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

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 $Λ$CDM and coupled dark energy models; we show that using the non-linear lensing signal we could discriminate between $Λ$CDM and exponential constant coupling models with $β_0\geq0.1$ at $4σ$ confidence level with a DES-like survey, and $β_0\geq0.05$ at $5σ$ confidence level with Euclid. We also demonstrate that estimating the coupled dark energy models' non-linear power spectrum, using the $Λ$CDM Halofit fitting formula, results in biases in the shear correlation function that exceed the survey errors.

9 pages, 5 figures, v2: accepted for publication in MNRAS