Radiative pressure feedback by a quasar in a galactic bulge

We show that Eddington-limited black hole luminosities can be sufficient to deplete a galaxy bulge of gas through radiation pressure, when the ionization state of the gas and the presence of dust are properly taken into account. Once feedback starts to be effective it can consistently drive all the gas out of the whole galaxy. We estimate the amount by which the effect of radiation pressure on dusty gas boosts the mass involved in the Eddington limit, and discuss the expected column density at which the gas is ejected. An example is shown of the predicted observed nuclear spectrum of the system at the end of an early, obscured phase of growth when the remaining column density NH ~ 1024 fcm-2, where f is the gas fraction in the bulge.