The enhancement of rapidly quenched galaxies in distant clusters at
  0.5<z<1.0
  We investigate the relationship between environment and galaxy evolution in
the redshift range $0.5 < z < 1.0$. Galaxy overdensities are selected using a
Friends-of-Friends algorithm, applied to deep photometric data in the
Ultra-Deep Survey (UDS) field. A study of the resulting stellar mass functions
reveals clear differences between cluster and field environments, with a strong
excess of low-mass rapidly quenched galaxies in cluster environments compared
to the field. Cluster environments also show a corresponding deficit of young,
low-mass star-forming galaxies, which show a sharp radial decline towards
cluster centres. By comparing mass functions and radial distributions, we
conclude that young star-forming galaxies are rapidly quenched as they enter
overdense environments, becoming post-starburst galaxies before joining the red
sequence. Our results also point to the existence of two environmental
quenching pathways operating in galaxy clusters, operating on different
timescales. Fast quenching acts on galaxies with high specific star-formation
rates, operating on timescales shorter than the cluster dynamical time ($ < 1$
Gyr). In contrast, slow quenching affects galaxies with moderate specific
star-formation rates, regardless of their stellar mass, and acts on longer
timescales ($\gtrsim 1$ Gyr). Of the cluster galaxies in the stellar mass range
$9.0 < \log(M_{*}/M_{\odot}) < 10.5$ quenched during this epoch, we find that
73% were transformed through fast quenching, while the remaining 27% followed
the slow quenching route.
