7 February 2013

Speaker: Megan Urry (Yale)

Title:Cosmic Black Hole Growth and Galaxy Co-Evolution

Abstract:The growth of black holes over billions of years releases energy that may quench star formation and strongly affect galaxy evolution. Using multiwavelength surveys to trace the cosmic history of black hole growth at the centers of galaxies, we find that most Active Galactic Nuclei are heavily obscured, and thus are not found in large area optical surveys like the Sloan Digital Sky Survey, and that obscuration is more common in the young Universe and in moderate luminosity AGN. Most black hole growth takes place in these moderate luminosity AGN rather than in their higher luminosity counterparts ("quasars"), and feedback in such systems would affect many more galaxies than do quasars. Most moderate luminosity AGN are hosted in galaxies with significant disks, even at the peak epoch of star formation and black hole growth, suggesting that major mergers do not trigger most black hole growth, though they are probably important in the most luminous quasars. Finally, we find an intriguing dependence of AGN activity on host galaxy morphology which is not yet fully explained.

Video of the Presentation (Talks can be viewed with RealPlayer. Free download is available from www.real.com )