2025/09/30 by Chan-Gyung Park, Chan‐Gyung Park, Bharat Ratra +2 · 4 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Radio Astronomy Observations and Technology
paper · pdf · doi:10.1142/s0218271826500343
We present updated observational constraints on the spatially flat [Formula: see text]CDM cosmological model, in which dark energy is described by a minimally coupled scalar field [Formula: see text] with an inverse power-law potential energy density [Formula: see text]. Using a combination of Planck 2018 cosmic microwave background (CMB) temperature, polarization (P18), and lensing power spectra (lensing), along with a comprehensive compilation of non-CMB data including baryon acoustic oscillation, type Ia supernova, Hubble parameter and growth rate measurements, we analyze parameter constraints of the [Formula: see text]CDM and [Formula: see text]CDM+[Formula: see text] models where [Formula: see text] is the CMB lensing consistency parameter. We find that the scalar field parameter [Formula: see text], which governs dark energy dynamics, is more tightly constrained by non-CMB data than by CMB data alone. From P18+lensing+non-CMB data, we obtain [Formula: see text] in the [Formula: see text]CDM model and [Formula: see text] in the [Formula: see text]CDM+[Formula: see text] model, mildly favoring evolving dark energy over a cosmological constant by [Formula: see text] and [Formula: see text]. The estimated Hubble constant is [Formula: see text] km s[Formula: see text] Mpc[Formula: see text] for P18+lensing+non-CMB data in the [Formula: see text]CDM model, consistent with median statistics and some local determinations, but in tension with other local determinations. The constraints for matter density and clustering amplitude ([Formula: see text], [Formula: see text]) of the flat [Formula: see text]CDM model statistically agree with [Formula: see text]CDM model values. Allowing the CMB lensing consistency parameter [Formula: see text] to vary reduces tensions between CMB and non-CMB data, although we find [Formula: see text], [Formula: see text] higher than unity, consistent with the excess smoothing seen in Planck data. Model comparison using AIC and DIC shows that the [Formula: see text]CDM model provides a fit comparable to [Formula: see text]CDM, with the [Formula: see text]CDM+[Formula: see text] extension slightly preferred in some cases. Overall, our results indicate that while the [Formula: see text]CDM model remains an excellent fit, current data leave open the possibility of mildly evolving quintessence-like dynamical dark energy, without a phantom-divide crossing.