Fast variability of tera-electron volt gamma rays from the radio galaxy M87. - Aharonian F; Akhperjanian AG; Bazer-Bachi AR; Beilicke M; Benbow W; Berge D; Bernlöhr K; Boisson C; Bolz O; Borrel V; Braun I; Brown AM; et al. (Science (New York, N.Y.), 2006)