Redshift-drift as a test for discriminating between decelerating inhomogeneous and accelerating universe models

TL;DR

This paper explores how redshift drift measurements can distinguish between inhomogeneous decelerating universe models and accelerating models, focusing on Szekeres Swiss-cheese cosmologies and their observational signatures.

Contribution

It provides a detailed analysis of redshift drift in Szekeres inhomogeneous models and compares these predictions with other cosmological scenarios to address model degeneracy.

Findings

Redshift drift signals differ significantly between inhomogeneous and accelerating models.

Szekeres Swiss-cheese models with large voids produce distinctive redshift drift signatures.

Comparison with other models highlights potential observational tests for universe acceleration.

Abstract

Exact inhomogeneous solutions of Einstein's equations have been used in the literature to build models reproducing the cosmological data without dark energy. However, owing to the degrees of freedom pertaining to these models, it is necessary to get rid of the degeneracy often exhibited by the problem of distinguishing between them and accelerating universe models. We give an overview of redshift drift in inhomogeneous cosmologies, and explain how it serves to this purpose. One class of models which fits the data is the Szekeres Swiss-cheese class where non-spherically symmetric voids exhibit a typical size of about 400 Mpc. We present our calculation of the redshift drift in this model, and compare it with the results obtained by other authors for alternate scenarios.