September 18th, 2008

Paper to be discussed will be "An Imprint of Superstructures on the Microwave Background due to the Integrated Sachs-Wolfe Effect," Granett et al., 2008, ApJ, 683, L99. Can be downloaded from http://lanl.arxiv.org/abs/0805.3695. Supplementary material can be downloaded from http://lanl.arxiv.org/abs/0805.2974

This paper deals with measuring hot and cold spots in the Cosmic Microwave Background and comparing them to cluster and void structures identified in the Sloan Digital Sky Survey. The temperature imprints left in the CMB are interpreted by the authors as arising from the late-time Integrated Sachs-Wolfe (ISW) effect. The ISW temperature fluctuations are believed to be direct evidence for dark energy, causing the superclusters and supervoids to expand as photons from the CMB pass through them.