Sunyaev Zel'dovich effect in galaxy clusters cavities: thermal or non-thermal origin?

TL;DR

This paper investigates whether the Sunyaev Zel'dovich effect observed in galaxy cluster cavities is caused by thermal high-temperature gas or non-thermal relativistic electrons, proposing methods to distinguish between these origins.

Contribution

It analyzes the influence of high-temperature gas density on the SZ effect and discusses observational strategies at higher energy bands to identify its origin.

Findings

Density of high-temperature gas affects the SZ effect interpretation.

Higher energy observations can help distinguish thermal from non-thermal SZ effects.

Proposes a framework for future observational tests.

Abstract

Several galaxy clusters host X-ray cavities, often filled with relativistic electrons emitting in the radio band. In the cluster MS 0735.6+7421 the cavities have been detected through the Sunyaev Zel'dovich (SZ) effect, but it has not been possible to determine if this effect is thermal (produced by a very high temperature gas filling the cavity) or non-thermal (produced by the relativistic electrons that produce the diffuse radio emission detected in the cavity). In this paper we discuss the role of the density of the high temperature gas inside the cavities in determining whether the dominant SZ effect is the thermal or the non-thermal one, and how it can be possible to distinguish between the two possibilities, discussing the role of observations at higher energy bands.