The cosmic shear three-point functions

¹ Institut d'Astrophysique de Paris, 98bis bd Arago, 75014 Paris, France e-mail: benabed@iap.fr
² Center for Cosmology and Particule Physics, Department of Physics, New York University, New York, NY 10003, USA

Received: 30 August 2005
Accepted: 13 April 2006

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 power-law 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 M_ap 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.