The black hole masses of Seyfert galaxies and quasars

The central black hole masses of a sample of 30 luminous quasars are estima ted using HP fall width half-maximum (FWHM) measurements from a combination of new and previously published nuclear spectra. The quasar black hole mas s estimates are combined with reverberation-mapping measurements for a samp le of Seyfert galaxies in order to study active galatic nucleus (AGN) black hole masses over a wide range in nuclear luminosity. The link between bulg e luminosity and black hole mass is investigated using two-dimensional disc /bulge decompositions of the host galaxy images, the vast majority of which are high-resolution Hubble Space Telescope (HST) observations. It is found that black hole mass and bulge luminosity are well correlated and follow a relation consistent with that expected if black hole and bulge mass are di rectly proportional. Contrary to the recent results of Wandel, no evidence that Seyfert galaxies follow a different M-bh-M-bulge, relation to quasars is found. However, the black hole mass distributions of the radio-loud and radio-quiet quasar subsamples are found to be significantly different, with the median black hole mass of the radio-loud quasars a factor of three lar ger than their radio-quiet counterparts. Finally, utilizing the elliptical galaxy fundamental plane to provide stellar velocity dispersion estimates, a comparison is performed between the virial H beta black hole mass estimat es and those of the M-bh-sigma correlations of Gebhardt et al. and Merritt & Ferrarese. With the disc geometry of the broad-line region adopted in thi s paper, the virial H beta black hole masses indicate that the correct norm alization of the black hole versus bulge mass relation is M-bh similar or e qual to 0.0025M(bulge), while the standard assumption of purely random broa d-line velocities leads to M-bh similar or equal to 0.0008M(bulge). The nor malization Of M-bh similar or equal to 0.0025M(bulge), provided by the disc model is in remarkably good agreement with that inferred for our quasar sa mple using the (completely independent) M-bh-sigma correlations.