Signs of dynamical dark energy in current observations

• Published in: PHYSICS OF THE DARK UNIVERSE 2019-09, Vol.25, p.100311, Article 100311
• Main Authors: Solà Peracaula, Joan, Gómez-Valent, Adrià, de Cruz Pérez, Javier
• Format: Article
• Language: English
• Subjects: Cosmological parameters; Dark energy; Large-scale structure of universe
• ISSN: 2212-6864; 2212-6864
• DOI: 10.1016/j.dark.2019.100311

Investigations on dark energy (DE) are currently inconclusive about its time evolution. Hints of this possibility do however glow now and then in the horizon. Herein we assess the current status of dynamical dark energy (DDE) in the light of a large body of updated SNIa+H(z)+BAO+LSS+CMB observations, using the full Planck 2015 CMB likelihood. The performance of the ΛCDM model (with equation of state w=−1 for Λ) is confronted with that of the general XCDM and CPL parametrizations, as well as with the traditional ϕCDM model based on the scalar field potential V∼ϕ−α. In particular, we gauge the impact of the bispectrum in the LSS and BAO parts, and show that the subset of CMB+BAO+LSS observations may contain the bulk of the DDE signal. The departure from w=−1 is significant: roughly 2.6σ for XCDM and 2.9σ for ϕCDM. In both cases the full Bayesian evidence is found to be positive even for a prior range of the DDE parameters extending over several standard deviations from the mean when the bispectrum is taken into account. Positive signs follow as well from the preliminary results of Planck 2018 data using the compressed CMB likelihood. As a bonus we also find that the σ8-tension becomes reduced with DDE.