A Comparative Test of the LCDM and R_h=ct Cosmologies Based on Upcoming Redshift Drift Measurements

TL;DR

This paper evaluates how upcoming redshift drift measurements from ELT and Cosmic Accelerometer can differentiate between the $ m f R_h=ct$ universe and $ m f extbf{ extLambda}CDM$ cosmology, providing a model-independent test of fundamental cosmology.

Contribution

It assesses the potential of future redshift drift observations to distinguish between $ m f R_h=ct$ and $ m f extLambda$CDM cosmologies, including modified gravity models.

Findings

ELT can distinguish $R_h=ct$ from other models at >3σ for $z extgreater 3.6$ after 20 years.

Cosmic Accelerometer can achieve similar results at $z extgreater 2.6$ after 10 years.

Upcoming measurements will provide a model-independent test of cosmological models.

Abstract

A measurement of the redshift drift constitutes a model-independent probe of fundamental cosmology. Several approaches are being considered to make the necessary observations, using (i) the Extremely Large Telescope (ELT), (ii) the Cosmic Accelerometer, and (iii) the differential redshift drift methodology. Our focus in this {\it Letter} is to assess how these upcoming measurements may be used to compare the predictions of $\Lambda$CDM with those of the alternative Friedmann-Lema\^itre-Robertson-Walker cosmology known as the $R_{\rm h}=ct$ universe, and several other models, including modified gravity scenarios. The ELT should be able to distinguish between $R_{\rm h}=ct$ and the other models at better than $3\sigma$ for $z\gtrsim 3.6$ after 20 years of monitoring, while the Cosmic Accelerometer may be able to achieve the same result with sources at $z\gtrsim 2.6$ after only 10 years.