paper

Joint Constraints on the Hubble Constant, Spatial Curvature, and Sound Horizon from the Late-time Universe with Cosmography

arXiv:2310.16512 · doi:10.3847/1538-4357/acee6e

Abstract

In this paper, using the latest Pantheon+ sample of Type Ia supernovae (SNe Ia), Baryon Acoustic Oscillation (BAO) measurements, and observational Hubble data (OHD), we carry out a joint constraint on the Hubble constant , the spatial curvature , and the sound horizon at the end of drag epoch . To be model-independent, four cosmography models, i.e., the Taylor series in terms of redshift , , , and the Padé approximants, are used without the assumption of flat Universe. The results show that the is anti-correlated with and , indicating smaller or would be helpful in alleviating the Hubble tension. And the values of and are consistent with the estimate derived from the Planck Cosmic Microwave Background (CMB) data based on the flat CDM model, but is in 2.33.0 tension with that obtained by \cite{Riess2022} in all these cosmographic approaches. Meanwhile, a flat Universe is preferred by the present observations under all approximations except the third order of and of the Taylor series. Furthermore, according to the values of the Bayesian evidence, we found that the flat CDM remains to be the most favored model by the joint datasets, and the Padé approximant of order (2,2), the third order of and are the top three cosmographic expansions that fit the datasets best, while the Taylor series in terms of are essentially ruled out.

18 pages, 4 figures

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