Identification of 1.4 Million AGNs in the Mid-Infrared using WISE Data
  We present an all-sky sample of ~ 1.4 million 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 ~ 38 AGNs per square degree on the sky, and their apparent magnitude
distribution peaks at g ~ 20, extending to objects as faint as g ~ 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 QSO in our sample) rate to be <
4.0 x 10^-5. We conclude that our sample contains almost no
optically-identified stars (< 0.041%), making this sample highly promising for
future celestial reference frame work by significantly increasing 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 > 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 < 19. Our sample includes
approximately 1.1 million previously uncatalogued AGNs.
