Time lags of flaring AGN

Abstract

In order to distinguish the leptonic from the hadronic origin of the non-thermal emission of a flaring AGN we present a semi-analytical model that describes the temporal development of the emergent particles (i.e. photons and neutrinos) based on their leptonic and hadronic origin respectively. The approach starts with the transport equation of the injected relativistic particles and takes spatial diffusion and continuous energy losses into account. On the one hand, a relativistic electron pick-up is considered, that leads to synchrotron, as well as external Compton emission and on the other hand, a relativistic proton pick-up, which results in high energy photons and neutrinos by inelastic proton-proton collisions. The paper ends up in the temporal development of the emergent photon and neutrino intensities of AGN flares in hadronic and leptonic interaction scenarios and gives useful predictions of flare durations and time lags between photons of different wavelength and high energy neutrinos.