3 years ago

Current Signs of Dynamical Dark Energy.

Joan Sola Peracaula, Adria Gomez-valent, Javier De Cruz Perez

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. Depending on the datasets used and the methodology employed one may reach different levels of evidence or no evidence at all. 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 $\Lambda$CDM model (with equation of state $w=-1$ for $\Lambda$) is confronted with that of the general XCDM and CPL parametrizations, as well as with the traditional $\Phi$CDM model based on the scalar field potential $V\sim \Phi^{\alpha}$. 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 $2.6\sigma$ for XCDM and $2.9\sigma$ for $\Phi$CDM. 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. We report also on positive signs from the preliminary results of Planck 2018 data using the compressed CMB likelihood.

Publisher URL: http://arxiv.org/abs/1811.03505

DOI: arXiv:1811.03505v2

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