1321+045: a Compact Steep Spectrum radio source in a cool-core galaxy cluster

TL;DR

This study examines a compact steep spectrum radio source in a galaxy cluster, revealing recent and possibly multiple episodes of jet activity, providing insights into early AGN feedback in cool-core clusters.

Contribution

It presents detailed radio and X-ray observations of a CSS source in a cool-core cluster, highlighting recent jet activity and suggesting complex jet history.

Findings

Jet activity occurred approximately 2 million years ago.

A very recent (~hundreds of years old) jet structure was detected.

The system may have experienced one or two episodes of jet activity.

Abstract

Cluster-central gigahertz peak and compact steep spectrum (CSS) sources offer an opportunity to study the earliest phases of AGN feedback, but few have yet been examined in detail. We present results from radio and X-ray observations of 1321+045, a CSS source in a 4.4 keV cluster at z=0.263. The cluster has a strongly cooling core, and disturbances from a minor cluster merger may have triggered a period of jet activity which formed the 16 kpc radio lobes 2.0 [+0.3,-0.2] Myr ago. However, new VLBA imaging shows a ~20 pc jet on a different projected axis, which is probably only a few hundred years old. We consider possible histories for the system, with either one or two periods of jet activity. While this single system is informative, a broader study of the youngest cluster-central radio sources is desirable.