English

$\Lambda$CDM is alive and well

Cosmology and Nongalactic Astrophysics 2024-05-03 v3

Abstract

The Λ\LambdaCDM model faces several tensions with recent cosmological data and their increased accuracy. The mismatch between the values of the Hubble constant H0H_0 obtained from direct distance ladder measurements and from the cosmic microwave background (CMB) is the most statistically significant, but the amplitude of the matter fluctuations is also regarded as a serious concern, leading to the investigation of a plethora of models. We first show that the combination of several recent measurements from local probes leads to a tight constraint on the present-day matter density ΩM\Omega_M as well as on the amplitude of the matter fluctuations, both acceptably consistent with the values inferred from the CMB. Secondly, we show that the data on cosmic chronometers allow to derive an accurate value of the Hubble constant H0H_0 for Λ\LambdaCDM models: H0=67.4±1.34H_0 = 67.4 \pm 1.34 km/s/Mpc. This implies that, within Λ\LambdaCDM, some determinations of H0H_0 are biased. Considering a bias on the Hubble constant as a nuisance parameter within Λ\LambdaCDM, we examine such a Λ\LambdaCDM+H0+ H_0 bias model on the same statistical grounds as alternative cosmological models. We show that the former statistically supersede most existing extended models proposed up to now. In a third step, we show that the value of ΩM\Omega_M we obtained, combined with H0H_0 from SH0ES, leads to an accurate measurement of ωM\omega_M, providing an additional low-redshift test for cosmological models. From this test, most extensions seem to be confronted with a new tension, whereas the Λ\LambdaCDM with H067H_0 \sim 67 has none. We conclude that a standard Λ\LambdaCDM model with an unknown bias in the Cepheids distance calibration represents a model that reaches a remarkable agreement, statistically better than previously proposed extensions with H073H_0 \sim 73 for which such a comparison can be performed. (abridged)

Keywords

Cite

@article{arxiv.2205.05017,
  title  = {$\Lambda$CDM is alive and well},
  author = {Alain Blanchard and Jean-Yves Héloret and Stéphane Ilić and Brahim Lamine and Isaac Tutusaus},
  journal= {arXiv preprint arXiv:2205.05017},
  year   = {2024}
}

Comments

10 pages, 5 figures, revised version to be published on the Open Journal of Astrophysics

R2 v1 2026-06-24T11:13:22.784Z