Constraints on dark matter annihilation from M87 - Signatures of prompt and inverse-Compton gamma raysSheetal Saxena, Alexander Summa, Dominik Elsässer, Michael Rüger and Karl MannheimEur. Phys. J. C, 71 11 (2011) 1815DOI: https://doi.org/10.1140/epjc/s10052-011-1815-y