Variability along the Blazar-Sequence - Hints for extragalactic Cosmic Rays?

摘要

The spectral energy distribution and variability of several blazars (Mkn 501, 1 ES 2344+51.4, PKS 2155-30.4,1 ES 1218+30.4, 3C 454.3) along the blazar sequence is investigated using a selfconsistent and timedependent lepto-hadronichybrid emission model. The BL Lac objects in the list are successfully modelled with purely leptonic radiationprocesses (essentially Synchrotron Self-Compton emission), while the Flat Spectrum Radio Quasar requires highly rel-ativistichadrons to be present within the jet. Variability is exploited as well with our model to distinguish betweenSelf-Compton and hadronic gamma radiation making use of their different signatures in lightcurves. As a consequenceactive galactic nuclei with z > 0.5 are the best candidates as sources of extragalactic consmic rays, since High-PeakedBL Lac objects do not seem to accelerate protons to energies above thermal. Furthermore the parameters found during themodelling of the objects agree very well with obervations of e.g. superluminal motion or typical variability timescales.