Using non-DESI data to confirm and strengthen the DESI 2024 spatially flat <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>w</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:msub> <mml:mrow> <mml:mi>w</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> </mml:mrow> </mml:msub> <mml:mi>CDM</mml:mi> </mml:mrow> </mml:math> cosmological parametrization result
Chan‐Gyung Park, Javier de Cruz Pérez, Bharat Ratra
Abstract
We use a combination of Planck cosmic microwave background (CMB) anisotropy data and non-CMB data that include $\mathrm{Pantheon}+\text{type}$ Ia supernovae (SNIa), Hubble parameter [$H(z)$], growth factor ($f{\ensuremath{\sigma}}_{8}$) measurements, and a collection of baryon acoustic oscillation (BAO) data, but not recent DESI 2024 BAO measurements, to confirm the DESI 2024 ($\mathrm{DESI}+\mathrm{CMB}+\mathrm{PantheonPlus}$) data compilation support for dynamical dark energy with an evolving equation of state parameter $w(z)={w}_{0}+{w}_{a}z/(1+z)$. From our joint compilation of CMB and non-CMB data, in a spatially-flat cosmological model, we obtain ${w}_{0}=\ensuremath{-}0.850\ifmmode\pm\else\textpm\fi{}0.059$ and ${w}_{a}=\ensuremath{-}0.5{9}_{\ensuremath{-}0.22}^{+0.26}$ and find that this dynamical dark energy is favored over a cosmological constant by $\ensuremath{\sim}2\ensuremath{\sigma}$. Our data constraints on the flat ${w}_{0}{w}_{a}\mathrm{CDM}$ parametrization are slightly more restrictive than the DESI 2024 constraints, with the DESI 2024 and our values of ${w}_{0}$ and ${w}_{a}$ differing by $\ensuremath{-}0.27\ensuremath{\sigma}$ and $0.44\ensuremath{\sigma}$, respectively. Our data compilation slightly more strongly favors the flat ${w}_{0}{w}_{a}\mathrm{CDM}$ model over the flat $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model than does the DESI 2024 data compilation. We note that our CMB and non-CMB data ${w}_{0}{w}_{a}\mathrm{CDM}$ parametrization cosmological constraints are discrepant at $2.7\ensuremath{\sigma}$, a little larger than the $1.9\ensuremath{\sigma}$ discrepancy between DESI DR1 BAO and CMB data flat $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model cosmological constraints. We also show that if we remove the $\mathrm{Pantheon}+\mathrm{SNIa}$ contribution from the non-CMB data, for the ${w}_{0}{w}_{a}\mathrm{CDM}$ parametrization we still find tension between P18 and non-CMB data ($2.5\ensuremath{\sigma}$) and $\mathrm{P}18+\mathrm{lensing}$ and non-CMB data ($2.4\ensuremath{\sigma}$). Even after the exclusion of $\mathrm{Pantheon}+\mathrm{SNIa}$ data the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model is still disfavored at $\ensuremath{\sim}2\ensuremath{\sigma}$ c.l.