A Keck/Deimos Survey of Red Giant Branch Stars in the Outskirts of M31

Abstract

We are using the DEIMOS multi-object spectrograph on the Keck II 10m telescope to conduct a spectroscopic survey of red giant branch stars in the outskirts of M31. To date, velocities have been obtained for most of the major substructures in the halo as well as at several positions in the far outer disk and inner halo. First results concerning the giant stellar stream and major axis substructures are presented here.