2006/12/12 by A. Boehm, Boehm, Asmus, L. Wisotzki +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.astro-ph/0612310
openalex publication_date 2006/12/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is still a matter of debate whether the properties of galaxies hosting an Active Galactic Nucleus (AGN) are different from the properties of quiescent galaxies. We constructed a sample of ~50 AGN at a mean redshift of ~0.6 that lack a detectable optical nucleus. This characteristic allows to study the properties of the host galaxies with much higher accuracy than in the case of "normal" AGN which show a prominent central point source in optical images. A comparison sample of X-ray faint, quiescent galaxies at intermediate redshifts shows a clear bimodality in terms of both rest-frame colors and morphological concentration indicators. In contrast to this, the AGN host galaxies comprise a large fraction of objects that have early-type morphologies but relatively blue rest-frame colors, possibly due to recent or ongoing star formation. A fraction of the "optically dull" AGN in our sample show evidence for kpc-scale absorption; low Supermassive Black Hole accretion rates are more likely in other cases.