Modeling Flares Produced in Blazars

Abstract

We model light curves of flares observed in blazars, assuming that they are produced by relativistic electrons/positrons injected by forward-reverse shocks traveling down the jet with relativistic speeds. We approximate the radiating region as a thin shell enclosed between the two shock fronts. In addition to the conventional radiation processes such as synchrotron radiation and its Comptonization, we take into account Comptonization of light originating in the broad emission line region, and Comptonization of IR radiation from hot dust. We demonstrate that flares produced in the adiabatic regime decay much slower than flares produced in the radiative regime. The lack of such a difference between the X-ray and $γ$-ray flares in 3C279 strongly supports the synchrotron-self Compton (SSC) mechanism as responsible for X-ray production in this object. Finally, we discuss a possible scenario which can explain the `cooling' nature of the MeV peak in blazars by comparing the flares produced in soft $γ$-ray band and above 100 MeV.