Dynamics of Dark Matter Cusps

Abstract

Formation and disruption of dark-matter cusps are reviewed. Accumulation of baryons at the center of a halo can displace the dark matter, converting singular density cusps into low-density cores. The displaced mass can be of order 10 M_b with M_b the mass of the infalling population. If M_b is identified with the masses of the black holes currently observed at the centers of bright galaxies, predicted core radii are ~a few hundred pc. Other mechanisms, such as early mass outflow, may explain the large dark-matter cores in dwarf and low-surface-brightness galaxies. Predictions of dark matter annihilation radiation from the center of the Milky Way galaxy are shown to be strongly dependent on the galaxy's merger history.

11 pages, 5 postscript figures. To appear in DARK 2002: 4th International Heidelberg Conference on Dark Matter in Astro and Particle Physics, 4-9 Feb 2002, Cape Town, South Africa, H.V. Klapdor-Kleingrothaus, R. Viollier (eds.)