Chandra unveils a binary Active Galactic Nucleus in Mrk463

TL;DR

This study confirms that Mrk463 hosts a binary Active Galactic Nucleus with two luminous, unresolved nuclei separated by about 3.8 kpc, providing clear evidence of dual AGN activity in this galaxy.

Contribution

First unambiguous detection of a binary AGN in Mrk463, demonstrating the presence of two active nuclei with distinct properties using multi-wavelength data.

Findings

Detection of two luminous nuclei in Mrk463 with Chandra.

Confirmation of the AGN nature of both nuclei, especially the West nucleus.

Mrk463 is the clearest binary AGN case after NGC6240.

Abstract

We analyse Chandra, XMM-Newton and HST data of the double-nucleus Ultraluminous Infrared Galaxy (ULIRG), Mrk463. The Chandra detection of two luminous ($\mathrm{L}_\mathrm{2-10 keV}=1.5\times10^{43}$ and $3.8\times10^{42}$ erg cm$^{-2}$ s$^{-1}$), unresolved nuclei in Mrk~463 indicates that this galaxy hosts a binary AGN, with a projected separation of $\simeq3.8$ kpc ($3.83\pm0.01$ arcsec). While the East nucleus was already known to be a Seyfert 2 (and this is further confirmed by our Chandra detection of a neutral iron line), this is the first unambiguous evidence in favour of the AGN nature of the West nucleus. Mrk463 is therefore the clearest case so far for a binary AGN, after NGC6240.