Cosmological joint analysis with cosmic growth and expansion rate

TL;DR

This paper compares traditional and joint analysis methods for cosmological data, demonstrating that Linder's joint method provides more significant constraints on cosmological parameters than the traditional approach.

Contribution

It introduces a comparison between the traditional $ ext{chi}^2$ method and Linder's joint $H(z)-f\sigma_8$ diagram method using AIC and BIC criteria.

Findings

The joint method yields more significant constraints than the traditional method.

Linder's joint approach better distinguishes between cosmological models.

The study uses $ ext{AIC}$ and $ ext{BIC}$ to evaluate method effectiveness.

Abstract

The measurements of expansion rate $H(z)$ and the growth rate $f\sigma_8(z)$ describe the evolution of the universe, and both of them can constrain the cosmological models through data analysis. Due to the lack of data points, these datasets are combined by the traditional combined method ($\chi^2$ method) to select a best-fitting cosmological model. In 2017, Linder proposed a joint method, which describes the evolution of the universe through $H(z)-f\sigma_8$ diagram instead of the redshift z. Compared to individual datasets, Linder demonstrated the advantages of the joint method to distinguish cosmologies. In this paper, we compare the significance between the traditional combined method and Linder's joint method by constraining the density parameter $\Omega_M$ using Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). The result shows that the joint method is more significant than the traditional combined method.