case western reserve university



The Luminous Tip of the Dark Matter Iceberg

Mike Hudson (Waterloo)

Stars make up only a few percent of the mass density in the Universe, with the bulk of the mass residing in virialized halos of dark matter. But not all dark matter halos "host" the same fraction of stars: low mass halos, i.e. dwarf galaxies, have very small proportion of stars, as do the high mass ones, i.e. clusters of galaxies. I will review the observational situation, highlighting some recent recent from dynamics and weak gravitational lensing, discuss the theoretical implications, and point to some new directions that will shed light on the co- evolutionary history of galaxies and their dark matter halos.