A Compton-thick nucleus in the dual active galactic nuclei of Mrk 266

We present the results from our analysis of NuSTAR data of the luminous infrared galaxy Mrk 266, which contains two nuclei, south-western (SW) and north-eastern (NE), which were resolved in previous Chandra imaging. Combining this with the Chandra data, we intepret the hard X-ray spectrum obtained from a NuSTAR observation to result from a steeply rising flux from a Compton-thick active galactic nuclei (AGN) in the SW nucleus which is very faint in the Chandra band, confirming the previous claim. This hard X-ray component is dominated by reflection, and its intrinsic 2-10 keV luminosity is likely to be ∼1 × 10⁴³ erg s^-1. Although it is bright in soft X-ray, only a moderately absorbed NE nucleus has a 2-10 keV luminosity of 4 × 10⁴¹ erg s^-1, 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.