Presentation 1 : Poster
Time dependent reflected spectrum of accretion discs in flare model
Suzy Collin, Se'verine Coupe', Anne-Marie Dumont
We consider the time dependent illumination of an accretion disc
in Active Galactic Nuclei according to the flare model, which postulates the sudden release of a large X-ray flux above a small region of the accretion disc. Taking into account the fact that this region is not illuminated before the flare, the increase of the reflected spectrum takes place on a cold reflector. The reflected spectrum begins to display the characteristics of a hot skin only a few hours after the onset of the flare. Due to the overlapping of different flares in non-equilibrium state and to thermal instabilities evolving slowly through thermal conductivity, the observed soft X-ray spectrum and the Fe K$\alpha$ line should be completely decorrelated from the hard X-ray continuum. We show examples of such spectra.