Supermassive Black Holes in Active Galactic Nuclei. II. Calibration of the MBH–σ∗ Relationship for AGNs

We calibrate reverberation-based black hole masses in active galactic nuclei (AGNs) by using the correlation between black hole mass, MBH, and bulge/spheroid stellar velocity dispersion, σ∗. We use new measurements of σ∗ for 6 AGNs and published velocity dispersions for 10 others, in conjunction with improved reverberation mapping results, to determine the scaling factor required to bring reverberation-based black hole masses into agreement with the quiescent galaxy MBH–σ∗ relationship. The scatter in the AGN BH masses is found to be less than a factor of 3. The current observational uncertainties preclude use of the scaling factor to discriminate between broad-line region models. Subject headings: galaxies: active — galaxies: nuclei — galaxies: Seyfert