DEIMOS Observations of WISE-Selected, Optically Obscured AGNs
  While there are numerous criteria for photometrically identifying active
galactic nuclei (AGNs), searches in the optical and UV tend to exclude galaxies
that are highly dust obscured. This is problematic for constraining models of
AGN evolution and estimating the AGN contribution to the cosmic X-ray and IR
backgrounds, as highly obscured objects tend to be underrepresented in
large-scale surveys. To address this, we identify potentially obscured AGNs
using mid-IR color colors from the Wide-field Infrared Survey Explorer (WISE)
catalog. This paper presents the results of optical spectroscopy of obscured
AGN candidates using Keck DEIMOS, and their physical properties derived from
these spectra. We find that a $W1-W2>0.8$ color criterion effectively selects
AGNs with a higher median level of $E(B-V)$ extinction compared to the AGNs
found in the SDSS DR7 survey. This optical extinction can be measured using SED
modeling or by using $r-W1$ as a measure of optical to IR flux. We find that
specific, targeted observations are necessary to find the most highly optically
obscured AGNs, and that additional far-IR photometry is necessary to further
constrain the dust properties of these AGNs.
