Weak lensing predictions for modified gravities at non-linear scales

TL;DR

This paper predicts weak lensing signals in modified gravity models, incorporating nonlinear effects, to enhance the ability of future surveys to distinguish these models from standard cosmology.

Contribution

It introduces a method to estimate nonlinear power spectra in modified gravity models and demonstrates their impact on weak lensing predictions, improving model discrimination.

Findings

Weak lensing can effectively differentiate modified gravity models from dark energy.

Inclusion of nonlinear effects significantly enhances the discriminatory power of lensing.

Future surveys can constrain nonlinear power spectrum parameters and growth factors.

Abstract

We present a set of predictions for weak lensing correlation functions in the context of modified gravity models, including a prescription for the impact of the nonlinear power spectrum regime in these models. We consider the DGP and f(R) models, together with dark energy models with the same expansion history. We use the requirement that gravity is close to GR on small scales to estimate the non-linear power for these models. We then calculate weak lensing statistics, showing their behaviour as a function of scale and redshift, and present predictions for measurement accuracy with future lensing surveys, taking into account cosmic variance and galaxy shape noise. We demonstrate the improved discriminatory power of weak lensing for testing modified gravities once the nonlinear power spectrum contribution has been included. We also examine the ability of future lensing surveys to constrain a parameterisation of the non-linear power spectrum, including sensitivity to the growth factor.