THE COSMOS ACTIVE GALACTIC NUCLEUS SPECTROSCOPIC SURVEY. I. XMM-NEWTON COUNTERPARTS
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Observatories of the Carnegie Institute of Washington, Santa Barbara Street, Pasadena, CA 91101 (United States)
- Max Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany)
- California Institute of Technology, MC 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna (Italy)
- Max Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)
- Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland)
We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg{sup 2} Cosmic Evolution Survey field, with a yield of 485 high-confidence redshifts. The majority of the spectra were obtained over three seasons (2005-2007) with the Inamori Magellan Areal Camera and Spectrograph instrument on the Magellan (Baade) telescope. We also include in the sample previously published Sloan Digital Sky Survey spectra and supplemental observations with MMT/Hectospec. We detail the observations and classification analyses. The survey is 90% complete to flux limits of f {sub 0.5-10keV} > 8 x 10{sup -16} erg cm{sup -2} s{sup -1} and i {sup +} {sub AB} < 22, where over 90% of targets have high-confidence redshifts. Making simple corrections for incompleteness due to redshift and spectral type allows for a description of the complete population to i {sup +} {sub AB} < 23. The corrected sample includes a 57% broad emission line (Type 1, unobscured) active galactic nucleus (AGN) at 0.13 < z < 4.26, 25% narrow emission line (Type 2, obscured) AGN at 0.07 < z < 1.29, and 18% absorption line (host-dominated, obscured) AGN at 0 < z < 1.22 (excluding the stars that made up 4% of the X-ray targets). We show that the survey's limits in X-ray and optical fluxes include nearly all X-ray AGNs (defined by L {sub 0.5-10keV} > 3 x 10{sup 42} erg s{sup -1}) to z < 1, of both optically obscured and unobscured types. We find statistically significant evidence that the obscured-to-unobscured AGN ratio at z < 1 increases with redshift and decreases with luminosity.
- OSTI ID:
- 21300712
- Journal Information:
- Astrophysical Journal, Vol. 696, Issue 2; Other Information: DOI: 10.1088/0004-637X/696/2/1195; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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