The prevalence of AGN feedback in massive galaxies at z ≈ 1

Chris Simpson, Paul Westoby, Vinod Arumugam, Rob Ivison, Will Hartley, Omar Almaini

Research output: Contribution to journalArticlepeer-review


We use the optical-infrared imaging in the UKIDSS Ultra Deep Survey field, in combination with the new deep radio map of Arumugam et al., to calculate the distribution of radio luminosities among galaxies as a function of stellar mass in two redshift bins across the interval 0.4 < z ≤ 1.2. This is done with the use of a new Bayesian method to classify stars and galaxies in surveys with multiband photometry, and to derive photometric redshifts and stellar masses for those galaxies. We compare the distribution to that observed locally and find agreement if we consider only objects believed to be weak-lined radio-loud galaxies. Since the local distribution is believed to be the result of an energy balance between radiative cooling of the gaseous halo and mechanical active galactic nucleus (AGN) heating, we infer that this balance was also present as long ago as z ≈ 1. This supports the existence of a direct link between the presence of a low-luminosity ('hot-mode') radio-loud AGN and the absence of ongoing star formation.

Original languageEnglish
Pages (from-to)2647-2656
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 20 Jun 2013


  • Galaxies: Active
  • Galaxies: Distances and redshifts
  • Galaxies: evolution-radio continuum: galaxies
  • Surveys


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