The nearest massive galaxy beyond our own, M31, hosts many faint dwarf spheroidal (dSph) satellites. In this work, we spectroscopically observed individual stars in two recently-discovered satellite candidates of M31, And XXVIII & And XXIX. Our observations reveal they are genuine satellite galaxies of M31 with kinematics dominated by dark matter. Furthermore, despite being far from M31 relative to many of its other satellites, these galaxies show internal motions similar to the other satellites of both M31 and the Milky Way.
The Outer Limits of the M31 System: Kinematics of the Dwarf Galaxy Satellites And XXVIII & And XXIX (ADS | arXiv)
Tollerud, E., Geha, M., Vargas, L., and Bullock, J., 2013, ApJ, 768, 50