Searching for Dust in the Intracluster Medium from Reddening of Background Galaxies

Abstract

We report a search for the presence of dust in the intracluster medium based on the study of statistical reddening of background galaxies. Armed with the Red-sequence Cluster Survey data, from which we extracted (1) a catalog of 458 clusters with z clust < 0.5 and (2) a catalog of ∼90,000 galaxies with photometric redshift 0.5 < z ph < 0.8 and photometric redshift uncertainty δz ph /(1 + z ph ) < 0.06, we have constructed several samples of galaxies according to their projected distances to the cluster centers. No significant color differences [(E(B -R C )) = 0.005 ± 0.008 and (E(V -z′)) = 0.000 ± 0.008] were found for galaxies in the background to the clusters compared to the references. Assuming a Galactic extinction law, we derive an average visual extinction of (A V ) = 0.004 ± 0.010 toward the inner R 200 of clusters. © 2008. The American Astronomical Society. All rights reserved.