English

Is there a concordance value for $H_0$?

Cosmology and Nongalactic Astrophysics 2016-11-09 v2

Abstract

We test the theoretical predictions of several cosmological models against different observables to compare the indirect estimates of the current expansion rate of the Universe determined from model fitting with the direct measurements based on Cepheids data published recently. We perform a statistical analysis of type Ia supernova (SN Ia), Hubble parameter, and baryon acoustic oscillation data. A joint analysis of these datasets allows us to better constrain cosmological parameters, but also to break the degeneracy that appears in the distance modulus definition between H0H_0 and the absolute B-band magnitude of SN Ia, M0M_0. From the theoretical side, we considered spatially flat and curvature-free Λ\LambdaCDM, wwCDM, and inhomogeneous Lema\^{i}tre-Tolman-Bondi (LTB) models. To analyse SN Ia we took into account the distributions of SN Ia intrinsic parameters. For the Λ\LambdaCDM model we find that Ωm=0.35±0.02\Omega_m=0.35\pm0.02, H0=(67.8±1.0)H_0=(67.8\pm1.0)\,km\,s1/^{-1}/Mpc, while the corrected SN absolute magnitude has a normal distribution N(19.13,0.11){\cal N}(19.13,0.11). The wwCDM model provides the same value for Ωm\Omega_m, while H0=(66.5±1.8)H_0=(66.5\pm1.8)\,km\,s1/^{-1}/Mpc and w=0.93±0.07w=-0.93\pm0.07. When an inhomogeneous LTB model is considered, the combined fit provides H0=(64.2±1.9)H_0=(64.2\pm1.9)\,km\,s1/^{-1}/Mpc. Both the Akaike information criterion and the Bayes factor analysis cannot clearly distinguish between Λ\LambdaCDM and wwCDM cosmologies, while they clearly disfavour the LTB model. For the Λ\LambdaCDM, our joint analysis of the SN Ia, the Hubble parameter, and the baryon acoustic oscillation datasets provides H0H_0 values that are consistent with CMB-only Planck measurements, but they differ by 2.5σ2.5\sigma from the value based on Cepheids data.

Keywords

Cite

@article{arxiv.1607.05677,
  title  = {Is there a concordance value for $H_0$?},
  author = {Vladimir V. Luković and Rocco D'Agostino and Nicola Vittorio},
  journal= {arXiv preprint arXiv:1607.05677},
  year   = {2016}
}

Comments

Accepted for publication in A&A, 9 pages, 7 figures

R2 v1 2026-06-22T14:58:46.419Z