A Compton-thick nucleus in the dual AGN of Mrk 266

TL;DR

This study reveals a Compton-thick AGN in the SW nucleus of Mrk 266 with a reflection-dominated hard X-ray spectrum, highlighting the challenges in detecting dual AGN in obscured galaxy mergers.

Contribution

First combined NuSTAR and Chandra analysis confirming a Compton-thick AGN in Mrk 266's SW nucleus and characterizing the faint NE nucleus as a low-luminosity AGN.

Findings

SW nucleus hosts a Compton-thick AGN with ~10^43 erg/s luminosity

NE nucleus is a low-luminosity AGN with ~4x10^41 erg/s luminosity

Implications for detecting dual AGN in obscured galaxy mergers

Abstract

We present results of our analysis of NuSTAR data of the luminous infrared galaxy Mrk 266, which contains two nuclei, SW and NE, resolved in previous Chandra imaging. Combining with the Chandra data, we intepret the hard X-ray spectrum obtained from a NuSTAR observation as resulting from steeply rising flux from a Compton-thick AGN in the SW nucleus which is very faint in the Chandra band, confirming the previous claim of Mazzarella et al. (2012). This hard X-ray component is dominated by reflection, and its intrinsic 2-10 keV luminosity is likely to be ~1e43 erg/s. Although it is bright in soft X-ray, only moderately absorbed NE nucleus has a 2-10 keV luminosity of 4e41 erg/s, placing it in the low-luminosity AGN class. These results have implications for understanding the detectability and duty cycles of emission from dual AGN in heavily obscured mergers.