A radiation-hydrodynamical model for supermassive black hole-to-bulge massrelation and quasar formation

As a potential mechanism to build up supermassive black holes (BHs) in a sp heroidal system, we consider the radiation drag effect by bulge stars, whic h extracts angular momentum from interstellar gas and thus allows the gas t o accrete onto the galactic center. By incorporating the radiation hydrodyn amical equation with simple stellar evolution, it is shown that the BH- to- bulge mass ratio, f(BH), is basically determined by a fundamental fBH cons tant, that is, the energy conversion efficiency for nuclear fusion of hydro gen to helium,epsilon =0.007. More specifically, f(BH) is predicted to be 0 .3 epsilon -0.5 epsilon. Based on the present model for BH growth, a scenar io for quasar formation is addressed in relation to ultraluminous infrared galaxies.