The Physics of Galaxy Cluster Outskirts

TL;DR

This paper reviews the current observational and theoretical understanding of galaxy cluster outskirts, highlighting recent advances and future prospects in studying these low-density, challenging regions of galaxy clusters.

Contribution

It provides a comprehensive overview of recent observational techniques and theoretical models related to galaxy cluster outskirts, and discusses future observational prospects.

Findings

Advances in X-ray, SZ, and optical observations have improved understanding of cluster outskirts.

Theoretical models now better explain matter infall and virialization processes.

Future observatories will further enhance exploration of these regions.

Abstract

As the largest virialized structures in the universe, galaxy clusters continue to grow and accrete matter from the cosmic web. Due to the low gas density in the outskirts of clusters, measurements are very challenging, requiring extremely sensitive telescopes across the entire electromagnetic spectrum. Observations using X-rays, the Sunyaev-Zeldovich effect, and weak lensing and galaxy distributions from the optical band, have over the last decade helped to unravel this exciting new frontier of cluster astrophysics, where the infall and virialization of matter takes place. Here, we review the current state of the art in our observational and theoretical understanding of cluster outskirts, and discuss future prospects for exploration using newly planned and proposed observatories.