Galaxy sizes as a function of environment at intermediate redshift from
  the ESO Distant Cluster Survey
  In order to assess whether the environment has a significant effect on galaxy
sizes, we compare the mass--size relations of cluster and field galaxies in the
$0.4 < z < 0.8$ redshift range from the ESO Distant Cluster Survey (EDisCS)
using HST images. We analyse two mass-selected samples, one defined using
photometric redshifts ($10.2 \le \log M_\ast/M_{\odot} \le 12.0$), and a
smaller more robust subsample using spectroscopic redshifts ($10.6 \le \log
M_\ast/M_{\odot} \le 11.8$). We find no significant difference in the size
distributions of cluster and field galaxies of a given morphology. Similarly,
we find no significant difference in the size distributions of cluster and
field galaxies of similar rest-frame $B-V$ colours. We rule out average size
differences larger than $10$--$20$\% in both cases. Consistent conclusions are
found with the spectroscopic and photometric samples. These results have
important consequences for the physical process(es) responsible for the size
evolution of galaxies, and in particular the effect of the environment. The
remarkable growth in galaxy size observed from $z\sim2.5$ has been reported to
depend on the environment at higher redshifts ($z>1$), with early-type/passive
galaxies in higher density environments growing earlier. Such dependence
disappears at lower redshifts. Therefore, if the reported difference at
higher-$z$ is real, the growth of field galaxies has caught up with that of
cluster galaxies by $z\sim1$. Any putative mechanism responsible for galaxy
growth has to account for the existence of environmental differences at high
redshift and their absence (or weakening) at lower redshifts.
