Ultra-high-energy photons from active galactic nuclei - Theory

Abstract

view Abstract Citations (10) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ultra--High-Energy Photons from Active Galactic Nuclei: Theory Sikora, Marek ; Shlosman, Isaac Abstract First-order Fermi acceleration in collisionless shocks is supposed to operate in the central regions of active galactic nuclei (AGNs). Most of the shock energy is channeled into relativistic protons. Protons are effectively "cooled" as a result of interactions with the soft radiation produced by accreting matter. Among final products of such collisions are ultra-high-energy photons. For a certain range of parameters, we find that a substantial part of these photons leak out of the central region. They are absorbed by radio photons within 1 pc or escape much further, being uniformly absorbed within 10-30 kpc by the background microwave radiation. The above outcome depends upon the compactness of the central source. In both cases ultrarelativistic pairs are created. These pairs cool by means of synchrotron radiation in the interstellar magnetic field and form either compact hard γ-ray sources (~10^4^-10^6^ MeV) or extended X-ray and γ-ray halos (0.01-100 MeV) around AGNs. Detection of such radiation would strongly support the hypothesis that proton-photon injection of ultrarelativistic pairs is responsible for nonthermal radiation from AGNs. Publication: The Astrophysical Journal Pub Date: January 1989 DOI: 10.1086/167036 Bibcode: 1989ApJ...336..593S Keywords: Active Galactic Nuclei; Photons; Relativistic Particles; Accretion Disks; Gamma Ray Astronomy; Interstellar Magnetic Fields; Particle Acceleration; Relic Radiation; Synchrotron Radiation; Astrophysics; QUASARS; GALAXIES: NUCLEI; PARTICLE ACCELERATION; RADIATION MECHANISMS full text sources ADS | data products SIMBAD (1)

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