Constraining Dark Energy Evolution with Gravitational Lensing by Large Scale Structures

Abstract

We study the sensitivity of weak lensing by large scale structures to the evolution of dark energy. We explore a 2-parameters model of dark energy evolution, inspired by tracking quintessence models. To this end, we compute the likelihood of a few representative models with varying and non varying equation of states. Based on an earlier work, we show that the evolution of dark energy has a much stronger impact on the non-linear structure growth than on the angular diameter distance, which makes large scale structure measurements a very efficient probe of this evolution. For the different models, we investigate the dark energy parameters degeneracies with the mass power spectrum shape Gamma, normalisation sigma_8, and with the matter mean density Omega_M. This result is a strong motivation for performing large scale structure simulations beyond the simple constant dark energy models, in order to calibrate the non-linear regime accurately. Prospective for the Canada France Hawaii Telescope Legacy Survey (CFHTLS) and Super-Novae Acceleration Probe (SNAP) are given. These results complement nicely the cosmic microwave background and Super-Novae constraints. Weak lensing is shown to be more sensitive to a variation of the equation of state, whereas CMB and SNIa give information on its constant part.

Submitted to Physical Review D