Dark satellites and the morphology of dwarf galaxies

Paper

Manuscript submitted to ApJ Letters by Helmi, Sales, Starkenburg et al.

Movies

Simulation of a merger between a disky dwarf galaxy and a dark satellite. Only the "visible" components are shown (i.e. the stars in this case). The dwarf has stellar mass of 8 x 10^7 Msun h^{-1} and is embedded in a dark matter halo of 10^{10} Msun h^{-1}. Although the mass ratio between the dark satellite and the host halo is 20%, this is a significant major merger for the dwarf galaxy, as Msat/Mdisk = 25!!