Search for TeV gamma ray emission from the Andromeda galaxy

Using the HEGRA system of imaging atmospheric Cherenkov telescopes, the Andromeda galaxy (M31) was sur- veyed for TeV gamma ray emission. Given the large field of view of the HEGRA telescopes, three pointings were sufficient to cover all of M31, including also M32 and NGC 205. No indications for point sources of TeV gamma rays were found. Upper limits are given at a level of a few percent of the Crab flux. A specific search for monoenergetic gamma-ray lines from annihi- lation of supersymmetric dark matter particles accumulating near the center of M31 resulted in flux limits in the 10 −13 cm −2 s −1 range, well above the predicted MSSM flux levels except for models with pronounced dark-matter spikes or strongly enhanced annihilation rates.