The Chandra COSMOS Survey. III. Optical and infrared identification of X-ray point sources
Por:
Civano F., Elvis M., Brusa M., Comastri A., Salvato M., Zamorani G., Aldcroft T., Bongiorno A., Capak P., Cappelluti N., Cisternas M., Fiore F., Fruscione A., Hao H., Kartaltepe J., Koekemoer A., Gilli R., Impey C.D., Lanzuisi G., Lusso E., Mainieri V., Miyaji T., Lilly S., Masters D., Puccetti S., Schawinski K., Scoville N.Z., Silverman J., Trump J., Urry M., Vignali C., Wright N.J.
Publicada:
1 ago 2012
Resumen:
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.9deg 2 of the COSMOS field down to limiting depths of 1.9 × 10 -16ergcm -2s -1 in the soft (0.5-2keV) band, 7.3 × 10 -16ergcm -2s -1 in the hard (2-10keV) band, and 5.7 × 10 -16ergcm -2s -1 in the full (0.5-10keV) band. In this paper we report the i, K, and 3.6µm identifications of the 1761 X-ray point sources. We use the likelihood ratio technique to derive the association of optical/infrared counterparts for 97% of the X-ray sources. For most of the remaining 3%, the presence of multiple counterparts or the faintness of the possible counterpart prevented a unique association. For only 10 X-ray sources we were not able to associate a counterpart, mostly due to the presence of a very bright field source close by. Only two sources are truly empty fields. The full catalog, including spectroscopic and photometric redshifts and classification described here in detail, is available online. Making use of the large number of X-ray sources, we update the "classic locus" of active galactic nuclei (AGNs) defined 20years ago in soft X-ray surveys and define a new locus containing 90% of the AGNs in the survey with full-band luminosity >10 42ergs -1. We present the linear fit between the total i-band magnitude and the X-ray flux in the soft and hard bands, drawn over two orders of magnitude in X-ray flux, obtained using the combined C-COSMOS and XMM-COSMOS samples. We focus on the X-ray to optical flux ratio (X/O) and we test its known correlation with redshift and luminosity, and a recently introduced anti-correlation with the concentration index (C). We find a strong anti-correlation (though the dispersion is of the order of 0.5 dex) between X/O computed in the hard band and C and that 90% of the obscured AGNs in the sample with morphological information live in galaxies with regular morphology (bulgy and disky/spiral), suggesting that secular processes govern a significant fraction of the black hole growth at X-ray luminosities of 10 43-10 44.5ergs -1. We also investigate the degree of obscuration of the sample using the hardness ratio, and we compare the X-ray color with the near-infrared to optical color. © © 2012. The American Astronomical Society. All rights reserved.
Filiaciones:
Civano F.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Elvis M.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Brusa M.:
Max Planck Institut für Extraterrestrische Physik, Giessenbach Strasse 1, D-85748 Garching, Germany
Comastri A.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Salvato M.:
Max Planck Institut für Extraterrestrische Physik, Giessenbach Strasse 1, D-85748 Garching, Germany
Excellence Cluster, Boltzmannstrass 2, Garching D-85748, Germany
Zamorani G.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Aldcroft T.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Bongiorno A.:
Max Planck Institut für Extraterrestrische Physik, Giessenbach Strasse 1, D-85748 Garching, Germany
INAF-Osservatorio Astronomico di Roma, via Frascati 33, Monteporzio-Catone (Roma) I-00040, Italy
Capak P.:
California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125, United States
Cappelluti N.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Cisternas M.:
Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
Fiore F.:
INAF-Osservatorio Astronomico di Roma, via Frascati 33, Monteporzio-Catone (Roma) I-00040, Italy
Fruscione A.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Hao H.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Kartaltepe J.:
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, United States
Koekemoer A.:
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, United States
Department of Physics and Astronomy, University of California, 900 University Avenue, Riverside, CA 92521, United States
Gilli R.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Impey C.D.:
Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, United States
Lanzuisi G.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
INAF-Osservatorio Astronomico di Roma, via Frascati 33, Monteporzio-Catone (Roma) I-00040, Italy
Lusso E.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Mainieri V.:
ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany
Miyaji T.:
Univ Nacl Autonoma Mexico Ensenada, Ensenada 22860, Baja California, Mexico
Lilly S.:
Institute of Astronomy, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
Masters D.:
Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101, United States
Puccetti S.:
ASI Science Data Center, via Galileo Galilei, I-00044 Frascati, Italy
Schawinski K.:
Department of Physics, Yale University, New Haven, CT 06511, United States
Scoville N.Z.:
California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125, United States
Silverman J.:
Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8568, Japan
Trump J.:
Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, United States
Urry M.:
Department of Physics, Yale University, New Haven, CT 06511, United States
Vignali C.:
INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Dipartimento di Astronomia, Universitá di Bologna, via Ranzani 1, I-40127 Bologna, Italy
Wright N.J.:
Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
|