Not yet reviewed by Pith; the record is open.

Dwarf galaxies pose significant challenges for cosmological models. In particular, current models predict a dark matter density that is divergent at the center, in sharp contrast with observations which indicate an approximately constant central density core. Energy feedback, from supernova explosions and stellar winds, has been proposed as a major factor shaping the evolution of dwarf galaxies. We present detailed cosmological simulations with sufficient resolution both to model the relevant physical processes and to directly assess the impact of stellar feedback on observable properties of dwarf galaxies. We show that feedback drives large-scale, bulk motion of the interstellar gas resulting in significant gravitational potential fluctuations and a consequent reduction in the central matter density, bringing the theoretical predictions in agreement with observations.