August 27, 2024Open Access

Constraints on Redshift-Binned Dark Energy using DESI BAO Data

Key Points

The analysis indicates a transition pattern from phantom to quintessence, suggesting variability in dark energy behavior across redshifts.
Significances for the dark energy parameter $w_1$ are noted at 1.9σ, 2.6σ, and 3.3σ, with $w_3$ observed as less than -1 at 1.6σ levels across datasets.
Data modeling incorporates BAO data from DESI, Planck CMB power spectrum, and type Ia supernova measurements for robust evaluation of dark energy states in our universe based on a redshift scale approach. Results suggest that while some constraints on dark energy exist, conclusive distinctions between its states remain ambiguous, highlighting a need for further exploration.

Abstract

We parameterize the equation of state of late-time dark energy as w₁₈₍ (z), with three redshift bins, characterized by a constant equation of state in each bin. Then, we constrain the parameters of the w₁₈₍CDM model using datasets from DESI BAO data, Planck CMB power spectrum, ACT DR6 lensing power spectrum, and type Ia supernova distance-redshift data of Pantheon Plus/DES Y5/Union3. The significances for w₁>-1 is 1. 9, 2. 6 and 3. 3, and w₂ is consistent with -1 within 1 level, while 1. 6, 1. 5 and 1. 5 for w₃-1 at 1. 9, 1. 7 and 2. 9 level, meanwhile w₃<-1 at 1. 3, 1. 3 and 1. 3 level, respectively. In all, our results indicate that the transition of dark energy from phantom at high redshifts to quintessence at low redshifts is not conclusive.

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