  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 ~ f * 1e24
cm^-2 where f is the gas fraction in the bulge.
