English

Constraints on AvERA Cosmologies from Cosmic Chronometers and Type Ia Supernovae

Cosmology and Nongalactic Astrophysics 2026-01-14 v3

Abstract

We constrain AvERA cosmologies in comparison with the flat Λ\LambdaCDM model using cosmic chronometer (CC) data and the Pantheon+ sample of type Ia supernovae (SNe Ia). The analysis includes fits to both CC and SN datasets using the \texttt{dynesty} dynamic nested sampling algorithm. For model comparison, we use the Bayesian model evidences and Anderson-Darling tests applied to the normalized residuals to assess consistency with a standard normal distribution. Best-fit parameters are derived within the redshift ranges z2z \leq 2 for CCs and z2.3z \leq 2.3 for SNe. For the baseline AvERA cosmology, we obtain best-fit values of the Hubble constant of H0=68.323.27+3.21 km s1 Mpc1{H_0=68.32_{-3.27}^{+3.21}~\mathrm{km~s^{-1}~Mpc^{-1}}} from the CC analysis and H0=71.991.03+1.05 km s1 Mpc1{H_0=71.99_{-1.03}^{+1.05}~\mathrm{km~s^{-1}~Mpc^{-1}}} from the SN analysis, each consistent within 1σ1\sigma with the corresponding AvERA simulation value of H(z=0)H(z=0). While both the CC and SN datasets yield higher Bayesian evidence for the flat Λ\LambdaCDM model, they favor the AvERA cosmologies according to the Anderson-Darling test. We have identified signs of overfitting in each model, which suggests the possibility of overestimating the uncertainties in the Pantheon+ covariance matrix.

Keywords

Cite

@article{arxiv.2503.21369,
  title  = {Constraints on AvERA Cosmologies from Cosmic Chronometers and Type Ia Supernovae},
  author = {Adrienn Pataki and Péter Raffai and István Csabai and Gábor Rácz and István Szapudi},
  journal= {arXiv preprint arXiv:2503.21369},
  year   = {2026}
}

Comments

7 pages, 3 figures