Why z > 1 radio-loud galaxies are commonly located in protoclusters

N. A. Hatch*, D. Wylezalek, J. D. Kurk, D. Stern, C. De Breuck, M. J. Jarvis, A. Galametz, A. H. Gonzalez, W. G. Hartley, A. Mortlock, N. Seymour, J. A. Stevens

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Distant powerful radio-loud active galactic nuclei (RLAGN) tend to reside in dense environments and are commonly found in protoclusters at z > 1.3. We examine whether this occurs because RLAGN are hosted by massive galaxies, which preferentially reside in rich environments. We compare the environments of powerful RLAGN at 1.3 <z <3.2 from the Clusters Around Radio-Loud AGN survey to a sample of radio-quiet galaxies matched in mass and redshift. We find that the environments of RLAGN are significantly denser than those of radio-quiet galaxies, implying that not more than 50 per cent of massive galaxies in this epoch can host powerful radio-loud jets. This is not an observational selection effect as we find no evidence to suggest that it is easier to observe the radio emission when the galaxy resides in a dense environment. We therefore suggest that the dense Mpc-scale environment fosters the formation of a radio jet from an AGN. We show that the number density of potential RLAGN host galaxies is consistent with every >10(14) M-circle dot cluster having experienced powerful radio-loud feedback of duration similar to 60 Myr during 1.3 <z <3.2. This feedback could heat the intracluster medium to the extent of 0.5-1 keV per gas particle, which could limit the amount of gas available for further star formation in the protocluster galaxies.

Original languageEnglish
Pages (from-to)280-289
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume445
Issue number1
DOIs
Publication statusPublished - 21 Nov 2014

Keywords

  • galaxies: active
  • galaxies: high-redshift
  • ACTIVE GALACTIC NUCLEI
  • SUPERMASSIVE BLACK-HOLES
  • INITIAL MASS FUNCTION
  • LESS-THAN 3.2
  • SIMILAR-TO 2
  • CLUSTER ENVIRONMENTS
  • LUMINOSITY FUNCTION
  • SKY SURVEY
  • DEEP SURVEY
  • QUIESCENT GALAXIES

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