Testing spatial curvature in an anisotropic extension of $w$CDM model with low redshift data

TL;DR

This study constrains a Bianchi type I anisotropic extension of the wCDM model with spatial curvature using various low redshift data, finding minimal anisotropy and implications for the universe's curvature and H0 tension.

Contribution

It provides observational constraints on an anisotropic wCDM model with curvature, highlighting the interplay between anisotropy, curvature, and the H0 tension.

Findings

Anisotropy is of order 10^{-13} and slightly reduces H0 tension.

A closed universe is favored in some data combinations.

Quintessence dark energy is preferred at 95% CL.

Abstract

In this letter, we report the observational constraints on a Bianchi type I anisotropic extension of $w$CDM model with spatial curvature from observational data including Baryon Acoustic Oscillations (BAO), Cosmic chronometers (CC), Big Bang nucleosynthesis (BBN), Pantheon+ (PP) compilation of SNe Ia and SH0ES Cepheid host distance anchors. The anisotropy is found to be of the order $10^{-13}$, which interplay with spatial curvature to reduce $H_0$ tension by $\sim 1\sigma$ as found in the analyses with BAO+CC+BBN+PP combination of data, while no significant effect of anisotropy is observed with BAO+CC+BBN+PPSH0ES combination of data. A closed Universe is favored by $w$CDM as well as anisotropic $w$CDM models with spatial curvature in analyses with BAO+CC+BBN+PP combination of data. An observation of an open Universe from $w$CDM model with spatial curvature in analyses with BAO+CC+BBN+PPSH0ES combination of data and a closed Universe from anisotropic $w$CDM model with curvature in analyses with same combination of data is made. The quintessence form of dark energy is favored at 95\% CL in both analyses.