X-ray sources, with a potentially significant contribution to the total extragalactic X-ray flux at energies below \\sim 10 keV. In order to investigate and clarify this possibility, we have used a sample of NELG found in 5 deep ROSAT fields and similar samples belonging to the Cambridge-Cambridge ROSAT Serendipity Survey and to the {\\it Einstein} Observatory Extended Medium Sensitivity Survey sample. The principal results of this investigation are as follows: a) for a given optical luminosity, the typical X-ray luminosity of NELGs is about one or two orders of magnitude higher than that of normal galaxies; b) the ratio of the surface density of NELGs compared with BLAGN increases from about 0.04 at fx >= 6 x 10^{-13} erg cm^{-2} s^{-1} to about 0.1 at fx >= 10^{-14} erg cm^{-2} s^{-1}, suggesting that the surface density of NL galaxies might be very close to that of BLAGN at f...

  1. SEDS: THE SPITZER EXTENDED DEEP SURVEY. SURVEY DESIGN, PHOTOMETRY, AND DEEP IRAC SOURCE COUNTS

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Hernquist, L.; Hora, J. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Arendt, R. [Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Barmby, P. [University of Western Ontario, London, ON N6A 3K7 (Canada); Barro, G.; Faber, S.; Guhathakurta, P. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States); Bell, E. F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Bouwens, R. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Cattaneo, A. [Aix Marseille Universite, CNRS, Laboratoire d' Astrophysique de Marseille, UMR 7326, F-13388, Marseille (France); Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218 Hawthorn, VIC 3122 (Australia); Dave, R. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Dunlop, J. S. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Egami, E. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Finlator, K. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, CK-2100 Copenhagen O (Denmark); Grogin, N. A., E-mail: mashby@cfa.harvard.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2013-05-20

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg{sup 2} to a depth of 26 AB mag (3{sigma}) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 {mu}m. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 {+-} 1.0 and 4.4 {+-} 0.8 nW m{sup -2} sr{sup -1} at 3.6 and 4.5 {mu}m to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  2. Engineering surveying

    CERN Document Server

    Schofield, W

    2001-01-01

    The aim of Engineering Surveying has always been to impart and develop a clear understanding of the basic topics of the subject. The author has fully revised the book to make it the most up-to-date and relevant textbook available on the subject.The book also contains the latest information on trigonometric levelling, total stations and one-person measuring systems. A new chapter on satellites ensures a firm grasp of this vitally important topic.The text covers engineering surveying modules for civil engineering students on degree courses and forms a reference for the engineering surveying module in land surveying courses. It will also prove to be a valuable reference for practitioners.* Simple clear introduction to surveying for engineers* Explains key techniques and methods* Details reading systems and satellite position fixing

  3. A low density of the extragalactic background light revealed by the H.E.S.S. spectra of the BL Lac objects 1ES 1101-232 and H 2356-309

    Science.gov (United States)

    Costamante, Luigi

    2007-06-01

    The study of the TeV emission from extragalactic sources is hindered by the uncertainties on the diffuse Extragalactic Background Light (EBL). The recent H.E.S.S. results on the blazars 1ES 1101-232 and H 2356-309 represent a breakthrough on this issue. Their unexpectedly hard spectra allow an upper limit to be derived on the EBL in the optical/near-infrared range, which is very close to the lower limit given by the resolved galaxy counts. This result seems to exclude a large contribution to the EBL from other sources (e.g. Population III stars) and indicates that the intergalactic space is more transparent to γ-rays than previously thought. A discussion of EBL absorption effects and further observational tests with Cherenkov telescopes are presented.

  4. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies. rmark@imv.au.dk   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...... and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public...... carried out in a Danish county in order to improve treatment of people who have suffered from long-term illnesses. The surveys concern not only feed back on how people experience their present and past interaction with the social services and health care system; they also ask people to indicate the state...

  5. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies. rmark@imv.au.dk   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...... and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public...... be imagined as a positive end, as ‘making explicit’ (in a popular psychological perspective) is considered to be therapeutic and good in itself? We will discuss those questions from a Foucaultian and ANT perspective, where one does not accept that pre-existing subjects are exposed to survey procedures...

  6. Survey Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cleaned and QCd data for the Fishing Effort Survey. Questions on fishing and other out are asked on weather and outdoor activity, including fishing trips. Used for...

  7. Photographic photometry of compact extragalactic objects. VI. [BL Lac OJ 287, B2 1101+38, IZw 1727+50, IZw 0051+12, 3C 351, 3C 120

    Energy Technology Data Exchange (ETDEWEB)

    Hagen-Thorn, V.A.; Perevozchikova, A.I.; Skulova, N.M.; Ershtadt, S.G.; Yakovleya, V.A.

    1978-01-01

    The results of photographic photometry in B band of 7 compact extragalactic objects for 1975 are given. The light curves of BL Lac (1968-1975) and OJ 287 (1971-1975) are investigated for periodicity. It is found that the light curves of both objects seem to have components with amplitudes of 0.5 m and periods of 178 days for BL Lac and 184 days for OJ 287. 11 figures, 1 table.

  8. Powerful sources, extragalactic magnetic fields, astro-particles: astrophysical puzzles seen through ultrahigh energy cosmic ray spectacles; Sources energetiques, champs magnetiques extra-galactiques, astroparticules: enigmes astrophysiques vues par les rayons cosmiques de ultra-haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Kotera, K.

    2009-09-15

    This work explores the relationships between powerful sources in the Universe, extragalactic magnetic fields and secondary cosmos particles (neutrinos and gamma rays), through the study of the propagation of ultrahigh energy cosmic rays. In this manuscript, I first review the experimental and theoretical status of the cosmic ray field. I then present a detailed review of the secondary particle emission mechanisms during cosmic ray propagation, and on the current knowledge of the extragalactic magnetic fields. In regards of all the uncertainties on the distribution of those field and the complexity of the existing models, I introduce parametrized semi-analytical and analytical modeling of cosmic ray transport in these fields. These models enables one to take into account key phenomena that are often neglected in the literature (for example the effects of the magnetic enrichment from astrophysical sources or of the small scale turbulence). I also developed a numerical tool that combines and improve existing codes, in order to treat interaction processes during cosmic ray propagation. I make use of these techniques to consider many paramount problems concerning ultrahigh energy cosmic rays, like the effect of the extragalactic magnetic field in the region of the second knee, the interpretation of the anisotropy detected by the Auger Observatory and multi-messenger aspects from sources located in magnetized environments. (author)

  9. The Properties of Galaxies in Low Density Regions from the ALFALFA Survey

    Science.gov (United States)

    Toribio, M. C.; Solanes, J. M.; Alfalfa Collaboration

    2010-10-01

    Galaxies detected in the 21-cm line of neutral hydrogen (H I) from the on-going Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic H I survey have been cross-correlated with Sloan Digital Sky Survey (SDSS) Data Release 7 (Abazajian et al. 2009) in order to define a reference sample of H I content in regions of low galactic density. This observational sample will be used in the future to derive new standards of normal atomic gas content that allow a statistical investigation of the H I properties of galaxies in differing environments of the local universe. As a previous step, we compare here morphological indicators, like color or light concentration index, of ALFALFA detections and non-detections in low density regions. Our examination is extended also to a small data set of isolated galaxies. This kind of analysis is necessary in order to characterize as accurately as possible the type of galaxies that ALFALFA is detecting.

  10. The Properties of Galaxies in Low Density Regions from the ALFALFA Survey

    CERN Document Server

    Toribio, M C

    2009-01-01

    Galaxies detected in the 21-cm line of neutral hydrogen (HI) from the on-going Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic HI survey have been cross-correlated with Sloan Digital Sky Survey Data Release 7 (Abazajian et al. 2009) in order to define a reference sample of HI content in regions of low galactic density. This observational sample will be used in the future to derive new standards of normal atomic gas content that allow a statistical investigation of the HI properties of galaxies in differing environments of the local universe. As a previous step, we compare here morphological indicators, like color or light concentration index, of ALFALFA detections and non-detections in low density regions. Our examination is extended also to a small data set of isolated galaxies. This kind of analysis is necessary in order to characterize as accurately as possible the type of galaxies that ALFALFA is detecting.

  11. Divergent pointing with the Cherenkov Telescope Array for surveys and beyond

    CERN Document Server

    ,

    2015-01-01

    The galactic and extragalactic surveys are two of the main proposed legacy projects of the Cherenkov Telescope Array (CTA), providing an unbiased view of the Universe at energies above tens of GeV. Considering Cherenkov telescopes' limited field of view ($<10^\\circ$), the time needed for those projects is large. The many telescopes of CTA will allow taking full advantage of new pointing modes in which telescopes point slightly offset from one another. This divergent pointing mode leads to an increase of the array field of view ($\\sim 14^\\circ$ or larger) with competitive performance compared to normal pointing. We present here a study of the performance of the divergent pointing for different array configurations and number of telescopes. We briefly discuss the prospect of using divergent pointing for surveys.

  12. Driftscan Surveys in the 21 cm Line with the Arecibo and Nancay Telescopes

    CERN Document Server

    Briggs, F H; Kraan-Korteweg, R C; Van Driel, W

    1997-01-01

    Driftscan methods are highly efficient, stable techniques for conducting extragalactic surveys in the 21cm line of neutral hydrogen. Holding the telescope still while the beam scans the sky at the sidereal rate produces exceptionally stable spectral baselines, increased stability for RFI signals, and excellent diagnostic information about system performance. Data can be processed naturally and efficiently by grouping long sequences of spectra into an image format, thereby allowing thousands of individual spectra to be calibrated, inspected and manipulated as a single data structure with standard tools that already exist in astronomical software. The behavior of spectral standing waves (multi-path effects) can be appraised and excised in this environment, making observations possible while the Sun is up. The method is illustrated with survey data from Arecibo and Nancay.

  13. A search for dispersed radio bursts in archival Parkes Multibeam Pulsar Survey data

    CERN Document Server

    Bagchi, Manjari; McLaughlin, Maura

    2012-01-01

    A number of different classes of potentially extra-terrestrial bursts of radio emission have been observed in surveys with the Parkes 64m radio telescope, including "Rotating Radio Transients", the "Lorimer burst" and "perytons". Rotating Radio Transients are radio pulsars which are best detectable in single-pulse searches. The Lorimer burst is a highly dispersed isolated radio burst with properties suggestive of extragalactic origin. Perytons share the frequency-swept nature of the Rotating Radio Transients and Lorimer burst, but unlike these events appear in all thirteen beams of the Parkes Multibeam receiver and are probably a form of peculiar radio frequency interference. In order to constrain these and other radio source populations further, we searched the archival Parkes Multibeam Pulsar Survey data for events similar to any of these. We did not find any new Rotating Radio Transients or bursts like the Lorimer burst. We did, however, discover four peryton-like events. Similar to the perytons, these fou...

  14. Measuring Large-Scale Structure at z ~ 1 with the VIPERS galaxy survey

    Science.gov (United States)

    Guzzo, Luigi

    2016-10-01

    The VIMOS Public Extragalactic Redshift Survey (VIPERS) is the largest redshift survey ever conducted with the ESO telescopes. It has used the Very Large Telescope to collect nearly 100,000 redshifts from the general galaxy population at 0.5 properties and the relation of the latter to large-scale structure. This paper presents an overview of the galaxy clustering results obtained so far, together with their cosmological implications. Most of these are based on the ~ 55,000 galaxies forming the first public data release (PDR-1). As of January 2015, observations and data reduction are complete and the final data set of more than 90,000 redshifts is being validated and made ready for the final investigations.

  15. Discovery of gamma-ray emission from the extragalactic pulsar wind nebula N157B with the High Energy Stereoscopic System

    CERN Document Server

    Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Becker, J; Bernlöhr, K; Birsin, E; Biteau, J; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Cologna, G; Conrad, J; Couturier, C; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gajdus, M; Gallant, Y A; Garrigoux, T; Gast, H; Gérard, L; Giebels, B; Glicenstein, J F; Glück, B; Göring, D; Grondin, M -H; Häffner, S; Hague, J D; Hahn, J; Hampf, D; Harris, J; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Khélifi1, B; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Krayzel, F; Laffon, H; Lamanna, G; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Menzler, U; Moderski, R; Mohamed, M; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nguyen, N; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sheidaei, F; Skilton, J L; Sol, H; Spengler, G; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; White, R; Wierzcholska, A; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S

    2012-01-01

    We present the significant detection of the first extragalactic pulsar wind nebula (PWN) detected in gamma rays, N157B, located in the large Magellanic Cloud (LMC). Pulsars with high spin-down luminosity are found to power energised nebulae that emit gamma rays up to energies of several tens of TeV. N157B is associated with PSRJ0537-6910, which is the pulsar with the highest known spin-down luminosity. The High Energy Stereoscopic System telescope array observed this nebula on a yearly basis from 2004 to 2009 with a dead-time corrected exposure of 46 h. The gamma-ray spectrum between 600 GeV and 12 TeV is well-described by a pure power-law with a photon index of 2.8 \\pm 0.2(stat) \\pm 0.3(syst) and a normalisation at 1 TeV of (8.2 \\pm 0.8(stat) \\pm 2.5(syst)) \\times 10^-13 cm^-2s^-1TeV^-1. A leptonic multi-wavelength model shows that an energy of about 4 \\times 10^49erg is stored in electrons and positrons. The apparent efficiency, which is the ratio of the TeV gamma-ray luminosity to the pulsar's spindown lum...

  16. Extra-galactic background light measurements from the far-UV to the far-IR from deep ground and space-based galaxy counts

    CERN Document Server

    Driver, Simon P; Davies, Luke J; Robotham, Aaron S G; Wright, Angus H; Windhorst, Rogier A; Cohen, Seth; Emig, Kim; Jansen, Rolf A; Dunne, Loretta

    2016-01-01

    We combine wide and deep galaxy number-count data from GAMA, COSMOS/G10, HST ERS, HST UVUDF and various near-, mid- and far- IR datasets from ESO, Spitzer and Herschel. The combined data range from the far-UV (0.15microns) to far-IR (500microns), and in all cases the contribution to the integrated galaxy light (IGL) of successively fainter galaxies converges. Using a simple spline fit, we derive the IGL and the extrapolated-IGL in all bands. We argue undetected low surface brightness galaxies and intra-cluster/group light is modest, and that our extrapolated-IGL measurements are an accurate representation of the extra-galactic background light. Our data agree with most earlier IGL estimates and with direct measurements in the far-IR, but disagree strongly with direct estimates in the optical. Close agreement between our results and recent very high-energy experiments (H.E.S.S. and MAGIC), suggest that there may be an additional foreground affecting the direct estimates. The most likely culprit could be the ad...

  17. Lower limits on the anisotropy of the extragalactic gamma-ray background implied by the 2FGL and 1FHL catalogs

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E.; Smith, Kendrick M. [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Pfrommer, Christoph; Puchwein, Ewald [Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Chang, Philip [Department of Physics, University of Wisconsin-Milwaukee, 1900 E. Kenwood Boulevard, Milwaukee, WI 53211 (United States)

    2014-11-20

    In principle, the angular anisotropy in the extragalactic gamma-ray background (EGRB) places severe constraints upon putative populations of unresolved gamma-ray point sources. Existing estimates of the EGRB anisotropy have been constructed by excising known point sources, e.g., taken from the First or Two Year Fermi-LAT Source Catalog (1FGL or 2FGL, respectively) and statistically analyzing the residual gamma-ray sky maps. We perform an independent check of the EGRB anisotropy limits by comparing the values obtained from the 1FGL-masked sky maps to the signal implied by sources that lie below the 1FGL detection threshold in the more sensitive 2FGL and 1FHL (First Fermi-LAT catalog of >10 GeV sources). As such, our analysis provides an internal consistency check of implications for source counts and spectral index distributions of gamma-ray bright active galactic nuclei obtained from Fermi-LAT data. Based on this, we find evidence for substantially larger anisotropies than those previously reported at energies above 5 GeV, where BL Lac objects are likely to provide the bulk of their contribution to the EGRB. This uncertainty in the EGRB anisotropy cautions against using it as an independent constraint for the high-redshift gamma-ray universe. Moreover, this would suggest that contrary to previous claims, smooth extensions of the resolved point-source population may be able to simultaneously explain both the isotropic and anisotropic components of the EGRB.

  18. Absorption of High Energy $\\gamma$ Rays by Interactions With Starlight Photons in Extragalactic Space at High Redshifts and the High Energy $\\gamma$-Ray Background

    CERN Document Server

    Salamon, M H

    1998-01-01

    We calculate the absorption of 10-500 GeV gamma-rays at high redshifts. This calculation requires the determination of the high-redshift evolution of the intergalactic starlight photon field, including its IR-UV spectral energy distribution. To estimate this evolution, we have followed a recent analysis of Fall, Charlot and Pei which gives results consistent with recent data. We give our results for the gamma-ray opacity as a function of redshift out to a redshift of 3. We also give predicted gamma-ray spectra for selected blazars and give an extragalactic unresolved blazar background spectrum up to 500 GeV. Our results indicate that this background should steepen significantly above 20 GeV owing to intergalactic absorption. Future observations of this steepening would provide a test for the blazar background origin hypothesis. We have used our results to discuss upper limits on the redshifts of gamma-ray bursts. We note that the 17 Feb. 1994 burst observed by EGRET must have originated at a redshift less tha...

  19. A Magnetically-Switched, Rotating Black Hole Model For the Production of Extragalactic Radio Jets and the Fanaroff and Riley Class Division

    CERN Document Server

    Meier, D L

    1998-01-01

    A model is presented in which both Fanaroff and Riley class I and II extragalactic jets are produced by magnetized accretion disk coronae in the ergospheres of rotating black holes. While the jets are produced in the accretion disk itself, the output power still is an increasing function of the black hole angular momentum. For high enough spin, the black hole triggers the magnetic switch, producing highly-relativistic, kinetic-energy-dominated jets instead of Poynting-flux-dominated ones for lower spin. The coronal mass densities needed to trigger the switch at the observed FR break power are quite small ($\\sim 10^{-15} g cm^{-3}$), implying that the source of the jet material may be either a pair plasma or very tenuous electron-proton corona, not the main accretion disk itself. The model explains the differences in morphology and Mach number between FR I and II sources and the observed trend for massive galaxies to undergo the FR I/II transition at higher radio power. It also is consistent with the energy co...

  20. ALMA Census of Faint 1.2 mm Sources Down to ~0.01 mJy: Extragalactic Background Light and Dust-Poor High-z Galaxies

    CERN Document Server

    Fujimoto, Seiji; Ono, Yoshiaki; Shibuya, Takatoshi; Ishigaki, Masafumi; Momose, Rieko

    2015-01-01

    We present statistics of 89 faint 1.2-mm continuum sources with a flux density of ~0.01-1 mJy detected by about 100 deep ALMA pointing data that include the complete deep datasets archived by 2015 March. These faint sources are identified in 50 blank fields and behind one cluster, Abell 1689, that magnifies the background sources by gravitational lensing. Evaluating various important effects including the false detection, detection completeness, and flux boosting as well as the lensing magnification by modeling and simulations, we derive number counts of 1.2 mm continuum sources. We find that the number counts are well represented by the Schechter function down to ~0.01 mJy, and that the total integrated 1.2 mm flux of the securely identified sources is 22.8^(+6.1)_(-6.4) Jy deg^(-2) that corresponds to 104^(+27)_(-30)% of the extragalactic background light (EBL) measured by COBE observations. These results suggest that the major 1.2 mm EBL contributors are sources with >~0.01 mJy, and that very faint 1.2 mm ...