Dark Energy in Chains

TL;DR

This paper analyzes how dark energy influences cosmic microwave background and supernova data, constraining its properties and distinguishing between dynamical models and a cosmological constant using recent observational data.

Contribution

It provides the most general parameterization of dark energy's equation of state and uses combined data sets to constrain its current value and differentiate models.

Findings

Current dark energy equation of state w < -0.8 at 2 sigma

Sigma8 can discriminate between Quintessence and Lambda CDM models

Dark energy perturbations impact CMB and supernova observations

Abstract

Dark energy affects the CMB through its perturbations and affects both CMB and Sn-Ia through its background evolution. Using recent CMB and Sn-Ia data sets, together with the most general parameterization of the dark energy equation of state available, we find that today w < -0.8 (2 sigma). We also find that the value of the normalization of the power spectrum on cluster scales, sigma8, can be used to discriminate between dynamical models of dark energy (Quintessence models) and a cosmological constant model (Lambda CDM).