Signs of Dynamical Dark Energy in Current Observations. (arXiv:1811.03505v3 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Sola_J/0/1/0/all/0/1">Joan Sola</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gomez_Valent_A/0/1/0/all/0/1">Adria Gomez-Valent</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perez_J/0/1/0/all/0/1">Javier de Cruz Perez</a>
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 $Lambda$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 $Vsim Phi^{-alpha}$. 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 $2.6sigma$ for
XCDM and $2.9sigma$ 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. 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 $sigma_8$-tension becomes reduced with DDE.
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 $Lambda$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 $Vsim Phi^{-alpha}$. 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 $2.6sigma$ for
XCDM and $2.9sigma$ 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. 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 $sigma_8$-tension becomes reduced with DDE.
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