Sweating the Small Stuff: Solving Small-Scale Challenges to LCDM with Dwarf Galaxy Simulations at the High Resolution Limit
The currently favored cosmological paradigm - Lambda Cold Dark Matter Theory (LCDM) - has been widely successful in predicting the counts, clustering, colors, morphologies, and evolution of galaxies on large scales, as well as a variety of cosmological observables. Despite these successes, several challenges have arisen to this model in recent years, most of them occurring at the smallest scales — those of dwarf galaxies (M* < 109 Msun). I will review several of these small scale challenges, including the Missing Satellites Problem, the Cusp-Core Controversy, and the tension between the regularity of galactic scaling relations and the diversity of rotation curves. In reviewing current attempts to rectify these issues — many of which rely on the inclusion of baryonic effects in simulations — I will introduce a new set of high resolution cosmological hydrodynamic zoom-in simulations (GIZMO/FIRE2) of isolated dwarf galaxies — the highest resolution ever run to z=0. This new generation of mbar ~ few x 10 Msun simulations marks a transition point between simulations that treat star formation within a single stellar population in the aggregate, and simulations that model the individual collapse and fragmentation of a molecular clouds into individual stars, and will allow us to probe smaller physical scales than previously possible in cosmological simulations.
