Are Dynamical Dark-Energy Cosmologies Old Enough?
Abstract
Recent analysis combining baryon acoustic oscillation measurements with cosmic microwave background and Type Ia supernova data show an apparent preference for a time-dependent dark-energy equation of state within w0wa parameterizations. Here we test the robustness of this result against an independent cosmological consistency requirement, namely that the expansion history must provide sufficient time to accommodate the oldest observed stellar populations. Motivated by recent stellar and globular-cluster age determinations, we impose progressively stronger lower bounds, t0 ≥ 13.6, $13.75$, $13.8$, and $13.85$ Gyr, on the expansion histories allowed by DESI DR2+CMB+Pantheon+ data. We find a systematic displacement of the posterior in the (w0,wa) plane toward the ΛCDM prediction, (w0,wa)=(−1,0), as the minimum allowed age is increased. For t0 ≥ 13.85 Gyr, the Mahalanobis separation from ΛCDM decreases from 2.56σ to 1.72σ, bringing the ΛCDM prediction inside the 95\% credible region. Our results show that the current evidence for dynamical dark energy is sensitive to independent cosmic-age information and that stellar chronometry provides a direct robustness test of the DESI-favored expansion histories. Requiring sufficiently old cosmologies can appreciably reduce the statistical preference for departures from the standard ΛCDM model.
Related
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- Bayesian and frequentist perspectives agree on dynamical dark energy
- Updated observational constraints on ϕCDM dynamical dark energy cosmological models
- Investigating the Combo correlation of gamma-ray bursts as a tracer of dynamical dark energy
- A new window on dynamical dark energy: combining DESI-DR2 BAO with future gravitational wave observations
BibTeX
@misc{sousaneto2026dynamical,
title = {{Are Dynamical Dark-Energy Cosmologies Old Enough?}},
author = {Agripino Sousa-Neto and Susana J. Landau and Jailson Alcaniz},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27209},
eprint = {2610.27209},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27209},
}
RIS
TY - UNPB
TI - Are Dynamical Dark-Energy Cosmologies Old Enough?
AU - Agripino Sousa-Neto
AU - Susana J. Landau
AU - Jailson Alcaniz
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2610.27209
UR - https://arxiv.org/abs/2610.27209
AB - Recent analysis combining baryon acoustic oscillation measurements with cosmic microwave background and Type Ia supernova data show an apparent preference for a time-dependent dark-energy equation of state within w_0w_a parameterizations. Here we test the robustness of this result against an independent cosmological consistency requirement, namely that the expansion history must provide sufficient time to accommodate the oldest observed stellar populations. Motivated by recent stellar and globular-cluster age determinations, we impose progressively stronger lower bounds, t_0 ≥ 13.6, $13.75$, $13.8$, and $13.85$ Gyr, on the expansion histories allowed by DESI DR2+CMB+Pantheon+ data. We find a systematic displacement of the posterior in the (w_0,w_a) plane toward the ΛCDM prediction, (w_0,w_a)=(−1,0), as the minimum allowed age is increased. For t_0 ≥ 13.85 Gyr, the Mahalanobis separation from ΛCDM decreases from 2.56σ to 1.72σ, bringing the ΛCDM prediction inside the 95\% credible region. Our results show that the current evidence for dynamical dark energy is sensitive to independent cosmic-age information and that stellar chronometry provides a direct robustness test of the DESI-favored expansion histories. Requiring sufficiently old cosmologies can appreciably reduce the statistical preference for departures from the standard ΛCDM model.
ER -