Do radio core-halos and cold fronts in non major merging clusters originate from the same gas sloshing?

TL;DR

This study suggests that the diffuse radio emission in relaxed galaxy clusters with cold fronts is likely caused by turbulence-driven re-acceleration of electrons during gas sloshing, linking radio halos and cold fronts.

Contribution

It proposes a connection between radio core-halos and cold fronts in non-major merging clusters, emphasizing turbulence re-acceleration during gas sloshing as the origin.

Findings

Radio emission is re-accelerated by turbulence within cold fronts.

Relativistic electrons' lifetime is shorter than their transport timescale.

Radio emission correlates with gas sloshing and cold front structures.

Abstract

We show an interesting correlation between the surface brightness and temperature structure of the relaxed clusters RXJ1720.1+2638 and MS1455.0+2232, hosting a pair of cold fronts, and their central core--halo radio source. We discuss the possibility that the origin of this diffuse radio emission may be strictly connected with the gas sloshing mechanism suggested to explain the formation of cold fronts in non major merging clusters. We show that the radiative lifetime of the relativistic electrons is much shorter than the timescale on which they can be transported from the central galaxy up to the radius of the outermost cold front. This strongly indicates that the observed diffuse radio emission is likely produced by electrons re--accelerated via some kind of turbulence generated within the cluster volume limited by the cold fronts during the gas sloshing.