Cosmological Constraints from Strong Gravitational Lensing in Galaxy Clusters

Abstract

Current efforts in observational cosmology are focused on characterizing the mass-energy content of the Universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubble Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy cluster Abell 1689, we used a parametric model to simultaneously constrain the cluster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from X-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives Ωm = 0.25 +/- 0.05 and wx = -0.97 +/- 0.07 which are consistent with results from other methods. Inclusion of our method with all other techniques available brings down the current 2σ contours on the dark energy equation of state parameter wx by about 30%.

32 pages, 8 figures, includes Supplementary Online Material. Published by Science on August 20, 2010