Carnegie Mellon University

Astro Lunch

Substructure abundance and the haloes of Milky Way dwarfs

The clustering properties of dark matter on the scale of dwarf galaxies  are fiercely debated: what are the structural properties of subhaloes,  are they cuspy or cored, and how many subhaloes are to be expected for  different dark matter recipes? I will discuss how to obtain unbiased  halo mass estimates from projected stellar velocity dispersions of Milky  Way dwarfs, and compare my findings to controlled cosmological  simulations of the formation of Milky Way-like haloes, tailored to  follow the tidal evolution of substructures reliably over several orders  of magnitude in mass loss. This comparison reveals puzzling properties  for subhaloes hosting ultra-faint dwarfs and thereby highlights observational challenges and basic questions about cold dark matter.