Variation in VHE Gamma Rays from M 87 (IMAGE) Max-Planck-Gesellschaft Caption Fig. 2: The variation in VHE gamma rays from M 87: Lower panel: Year-by-year intensity as a function of time, as seen by H.E.S.S. (and HEGRA). Upper panel: Night-by-night variations with bursts on time-scales of a few days, as measured in 2005 from M 87. Credit Image: H.E.S.S Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.