Witnessing galaxy clusters: from maturity to childhood

TL;DR

This paper reviews methods for detecting galaxy clusters across different redshifts, highlighting recent discoveries of high-redshift proto-clusters and discussing their significance for cosmology and galaxy evolution.

Contribution

It provides a comprehensive overview of detection techniques, recent high-redshift cluster discoveries, and their implications for future surveys and cosmological studies.

Findings

Detection methods vary across wavelengths and techniques.

High-redshift proto-clusters have been recently identified.

Cluster samples inform cosmological and galaxy evolution constraints.

Abstract

Galaxy clusters are the largest structures in Universe. They are very important as both cosmological probes and astrophysical laboratories. Several methods have been developed to detect galaxy clusters with different techniques (optical, X-rays, Weak Lensing and Sunyaev-Zeldovich effect) providing cluster samples with a well-characterized purity and completeness rates up to moderate redshift (z$<$1.2). These samples allow us to study the systematic of different methods and to obtain reliable mass estimations. On the contrary, high redshift clusters only started to be explored very recently with the advent of deep IR and X-ray data surveys, providing the first proto-clusters (z$>$1.5-2) ever detected. In this talk, I introduce these techniques and review some of the cluster samples obtained including particular striking cases. I discuss their relevance in terms of cosmological and galaxy evolution constraints and finally, I briefly refer to the cluster science predictions for the next generation surveys.