Dynamical analysis of elliptical galaxy halos

Abstract

We describe a non-parametric method for determining both the anisotropy and mass profiles of elliptical galaxies from velocity dispersions and velocity profile shapes along the line of sight. In this way, mass-to-light ratios out to 2-3 effective radii can be derived from stellar absorption line spectroscopy. We discuss two illustrative cases, NGC 1399 and NGC 6703. So far, all ellipticals which have been analysed show evidence for dark matter dominating in the outer parts. The circular velocity curves are nearly flat, as in spiral galaxies.

2 pages, 1 figure, Galaxy Dynamics conference held at Rutgers University, Aug. 98