Limits on supersymmetric dark matter from EGRET observations of the Galactic center region

In most supersymmetic models, neutralino dark matter particles are predicted to accumulate in the Galactic center and annihilate generating, among other products, gamma rays. The Energetic Gamma Ray Experiment Telescope has made observations in this region, and is sensitive to gamma rays from 30 MeV to similar to30 GeV. We have used an improved point source analysis including an energy dependent point spread function and an unbinned maximum likelihood technique, which has allowed us to lower the limits on gamma ray flux from the Galactic center by more than 1 order of magnitude. We find that the present Energetic Gamma Ray Experiment Telescope data can limit many supersymmetric models if the density of the Galactic dark matter halo is cuspy or spiked toward the Galactic center. We also discuss the ability of the Gamma ray Large Area Space Telescope to test these models.