Flaring Patterns in Blazars

Blazars radiate from relativistic jets launched by a supermassive black hole along our line of sight; the subclass of FSRQs exhibits broad emission lines, a telltale sign of a gas-rich environment and high accretion rate, contrary to the other subclass of the BL Lacertae objects. We show that this dichotomy of the sources in physical properties is enhanced in their flaring activity. The BL Lac flares yielded spectral evidence of being driven by further acceleration of highly relativistic electrons in the jet. Here we discuss spectral fits of multi-lambda data concerning strong flares of the two flat spectrum radio quasars 3C 454.3 and 3C 279 recently detected in gamma rays by the AGILE and Fermi satellites. We find that optimal spectral fits are provided by external Compton radiation enhanced by increasing production of thermal seed photons by growing accretion. We find such flares to trace patterns on the jet power - electron energy plane that diverge from those followed by flaring BL Lacs, and discuss why these occur.