Guenther Hasinger

Title

Evolution of Black Holes in the Universe 

Abstract

Different feeding modes have been identified for growing black holes, starting from small flares occurring almost daily in our Galactic Center black hole, and going up to major flares due to tidal disruption of otherwise dormant black holes. Furthermore, major mergers between two galaxies seem to play an important role in the feeding of black holes. X-ray observations allow detailed diagnostics of the relativistic accretion flow in the strong gravitational field near the event horizon. The X-ray sky is dominated by a diffuse extragalactic background radiation, which we were able to resolve almost completely into discrete sources using the X-ray satellites ROSAT, Chandra and XMM-Newton. This allows us to track the growth phase of the population of supermassive black holes throughout the history of the universe.