The Darkest Galaxies
By Marla Geha
In the past several years, fourteen Milky Way satellite galaxies have
been discovered, more than doubling the known population. These newly
discovered ``ultra-faint'' galaxies have emerged as the least luminous
and most dark matter-dominated galaxies in the known Universe. They
are dramatically reshaping our understanding of galaxy formation and
may hold the keys to deciphering the nature of dark matter. I will
review our current understand of the ultra-faint galaxies, focusing on
the constraints these objects provide on dark matter.