Dwarf spheroidal satellites: are they of tidal origin?

The Milky Way and Andromeda must have formed through an initial epoch of substructure merging. As a result of fundamental physical conservation laws, tidal dwarf galaxies (TDGs) have likely been produced. Here we show that such TDGs appear, after a Hubble time of dynamical evolution in the host dark matter halo, as objects that resemble known dwarf spheroidal satellite galaxies. We discuss the possibility that some of the Milky Way's satellites may be of tidal origin.