A Chandra Study of the Radio Galaxy NGC 326: Wings, Outburst History, and AGN Feedback

TL;DR

This study uses Chandra X-ray observations to analyze the morphology, outburst history, and AGN feedback mechanisms of the Z-shaped radio galaxy NGC 326, revealing features indicative of shocks, cavities, and reorientation events.

Contribution

It provides a detailed X-ray analysis of NGC 326, reconstructing its AGN outburst history and supporting the reorientation model for wing formation in X-shaped radio galaxies.

Findings

Detection of a high-temperature shock front.

Identification of cavities associated with radio wings.

Evidence supporting jet reorientation as the wing formation mechanism.

Abstract

NGC 326 is one of the most prominent X- or Z-shaped radio galaxies (XRGs/ZRGs) and has been the subject of several studies attempting to explain its morphology through either fluid motions or reorientation of the jet axis. We examine a 100 ks archival Chandra exposure and find several features associated with the radio galaxy: a high-temperature front that may indicate a shock, high-temperature knots around the rim of the radio emission, and a cavity associated with the eastern wing of the radio galaxy. A reasonable interpretation of these features in light of the radio data allows us to reconstruct the history of the AGN outbursts. The active outburst was likely once a powerful radio source which has since decayed, and circumstantial evidence favors reorientation as the means to produce the wings. Because of the obvious interaction between the radio galaxy and the ICM and the wide separation between the active lobes and wings, we conclude that XRGs are excellent sources in which to study AGN feedback in galaxy groups by measuring the heating rates associated with both active and passive heating mechanisms.