The Radio Universe at Low Surface Brightness: Feedback & accretion in the circumgalactic medium

TL;DR

This paper discusses how low-surface-brightness radio observations reveal the multi-phase circumgalactic medium's role in galaxy evolution, focusing on cold molecular gas and hot gas feedback effects.

Contribution

It introduces two novel science cases using radio observations to explore the multi-phase CGM around distant galaxies, emphasizing the importance of future radio interferometry.

Findings

Detection of widespread molecular gas indicating cold baryon cycle

Initial observations of Sunyaev-Zeldovich Effect showing quasar feedback

Highlighting the role of upcoming radio interferometers in CGM studies

Abstract

Massive galaxies at high-z are known to co-evolve with their circumgalactic medium (CGM). If we want to truly understand the role of the CGM in the early evolution of galaxies and galaxy-clusters, we need to fully explore the multi-phase nature of the CGM. We present two novel science cases that utilize low-surface-brightness observations in the radio regime to better understand the CGM around distant galaxies. At the lowest temperatures, observations of widespread molecular gas are providing evidence for the cold baryon cycle that grows massive galaxies. At the highest temperatures, observations of the Sunyaev-Zeldovich Effect are starting to reveal the effect of quasar feedback onto the hot gas in the CGM. We discuss the critical role that radio interferometers with compact configurations in the millimeter regime will play over the next decade in understanding the crucial role of the multi-phase CGM in galaxy evolution.