Bayesian Model Comparison of $R_h=ct$ versus $\Lambda$CDM using HII galaxy Hubble diagram

Abstract

We complement a recent analysis comparing $R_\mathrm{h}=ct$ with $\Lambda$CDM/$w$CDM using HII galaxies and giant extragalactic HII regions, by carrying out Bayesian model comparison. For this purpose, we calculate the Bayes factors for $R_\mathrm{h}=ct$ compared to flat $\Lambda$CDM/$w$CDM using the same dataset. When we use uniform priors on cosmological parameters, we find that the Bayes factors are close to 1, implying that $R_\mathrm{h}=ct$ is equally favored compared to $\Lambda$CDM/$w$CDM. However, when we use normal priors on cosmological parameters based on Planck cosmology, we find that $R_\mathrm{h}=ct$ is strongly favored over flat $\Lambda$CDM, while $R_\mathrm{h}=ct$ is marginally favored over flat $w$CDM.