IDENTIFICATION OF 1.4 MILLION ACTIVE GALACTIC NUCLEI IN THE MID-INFRARED USING WISE DATA

Abstract : We present an all-sky sample of approx. equal 1.4 million active galactic nuclei (AGNs) meeting a two-color infrared photometric selection criteria for AGNs as applied to sources from the Wide-field Infrared Survey Explorer final catalog release (AllWISE). We assess the spatial distribution and optical properties of our sample and find that the results are consistent with expectations for AGNs. These sources have a mean density of approx. equal 38 AGNs per square degree on the sky, and their apparent magnitude distribution peaks at g approx. equal 20, extending to objects as faint as g approx. equal 26. We test the AGN selection criteria against a large sample of optically identified stars and determine the leakage (that is, the probability that a star detected in an optical survey will be misidentified as a quasi-stellar object (QSO) in our sample) rate to be less than or = 4.0 x 10(exp -5). We conclude that our sample contains almost no optically identified stars (less than or = 0.041%), making this sample highly promising for future celestial reference frame work as it significantly increases the number of all-sky, compact extragalactic objects. We further compare our sample to catalogs of known AGNs/QSOs and find a completeness value of greater than or approx. 84% (that is, the probability of correctly identifying a known AGN/QSO is at least 84%) for AGNs brighter than a limiting magnitude of R less than or approx. 19. Our sample includes approximately 1.1 million previously uncataloged AGNs.