On the black hole-bulge mass relation in active and inactive galaxies

New black hole mass estimates are presented for a sample of 72 active galactic nuclei (AGNs) covering three decades in optical luminosity. Using a subsample of Seyfert galaxies, which have black hole mass estimates from both reverberation mapping and stellar velocity dispersions, we investigate the geometry of the AGNs' broad-line region. It is demonstrated that a model in which the orbits of the line-emitting material have a flattened geometry is favoured over randomly-orientated orbits. Using this model we investigate the M-bh-L-bulge relation for a combined 90-object sample consisting of the AGNs 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 (Deltalog 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 with that of the M-bh -sigma relation. These results indicate that reliable black hole mass estimates can be obtained for high redshift galaxies.