Fabrizio Tavecchio – INAF-OA Brera

Mercoledi 22 Maggio 2019  ore 11, Aula IB09 

Extragalactic relativistic jets are outflows of magnetized plasma expelled by supermassive black holes residing in the centers of distant galaxies. Particularly interesting are blazars, objects in which the jet points toward the Earth. The emission of blazars extends into the gammaray band, flagging the existence of particles (electrons, possibly protons) with energies exceeding 10 TeV. It is believed that these ultrarelativistic particles particles are accelerated either by magnetic reconnection – possibly triggered by instabilities in magnetically dominated jets – or shocks – for weakly magnetized flows. After a general introduction I will discuss how polarimetry can be used to probe the acceleration mechanisms active in blazars, discussing in particular the potential role of the upcoming planned IXPE satellite.