Searching for Mg II absorbers in and around galaxy clusters

Abstract

To study environmental effects on the circumgalactic medium (CGM), we use the samples of redMaPPer galaxy clusters, background quasars, and cluster galaxies from the Sloan Digital Sky Survey (SDSS). With similar to 82000 quasar spectra, we detect 197 Mg II absorbers in and around the clusters. The detection rate per quasar is 2.7 +/- 0.7 times higher inside the clusters than outside the clusters, indicating that Mg II 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 Mg II 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 +/- 10 percent. This finding supports that galaxy haloes can be truncated by interaction with the host cluster.