Evolutionary Map of the Universe (EMU): Observations of Filamentary Structures in the Abell S1136 Galaxy Cluster

TL;DR

This study uses radio and multi-wavelength data to reveal filamentary structures in the diffuse radio emission of galaxy cluster Abell S1136, challenging previous interpretations of the emission as a halo or tailed source.

Contribution

First detailed radio imaging of filamentary structures in Abell S1136, providing new insights into diffuse emission morphology in galaxy clusters.

Findings

Diffuse radio emission contains three narrow filaments

Filaments are 80-140 kpc in length

Emission properties differ from typical radio halos or tailed sources

Abstract

We present radio observations of the galaxy cluster Abell S1136 at 888 MHz, using the Australian Square Kilometre Array Pathfinder radio telescope, as part of the Evolutionary Map of the Universe Early Science program. We compare these findings with data from the Murchison Widefield Array, XMM-Newton, the Wide-field Infrared Survey Explorer, the Digitised Sky Survey, and the Australia Telescope Compact Array. Our analysis shows the X-ray and radio emission in Abell S1136 are closely aligned and centered on the BCG, while the X-ray temperature profile shows a relaxed cluster with no evidence of a cool core. We find that the diffuse radio emission in the centre of the cluster shows more structure than seen in previous low-resolution observations of this source, which appeared formerly as an amorphous radio blob, similar in appearance to a radio halo; our observations show the diffuse emission in the Abell S1136 galaxy cluster contains three narrow filamentary structures visible at 888 MHz, between$\sim 80$ and 140 kpc in length; however the properties of the diffuse emission do not fully match that of a radio (mini-)halo or (fossil) tailed radio source.