T H E C E N T E R S OF G A L A X I E S DOUGLAS RICHSTONE AND KARL GEBHARDT Department of Astronomy University of Michigan

This report has two major purposes. First, we summarize here work by our team on the determination of the density of stars near the centers of a large sample of galaxies observed with the Hubble Space Telescope. There appear to be two varieties of elliptical galaxies (and bulges). The stellar densities near the centers of small elliptical galaxies exceed those of globular clusters and the density of the universe at the recombination epoch. The radial dependence of density and implied gravitational force seems inconsistent (at least in the case of the smaller elliptical galaxies) with a long-lived triaxial configuration. It therefore seems likely tha t the central regions of less luminous elliptical galaxies are axisymmetric. For the more luminous ellipticals, the central densities are far more modest and the presence of a distinct core (defined below) is generally well established. Even in these