Vasylenko A. The X-ray spectral features of active galactic nuclei in 0.5-250 keV energy range

The work is devoted a study of the observed X-ray spectral features of active galactic nuclei in the 0.5-250 keV energy range and to the analysis of values of the spectral parameters and its changes. Based on the data of the 22-month Swift-BAT All-Sky Hard X-ray Survey catalogue the sample of 95 galaxies with active nuclei was formed as well as their X-ray spectral parameters were determined and analyzed. Interdependencies of the main spectral parameters, such as the photon index Г, relative reflection R, exponential cut-off energy, equivalent width of Fe K alpha line and the absorption column density were constructed and analyzed. The separation of galaxies with active nuclei by Seyfert types and by radio loudness were taken into account in these dependencies. It allowed us for the first time to find a tendency of systematically larger values of the reflection for small Г for Seyfert 2s as compared with Seyfert 1s. We found that parameter R is less important for radio loud galaxies as compared with radio-quiet ones and the equivalent widths of Fe K alpha line in radio-loud galaxies for the given values of reflection have smaller values than in radio-quiet galaxies. On the whole, our analysis do not fully correspond to the generally accepted Antonucci-Miller Unified Scheme of active galactic nucleus and requires that individual features of AGN be taken into account. For the X-ray spectrum of Seyfert 2 NGC 1194 galaxy, we found for the first time that the line in the energy range 6.3-6.5 keV consists of two components with energies of 6.38±0.04 keV and 6.51±0.05 keV, which may be described by relativistic profile for a Schwarzschild black hole. We have proposed the hypothesis according to which a double supermassive black hole with individual accretion disks, which have different inclination angles and sizes of inner stable orbit, is located in the centre of NGC 1194 nucleus. It is found that the shape of the NGC 3281 X-ray spectrum is consistent with the model, according to which, the gas-dust torus is consist of individual clouds; the torus's physical and geometrical parameters were also estimated. Nickel Ni K alpha and iron Fe K alpha emission lines were also studied for analyzing compliance of this model.