A MULTIWAVELENGTH STUDY OF A SAMPLE OF 70 mum SELECTED GALAXIES IN THE COSMOS FIELD. I. SPECTRAL ENERGY DISTRIBUTIONS AND LUMINOSITIES

Journal Article · Mon Feb 01 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/709/2/572· OSTI ID:21392252

Kartaltepe, Jeyhan S; Sanders, D B; Le Floc'h, E; Ilbert, O ^[1]; Frayer, D T ^[2]; Aussel, H ^[3]; Arnouts, S ^[4]; Salvato, M; Scoville, N Z; Capak, P ^[5]; Surace, J; Yan, L ^[6]; Brusa, M; Hasinger, G ^[7]; Caputi, K; Carollo, C M ^[8]; Civano, F; Elvis, M ^[9]; Faure, C ^[10]

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1. Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States)
2. Infrared Processing and Analysis Center, California Institute of Technology 100-22, Pasadena, CA 91125 (United States)
3. CNRS, AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII-UMR 7158, F-91191 Gif-sur-Yvette (France)
4. Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743 (United States)
5. California Institute of Technology, MC 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
6. Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
7. Max Planck Institut fuer Extraterrestrische Physik, D-85478 Garching (Germany)
8. Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland)
9. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
10. Laboratoire d'Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix (Switzerland)

We present a large robust sample of 1503 reliable and unconfused 70 mum selected sources from the multiwavelength data set of the Cosmic Evolution Survey. Using the Spitzer IRAC and MIPS photometry, we estimate the total infrared (IR) luminosity, L{sub IR} (8-1000 mum), by finding the best-fit template from several different template libraries. The long-wavelength 70 and 160 mum data allow us to obtain a reliable estimate of L{sub IR}, accurate to within 0.2 and 0.05 dex, respectively. The 70 mum data point enables a significant improvement over the luminosity estimates possible with only a 24 mum detection. The full sample spans a wide range in IR luminosity, L{sub IR} approx 10{sup 8}-10{sup 14} L{sub sun}, with a median luminosity of 10{sup 11.4} L{sub sun}. We identify a total of 687 luminous, 303 ultraluminous, and 31 hyperluminous infrared galaxies (LIRGs, ULIRGs, and HyLIRGs) over the redshift range 0.01 < z < 3.5 with a median redshift of 0.5. Presented here are the full spectral energy distributions (SEDs) for each of the sources compiled from the extensive multiwavelength data set from the ultraviolet (UV) to the far-infrared. A catalog of the general properties of the sample (including the photometry, redshifts, and L{sub IR}) is included with this paper. We find that the overall shape of the SED and trends with L{sub IR} (e.g., IR color temperatures and optical-IR ratios) are similar to what has been seen in studies of local objects; however, our large sample allows us to see the extreme spread in UV to near-infrared colors spanning nearly 3 orders of magnitude. In addition, using SED fits we find possible evidence for a subset of cooler ultraluminous objects than observed locally. However, until direct observations at longer wavelengths are obtained, the peak of emission and the dust temperature cannot be well constrained. We use these SEDs, along with the deep radio and X-ray coverage of the field, to identify a large sample of candidate active galactic nuclei (AGNs). We find that the fraction of AGNs increases strongly with L{sub IR}, as it does in the local universe, and that nearly 70% of ULIRGs and all HyLIRGs likely host a powerful AGN.

• OSTI ID: 21392252
• Journal Information: Astrophysical Journal, Vol. 709, Issue 2; Other Information: DOI: 10.1088/0004-637X/709/2/572; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COLOR
COSMOLOGY
ENERGY SPECTRA
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
LUMINOSITY
PHOTOMETRY
RED SHIFT
ULTRAVIOLET RADIATION
UNIVERSE
WAVELENGTHS
X RADIATION
ELECTROMAGNETIC RADIATION
EVOLUTION
IONIZING RADIATIONS
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SPECTRA