Constraints on dark energy from baryon acoustic peak and galaxy cluster gas mass measurements

TL;DR

This study combines baryon acoustic peak and galaxy cluster gas mass measurements to constrain dark energy models, finding consistency with a cosmological constant but allowing for slowly-evolving dark energy.

Contribution

It integrates multiple observational datasets to tighten constraints on dark energy parameters and assesses the viability of different dark energy models.

Findings

Data favor a flat universe with a cosmological constant.

Joint constraints are tighter than previous analyses.

Slowly-evolving dark energy remains compatible with observations.

Abstract

We use baryon acoustic peak measurements by Eisenstein et al. (2005) and Percival et al. (2007a) and galaxy cluster gas mass fraction measurements of Allen et al. (2008) to constrain parameters of three different dark energy models. For time-independent dark energy, the Percival et al. (2007a) constraints, which make use of the WMAP measurement of the apparent acoustic horizon angle, most effectively constrain a cosmological parameter close to spatial curvature and favor a close to spatially flat model. In a spatially-flat model the Percival et al. (2007a) data less effectively constrain time-varying dark energy. The joint baryon acoustic peak and galaxy cluster gas mass constraints are consistent with but tighter than those derived from other data. A time-independent cosmological constant in a spatially-flat model provides a good fit to the joint data, but slowly-evolving dark energy can not yet be ruled out.