Interpretation of the flares of M87 at TeV energies in the cloud-jet   interaction scenario
  Active galactic nuclei with misaligned jets have been recently established as a class of high-energy gamma-ray sources. M87, a nearby representative of this class, shows fast TeV variability on timescales less than one day. We present calculations performed in the framework of the scenario in which gamma-ray flares in non-blazar active galactic nuclei are produced by a red giant or a gas cloud interacting with the jet. We show that both the light curve and energy spectrum of the spectacular April 2010 flare can be reproduced by this model, assuming that a relatively massive cloud of approx 1.e29 g penetrates into the jet at few tens of Schwarzschild radii from the super-massive black hole. 
Maxim V. Barkov, Valenti Bosch-Ramon, Felix A. Aharonian
astro-ph.HE