Spinning Black Holes in Active Galactic Nuclei

Recent X-ray spectroscopy made with ASCA have shown broad, skewed iron line emission from Seyfert-1 galaxies. The large extent of the red tail allows probing of the innermost regions of the black hole's accretion disc. A model of line emission has been developed and very strong evidence for the presence of a rapidly rotating Kerr black hole has been established in the case of MCG--6-30-15. Issues related to the observed line equivalent width and the position/geometry of the primary source are discussed. Both the continuum and the reflected iron line are computed, in a consistent manner, for a source located on the axis of rotation.