Probing Dark Matter and Cosmic Structure Growth with Galaxy Clusters

Clusters of galaxies will be used as "cosmic laboratories" for the study of dark matter. Having already identified a collision of two clusters of galaxies where the dark matter has become spatially separated from the baryonic matter component, this projec t seeks to improve existing constraints on the particle physics properties of dark matter from a joint X-ray and weak gravitational lensing analysis of this system. An investigation will also be made of possible connections between the cluster collision and a short-duration gamma-ray burst observed in this system. In addition, the dark matter distribution in more "normal" clusters will be studied based on a combined strong and weak gravitational lensing analysis of "new" cluster lenses. These are being d iscovered in followup observations of very rich clusters found in the Sloan Digital Sky Survey. The results will be compared to predictions for theoretically motivated dark matter candidates. Clusters of galaxies serve as very sensitive probes of the gro wth of structure in the universe. The ESA Planck satellite is expected to detect a unique, large sample of clusters from their Sunyaev-Zel'dovich (SZ) effect. This project seeks to provide the additional data needed to turn the Planck cluster sample int o a powerful probe of the cosmological parameters governing structure growth, including dark energy. In particular, the relationship between cluster mass and the SZ effect will be calibrated.