The Shapes and Sizes of Elliptical Galaxy Halos from X-Ray Observations

We review the theory of how the shapes of the X-ray isophotes probe both the shape and radial distribution of gravitating matter in elliptical galaxies in a way that is more robust than the traditional spherical approach. We summarize and update the previous analyses of X-ray observations of NGC 720 and NGC 1332 and describe preliminary results for NGC 3923.