Description
One of the strongest predictions from the Cold Dark Matter (CDM) paradigm is the existence of a very large number of subhaloes that do not form in-situ stars (i.e. `dark'). Dwarf spheroidal galaxies (dSphs), being the most dark matter-dominated galaxies in the universe, provide a unique laboratory for testing these theories.
In this talk I will show that dSphs are particularly sensitive to perturbations from dark subhaloes owing to their low velocity dispersions and high phase-space densities. I will present N-body experiments that show how CDM subhaloes orbiting in dSphs can have a significant impact on the internal dynamics of these galaxies and induce secular evolution. In particular, self-graviating subhaloes generate a fluctuating gravitational field that injects energy into stellar orbits, causing a gradual expansion of dSphs in their CDM haloes.
