Model selection using time-delay lenses

TL;DR

This study uses a growing sample of time-delay gravitational lenses to compare two cosmological models, finding that current data favors the R_h=ct universe over the standard flat LCDM model.

Contribution

It demonstrates that current time-delay lens data supports the R_h=ct model more than the flat LCDM, providing a new observational test for cosmological theories.

Findings

Current lens data favors R_h=ct with ~84% likelihood.

Standard model has ~16% likelihood based on current data.

Future surveys will improve the accuracy of model comparisons.

Abstract

The sample of time-delay gravitational lenses appropriate for studying the geometry of the Universe continues to grow as dedicated campaigns, such as the Dark Energy Survey, the VST ATLAS survey, and the Large Synoptic Survey Telescope, complete their census of high-redshift sources. This catalog now includes hundreds of strong lensing systems, at least 31 of which have reasonably accurate time delay measurements. In this paper, we use them to compare the predictions of two competing Friedmann-Lemaitre-Robertson-Walker models: flat LCDM, characterized by two adjustable parameters (H_0 and Omega_m), and the R_h=ct universe (with H_0 as the single free variable). Over the past decade, the latter has accounted for the data better than the standard model, most recently the emergence of well-formed galaxies discovered by JWST at cosmic dawn. Here we show that the current sample of time-delay lenses favours R_h=ct with a likelihood of ~84% versus ~16% for the standard model. This level of accuracy will greatly improve as the ongoing surveys uncover many thousands additional lens systems over the next several years.