AEGIS: The Clustering of X-ray AGN Relative to Galaxies at z~1
  We measure the clustering of non-quasar X-ray AGN at z=0.7-1.4 in the AEGIS
field. Using the cross-correlation of 113 Chandra-selected AGN, with a median
log L_X=42.8 erg s^-1, with ~5,000 DEEP2 galaxies, we find that the X-ray AGN
are fit by a power law with a clustering scale length of r_0=5.95 +/-0.90 h^-1
Mpc and slope gamma=1.66 +/-0.22. X-ray AGN have a similar clustering amplitude
as red, quiescent and `green' transition galaxies at z~1 and are significantly
more clustered than blue, star-forming galaxies. The X-ray AGN clustering
strength is primarily determined by the host galaxy color; AGN in red host
galaxies are significantly more clustered than AGN in blue host galaxies, with
a relative bias that is similar to that of red to blue DEEP2 galaxies. We
detect no dependence of clustering on optical brightness, X-ray luminosity, or
hardness ratio within the ranges probed here. We find evidence for galaxies
hosting X-ray AGN to be more clustered than a sample of galaxies with matching
joint optical color and magnitude distributions. This implies that galaxies
hosting X-ray AGN are more likely to reside in groups and more massive dark
matter halos than galaxies of the same color and luminosity without an X-ray
AGN. In comparison to optically-selected quasars in the DEEP2 fields, we find
that X-ray AGN at z~1 are more clustered than optically-selected quasars (with
a 2.6-sigma significance) and therefore likely reside in more massive dark
matter halos. Our results are consistent with galaxies undergoing a quasar
phase while in the blue cloud before settling on the red sequence with a
lower-luminosity X-ray AGN, if they are similar objects at different
evolutionary stages.
