The scaling relations and the fundamental plane for radio halos and relics of galaxy clusters

TL;DR

This study investigates the relationships between radio emissions in galaxy clusters and their physical and dynamical properties, revealing a fundamental plane that links radio power, cluster mass, and dynamical state.

Contribution

It introduces a comprehensive analysis combining radio, optical, and X-ray data to establish a fundamental plane for radio halos and relics in galaxy clusters, emphasizing the role of dynamical parameters.

Findings

Radio powers correlate with cluster mass and dynamical parameters.

Including dynamical parameters reduces data scatter in scaling relations.

A fundamental plane relates radio power, mass proxies, and dynamical state.

Abstract

Diffuse radio emission in galaxy clusters is known to be related to cluster mass and cluster dynamical state. We collect the observed fluxes of radio halos, relics, and mini-halos for a sample of galaxy clusters from the literature, and calculate their radio powers. We then obtain the values of cluster mass or mass proxies from previous observations, and also obtain the various dynamical parameters of these galaxy clusters from optical and X-ray data. The radio powers of relics, halos, and mini-halos are correlated with the cluster masses or mass proxies, as found by previous authors, with the correlations concerning giant radio halos being, in general, the strongest ones. We found that the inclusion of dynamical parameters as the third dimension can significantly reduce the data scatter for the scaling relations, especially for radio halos. We therefore conclude that the substructures in X-ray images of galaxy clusters and the irregular distributions of optical brightness of member galaxies can be used to quantitatively characterize the shock waves and turbulence in the intracluster medium responsible for re-accelerating particles to generate the observed diffuse radio emission. The power of radio halos and relics is correlated with cluster mass proxies and dynamical parameters in the form of a fundamental plane.