Searching for MgII absorbers in and around galaxy clusters
  To study environmental effects on the circumgalactic medium (CGM), we use the
samples of redMaPPer galaxy clusters, background quasars and cluster galaxies
from the SDSS. With ~82 000 quasar spectra, we detect 197 MgII absorbers in and
around the clusters. The detection rate per quasar is 2.7$\pm$0.7 times higher
inside the clusters than outside the clusters, indicating that MgII absorbers
are relatively abundant in clusters. However, when considering the galaxy
number density, the absorber-to-galaxy ratio is rather low inside the clusters.
If we assume that MgII absorbers are mainly contributed by the CGM of massive
star-forming galaxies, a typical halo size of cluster galaxies is smaller than
that of field galaxies by 30$\pm$10 per cent. This finding supports that galaxy
haloes can be truncated by interaction with the host cluster.
