LEPTONIC AND HADRONIC MODELING OF<i>FERMI</i>-DETECTED BLAZARS

Abstract

We describe new implementations of leptonic and hadronic models for the\nbroadband emission from relativistic jets in AGN in a temporary steady state.\nFor the leptonic model, a temporary equilibrium between particle\ninjection/acceleration, radiative cooling, and escape from a spherical emission\nregion is evaluated, and the self-consistent radiative output is calculated.\nFor the hadronic model, a temporary equilibrium between particle\ninjection/acceleration, radiative and adiabatic cooling, and escape is\nevaluated for both primary electrons and protons. A new, semi-analytical method\nto evaluate the radiative output from cascades initiated by internal\ngamma-gamma pair production is presented. We use our codes to fit snap-shot\nspectral energy distributions of a representative set of Fermi-LAT detected\nblazars. We find that the leptonic model provides acceptable fits to the SEDs\nof almost all blazars with parameters close to equipartition between the\nmagnetic field and the relativistic electron population. However, the hard\ngamma-ray spectrum of AO 0235+164, in contrast to the very steep IR-optical-UV\ncontinuum, poses a severe problem for the leptonic model. If charge neutrality\nin leptonic models is provided by cold protons, the kinetic energy carried by\nthe jet should be dominated by protons. We find satisfactory representations of\nthe snapshot SEDs of most blazars in our sample with the hadronic model\npresented here. However, in the case of two quasars the characteristic break at\na few GeV energies can not be well modelled. All of our hadronic model fits\nrequire powers in relativistic protons in the range L_p ~ 1e47 - 1e49 erg/s.\n