The distribution of black hole ( BH ) masses { M _ { \bullet } } in galaxies is constrained by photometric and kinematic studies of individual galaxies , and by the properties of the quasar population .
I review our understanding of these topics , present new results of adiabatic BH growth models for HST photometry of elliptical galaxies with brightness profiles of the ‘ core ’ type , and discuss the implications of ground-based stellar kinematical data .
It is not yet possible to uniquely determine the BH mass distribution , but the available evidence is not inconsistent with a picture in which : ( i ) a majority of galaxies has BHs ; ( ii ) there is a correlation ( with large scatter ) between { M _ { \bullet } } and spheroid luminosity { L _ { sph } } of the form { M _ { \bullet } } \approx 10 ^ { -2 } { L _ { sph } } ( solar B-band units ) ; and ( iii ) the BHs formed in a quasar phase through mass accretion with efficiency \epsilon \approx 0.05 .