The cosmic shear three-point functions

Abstract

We investigate the three-point functions of the weak lensing cosmic shear, using both analytic methods and numerical results from N-body simulations. The analytic model, an isolated dark matter halo with a powerlaw profile chosen to fit the effective index at the scale probed, can be used to understand the basic properties of the eight three-point functions observed in simulations. We use this model to construct a single three-point function estimator that "optimally" combines the eight three-point functions. This new estimator is an alternative to Map statistics and provides up to a factor of two improvement in signal to noise compared to previously used combinations of cosmic shear three-point functions.