A detailed study of X-ray cavities in the intracluster environment of the cool core cluster Abell 3017

TL;DR

This study provides a comprehensive multi-wavelength analysis of Abell 3017, revealing X-ray cavities linked to radio lobes, evidence of merger-induced gas motions, and a newly detected radio phoenix, advancing understanding of cluster dynamics and feedback processes.

Contribution

It presents the first detection of a radio phoenix and detailed analysis of X-ray cavities and gas motions in Abell 3017, combining multi-wavelength observations and advanced image processing techniques.

Findings

Detection of X-ray cavities associated with radio lobes.

Identification of gas motions due to merger activity.

First observation of a radio phoenix in this cluster.

Abstract

We present a detailed analysis of a cool-core galaxy cluster Abell 3017, at a redshift of z=0.219, which has been identified to be merging with its companion cluster Abell 3016. This study has made use of X-ray Chandra, UV (GALEX), optical (ESO/VLT), mid-infrared (WISE), and radio uGMRT observations of this cluster. Using various image processing techniques, such as unsharp masking, 2-d fits using Beta models, contour binning and the use of surface brightness profiles, we show the existence of a pair of X-ray cavities, at a projected distance of $\sim$20'' (70 kpc) and $\sim$16'' (57 kpc), respectively from the core of Abell~3017. We also detect an excess of X-ray emission located at 25'' $\sim$(88 kpc) south of the centre of Abell 3017, is likely due to the bulk motions in the ICM either by gas sloshing or ram-pressure striping due to a merger. We find that the radio lobes are responsible for the observed X-ray cavities detected in this system. The lower values of the mid-IR WISE colour [W1-W2] and [W2-W3] imply that the central BCG of Abell~3017 is a star-forming galaxy. The current star formation rate of the central BCG, estimated from the ${\rm H\alpha}$ and GALEX FUV luminosities, are equal to be $\sim 5.06\pm 0.78$ Msun yr$^{-1}$ and $\sim 9.20\pm 0.81$ Msun yr$^{-1}$, respectively. We detect, for the first time, a radio phoenix $\sim$150 kpc away from the radio core, with a spectral index of ($\alpha \!\leq\! -1.8$). We also report the detection of $\rm~Pa_\alpha$ emission in this cluster using ESO VLT SINFONI imaging data.