Is excess smoothing of Planck CMB anisotropy data partially responsible for evidence for dark energy dynamics in other w(z)CDM parametrizations?
Chan‐Gyung Park, Bharat Ratra
Abstract
In this paper, we study spatially-flat dynamical dark energy parametrizations, [Formula: see text]CDM, with redshift-dependent dark energy equation of state parameter [Formula: see text] expressed using three different quadratic and other polynomial forms (as functions of [Formula: see text], where a is the scale factor), without and with a varying cosmic microwave background (CMB) lensing consistency parameter [Formula: see text]. We use Planck CMB anisotropy data (P18 and lensing) and a large, mutually-consistent non-CMB data compilation that includes Pantheon+ type Ia supernova, baryon acoustic oscillation (BAO), Hubble parameter ([Formula: see text]), and growth factor ([Formula: see text]) measurements, but not recent DESI BAO data. The six [Formula: see text]CDM ([Formula: see text]) parametrizations show higher consistency between the CMB and non-CMB data constraints compared to the XCDM ([Formula: see text]) and [Formula: see text]CDM ([Formula: see text]) cases. Constraints from the most-restrictive P18+lensing+non-CMB data compilation on the six [Formula: see text]CDM ([Formula: see text]) parametrizations indicate that dark energy dynamics is favored over a cosmological constant by [Formula: see text] when [Formula: see text], but only by [Formula: see text] when [Formula: see text] is allowed to vary (and [Formula: see text] at [Formula: see text] significance). Non-CMB data dominate the P18+lensing+non-CMB compilation at low z and favor quintessence-like dark energy. At high z P18+lensing data dominate, favoring phantom-like dark energy with significance from [Formula: see text] to [Formula: see text] when [Formula: see text], and from [Formula: see text] to [Formula: see text] when [Formula: see text] varies. These results suggest that the observed excess weak lensing smoothing of some of the Planck CMB anisotropy multipoles is partially responsible for the [Formula: see text] cases [Formula: see text] evidence for dark energy dynamics over a cosmological constant.