Weak Lensing by Galaxy Clusters

Abstract

In this talk I review some of the key questions that weak lensing observations of clusters can potentially answer, and sketch the progress that has been made to date in extracting quantitative estimates of masses and density profiles. A major difficulty in interpreting these measurements is the diverse methods that have been used to calibrate the shear-polarization relation, none of which are completely satisfactory. I describe some recent developments in the theory of weak lensing calibration. I then present some results from the UH8K camera and discuss their implication for cosmology. Finally, I outline a new strategy for obtaining high resolution optical imaging from the ground using an array of small telescopes, and describe how such an instrument can greatly improve the power of weak lensing observations