The Angular Clustering of Infrared-Selected Obscured and Unobscured
  Quasars
  Recent studies of luminous infrared-selected active galactic nuclei (AGN)
suggest that the reddest, most obscured objects display a higher angular
clustering amplitude, and thus reside in higher-mass dark matter halos. This is
a direct contradiction to the prediction of the simplest
unification-by-orientation models of AGN and quasars. However, clustering
measurements depend strongly on the "mask" that removes low-quality data and
describes the sky and selection function. We find that applying a robust,
conservative mask to WISE-selected quasars yields a weaker but still
significant difference in the bias between obscured and unobscured quasars.
These findings are consistent with results from previous Spitzer surveys, and
removes any scale dependence of the bias. For obscured quasars with $\langle z
\rangle = 0.99$ we measure a bias of $b_q = 2.67 \pm 0.16$, corresponding to a
halo mass of $\log (M_h / M_{\odot} h^{-1}) = 13.3 \pm 0.1$, while for
unobscured sources with $\langle z \rangle = 1.04$ we find $b_q = 2.04 \pm
0.17$ with a halo mass $\log (M_h / M_{\odot} h^{-1} )= 12.8 \pm 0.1$. This
improved measurement indicates that WISE-selected obscured quasars reside in
halos only a few times more massive than the halos of their unobscured
counterparts, a reduction in the factor of $\sim$10 larger halo mass as has
been previously reported using WISE-selected samples. Additionally, an
abundance matching analysis yields lifetimes for both obscured and unobscured
quasar phases on the order of a few 100 Myr ($\sim$ 1\% of the Hubble time) ---
however, the obscured phase lasts roughly twice as long, in tension with many
model predictions.
