On the Black Hole - Bulge Mass Relation in Active and Inactive Galaxies

Abstract.

New virial black-hole mass estimates are presented for a sample of 72 AGN covering three decades in optical luminosity. Using a model in which the AGN broad - line region (BLR) has a flattened geometry, we investigate the M _bh - L _bulge relation for a combined 90-object sample, consisting of the AGN plus a sample of 18 nearby inactive elliptical galaxies with dynamical black-hole mass measurements. It is found that, for all reasonable mass-to-light ratios, the M _bh -L _bulge relation is equivalent to a linear scaling between bulge and black-hole mass. The best-fitting normalization of the M _bh -M _bulge relation is found to be M _bh =0.0012M _bulge , in agreement with recent black-hole mass studies based on stellar velocity dispersions. Furthermore, the scatter around the M _bh -L _bulge relation for the full sample is found to be significantly smaller than has been previously reported ( $\Delta \log M_{bh}=0.39$ dex). Finally, using the nearby inactive elliptical galaxy sample alone, it is shown that the scatter in the M _bh -L _bulge relation is only 0.33 dex, comparable to that of the $M_{bh}-\sigma$ relation. These results indicate that reliable black-hole mass estimates can be obtained for high redshift galaxies.