Relativistic weak lensing from a fully non-linear cosmological density field

Understand

In this paper we examine cosmological weak lensing on non-linear scales and show that there are Newtonian and relativistic contributions and that the latter can also be extracted from standard Newtonian simulations.

• We use the post-Friedmann formalism, a post-Newtonian type framework for cosmology, to derive the full weak-lensing deflection angle valid on non-linear scales for any metric theory of gravity.
• We show that the only contributing term that is quadratic in the first order deflection is the expected Born correction and lens-lens coupling term.
• We use this deflection angle to analyse the vector and tensor contributions to the E- and B- mode cosmic shear power spectra.