First Galaxies and Faint Dwarfs: Clues to the Small Scale Structure of Cold Dark Matter

Coordinators: Leon Koopmans, Julio Navarro, Risa Wechsler

Scientific Advisors: Tom Abel, James Bullock, Marla Geha, Nick Gnedin, Laura Sales, Simona Vegetti

One of the biggest challenges of modern astrophysics is understanding the universe in the small and highly non-linear regime, in particular, that of the dwarf galaxies and below. Reconciling the faint-end of the luminosity function with the low mass-end of the mass function is a crucial test for models of cold dark matter and, therefore, the physics of dark matter itself. Several areas of research are engaged in this problem:

(1) First, understanding the inefficiency of galaxy formation in small halos requires deeper insights into the physics behind stellar feedback, cosmic reionization and the impact of radiation by the first stars on the primordial interstellar medium.

(2) Second, the validation of current theories, which predict a wealth of dark substructure orbiting around highly luminous (L*) galaxies, relies on observational constraints of the clumpiness of dark matter halos. This places gravitational lensing studies and dark matter annihilation signal detection among the most promising techniques available nowadays.

(3) Third, complete surveys and detailed studies of the faint and ultra-faint dwarf galaxies in the Local Group provide our best chance to determine the properties of the baryonic matter residing deep in the potential well of the smallest dark matter halos.

During this program, we intend to bring together experts from a wide range of disciplines and from various theoretical, computational, and observational points of view. The goal is to achieve a comprehensive view of the current issues and, through discussions and interactions among the participants, obtain new insights into the interplay between dwarf satellites and the physics of dark matter and galaxy formation.

To kick off the program, an associated conference is planned for the first week, February 13-17, 2012. Further information will be posted as it becomes available.