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X-ray flares from runaway pair production in active galactic nucleiThe hard X-ray spectrum of AGNs is nonthermal, probably arising from an electron-positron pair cascade, with some emission reflected off relatively cold matter. There has been interest in models on which protons are accelerated and create relativistic electrons on interaction with a local radiation field. It is shown here that a sufficient column density of protons can lead to runaway pair production: photons generated by the relativistic pairs are the targets for the protons to produce more pairs. This can produce X-ray fluxes with the characteristics observed in AGN. The model predicts the maximum ratio of luminosity to source size as well as their spectrum in the early phases. The same mechanism may also be able to create the knots of synchrotron-radiating pair plasma seen in sources such as 3C273.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Kirk, J. G.
(Max-Planck-Inst. fuer Kernphysik Heidelberg, Germany)
Mastichiadis, A.
(Max-Planck-Inst. fuer Kernphysik, Heidelberg, Germany; NASA, Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 15, 2013
Publication Date
November 12, 1992
Publication Information
Publication: Nature
Volume: 360
Issue: 6400
ISSN: 0028-0836
Subject Category
Distribution Limits
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