Abstract

We present the results of the first survey of intervening Mg II absorption systems associated with high-z cluster galaxies. We investigated the incidence (dN/dz) of Mg II absorbers in (z) = 0.6 cluster galaxies from the Red-Sequence Cluster Survey. While strong (W0 > 1.0 Å) absorbers show a significant excess (up to 10×), weak (W0 < 0.3 Å) absorbers conform to the field statistics. We argue that this dichotomy could be explained if cluster galaxies that give rise to weak Mg II absorption have their cold halos truncated as a consequence of environmental effects.