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   73019
   The main power source in quasars comes from matter accreting onto a
   supermassive black hole. X-rays are powerful diagnostic tool for the
   study of quasars, as they probe the highly energetic processes close to
   the black hole. This proposal concerns the study of the signatures of
   the central accretion disk that are present in the X-ray spectra of
   AGN. We propose the ASCA study of bright radio-quiet quasars from the
   PG sample, in order to study features such as the Fe K-alpha
   fluorescence line, soft excess and Compton reflection in their X-ray
   spectra, which are direct evidence of the accretion process. In
   particular, the study of the iron line probes material in orbits
   nearest to the central supermassive black hole.
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