2013ApJ...770...40M
PRIMUS: Infrared and X-Ray AGN Selection Techniques at 0.2 < z < 1.2
Mendez, Alexander J. ( Center for Astrophysics and Space Sciences, Department of Physics, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093, USA ); Coil, Alison L. ( Center for Astrophysics and Space Sciences, Department of Physics, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093, USA; Alfred P. Sloan Foundation Fellow. ); Aird, James ( Center for Astrophysics and Space Sciences, Department of Physics, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093, USA; Department of Physics, Durham University, Durham DH1 3LE, UK ); Diamond-Stanic, Aleksandar M. ( Center for Astrophysics and Space Sciences, Department of Physics, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093, USA; Center for Galaxy Evolution Fellow. ); Moustakas, John ( Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211, USA ); Blanton, Michael R. ( Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA ); Cool, Richard J. ( The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101, USA ; Hubble Fellow, Princeton-Carnegie Fellow. ); Eisenstein, Daniel J. ( Harvard College Observatory, 60 Garden St., Cambridge, MA 02138, USA ); Wong, Kenneth C. ( Steward Observatory, The University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721, USA ); Zhu, Guangtun ( Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA ) show affiliations
The Astrophysical Journal, Volume 770, Issue 1, article id. 40, 25 pp. (2013).
Published in Jun 2013
We present a study of Spitzer/IRAC and X-ray active galactic nucleus (AGN) selection techniques in order to quantify the overlap, uniqueness, contamination, and completeness of each. We investigate how the overlap and possible contamination of the samples depend on the depth of both the IR and X-ray data. We use Spitzer/IRAC imaging, Chandra and XMM-Newton X-ray imaging, and spectroscopic redshifts from the PRism MUlti-object Survey to construct galaxy and AGN samples at 0.2 < z < 1.2 over 8 deg2. We construct samples over a wide range of IRAC flux limits (SWIRE to GOODS depth) and X-ray flux limits (10 ks to 2 Ms). We compare IR-AGN samples defined using both the IRAC color selection of Stern et al. and Donley et al. with X-ray-detected AGN samples. For roughly similar depth IR and X-ray surveys, we find that ~75% of IR-selected AGNs are also identified as X-ray AGNs. This fraction increases to ~90% when comparing against the deepest X-ray data, indicating that at most ~10% of IR-selected AGNs may be heavily obscured. The IR-AGN selection proposed by Stern et al. suffers from contamination by star-forming galaxies at various redshifts when using deeper IR data, though the selection technique works well for shallow IR data. While similar overall, the IR-AGN samples preferentially contain more luminous AGNs, while the X-ray AGN samples identify a wider range of AGN accretion rates including low specific accretion rate AGNs, where the host galaxy light dominates at IR wavelengths. The host galaxy populations of the IR and X-ray AGN samples have similar rest-frame colors and stellar masses; both selections identify AGNs in blue, star-forming and red, quiescent galaxies.
Keywords:
Free Keywords: Astrophysics - Cosmology and Extragalactic Astrophysics; X-rays: galaxies; galaxies: active; galaxies: evolution; infrared: galaxies
Astronomy: X-rays: galaxies; galaxies: active; galaxies: evolution; infrared: galaxies
arXiv: Astrophysics - Cosmology and Extragalactic Astrophysics
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