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		| Paper: | 
		X-ray Variability of AGN and the Flare Model | 
	 
	
		| Volume: | 
		360, AGN Variability from X-Rays to Radio Waves | 
	 
	
		| Page: | 
		277 | 
	 
	
		| Authors: | 
		Goosmann, R.W.; Czerny, B.; Dumont, A.-M.; Mouchet, M.; Rozanska, A. | 
	 
	
	
		| Abstract: | 
		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 103 - 105 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. | 
	 
	
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