Gamma-ray observations of the Galactic center and Andromeda: dark matter implications

Fermi LAT has revealed an excess from the Galactic center that is compatible with a signal of dark matter annihilation, but other interpretations such as a population of millisecond pulsars have been found compelling. More recently, an excess toward the outer halo of M31 has been reported by Fermi LAT which, if interpreted in the framework of DM annihilation, is consistent with the DM interpretation of the Galactic center excess and within the constraints set by the Milky Way dwarf spheroidals. In this talk, I review these results and discuss some prospects for resolving the origin of these excesses.