Observations of Seyfert galaxies in X-ray region reveal the wide emissive lines in their spectra, which can arise in inner parts of accretion disks, where the effects of General Relativity must be counted. A spectrum of a solitary emission line (the K_alpha-line of iron, for example) of a hot spot in Kerr accretion disk is simulated, depending on the radial coordinate r and the angular momentum a=J/M of a black hole, under the assumption of an equatorial circular motion of a hot spot. Basing on results of numerical simulations it is shown that the characteristic two-peak line profile with the sharp edges arises at a large distance (r about (3-10)r_g). The inner regions emit the line, which is observed with one maximum and extremely wide red wing. High accuracy future spectral observations, being carried out, could detect the angular momentum a of the black hole.

Page created on February 8, 2002.