Measuring parameters of active galactic nuclei central engines with very high energy γ-ray flares

We discuss a ‘compact source’ model of very high energy emission from blazars in which the variability time is determined by the blazar central engine. In this model, electron or proton acceleration close to the supermassive black hole is followed by the development of electromagnetic cascade in a radiatively inefficient accretion flow. Assuming such a model for the TeV blazar PKS 2155−304, we show that the variability properties of the TeV …