Distant Radio Galaxies and their Environments

TL;DR

This paper reviews high-redshift radio galaxies, their constituents, environments, and role as progenitors of massive galaxies, highlighting their significance in understanding early Universe conditions and galaxy formation.

Contribution

It provides a comprehensive overview of HzRGs, their properties, environments, and their importance as progenitors of brightest cluster galaxies, including a catalog of known HzRGs.

Findings

HzRGs are massive forming galaxies.

They are often located in overdense protocluster regions.

HzRGs serve as key diagnostics of early Universe conditions.

Abstract

We review the properties and nature of luminous high-redshift radio galaxies (HzRGs, z > 2) and the environments in which they are located. HzRGs have several distinct constituents which interact with each other - relativistic plasma, gas in various forms, dust, stars and an active galactic nucleus (AGN). These building blocks provide unique diagnostics about conditions in the early Universe. We discuss the properties of each constituent. Evidence is presented that HzRGs are massive forming galaxies and the progenitors of brightest cluster galaxies in the local Universe. HzRGs are located in overdense regions in the early Universe and are frequently surrounded by protoclusters. We review the properties and nature of these radio-selected protoclusters. Finally we consider the potential for future progress in the field during the next few decades. A compendium of known HzRGs is given in an appendix.