The XXL survey: XLII. Detection and characterization of the galaxy
  population of distant galaxy clusters in the XXL-N/VIDEO field: A tale of
  variety
  Context. Distant galaxy clusters provide an effective laboratory in which to
study galaxy evolution in dense environments and at early cosmic times. Aims.
We aim to identify distant galaxy clusters as extended X-ray sources coincident
with overdensities of characteristically bright galaxies. Methods. We use
optical and near-infrared (NIR) data from the Hyper Suprime-Cam (HSC) and VISTA
Deep Extragalactic Observations (VIDEO) surveys to identify distant galaxy
clusters as overdensities of bright, $z_{phot}\geq 0.8$ galaxies associated
with extended X-ray sources detected in the ultimate XMM extragalactic survey
(XXL). Results. We identify a sample of 35 candidate clusters at $0.80\leq
z\leq 1.93$ from an approximately 4.5 deg$^2$ sky area. This sample includes 15
newly discovered candidate clusters, ten previously detected but unconfirmed
clusters, and ten spectroscopically confirmed clusters. Although these clusters
host galaxy populations that display a wide variety of quenching levels, they
exhibit well-defined relations between quenching, cluster-centric distance, and
galaxy luminosity. The brightest cluster galaxies (BCGs) within our sample
display colours consistent with a bimodal population composed of an old and red
subsample together with a bluer, more diverse subsample. Conclusions. The
relation between galaxy masses and quenching seem to be already in place at
$z\sim 1$, although there is no significant variation of the quenching fraction
with the cluster-centric radius. The BCG bimodality might be explained by the
presence of a younger stellar component in some BCGs but additional data are
needed to confirm this scenario.
