arXiv:2410.13627·v3·Cosmology and Nongalactic Astrophysics

Is the $w_{0} w_{a}$ CDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?

Chan-Gyung Park🇰🇷 · Javier de Cruz Perez🇪🇸 · Bharat Ratra🇺🇸

Abstract

We study the performance of the spatially-flat dynamical dark energy (DE) $w_{0} w_{a}$ CDM parameterization, with redshift-dependent DE fluid equation of state parameter $w (z) = w_{0} + w_{a} z / (1 + z)$ , with and without a varying CMB lensing consistency parameter $A_{L}$ , against Planck cosmic microwave background (CMB) data (P18 and lensing) and a combination of non-CMB data composed of baryonic acoustic oscillation (BAO) measurements that do not include DESI BAO data, Pantheon+ type Ia supernovae (SNIa) observations, Hubble parameter [ $H (z)$ ] measurements, and growth factor ( $f σ_{8}$ ) data points. From our most restrictive data set, P18+lensing+non-CMB, for the $w_{0} w_{a}$ CDM+ $A_{L}$ parameterization, we obtain $w_{0} = - 0.879 \pm 0.060$ , $w_{a} = - 0.3 9_{- 0.22}^{+ 0.26}$ , the asymptotic limit $w (z \to \infty) = w_{0} + w_{a} = - 1.2 7_{- 0.17}^{+ 0.20}$ , and $A_{L} = 1.07 8_{- 0.040}^{+ 0.036}$ (all $1 σ$ errors). This joint analysis of CMB and non-CMB data favors DE dynamics over a cosmological constant at $\sim 1 σ$ and $A_{L} > 1$ at $\sim 2 σ$ , i.e. more smoothing of the Planck CMB anisotropy data than is predicted by the best-fit model. For the $w_{0} w_{a}$ CDM parameterization with $A_{L} = 1$ the evidence in favor of DE dynamics is larger, $\sim 2 σ$ , suggesting that at least part of the evidence for DE dynamics comes from the excess smoothing of the Planck CMB anisotropy data. For the $w_{0} w_{a}$ CDM parameterization with $A_{L} = 1$ , there is a difference of $2.8 σ$ between P18 and non-CMB cosmological parameter constraints and $2.7 σ$ between P18+lensing and non-CMB constraints. When $A_{L}$ is allowed to vary these tensions reduced to $1.9 σ$ and $2.1 σ$ respectively. Our P18+lensing+non-CMB data compilation positively favors the $w_{0} w_{a}$ CDM parameterization without and with a varying $A_{L}$ parameter over the flat $Λ$ CDM model, and $w_{0} w_{a}$ CDM+ $A_{L}$ is also positively favored over $w_{0} w_{a}$ CDM.

Comments: 19 pages, 6 figures. Accepted for publication in International Journal of Modern Physics D. Related to the analyses of arXiv:2405.00502

Is the w0​wa​CDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?

Abstract

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Is the $w_{0} w_{a}$ CDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?

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