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J.-H. Woo, C. M. Urry (Yale University), M. O'Dowd (University of Melbourne)
We collected all estimates of black hole masses for AGN and galaxies that were available from the literature. These include some direct measurements of dynamical mass (mostly for nearby galaxies) and many more indirect estimates (mostly from reverberation mapping or from emission line widths combined with a size estimate from optical luminosity). We compare the values for black hole mass generated by the different methods and find, for individual objects, a scatter as high as a couple of orders of magnitude. We also evaluate a new estimate, based on properties of the AGN host galaxies, assuming they are like normal galaxies. In contrast to other studies, we find no significant correlation of black hole mass with luminosity, other than those induced by circular reasoning in the estimation of black hole mass. This shows there must be a large range of Eddington ratios in AGN, of at least three orders of magnitude. Comparing AGN and normal galaxies in the luminosity-black hole mass plane, we find no gap between them, suggesting that AGN activity decreases smoothly toward the non-active state.
The author(s) of this abstract have provided an email address for comments about the abstract: jhwoo@astro.yale.edu