Dust accretion and destruction in galaxy groups and clusters
  We examine the dust distribution around a sample of 70,000 low redshift
galaxy groups and clusters derived from the Sloan Digital Sky Survey. By
correlating spectroscopically identified background quasars with the galaxy
groups we obtain the relative colour excess due to dust reddening. We present a
significant detection of dust out to a clustercentric distance of 30 Mpc/h in
all four independent SDSS colours, consistent with the expectations of weak
lensing masses of similar mass halos and excess galaxy counts. The wavelength
dependence of this colour excess is consistent with the expectations of a Milky
Way dust law with R_V=3.1. Further, we find that the halo mass dependence of
the dust content is much smaller than would be expected by a simple scaling,
implying that the dust-to-gas ratio of the most massive clusters (~10E14
Msun/h) is ~3% of the local ISM value, while in small groups (~10E12.7 Msun/h)
it is ~55% of the local ISM value. We also find that the dust must have a
covering fraction on the order of 10% to explain the observed color
differences, which means the dust is not just confined to the most massive
galaxies. Comparing the dust profile with the excess galaxy profile, we find
that the implied dust-to-galaxy ratio falls significantly towards the group or
cluster center. This has a significant halo mass dependence, such that the more
massive groups and clusters show a stronger reduction. This suggests that
either dust is destroyed by thermal sputtering of the dust grains by the hot,
dense gas or the intrinsic dust production is reduced in these galaxies.
