1. The NuSTAR X-ray spectrum of the low-luminosity active galactic nucleus in NGC 7213
- Author
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Dominic J. Walton, D. Stern, P. Arévalo, Christopher S. Reynolds, Giorgio Matt, Fiona A. Harrison, Franz E. Bauer, David R. Ballantyne, Anne M. Lohfink, A. C. Fabian, Andrea Marinucci, Francesco Ursini, Stefano Bianchi, A. Tortosa, Ursini, F., Marinucci, A, Matt, G, Bianchi, S, Tortosa, A, Stern, D, Arevalo, P, Ballantyne, R, Bauer, E, Fabian, C, Harrison, A, Lohfink, M, Reynolds, S, and Walton, D.
- Subjects
Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,Astronomy ,Astronomy and Astrophysics ,Torus ,Astrophysics ,Corona ,Luminosity ,Spherical geometry ,Space and Planetary Science ,Optical depth (astrophysics) ,Equivalent width - 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 E_c > 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 kT_e > 40 keV and an optical depth τ ≲ 1, assuming a spherical geometry.
- Published
- 2015