Abstract

Dwarf galaxies are extremely diverse in their morphology, from rotationally-supported star-forming disks to gas-free spheroidal stellar systems with no star-formation and negligible rotation.  They are also believed to be the most dark matter dominated objects within the Lambda Cold Dark Matter (LCDM) model and, as such, they pose the most significant challenges to our cosmological scenario.  LCDM galaxy formation models make two clear predictions: i) galaxy formation should become increasingly inefficient in lower mass halos, implying that dwarfs are only able to collect a few percent of their baryonic content, and (ii) dwarfs, like any galaxy, should be surrounded by a wealth of dark-matter substructure, implying that faint satellites of dwarfs should be common.  I will present our current efforts using hydrodynamical simulations to address these predictions and to compare them with available observational constraints including: stellar halos, the inventory of  dwarfs in the Local Volume and dwarf galaxies in dense cluster environments such as Virgo and Coma.