The prevalence of AGN feedback in massive galaxies at z~1
  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
multi-band 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 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 active galactic nucleus and the absence
of ongoing star formation.
