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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 (Loptacc < Loptgal when m9 < 10-4, or when the galaxy magnitude is Moptgal > -13). However, for holes in spiral galaxies, where the optical luminosity is dominated by a stellar disk of luminosity ~ 2 x 1010 Lsun, the object will appear as a Seyfert galaxy rather than a quasar (Loptgal > Loptacc) for black holes of rather high mass (m9 < 0.03 or MH < 3 x 107 Msun). The simple accretion paradigm, therefore, accounts for several of the basic optical properties of Seyfert, radio galaxy, and quasar (parent) populations.