In the past five years more than a dozen tiny, dwarf galaxies have been discovered around the Milky Way. Many of these discoveries are 100 times less luminous than any galaxy previously kown and a million times less luminous than the Milky Way itself. These objects have made astronomers question the very meaning of the word "galaxy". The advent of wide field, digital sky surveys (in particular the Sloan Digital Sky Survey) facilitated these discoveries, and hint that "ultra-faint" galaxies like the recent discoveries might actually be the most numerous type of galaxies in the Universe.
This talk will highlight:
i. how we can see galaxies that are effectively invisible in images on the sky,
ii. the brewing controversy on the definition of the term "galaxy", and
iii. new photometric and spectroscopic studies of and searches for ultra-faint Milky Way satellites.
LCO Seminar Series, 6740 Cortona Dr, Suite 102, Goleta, CA93117
Beth Willman, who received her B.A. in astrophysics at Columbia University and a Ph.D. in astronomy at the University of Washington, has been a James Arthur Fellow at the Center for Cosmology and Particle Physics, and a Clay Fellow at the Harvard-Smithsonian Center for Astrophysics. Beth's research focus is Near Field Cosmology. She specializes in searching for and studying the least luminous galaxies in the known Universe. The overarching theme of her research is to use comparisons between theory and observations of the local universe to learn about dark matter and galaxy formation. In particular, Dr. Willman investigates whether observations of the Milky Way and the ultra-faint galaxies orbiting it are consistent with the Cold Dark Matter model of the Universe.