Black hole mass, velocity dispersion, and the radio source in active galactic nuclei

The recent discovery by Gebhardt et al. and Ferrarese & Merritt of a correl ation between nuclear black hole mass M-bh and stellar velocity dispersion a, in elliptical galaxies and spiral bulges has raised the question whether such a relationship exists for active galactic nuclei (AGNs). Estimates of M-bh for many AGNs, made using reverberation mapping techniques, allow exp loration of the relationship between black hole mass, the host galaxy, and the energetics of nuclear emission. However, since only a few AGNs have bot h M-bh and a, measurements, we use the [O III] lambda 5007 emission-line wi dths on the assumption that for most AGNs the forbidden line kinematics are dominated by virial motion in the host galaxy bulge. We find that a relati on does exist between M-bh and the [O III] line width for AGNs, which is si milar to the one found by Gebhardt et al., although with more scatter, as e xpected if secondary influences on the gas kinematics are also present. Our conclusion is that both active and inactive galaxies follow the same relat ionship between black hole mass and bulge gravitational potential. We find no compelling evidence for systematic differences in the mass estimates fro m reverberation mapping and stellar dynamics. We also find that for radio-q uiet AGNs, the radio power and black hole mass are highly correlated, linki ng emission on scales of kiloparsecs with the nuclear energy source.