Maximum Feedback and Dark Matter Profiles of Dwarf Galaxies

Abstract

The observed rotation curves of dark matter-dominated dwarf galaxies indicate low density cores, contrary to the predictions of CDM models. A possible solution of this problem involves stellar feedback. A strong baryonic wind driven by vigorous star formation can remove a large fraction of the gas, causing the dark matter to expand. We explore the maximum effect of the feedback with an instantaneous removal of the gaseous disk. The energy input depends on the compactness of the disk, hence the specific angular momentum of the disk. For the plausible cosmological parameters and a large range of the disk angular momentum, the feedback is insufficient to destroy the central halo cusp, while the inner density is lowered only by a modest factor of 2 to 6. Any realistic modeling of the feedback would have even lesser impact on dark matter. We find that no star formation effect can resolve the problems of CDM cusps.