Gamma-rays from the funnels of thick accretion disks around active galactic nuclei.
Abstract
We analyse the propagation of particles in the narrow funnel of a thick accretion disk. It is assumed that: (1) the funnel walls emit black body radiation with temperature decreasing outwards; (2) the magnetic and electric fields are longitudinal in the funnel. Such a scenario is consistent with models in which a large potential drop is induced by a rotating massive black hole threaded by a magnetic field (Blandford & Znajek; Macdonald & Thorne). The interaction of relativistic protons with thermal photons from the funnel results in direct production of e^+/-^ pairs and/or pions. We discuss the relative importance of these processes for different conditions in the funnel (temperature and electric field profiles). Injected e^+/-^ pairs interact with thermal photons in the Thomson or Klein-Nishina regime. Under some conditions, a pair avalanche results, which we assume saturates in the production of stable bunches, containing almost equal numbers of electrons and positrons. As a consequence, highly collimated γ-ray photons are produced. We obtain γ-ray spectra from our model in order to test its applicability to the γ-ray emitting AGNs recently reported by EGRET.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1995
- DOI:
- 10.48550/arXiv.astro-ph/9408013
- arXiv:
- arXiv:astro-ph/9408013
- Bibcode:
- 1995A&A...294..366B
- Keywords:
-
- Accretion Disks;
- Active Galactic Nuclei;
- Blazars;
- Electrons;
- Funnels;
- Gamma Rays;
- Positrons;
- Protons;
- Relativistic Particles;
- Astronomical Models;
- Black Body Radiation;
- Electron Avalanche;
- Gamma Ray Astronomy;
- High Energy Interactions;
- Astrophysics;
- GAMMA RAYS: THEORY;
- GALAXIES: ACTIVE;
- QUASARS: INDIVIDUAL: CTA 102;
- QSO 1633+382 (4C 38.41);
- Astrophysics
- E-Print:
- 10 pages, uuencoded and compressed PostScript, to appear in A&