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EP: Fachverband Extraterrestrische Physik

EP 16: Astrophysik I

EP 16.3: Vortrag

Donnerstag, 15. März 2012, 11:00–11:15, V55.21

Modelling of blazar SEDs with the nonlinear SSC cooling process — •Michael Zacharias and Reinhard Schlickeiser — Theoretische Physik IV, Ruhr-Universität Bochum, Germany

Currently, inverse Compton dominated blazars (mostly FSRQ) are modelled assuming strong external photon fields that are scattered by highly relativistic electrons in the jet of AGN. This is justified by the observed strong emission of the accretion disk, the broad line region, and/or the dusty torus leading to rather simple cooling terms for the electrons. Thus, a steady-state approach for the electron distribution is normally adopted.

However, observations of fast variability invalidate the steady-state assumption requiring a time-dependent treatment. In fact, this is also demanded by the nature of the SSC process, which is normally regarded as being irrelevant for FSRQ modelling. However, if one takes into account the time-dependent nature of the SSC process for the electron cooling, the emerging photon SEDs are significantly altered.

We were able to show that even in a simple SSC scenario the nonlinear cooling process results in a dominating inverse Compton peak, contrary to what is usually obtained using SSC. We also found that the synchrotron peak exhibits a unique broken power-law, which does not need the usually assumed underlying broken power-law electron distribution.

We applied our model to strong flares of the blazars 3C 279 and 3C 454.3 and obtained very good fits with reasonable parameters.