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AGN Variability from X-Rays to Radio Waves, Crimée : Ukraine (2004)
X-ray Variability of AGN and the Flare Model
R. W. Goosmann, B. Czerny, A.-M. Dumont, M. Mouchet1, A. Rózanska

Short-term variability of X-ray continuum spectra has been reported for several Active Galactic Nuclei. Significant X-ray flux variations are observed within time scales down to 10^3-10^5 seconds. We discuss short variability time scales in the frame of the X-ray flare model, which assumes the release of a large hard X-ray flux above a small portion of the accretion disk. The resulting observed X-ray spectrum is composed of the primary radiation and of a reprocessed Compton reflection component that we model with numerical radiative transfer simulations. The incident hard X-rays of the flare will heat up the atmosphere of the accretion disk and hence induce thermal expansion. Eventually, the flare source will be surrounded by an optically-thick medium, which should modify the observed spectra.
1 :  APC - UMR 7164 - AstroParticule et Cosmologie
APC - Cosmologie et gravitation
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique