Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN

TL;DR

This study analyzes four local AGN using simultaneous NuSTAR and XMM-Newton data, revealing their obscuration levels, inhomogeneous torus structures, and luminosity variability, advancing understanding of AGN characteristics.

Contribution

It provides the first detailed broadband X-ray spectral analysis of these four AGN with physically motivated models, confirming the presence of Compton-thick AGN and inhomogeneous obscuring material.

Findings

ESO 362-8 is confirmed as a Compton-thick AGN.

Two sources show significant luminosity variation over a decade.

All sources exhibit inhomogeneous torus structures.

Abstract

We present the results of the broadband X-ray spectral analysis of simultaneous NuSTAR and XMM-Newton observations of four nearby Compton-thick active galactic nuclei (AGN) candidates selected from the Swift-Burst Alert Telescope (BAT) 150-month catalog. This work is part of a larger effort to identify and characterize all Compton-thick (NH >= 10^24 cm^-2) AGN in the local Universe (z < 0.05). We used three physically motivated models -- MYTorus, borus02, and UXClumpy -- to fit and characterize these sources. Of the four candidates analyzed, 2MASX J02051994-0233055 was found to be an unobscured (NH < 10^22 cm^-2) AGN, 2MASX J04075215-6116126 and IC 2227 to be Compton-thin (10^22 cm^-2 < NH < 10^24 cm^-2) AGN, and one, ESO 362-8, was confirmed to be a Compton-thick AGN. Additionally, every source was found to have a statistically significant difference between their line-of-sight and average torus hydrogen column density, further supporting the idea that the obscuring material in AGN is inhomogeneous. Furthermore, half of the sources in our sample (2MASX J02051994-0233055 and 2MASX J04075215-6116126) exhibited significant luminosity variation in the last decade, suggesting that this might be a common feature of AGN.