Hadronic Production of TeV Gamma Ray Flares from Blazars
  We propose that TeV $\gamma$-ray emission from blazars is produced by collisions near the line of sight of high energy jet protons with gas targets (``clouds'') from the broad emission-line region (BLR). Intense TeV $\gamma$-ray flares (GRFs) are produced when BLR clouds cross the line of sight close to the black hole. The model reproduces the observed properties of the recently reported very short and intense TeV GRFs from the blazar Markarian 421. Hadronic production of TeV GRF from blazars implies that it is accompanied by a simultaneous emission of high energy neutrinos, and of electrons and positrons with similar intensities, light curves and energy spectra. Cooling of these electrons and positrons by emission of synchrotron radiation and inverse Compton scattering produces delayed optical, X-ray and $\gamma$-ray flares. 
Arnon Dar and Ari Laor