\def\ul#1{$\underline{\smash{\vphantom{y} \hbox{#1}}}$} \def\etal {{\sl et~al.}}
\bf High Energy Gamma-Ray Emission in Active Galaxies
Session 12 -- High Energy Observations of AGNs
Oral presentation, Monday, 10:30-12:00, Zellerbach Auditorium Room

## [12.07] \bf High Energy Gamma-Ray Emission in Active Galaxies

A. Mastichiadis$^{\dagger}$, D. Kazanas (NASA/GSFC)

Motivated by the recent EGRET detections of high-energy gamma-ray emission from radio loud Active Galactic Nuclei (AGN) we have made an attempt to construct self-consistent models for such emission. The extraordinary gamma-ray luminosity and the absence of any indication of the gamma-rays to the photon-photon pair process strongly suggest that the gamma-ray emission originates in a relativistically moving fluid which is subsequently amplified by the ensuing Lorentz boosting. We propose that the required relativisticlly expanding plasma has its origins near the vicinity of the black hole and that its pressure is dominated by relativistic protons accelerated in the same region. Relativistic expansion results from the conversion of the protons' internal energy into bulk motion. We construct models of such relativistically expanding plasmas by solving the Bernoulli equation appropriate for a relativistic proton gas. We conjecture that the observed gamma-rays result from the nuclear collisions of the relativistic protons powering the outflow and we compute the resulting production of high energy radiation in a self-consisten fashion. \vskip 0.2truein

\noindent $^{\dagger}$ NAS/NRC Senior Research Associate