CHEERS results on Mrk 573: Study of deep Chandra observations

TL;DR

This study uses deep Chandra X-ray observations to analyze the complex ionized and thermal structures in Mrk 573, revealing shock interactions, AGN variability, and extended emission inconsistent with a simple torus model.

Contribution

It provides high-resolution imaging and spectral analysis of Mrk 573, uncovering detailed substructures and challenging the traditional AGN unified model with evidence of clumpy obscuration.

Findings

Resolved substructures in ionizing cones using PSF-deconvolution.

Detected thermal gas indicating shock interactions.

Found extended emission inconsistent with a uniform torus.

Abstract

We present results on Mrk 573 obtained as part of the CHandra survey of Extended Emission-line Regions in nearby Seyfert galaxies (CHEERS). Previous studies showed that this source features a biconical emission in the soft X-ray band closely related with the Narrow Line Region as mapped by the [O iii] emission line and the radio emission, though on a smaller scale; we investigate the properties of soft X-ray emission from this source with new deep Chandra observations. Making use of the subpixel resolution of the Chandra/ACIS image and PSF-deconvolution, we resolve and study substructures in each ionizing cone. The two cone spectra are fitted with photoionization model, showing a mildly photoionized phase diffused over the bicone. Thermal collisional gas at about ~ 1.1 keV and ~ 0.8 keV appears to be located between the nucleus and the "knots" resolved in radio observations, and between the "arcs" resolved in the optical images, respectively; this can be interpreted in terms of shock interaction with the host galactic plane. The nucleus shows a significant flux decrease across the observations indicating variability of the AGN, with the nuclear region featuring higher ionization parameter with respect to the bicone region. The long exposure allows us to find extended emission up to ~ 7 kpc from the nucleus along the bicone axis. Significant emission is also detected in the direction perpendicular to the ionizing cones, disagreeing with the fully obscuring torus prescribed in the AGN unified model, and suggesting instead the presence of a clumpy structure.