AAS Meeting #193 - Austin, Texas, January 1999
Session 27. Radio Galaxies and Quasars II
Oral, Wednesday, January 6, 1999, 2:00-3:30pm, Room 6 (A and B)

## [27.05] Mass of the Central Black Hole - Bulge Mass, Relationship in the Ground' and Excited' States of Galaxies

Leonid M. Ozernoy (GMU and NASA/GSFC)

A recently found correlation between the absolute magnitude of a quasar and that of the quasar host galaxy [1] is shown here to be reduced to the known relationship between the mass of a central black hole and the bulge mass [2], provided that certain conditions are satisfied. The two conditions under which these relationships are mutualy related require that, at the quasar stage, i.e. in the excited' state of a galaxy [3,4], (i)~its central black hole shines with a fraction of the Eddington luminosity, which is a constant, i.e. luminosity-independent, and (ii) the host galaxy undergoes through a starburst episode. Both these conditions are met if the quasar phenomenon and the starburst phase accompany each other (presumably as a result of an interaction of the host galaxy with a companion). During a quiescent phase (the galaxy's ground' state [3,4]), both the quasar activity and starburst die out leaving behind a `naked' relationship between the mass of the central black hole and the bulge mass. A link between the two relationships established here would enable one to examine the deviations of individual quasars and host galaxies from the averaged statistical curves and thereby to characterize their individual status.

\noindent References: \\ \noindent [1] Bahcall, J. et al., 1997, ApJ 479, 642\\ \noindent [2] Magorrian, J. et al., 1998, AJ 115, 2285\\ \noindent [3] Ozernoy, L.M. 1974, Proc. of the First European Astr. Meeting (Berlin: Spriger), \hspace*{0.8cm}Vol. 3, p.65\\ \noindent [4] Van den Bergh, S. Galaxy Classification and Morphology (N.Y.: Cambridge Univ. Press), Ch. 13