cosmology seminar: F. William High, Chicago

TITLE Targeted weak-lensing follow-up of galaxy clusters in the South Pole Telescope survey ABSTRACT The South Pole Telescope (SPT) has detected clusters above a nearly uniform mass threshold over an extremely broad range in redshift by searching for the Sunyaev-Zel'dovich (SZ) effect. The observed abundance of clusters from a well selected sample is directly sensitive to the growth function of matter perturbations over the majority of the history of the universe, and provides constraints on dark energy with systematics that are complementary to traditional distance-based measures. The dominant source of uncertainty on dark energy constraints from this technique is our estimate of total cluster mass. We have observed 19 SPT clusters at 0.3 < z < 0.6 with Megacam on the Magellan-Clay 6.5 m telescope, and 14 SPT clusters at 0.6 < z < 1.3 with HST-ACS, to estimate total mass for these ~ (3-10)x10^15 Msun systems with weak gravitational lensing. These data will be used to improve constraints on cosmological parameters and on the scaling of X-ray and SZ comptonization, Y_X and Y_SZ.