Sebastián López
Universidad de Chile
 

"Probing Cluster Galaxies with Background QSOs"
 

I will show results of the first survey of intervening MgII absorption systems associated with high-z cluster galaxies. We investigated the incidence (dN/dz) of MgII absorbers in <z> = 0.6 cluster galaxies from the Red-Sequence Cluster Survey. While strong (W_0>1.0 Å) absorbers show a significant excess (up to 10x), weak (W_0<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 MgII absorption have their cold halos truncated as a consequence of environmental effects.