Weak lensing predictions for coupled dark energy cosmologies at non-linear scales

TL;DR

This paper uses simulations to predict non-linear weak lensing signals for coupled dark energy models, assessing their detectability with upcoming surveys like DES and Euclid, and highlighting potential biases in current modeling approaches.

Contribution

It provides the first non-linear weak lensing predictions for coupled dark energy models using simulations and evaluates their distinguishability with future surveys.

Findings

Euclid can detect coupling parameters $eta_0 extgreater=0.05$ at 5$\sigma$

DES can distinguish models with $eta_0 extgreater=0.1$ at 4$\sigma$

Using $ m ext{Halofit}$ for non-linear spectra introduces significant biases.

Abstract

We present non-linear weak lensing predictions for coupled dark energy models using the CoDECS simulations. We calculate the shear correlation function and error covariance expected for these models, for forthcoming ground-based (such as DES) and space-based (Euclid) weak lensing surveys. We obtain predictions for the discriminatory power of a ground-based survey similar to DES and a space-based survey such as Euclid in distinguishing between $\Lambda$CDM and coupled dark energy models; we show that using the non-linear lensing signal we could discriminate between $\Lambda$CDM and exponential constant coupling models with $\beta_0\geq0.1$ at $4\sigma$ confidence level with a DES-like survey, and $\beta_0\geq0.05$ at $5\sigma$ confidence level with Euclid. We also demonstrate that estimating the coupled dark energy models' non-linear power spectrum, using the $\Lambda$CDM Halofit fitting formula, results in biases in the shear correlation function that exceed the survey errors.