{'fraction_non_alphanumeric': 0.028192371475953566, 'fraction_numerical': 0.03150912106135987, 'mean_word_length': 4.644859813084112, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Rapid Variability of Gamma-Ray Blazars: A Model for Markarian 421

The extremely rapid burst of TeV photons from Markarian 421 (1996 May 15) can be reconciled with the standard properties of a relativistic γ-ray-emitting jet (bulk Lorentz factor Γ~10; size ~1017 cm) if one assumes that the electrons are accelerated in conical shocks with both opening and viewing angles ≈ 1/Γ. If the injection time and the cooling time are much less than the photon crossing time, an emission ring moves along the jet and leads to the appearance of a very rapid flare, in satisfactory agreement with the observations.