Searching for Dwarf Galaxies in Voids in Order to Constrain Cold Dark Matter Models

Dr. Stephen McNeil
Department of Physics and Astronomy
Brigham Young University

The dwarf galaxy population in low density volumes, or voids, is a test of galaxy formation models and how they treat dark matter; some models say dwarf galaxies cannot be in void centers while others say they can. Since it appears most dwarf galaxies are H-alpha emitters, a well-designed deep survey through a nearby void center will either find nothing, and thus constrain the population there to be at some percentage below the mean, or it will find H-alpha emitters and significantly challenge several otherwise successful theories. Either result is a significant step in better understanding galaxy formation and large-scale structure.  In 2013, a redshifted H-alpha imaging survey was begun for dwarf galaxies with −14.0 < Mr < 12.0 in the heart and back of the void FN8. Our first results have been surprising, furnishing significantly more candidate objects than anticipated.