Mapping the dark matter with weak gravitational lensing

Abstract

We consider the problem of reconstructing the projected mass distribution in clusters from coherent distortions of background galaxies. The ellipticity of a background galaxy provides an estimate of the trace-free components of the tidal field ∂ 2 Φ/∂θ y ∂θ j where Φ(θ) is the two-dimensional potential generated by the surface density Σ(θ). We present a technique for inverting this problem. The resulting surface density contains a strong, but incoherent, random component arising from the random intrinsic galaxy ellipticities. This can be removed by filtering