Chandra Detection of the Circumnuclear Molecular Torus of the Compton Thick AGN in NGC 5643

TL;DR

This study uses high-resolution Chandra imaging to identify a clumpy, elongated Fe Kα emission feature in NGC 5643, aligning with molecular torus structures and providing insights into the obscuring material around the AGN.

Contribution

It reports the first high-resolution detection of a spatially resolved Fe Kα feature in a Compton Thick AGN, linking X-ray and molecular emission from the obscuring torus.

Findings

Fe Kα emission is elongated and extends ~65 pc N-S.

The Fe Kα feature aligns with CO emission, indicating a common origin.

The structure is more extended than the molecular disk, suggesting a complex torus geometry.

Abstract

We report a clumpy elongated feature found with deep Chandra ACIS high-resolution imaging of the Fe K{\alpha} line emission in the nuclear region of the Compton Thick Active Galactic Nucleus (CT AGN) galaxy NGC 5643. This feature extends for ~65 pc N-S. No corresponding feature is seen in the 3.0-6.0 keV continuum. The Fe K{\alpha} feature is spatially consistent with the N-S elongation found in the CO(2-1) high resolution imaging with ALMA (Alonso-Herrero et al 2018), but slightly more extended than the rotating molecular disk of r=26 pc indicated by the kinematics of the CO(2-1) line. The Chandra detection of a corresponding N-S structure in the neutral Fe K{\alpha} line, would argue for both CO and Fe K{\alpha} emission originating from the obscuring torus.