The obscured active nucleus of NGC 7172 as seen by NuSTAR
arXiv:1808.08457 · doi:10.3103/S0884591318060053
Abstract
We analyse the properties of the X-ray emission from Seyfert 2 NGC 7172 which are based on the 32 ks observational data from NuSTAR in 2014. This source showed a constant Compton-thin obscuration , which is similar to that observed by XMM-Newton, Suzaku, ASCA and BeppoSAX over past 30 years. We revealed the presence of a moderate reflection component with <R>~0.44 and a narrow FeKα line with eV. The applied numerical models of torus confirmed the Compton-thin type of the Seyfert nucleus and allowed us to obtain an estimate of the torus opening angle and inclination . Using the observation data of previous observation, we demonstrate also the long-term variability of intrinsic luminosity (2-10 keV) almost by order and EW by factor on a timescale of years, that coincides to the distance of 3.7 pc between central source and reprocessing medium. Such changes of intrinsic luminosity without changes in value indicate the variability of a central source. In the same time the spectral analysis results with the presence of the lag between variability of intrinsic luminosity (2-10 keV) and EW , as well as a behaviour of intensity of the line are in agreement with the scenario, where observed line is generated in a distant gas-dust torus.
20 pages, 6 figures, in Russian, accepted for publication in Kin. and Phys. of Celestial Bodies