The Darkest Galaxies

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, least chemically enriched and most dark-matter-dominated galaxies in the known Universe. I will review our current understand of the ultra-faint galaxies, focusing on the constraints these object place on cosmology and galaxy formation.