X-Ray Spectral Signatures of Accreting Black Holes

The calculation of (general-relativistic) geodesics in the vicinity of spinning Black Holes (BHs), i.e. in Kerr metric, allows to interpret some features detected in the X-ray spectra of many Active Galactic Nuclei (AGN) and galactic BH candidates, like the typical asymmetric profile of the iron K¿ line. Our assumptions (Kerr metric, disc illumination from a central source) may also yield a simple explanation of the K¿ line equivalent width measured in some sources. In order to allow comparison with the data, we developed a computational tool aimed to fit the observed spectral features - including the disc-reflected continuum - on the base of fully relativistic models. The research we present here was performed under the supervision of V. Karas (AV ¿R, Prague), E. Massaro (Uni1, Rome), G. Matt (Uni3, Rome), J. Miller (SISSA, Trieste). The present results were submitted as a Dissertation for the degree of Doctor Philosophiae at SISSA (Trieste), in October 2000.