Previous abstract Next abstract
Because many quasars are also luminous X-ray sources whose strength is correlated with the radio core emission, it is believed that understanding the high-energy emission will yield important insights into the formation of the large-scale jets. Prior to the EGRET observations, jet formation models generally treated the acceleration and radiation mechanisms separately because very little was known of the physical environment where the particles are initially energized. Because the high-energy emission from these sources presumably originates close to the central engine, the EGRET spectral measurements offer us the first opportunity to seriously model the early jet formation phase within a few hundred Schwarzschild radii of the nucleus. We discuss a self-consistent jet model with the aim of utilizing the EGRET AGN spectral data to probe the physical conditions in the proximity of the blackhole. This model will directly couple the particle dynamics to the radiative emission. A viable mechanism for producing the high-energy gamma-rays observed by EGRET is the Compton upscattering of low-energy accretion disk photons by relativistically moving particles in the jet. However, as it is well known that the Compton process also acts as a decelerating force on the particles, we hypothesize that the scattering process results in a particle-photon-induced resistivity. Thus, if the energizing force on the particles is associated with an AGN magnetospheric phenomenon, the electromagnetic acceleration is fully dependent on the magnitude of the photon drag and hence is connected directly to the radiative emission itself. We apply the self-consistent acceleration mechanism to a simplified magnetic field geometry and compare the predicted gamma-ray spectra to the EGRET data in order to obtain tight constraints on the blackhole masses, accretion disk temperatures, and magnetic field strengths that produce spectra and fluxes consistent with the observations.
This work is supported by NASA GSRP fellowship NGT-51305.
Wednesday program listing