Cosmological constraints from low-redshift data

TL;DR

This paper reviews how low-redshift cosmological data like SN Ia, BAO, and CC constrain the standard and alternative models, addressing systematic issues, anisotropies, and the Hubble constant tension.

Contribution

It provides a comprehensive overview of low-redshift data constraints on cosmological models, including systematic biases and the Hubble tension.

Findings

Low-redshift data constrain cosmic acceleration and model parameters.

Systematic issues in SN Ia analysis impact cosmological constraints.

The low-redshift H0 measurement from CC data highlights tension with high-redshift estimates.

Abstract

In this paper we summarise the constraints that low-redshift data --such as supernovae Ia (SN Ia), baryon acoustic oscillations (BAO) and cosmic chronometers (CC)-- are able to set on the concordance model and its extensions, as well as on inhomogeneous but isotropic models. We provide a broad overlook into these cosmological scenarios and several aspects of data analysis. In particular, we review a number of systematic issues of SN Ia analysis that include magnitude correction techniques, selection bias and their influence on the inferred cosmological constraints. Furthermore, we examine the isotropic and anisotropic components of the BAO data and their individual relevance for cosmological model-fitting. We extend the discussion presented in earlier works regarding the inferred dynamics of cosmic expansion and its present rate from the low-redshift data. Specifically, we discuss the cosmological constraints on the accelerated expansion and related model-selections. In addition, we extensively talk about the Hubble constant problem, then focus on the low-redshift data constraint on $H_0$ that is based on CC. Finally, we present the way in which this result compares the two of high-redshift $H_0$ estimate and local (redshift zero) measurements that are in tension.