Monday, April 13, 2009 Joint Physics Colloquium, 4:30 PM, 102 Thaw Hall, PITT

Beth Willman

Haverford College

"The (Nearly) Invisible Galaxies"

Abstract:

Since 2004, more than 20 dwarf galaxies have been discovered around the Milky Way and M31 that are 100 times less luminous than any galaxy previously known. The advent of wide-field, digital surveys (in particular the Sloan Digital Sky Survey) facilitated these discoveries, and hint at a much larger population that will be revealed in future imaging datasets. Despite their tiny luminosities, spectroscopic observations demonstrate these objects to be the most dark matter dominated, most metal-poor galaxies known. These objects are changing our understanding of galaxy formation at the lowest luminosities, and are currently our most direct tracers of the properties of dark matter on small scales.