Searching for dust in the intracluster medium from reddening of background galaxies

TL;DR

This study investigates the presence of dust in the intracluster medium by analyzing the reddening of background galaxies, finding no significant evidence of dust-induced reddening in galaxy clusters.

Contribution

It provides the first statistical analysis of dust in the intracluster medium using background galaxy reddening with a large dataset, setting upper limits on dust extinction.

Findings

No significant reddening detected in background galaxies

Average visual extinction <A_V> = 0.004 ± 0.010

Dust presence in intracluster medium is minimal or below detection threshold

Abstract

We report a search for the presence of dust in the intra-cluster medium based on the study of statistical reddening of background galaxies. Armed with the Red Sequence Cluster survey data, from which we extracted (i) a catalog of 458 clusters with z_clust < 0.5 and (ii) a catalog of ~90,000 galaxies with photometric redshift 0.5 < z_ph < 0.8 and photometric redshift uncertainty delta z_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 pm 0.008, and <E(V-z')> = 0.000 pm 0.008] were found for galaxies background to the clusters, compared to the references. Assuming a Galactic extinction law, we derive an average visual extinction of <A_V> = 0.004 pm 0.010 towards the inner 1x R_200 of clusters.