Compton-thick AGN in the NuSTAR Era. IV. A Deep NuSTAR and XMM-Newton View of the Candidate Compton-thick AGN in ESO 116-G018

Abstract

We present a 2-78 keV spectral analysis of the deep NuSTAR and XMM-Newton observation of a nearby Seyfert 2 galaxy, ESO 116-G018, which is selected as a candidate Compton-thick (CT) active galactic nucleus (AGN) based on a previous Chandra-Swift-BAT study. Through our analysis, the source is, for the first time, confirmed to be a CT AGN at a >3σ confidence level, with the “line-of-sight” column density N _H,Z = [2.46-2.76] × 10²⁴ cm^-2. The “global average” column density of the obscuring torus is N _H,S = [0.46-0.62] × 10²⁴ cm^-2, which suggests a clumpy, rather than uniform, distribution of the obscuring material surrounding the accreting supermassive black hole. The excellent-quality data given by the combined NuSTAR and XMM-Newton observations enable us to produce a strong constraint on the covering factor of the torus of ESO 116-G018, which is found to be f _c = [0.13-0.15]. We also estimate the bolometric luminosity from the broadband X-ray spectrum to be L _bol = [2.57-3.41] × 10⁴⁴ erg s^-1.