Testing Linearly Coasting Cosmology by Strong Lensing System and Pantheon+ Data

TL;DR

This study tests the viability of linearly coasting cosmology using strong gravitational lensing data and Pantheon+ supernovae data, finding consistency with lensing but not with supernovae observations.

Contribution

It provides observational constraints on linearly coasting cosmology using multiple datasets, highlighting its compatibility with lensing data but inconsistency with supernovae data.

Findings

Linear coasting is consistent with strong lensing data within 1-sigma.

Pantheon+ supernovae data does not support linear coasting.

The study constrains power law cosmology using diverse observational data.

Abstract

The standard model of cosmology ($\Lambda$CDM) is facing a serious crisis caused by the inconsistencies in the measurements of some fundamental cosmological parameters (Hubble constant $H_{0}$ and cosmic curvature parameter $\Omega_{k}$ for example). On the other hand, a strictly linear evolution of the cosmological scale factor is found to be an excellent fit to a host of observations. Any model that can support such a coasting presents itself as a falsifiable model as far as the cosmological tests are concerned. In this article the observational data of strong gravitational lensing (SGL) systems from SLACS, BELLS, LSD and SL2S surveys has been used to test the viability of linearly coasting cosmology. Assuming the spherically symmetric mass distribution in lensing galaxies, the ratio of angular diameter distance from lens to source and angular diameter distance of the source is evaluated and is used to constrain the power law cosmology. Further, updated type Ia supernovae dataset (Pantheon+) with covariance matrix incorporating all statistical and systematic uncertainties is used to constrain the power law cosmology. It is found that the linear coasting is consistent with the SGL data within 1-$\sigma$ uncertainties but Pantheon+ sample does not support linear coasting.