Is the w0waCDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?
Chan‐Gyung Park, Javier de Cruz Pérez, Bharat Ratra
Abstract
We study the performance of the spatially flat dynamical dark energy [Formula: see text]CDM parameterization, with redshift-dependent dark energy fluid equation of state parameter [Formula: see text], with and without a varying cosmic microwave background (CMB) lensing consistency parameter [Formula: see text], against Planck 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 [[Formula: see text]] measurements and growth factor ([Formula: see text]) data points. From our most restrictive data set, P18+lensing+non-CMB, for the [Formula: see text]CDM+[Formula: see text] parameterization, we obtain [Formula: see text], [Formula: see text], the asymptotic limit [Formula: see text], and [Formula: see text] (all [Formula: see text] errors). This joint analysis of CMB and non-CMB data favors dark energy dynamics over a cosmological constant at [Formula: see text] and [Formula: see text] at [Formula: see text], i.e. more smoothing of the Planck CMB anisotropy data than is predicted by the best-fit model. For the [Formula: see text]CDM parameterization with [Formula: see text] the evidence in favor of dark energy dynamics is larger, [Formula: see text], suggesting that at least part of the evidence for dark energy dynamics comes from the excess smoothing of the Planck CMB anisotropy data. For the [Formula: see text]CDM parameterization with [Formula: see text], there is a difference of [Formula: see text] between P18 and non-CMB cosmological parameter constraints and [Formula: see text] between P18+lensing and non-CMB constraints. When [Formula: see text] is allowed to vary these tensions reduced to [Formula: see text] and [Formula: see text] respectively. Our P18+lensing+non-CMB data compilation positively favors the [Formula: see text]CDM parameterization without and with a varying [Formula: see text] parameter over the flat [Formula: see text]CDM model, and [Formula: see text]CDM+[Formula: see text] is also positively favored over [Formula: see text]CDM.