The NuSTAR X-ray spectrum of the low-luminosity active galactic nucleus in NGC 7213
Harrison, F. A.; Stern, D.; Bauer, F. E.; Bianchi, S.; Fabian, A. C.; Reynolds, C. S.; Matt, G.; Arévalo, P.; Ballantyne, D. R.; Ursini, F.; Walton, D. J.; Marinucci, A.; Lohfink, A. M.; Tortosa, A.
France, Italy, United States, Chile, United Kingdom
Abstract
We present an analysis of the 3-79 keV NuSTAR spectrum of the low-luminosity active galactic nucleus NGC 7213. In agreement with past observations, we find a lower limit to the high-energy cut-off of Ec > 140 keV, no evidence for a Compton-reflected continuum and the presence of an iron K α complex, possibly produced in the broad-line region. From the application of the MYTORUS model, we find that the line-emitting material is consistent with the absence of a significant Compton reflection if arising from a Compton-thin torus of gas with a column density of 5.0^{+2.0}_{-1.6}× 10^{23} cm-2. We report variability of the equivalent width of the iron lines on the time-scale of years using archival observations from XMM-Newton, Chandra and Suzaku. This analysis suggests a possible contribution from dusty gas. A fit with a Comptonization model indicates the presence of a hot corona with a temperature kTe > 40 keV and an optical depth τ ≲ 1, assuming a spherical geometry.