Institute for Advanced Study Astrophysics Seminar

ABSTRACT: Multiwavelength surveys like GOODS and COSMOS indicate that most actively growing black holes are heavily obscured, and this fraction increases in the young Universe and in lower luminosity AGN. Most black holes grow in moderate luminosity AGN, which dominate the X-ray ³background,² rather than in luminous quasars. In the peak epoch of black hole growth, at z~1-3, such AGN are hosted in galaxies with significant disks, and thus cannot have undergone a recent major merger. Using morphological classifications from Galaxy Zoo (at z~0), we identify two distinct modes of galaxy evolution, with mergers and AGN feedback affecting only a minority.