The Mass-Luminosity Relation in AGN
Abstract
Description
Probably the most fundamental characteristic of the quasar-AGN power house, the mass of the central black hole, is the least well known. I review the three main classes of mass estimation methods---broad emission-line kinematics, X-ray variability and accretion-disk modeling, and the masses they give in terms of the Eddington ratio, $L/L_{\rm Edd}$. The broad emission lines are probably the best probe of the central mass. They provide mass estimates that suggest a narrow spread for the Eddington ratio - 1--2 orders of magnitude over more than six orders of magnitude in continuum luminosity, possibly indicating a universal $M/L$ ratio for AGN. However, other methods give a larger spread and possibly a luminosity- dependent Eddington ratio. Potential sources of errors and bias are discussed.
13 pages, Latex (aspconf.sty), 4 postscript figures. Also available at http://shum.cc.huji.ac.il/~amri/papers/ml Review to appear in procs. of "Structure and Kinematics of Quasar Broad Line Regions" (23-26 March 1998, Lincoln, Nebraska) eds. Gaskell, C. M., Brandt, W. N., Dietrich, M., Dultzin-Hacyan, D. & Eracleous, M. (ASP Press: San Francisco)
13 pages, Latex (aspconf.sty), 4 postscript figures. Also available at http://shum.cc.huji.ac.il/~amri/papers/ml Review to appear in procs. of "Structure and Kinematics of Quasar Broad Line Regions" (23-26 March 1998, Lincoln, Nebraska) eds. Gaskell, C. M., Brandt, W. N., Dietrich, M., Dultzin-Hacyan, D. & Eracleous, M. (ASP Press: San Francisco)