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The obscured active nucleus of NGC 7172 as seen by NuSTAR

Vasylenko, Anatoliy (2018) The obscured active nucleus of NGC 7172 as seen by NuSTAR. .

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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 $N_{H}\approx 8\cdot 10^{22} cm^{-2}$, 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 FeK{\alpha} line with $67^{+13}_{-14}$ 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 ${\Theta}_{t}\sim59\deg$ and inclination ${\Theta}_{i}\sim61\deg$. Using the observation data of previous observation, we demonstrate also the long-term variability of intrinsic luminosity $L_{intr}$(2-10 keV) almost by order and EW $FeK_{\alpha}$ by factor $\sim4$ on a timescale of $\sim12$ years, that coincides to the distance of $d\sim$3.7 pc between central source and reprocessing medium. Such changes of intrinsic luminosity without changes in $N_{H}$ 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 $L_{intr}$(2-10 keV) and EW $FeK_{\alpha}$, as well as a behaviour of intensity $I_{FeK_{\alpha}}$ of the line are in agreement with the scenario, where observed $FeK_{\alpha}$ line is generated in a distant gas-dust torus.

Item Type:Report or Paper (Discussion Paper)
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Record Number:CaltechAUTHORS:20180828-095408525
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89201
Deposited By: Joy Painter
Deposited On:28 Aug 2018 16:57
Last Modified:03 Oct 2019 20:14

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