Agn Host Galaxies at Z ∼ 0 . 4 – 1 . 3 : Bulge - Dominated and Lacking Merger – Agn Connection

We investigate morphological structure parameters and local environments of distant moderate-luminosity active galactic nucleus (AGN) host galaxies in the overlap between the HST/ACS observations of the Great Observatories Origins Deep Survey (GOODS) and the two Chandra Deep Fields. We compute near-neighbor counts and BV iz asymmetry (A) and concentration (C) indices for ≈ 35, 500 GOODS/ACS galaxies complete to z 850 ≈ 26.6, including the resolved hosts of 322 X-ray–selected AGNs. Distributions of (1) z 850 asymmetry for 130 z 850 < 23 AGN hosts and (2) near-neighbor counts for 173 z 850 < 24 AGN hosts are both consistent with non-AGN control samples. This implies no close connection between recent galaxy mergers and moderate-luminosity AGN activity out to appreciable look-back times (z 1.3), approaching the epoch of peak AGN activity in the universe. The distribution of z 850 C for the AGN hosts is offset by ∆C ≈ +0.5 compared to the non-AGN, a 6.4 σ discrepancy much larger than can be explained by the possible influence of unresolved emission from the AGN or a circumnuclear starburst. The local universe association between AGN and bulge-dominated galaxies thus persists to substantial look-back time. We discuss implications in the context of the low-redshift supermassive central black hole mass correlation with host galaxy properties, including concentration. The connection between active galactic nuclei (AGNs) and their host galaxies, and the evolution in that relationship over cosmic time, have attracted great interest in recent years. This includes the discoveries that most nearby massive galaxies harbor central supermas-sive black holes (SMBHs; Magorrian et al. 1998), that AGNs in the local universe (z 1) reside predominantly in massive, bulge-dominated host galaxies (Kauffmann et al. 2003), and that a tight correlation exists locally between SMBH mass and host galaxy properties such as bulge velocity dispersion and light-profile concentration which have now resolved much of the cosmic X-ray background into moderate-luminosity AGNs at z ∼ 1 (Alexander et al. 2003; Barger et al. 2003; Szokoly et al. 2004), provide a unique AGN sample to probe these locally observed SMBH-host relationships out to epochs nearing the peaks of star formation and AGN activity in the universe. This is one of the aims of the Great Observatories Origins Deep Survey (GOODS; Giavalisco et al. 2004), which has obtained deep multicolor Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) image mosaics across the most sensitive regions of the CDF areas. …