The origin of the continuum of active galactic nuclei.
Abstract
The high-energy continuum of active galactic nuclei can be interpreted by nonthermal models in which electron-positron pairs play a crucial role. The produced primary γ-rays interact with softer photons in the inner, high photon density regions of the source. The created pairs are relativistic, and contribute to the emission, especially in the X-ray band. When the photon density is large enough, therefore for large values of the luminosity-to size ratio, the spectrum produced by the reprocessing due to pairs is predicted to have a characteristic spectral index of one. This power law continuum partly impringes on cold matter, possibly in an accretion disk. The resulting Compton reflected radiation contributes to the C-ray emission, and the predicted overall spectrum is in agreement with the observed shape of the high-energy continuum. The proposed model is easily testable: observations in the hard-X-ray band above are crucial to discriminate these nonthermal models against thermal ones.
- Publication:
-
Nuovo Cimento C Geophysics Space Physics C
- Pub Date:
- October 1992
- DOI:
- 10.1007/BF02507859
- Bibcode:
- 1992NCimC..15..839G
- Keywords:
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- Active Galactic Nuclei;
- Compton Effect;
- Galactic Evolution;
- Gamma Rays;
- Pair Production;
- X Ray Sources;
- Luminous Intensity;
- Thermal Plasmas