Radiative Feedback from Quasars and the Growth of Supermassive Black Holes

We discuss the role of feedback via photoionization and Compton heating in the co-evolution of massive black holes at the center of spheroidal galaxies and their stellar and gaseous components. We first assess the energetics of the radiative feedback from a typical quasar on the ambient interstellar gas. We then demonstrate that the observed Mbh-sigma relation could be established at a relatively early epoch in galactic evolution when the formation of the stellar bulge was almost completed and the gas-to-stars mass ratio was reduced to a low level ~0.01 such that cooling could not keep up with radiative heating. A considerable amount of gas was expelled at that time and black hole accretion proceeded at a much lower rate thereafter.