In Astronomy and Astrophysics Review, Volume 15, Issue 2, pp.67-144, 2008.
astro-ph/0802.2770

For a PDF version of the article, click here.

DISTANT RADIO GALAXIES AND THEIR ENVIRONMENTS


G. K. Miley 1 and C. De Breuck 2


1 Sterrewacht, Leiden University, Postbus 9513, 2300RA Leiden, The Netherlands
Phone: +31 71 5275849
miley@strw.leidenuniv.nl
2 European Southern Observatory, Karl-Schwarzschild-Strasse 2 D-85748, Garching, Germany
Phone: +49 89 32006613
cdebreuc@eso.org


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.


Key words: Radio galaxies; High-redshift; Massive galaxies; Clusters


Table of Contents

INTRODUCTION
Scope of this article - HzRGs
History
Hunting for HzRGs
Redshift distribution of HzRGs
Constituents of HzRGs

RELATIVISTIC PLASMA
HzRGS and low-redshift radio galaxies
Radio sizes and morphologies. Size as an evolutionary clock
Radio size vs redshift correlation
Radio spectral index vs redshift correlation
Nonthermal X-ray emission

GAS AND DUST
Hot ionised gas - Radio depolarization
Warm ionized gas
Neutral Gas
Molecular Gas
Dust

STARS
Old stars: HzRGs as the most massive galaxies
Young stars - UV absorption lines
The alignment effect - Jet-induced star formation

ACTIVE GALACTIC NUCLEUS (AGN)
Hidden or dormant quasar - The Unification Church
Supermassive black hole - Powerhouse of the AGN
Extinction of the "dinosaurs"

NATURE OF HzRG HOSTS - MASSIVE FORMING GALAXIES
The Spiderweb Galaxy - a case study

ENVIRONMENT OF HzRGS - PROTOCLUSTERS
Finding protoclusters using HzRGs
Properties of radio-selected protoclusters
Are radio-selected protoclusters typical?
Protocluster evolution

CONCLUSIONS AND FUTURE

APPENDIX: KNOWN HzRGs

REFERENCES

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