The Near Environments of AGN from z=0.2 to 2.0

Using Hubble ACS images taken as part of the Cosmic Evolution Survey (COSMOS), an HST Treasury Project to map 2 square degrees of sky, we investigate host morphologies and close companions of AGN at redshifts from z ∼0.2 to ∼2.0. After initial X-ray and radio selection, COSMOS team members have performed spectroscopic follow-up observations to confirm ∼350 AGN so far, with an expected total yield of ∼1100 from ongoing observations. We use the high-resolution HST images of these AGN to characterize their hosts with simple morphological models, including Sérsic profile fits and asymmetry via Fourier-component analysis. Furthermore, we search for nearby companion galaxies to the AGN hosts. Completion of these studies on the entire sample will enable us to constrain theories in which galaxy mergers fuel AGN.