English

General Cosmography Model with Spatial Curvature

Cosmology and Nongalactic Astrophysics 2020-01-08 v3

Abstract

The cosmographic approach is adopted to determine the spatial curvature (i.e., ΩK\Omega_K) combining the latest released cosmic chronometers data (CC), the Pantheon sample of type Ia supernovae observations, and the baryon acoustic oscillation measurements. We use the expanded transverse comoving distance DM(z)D_M(z) as a basic function for deriving H(z)H(z) and the other cosmic distances. In this scenario, ΩK\Omega_K can be constrained only by CC data. To overcome the convergence issues at high-redshift domains, two methods are applied: the Pad\'{e} approximants and the Taylor series in terms of the new redshift y=z/(1+z)y=z/(1+z). Adopting the Bayesian evidence, we find that there is positive evidence for the Pad\'{e} approximant up to order (2,22,2) and weak evidence for the Taylor series up to 3-rd order against ΛCDM+ΩK\Lambda\text{CDM}+\Omega_K model. The constraint results show that a closed universe is preferred by the present observations under all the approximants used in this study. And the tension level of the Hubble constant H0H_0 is less than 2σ2\sigma significance between different approximants and the local distance ladder determination. For each assumed approximant, H0H_0 is anti-correlated with ΩK\Omega_K and the sound horizon at the end of the radiation drag epoch, which indicates that the H0H_0 tension problem can be slightly relaxed by introducing ΩK\Omega_K or any new physics which can reduce the sound horizon in the early universe.

Keywords

Cite

@article{arxiv.1903.11433,
  title  = {General Cosmography Model with Spatial Curvature},
  author = {En-Kun Li and Minghui Du and Lixin Xu},
  journal= {arXiv preprint arXiv:1903.11433},
  year   = {2020}
}

Comments

13 pages, 4 figures, major revised, update data and conclusions

R2 v1 2026-06-23T08:20:52.296Z