Observational constraints on growth of massive black holes

We study the observational constraints on the growth of massive black holes (BHs) in galactic nuclei. We use the velocity dispersions of early-type galaxies obtained by the Sloan Digital Sky Survey and the relation between BH mass and velocity dispersion to estimate the local BH mass density to be (z = 0) (2.5 0.4) 10 5 h 2 0.65 M Mpc -3 . We also use the quasistellar object (QSO) luminosity function from the 2dF Redshift Survey to estimate the BH mass density accreted during optically bright QSO phases. The local BH mass density is consistent with the density accreted during optically bright QSO phases if QSOs have a massto-energy conversion efficiency 0.1. By studying the continuity equation for the BH mass…

• NS
  National Science Foundation
• NA
  National Aeronautics and Space Administration