Can Feedback Solve the Too Big to Fail Problem?

TL;DR

This paper investigates whether supernova feedback can reduce dark matter densities in dwarf galaxies enough to solve the 'Too Big to Fail' problem, finding it unlikely that feedback alone is sufficient.

Contribution

The study models supernova feedback effects on dark matter halos and quantifies the energy needed to match observed dwarf galaxy densities, highlighting limitations of feedback as a sole solution.

Findings

Over 40,000 supernovae energy needed for observed densities

Single blow-out events are more effective than multiple bursts

Supernova feedback alone likely cannot solve the 'Too Big to Fail' problem

Abstract

The observed central densities of Milky Way dwarf spheroidal galaxies (dSphs) are significantly lower than the densities of the largest (Vmax about 35 km/s) subhalos found in dissipationless simulations of Galaxy-size dark matter hosts. One possible explanation is that gas removal from feedback can lower core densities enough to match observations. We model the dynamical effects of supernova feedback through the use of a time-varying central potential in high resolution, idealized numerical simulations and explore the resulting impact on the mass distributions of dwarf dark matter halos. We find that in order to match the observed central masses of M_star about 10^6 M_sun dSphs, the energy equivalent of more than 40,000 supernovae must be delivered with 100% efficiency directly to the dark matter. This energy requirement exceeds the number of supernovae that have ever exploded in most dSphs for typical initial mass functions. We also find that, per unit energy delivered and per cumulative mass removed from the galaxy, single blow-out events are more effective than repeated small bursts in reducing central dark matter densities. We conclude that it is unlikely that supernova feedback alone can solve the "Too Big to Fail" problem for Milky Way subhalos.