Dissipation of magnetic fields in active galactic nuclei |
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Authors: | H Lesch |
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Institution: | (1) Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-5300 Bonn 1, FRG |
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Abstract: | A model for the emission processes causing rapid variability (less than one day) in active galactic nuclei is developed. Relativistic electron beams escape from reconnection sheets in coronae of accretion disks and excite plasma turbulence with a typical frequency
, which depends on the electron number densityn (see also the contribution by R. van Oss). The finite lengths of different beams emerging from different reconnection sheets allows that the waves arecoherently scattered to frequencies ![sime](/content/vwj583724h1w3876/xxlarge8771.gif) 2 pe. For Lorentz factors ![gamma](/content/vwj583724h1w3876/xxlarge947.gif) 103 and densities typical for disk coronaen 106
cm
–3 (derived from iron line observations) one easily reaches the optical, frequency range. The time scale of the variability is then caused by the relaxation of the electron beams. Likewise, this model explains the very rapid variability in the X-ray (less than 10 minutes) by changing the parameters slightly. According to this scenario the higher the variable frequency is, the closer to the central black hole it should originate. |
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Keywords: | AGN intraday variability coherent radiation |
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