Environment of $1\le z \le 2$ obscured and unobscured AGNs in the
  Extended Chandra Deep Field South
  In unified models, different types of active galaxy nuclei correspond to a
single class of objects, where their observed differences are solely due to the
different orientations of the obscuring material around the central inner
regions. Recent studies also show that this obscuring material can even extend
at galactic scales due to debris and/or mergers. In standard unified models the
different AGN types are expected to show similar galaxy environments. We aim to
investigate properties and environment of obscured and unobscured AGNs selected
from the MUSYC survey, in order to test the unified model and evolutionary
scenarios. The sample of AGNs was selected from images obtained with the IRAC
Camera, based on their MIR colors. We selected two samples of AGNs with
redshifts in the range $1\le z \le 2$ and $M_v\leq -$21: obscured and
unobscured AGNs by means of a simple optical-MIR color cut criterion. We find
that obscured AGNs are intrinsically optically faint in the R band, suggesting
that luminous IR-selected AGNs have a significant dust extinction. From a
cross-correlation with several X-ray surveys, we find that the majority of the
AGNs have X-ray luminosities similar to those found in Seyfert-like galaxies.
Neighbouring galaxies located close to ($\sim$200 kpc) obscured AGNs tend to
have redder colors, compared to the local environment of unobscured AGNs.
Results obtained from a KS test show that the two color distributions are
different at $\sim$95% confidence level. We find that obscured AGNs are located
in denser local galaxy environments compared to the unobscured AGN sample. Our
results suggest that AGN obscuration can occur at galactic scales, possibly due
to galaxy interactions or mergers, and that the simple unified model based
solely on the local torus orientation may not be sufficient to explain all the
observations.
