The Dark Matter Content of Galaxies

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

AST 0206031 Jimenez The field of Cosmology has had unprecedented development in the last 80 years. We now have an extremely successful and simple model: the universe was created during the Big Bang, expanded in an inflationary phase, and the galaxies were formed via gravitational instabilities from tiny initial quantum fluctuations. Furthermore, we now know that the universe is made up mostly of a mysterious "dark energy" (70%) with the remaining mass consisting of some kind of dark matter (25%) and ordinary matter (5%). This model has passed impressive tests at physical scales larger than that of galaxy clusters. However, at galaxy scales, the current paradigm is not as successful. There seems to be much less dark matter at the centers of galaxies than is predicted by computer simulations. This project will study an important ingredient, which has been missing from these computer simulations: supermassive black holes and other condensed forms of matter. Preliminary simulations by Dr Jimenez and his collaborators have shown that such objects can displace a significant amount of dark matter from the centers of galaxies. These preliminary calculations will be extended and refined with the aim of testing whether the standard paradigm can be reconciled with the observations. In addition, this project will investigate the nature of the elusive dark matter particles. This will be done by calculating the flux of gamma rays expected from the self-annihilation of dark matter particles at the galactic center. This flux depends both on the evolutionary history of the galaxy, and on the precise masses of the dark matter particles. ***