General physical properties of bright Fermi blazars

Abstract

We studied all blazars of known redshift detected by the Fermi satellite\nduring its first three months survey. For the majority of them, pointed Swift\nobservations ensures a good multiwavelength coverage, enabling us to to\nreliably construct their spectral energy distributions (SED). We model the SEDs\nusing a one-zone leptonic model and study the distributions of the derived\ninteresting physical parameters as a function of the observed gamma-ray\nluminosity. We confirm previous findings concerning the relation of the\nphysical parameters with source luminosity which are at the origin of the\nblazar sequence. The SEDs allow to estimate the luminosity of the accretion\ndisk for the majority of broad emitting line blazars, while for the line-less\nBL Lac objects in the sample upper limits can be derived. We find a positive\ncorrelation between the jet power and the luminosity of the accretion disk in\nbroad line blazars. In these objects we argue that the jet must be\nproton-dominated, and that the total jet power is of the same order of (or\nslightly larger than) the disk luminosity. We discuss two alternative scenarios\nto explain this result.\n