Will GLAST Identify Dark Matter?

The nature of the cosmic dark matter is unknown. One strong possibility is that dark matter consists of weakly interacting massive particles (WIMPs) in the 100 GeV mass range. Such particles would annihilate in the galactic halo, producing high-energy gamma rays. I discuss the ability of GLAST to distinguish between WIMP annihilation sources and known astrophysical source classes. Focusing on the emission from the halo substructure predicted by the cold dark matter model, the WIMP gamma-ray spectrum is nearly unique; separation from known source classes can be done in a convincing way by including spectral and spatial information. Astrophysical detection of dark matter by GLAST would be particularly timely, given the new probes of this energy range that will be available at the Large Hadron Collider, starting in 2008