Prospects for dark energy evolution: a frequentist multi-probe approach

¹ DSM/DAPNIA, CEA/Saclay, 91191 Gif-sur-Yvette, France e-mail: yeche@hep.saclay.cea.fr
² Centre de Physique des Particules de Marseille, CNRS/IN2P3-Luminy and Université de la Méditerranée, Case 907, 13288 Marseille Cedex 9, France
³ Centre de Physique Théorique, CNRS-Luminy and Université de Provence, Case 907, 13288 Marseille Cedex 9, France

Received: 7 July 2005
Accepted: 24 October 2005

Abstract

A major quest in cosmology is to understand the nature of dark energy. It is now well known that the use of several cosmological probes is required to break the underlying degeneracies on cosmological parameters. In this paper, we present a method based on a frequentist approach that combines probes without any prior constraints. As one application, the current supernovae type Ia and cosmic microwave background data are analyzed with an evolving dark energy component, and our results are first compared to other analyses. We emphasize the consequences of implementing the dark energy perturbations for an equation of state that varies with time. We then simulate the expectations of different future projects. The constraints from weak lensing surveys on the measurement of dark energy evolution are combined with the measurements from the cosmic microwave background and type Ia supernovae. We present the impacts for mid-term and long-term surveys and confirm that the combination with weak lensing is very powerful in breaking parameter degeneracies. A second generation of experiments is, however, required to achieve a 0.1 error on the parameters describing the evolution of dark energy.