2.2 Observations Explained

Several interesting corollaries immediately follow from this picture. For black holes in elliptical galaxies, only dwarf ellipticals are brighter than their central quasar (L^opt_acc < L^opt_gal when m₉ < 10^-4, or when the galaxy magnitude is M^opt_gal > -13). However, for holes in spiral galaxies, where the optical luminosity is dominated by a stellar disk of luminosity ~ 2 x 10¹⁰ L, the object will appear as a Seyfert galaxy rather than a quasar (L^opt_gal > L^opt_acc) for black holes of rather high mass (m₉ < 0.03 or M_H < 3 x 10⁷ M). The simple accretion paradigm, therefore, accounts for several of the basic optical properties of Seyfert, radio galaxy, and quasar (parent) populations.