THE SHAPES OF DARK HALOS

Abstract

The shapes of dark halos (e.g. spherical, oblate or triaxial) provide important clues to the formation history of the halos, to their baryon content and to the nature of the dark matter. The halo shapes also influence the dynamics of the galaxy they harbor. This review discusses the current status of theoretical predictions (halo formation in a cosmological context with and without a dissipative component) and of the observational constraints on halo shapes. Halos are neither predicted nor observed to be spherical.