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Dark energy in light of recent DESI BAO and Hubble tension

Hao Wang, Yun-Song Piao

TL;DR

The paper investigates whether DESI's reported $ obreak( ext{evolving DE})$ signal remains when the Hubble tension is addressed by pre-recombination resolutions like axion-like EDE and AdS-EDE. It performs MCMC fits to the $w_0w_a$CDM model using DESI BAO in combination with Planck18 CMB and Pantheon Plus, incorporating SH0ES priors and those EDE scenarios. The results show that although $w_0>-1$ and $w_a<0$ are still favored, the evidence for evolution weakens and the CC becomes $<2σ$ consistent, with $H_0$ rising to about $72$ km s$^{-1}$ Mpc$^{-1}$ and $S_8$ behavior depending on the EDE model. The findings suggest DESI's evolving-DE signal may be tied to how cosmological tensions are modeled, urging caution in ruling out $\\Lambda$CDM and motivating future surveys like Euclid, with implications for inflationary parameter $n_s$ as well.

Abstract

Recently, Dark Energy Spectroscopic Instrument (DESI) collaboration based on their first year data has reported a $\gtrsim 3σ$ evidence for an evolving dark energy (DE) against the cosmological constant (CC), so the standard $Λ$CDM model. However, it is necessary to access the impact of DESI data on the state equation $w_0$-$w_a$ of DE in the Hubble-tension-free cosmologies, where $w_0$ and $w_a$ is the parameters of state equation of DE. In this paper, using recent DESI BAO measurements combined with Planck CMB and Pantheon Plus dataset, we perform the Monte Carlo Markov Chain (MCMC) analysis for the $w_0w_a$CDM model with possible pre-recombination resolutions of the Hubble tension. It is found that though $w_0>-1$ and $w_a<0$ are still preferred, the CC is also $<2σ$ consistent, while the bestfit Hubble constant $H_0$ are higher than those with pre-DESI BAO data but without the further exacerbation of $S_8$ tension. According to our results, the resolutions of Hubble tension are likely to suppress the \textit{preference} of DESI for the evolving DE, thus the claim of ruling out the CC needs to be more cautious regarding not only the recent observational data but also the cosmological tensions.

Dark energy in light of recent DESI BAO and Hubble tension

TL;DR

The paper investigates whether DESI's reported signal remains when the Hubble tension is addressed by pre-recombination resolutions like axion-like EDE and AdS-EDE. It performs MCMC fits to the CDM model using DESI BAO in combination with Planck18 CMB and Pantheon Plus, incorporating SH0ES priors and those EDE scenarios. The results show that although and are still favored, the evidence for evolution weakens and the CC becomes consistent, with rising to about km s Mpc and behavior depending on the EDE model. The findings suggest DESI's evolving-DE signal may be tied to how cosmological tensions are modeled, urging caution in ruling out CDM and motivating future surveys like Euclid, with implications for inflationary parameter as well.

Abstract

Recently, Dark Energy Spectroscopic Instrument (DESI) collaboration based on their first year data has reported a evidence for an evolving dark energy (DE) against the cosmological constant (CC), so the standard CDM model. However, it is necessary to access the impact of DESI data on the state equation - of DE in the Hubble-tension-free cosmologies, where and is the parameters of state equation of DE. In this paper, using recent DESI BAO measurements combined with Planck CMB and Pantheon Plus dataset, we perform the Monte Carlo Markov Chain (MCMC) analysis for the CDM model with possible pre-recombination resolutions of the Hubble tension. It is found that though and are still preferred, the CC is also consistent, while the bestfit Hubble constant are higher than those with pre-DESI BAO data but without the further exacerbation of tension. According to our results, the resolutions of Hubble tension are likely to suppress the \textit{preference} of DESI for the evolving DE, thus the claim of ruling out the CC needs to be more cautious regarding not only the recent observational data but also the cosmological tensions.
Paper Structure (6 sections, 3 equations, 4 figures, 4 tables)

This paper contains 6 sections, 3 equations, 4 figures, 4 tables.

Table of Contents

  1. INTRODUCTION
  2. DATA AND METHODOLOGY
  3. RESULTS
  4. Discussion
  5. Results of the $w_0w_a$CDM model w/o SH0ES
  6. 2D contour results of $w_0w_a$CDM+EDE models

Figures (4)

  • Figure 1: 2D contours at 68% and 95% CL of the parameters $w_0$-$w_a$ for the $w_0w_a$CDM model with axion-like EDE and AdS-EDE, respectively, fitting to Planck18+DESI+Pantheon+SH0ES dataset. Left panel: scattered plot for the $w_0w_a$CDM model. Right panel: scattered plot for the $w_0w_a$CDM+(AdS-)EDE model.
  • Figure 2: Residuals of $D_H(z)/r_d$, $D_M(z)/r_d$ and $D_V(z)/r_d$ for the bestfit values of the $w_0w_a$CDM+EDE model with respect to the $w_0w_a$CDM model fitting to Planck18+DESI+PantheonPlus+SH0ES datasets. The blue and pink shadows are $1\sigma$ regions of $D_H(z)/r_d$, $D_M(z)/r_d$ and $D_V(z)/r_d$, respectively. The DESI data points and error bars are as listed in Table.\ref{['DESI']}.
  • Figure 3: 2D contours at 68% and 95% CL of the parameters $w_0$-$w_a$ for the $w_0w_a$CDM model fitting to Planck18+DESI+Pantheon dataset and Planck18+DESI+Pantheon+SH0ES dataset, respectively.
  • Figure 4: 2D contours at 68% and 95% CL for the parameters of the $w_0w_a$CDM model with axion-like EDE and AdS-EDE, respectively, fitting to Planck18+DESI+Pantheon+SH0ES dataset.