IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA
Name
Donley-2012-Identifying luminous.pdf
Size
10.15 MB
Format
Adobe PDF
Checksum (MD5)
8e4a6512c8bc0f8ce8eab7e6b9d0a0bd
Author(s)
Donley, J. L.
Koekemoer, A. M.
Brusa, M.
Capak, P.
Civano, F.
Ilbert, O.
Impey, C. D.
Kartaltepe, J. S.
Miyaji, T.
Salvato, M.
Date Issued
March 2012
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Donley, J. L., A. M. Koekemoer, M. Brusa, P. Capak, C. N. Cardamone, F. Civano, O. Ilbert, et al. “IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA.” The Astrophysical Journal 748, no. 2 (March 16, 2012): 142. © 2012 The American Astronomical Society
Version
Final published version
Abstract
Spitzer/IRAC selection is a powerful tool for identifying luminous active galactic nuclei (AGNs). For deep IRAC data, however, the AGN selection wedges currently in use are heavily contaminated by star-forming galaxies, especially at high redshift. Using the large samples of luminous AGNs and high-redshift star-forming galaxies in COSMOS, we redefine the AGN selection criteria for use in deep IRAC surveys. The new IRAC criteria are designed to be both highly complete and reliable, and incorporate the best aspects of the current AGN selection wedges and of infrared power-law selection while excluding high-redshift star-forming galaxies selected via the BzK, distant red galaxy, Lyman-break galaxy, and submillimeter galaxy criteria. At QSO luminosities of log L [subscript 2-10 keV](erg s[superscript –1]) ≥44, the new IRAC criteria recover 75% of the hard X-ray and IRAC-detected XMM-COSMOS sample, yet only 38% of the IRAC AGN candidates have X-ray counterparts, a fraction that rises to 52% in regions with Chandra exposures of 50-160 ks. X-ray stacking of the individually X-ray non-detected AGN candidates leads to a hard X-ray signal indicative of heavily obscured to mildly Compton-thick obscuration (log N [subscript H] (cm[superscript –2]) = 23.5 ± 0.4). While IRAC selection recovers a substantial fraction of luminous unobscured and obscured AGNs, it is incomplete to low-luminosity and host-dominated AGNs.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0004-637x/748/2/142
