http://arxiv.org/abs/2205.07033
The mismatch between different independent measurements of the expansion rate of the Universe is known as the Hubble constant ($H_0$) tension, and it is a serious and pressing problem in cosmology. We investigate this tension considering the dataset from the Pantheon sample, a collection of 1048 Type Ia Supernovae (SNe Ia) with a redshift range $0<z<2.26$. We perform a binned analysis in redshift to study if the $H_0$ tension also occurs in SNe Ia data. Hence, we build equally populated subsamples in three and four bins, and we estimate $H_{0}$ in each bin considering the $\Lambda$CDM and $w_{0}w_{a}$CDM cosmological models. We perform a statistical analysis via a Markov Chain Monte Carlo (MCMC) method for each bin. We observe that $H_0$ evolves with the redshift, using a fit function $H_{0}(z)=\tilde{H}{0} (1+z)^{-\alpha}$ with two fitting parameters $\alpha$ and $\tilde{H}{0}$. Our results show a decreasing behavior of $H_0$ with $\alpha\sim 10^{-2}$ and a consistency with no evolution between 1.2 $\sigma$ and 2.0 $\sigma$. Considering the $H_0$ tension, we extrapolate $H_{0}(z)$ until the redshift of the last scattering surface, $z=1100$, obtaining values of $H_0$ consistent in 1 $\sigma$ with the cosmic microwave background (CMB) measurements by Planck. Finally, we discuss possible $f(R)$ modified gravity models to explain a running Hubble constant with the redshift, and we infer the form of the scalar field potential in the dynamically equivalent Jordan frame.
T. Schiavone, G. Montani, M. Dainotti, et. al.
Tue, 17 May 22
80/95
Comments: 9 pages, 2 figures, 1 table, Proceedings of the 17th Italian-Korean Symposium on Relativistic Astrophysics, August 2-6, 2021. It is based on arXiv:2103.02117 and arXiv:2201.09848