AEGIS: Host Galaxy Morphologies of X-ray and Infrared-selected AGN at   0.2 < z < 1.2
  We visually and quantitatively determine the host galaxy morphologies of 94 intermediate redshift (0.2 < z < 1.2) active galactic nuclei (AGN), selected using Chandra X-ray and Spitzer mid-infrared data in the Extended Groth Strip. Using recently developed morphology measures, the second-order moment of the brightest 20% of a galaxy's flux (M_{20}) and the Gini coefficient, we find that X-ray-selected AGN mostly reside in E/S0/Sa galaxies (53^{+11}_{-10}%), while IR-selected AGN show no clear preference for host morphology. X-ray-selected AGN hosts are members of close pairs more often than the field population by a factor of 3.3+/-1.4, but most of these pair members appear to be undisturbed early-type galaxies and do not tend to show direct evidence of gravitational perturbations or interactions. Thus, the activation mechanism for AGN activity remains unknown, even for pair members. 
C. M. Pierce, J. M. Lotz, E. S. Laird, L. Lin, K. Nandra, J. R.   Primack, S. M. Faber, P. Barmby, S. Q. Park, S. P. Willner...