EVOLUTION OF GALAXIES AND THEIR ENVIRONMENTS AT z = 0.1-3 IN COSMOS
- California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Highway, Kamuela, HI 96743 (United States)
- AIM Unite Mixte de Recherche CEA CNRS, Universite Paris VII UMR n158, Paris (France)
- INAF-Osservatorio Astronomico di Roma, Via di Frascati 33, I-00040 Monteporzio Catone, Rome (Italy)
- Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8582 (Japan)
- Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States)
- Spitzer Science Center, MS 314-6, California Institute of Technology, Pasadena, CA 91125 (United States)
- Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-strasse 27, CH-8093 Zurich (Switzerland)
- Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)
- Max Planck Institut fuer Extraterrestrische Physik, D-85478 Garching (Germany)
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- Laboratoire d'Astrophysique de Marseille, B. P. 8, Traverse du Siphon, F-13376 Marseille Cedex 12 (France)
- INAF-Osservatorio Astronomico di Brera, via Brera, 28, 20159 Milano (Italy)
- Physics Department, Graduate School of Science, Ehime University, 2-5 Bunkyou, Matsuyama 790-8577 (Japan)
Large-scale structures (LSSs) out to z < 3.0 are measured in the Cosmic Evolution Survey (COSMOS) using extremely accurate photometric redshifts (photoz). The K{sub s} -band-selected sample (from Ultra-Vista) is comprised of 155,954 galaxies. Two techniques-adaptive smoothing and Voronoi tessellation-are used to estimate the environmental densities within 127 redshift slices. Approximately 250 statistically significant overdense structures are identified out to z = 3.0 with shapes varying from elongated filamentary structures to more circularly symmetric concentrations. We also compare the densities derived for COSMOS with those based on semi-analytic predictions for a {Lambda}CDM simulation and find excellent overall agreement between the mean densities as a function of redshift and the range of densities. The galaxy properties (stellar mass, spectral energy distributions (SEDs), and star formation rates (SFRs)) are strongly correlated with environmental density and redshift, particularly at z < 1.0-1.2. Classifying the spectral type of each galaxy using the rest-frame b - i color (from the photoz SED fitting), we find a strong correlation of early-type galaxies (E-Sa) with high-density environments, while the degree of environmental segregation varies systematically with redshift out to z {approx} 1.3. In the highest density regions, 80% of the galaxies are early types at z = 0.2 compared to only 20% at z = 1.5. The SFRs and the star formation timescales exhibit clear environmental correlations. At z > 0.8, the SFR density is uniformly distributed over all environmental density percentiles, while at lower redshifts the dominant contribution is shifted to galaxies in lower density environments.
- OSTI ID:
- 22156547
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 206, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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