Constraints on cosmological models from lens redshift data

TL;DR

This study uses gravitational lens redshift data from multiple surveys, combined with other cosmological measurements, to constrain dark energy models, finding that current data weakly restricts parameters but supports the flat $\\Lambda$CDM model within 1 sigma.

Contribution

It introduces a comprehensive analysis of lens redshift data from various surveys to constrain dark energy models, incorporating improved galaxy velocity dispersion measurements and semi-analytical galaxy formation models.

Findings

Current lens redshift data provide weak constraints on dark energy parameters.

Combining lens data with BAO and CMB data yields more stringent constraints.

Results support the flat $\Lambda$CDM model within 1 sigma.

Abstract

Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structures, formations, and evolutions). Now several hundreds of strong lens systems produced by massive galaxies have been discovered, which may form well-defined samples useful for statistical analyses. To collect a relatively complete lens redshift data from various large systematic surveys of gravitationally lensed quasars and check the possibility to use it as a future complementarity to other cosmological probes. We use the distribution of gravitationally-lensed image separations observed in the Cosmic Lens All-Sky Survey (CLASS), the PMN-NVSS Extragalactic Lens Survey (PANELS), the Sloan Digital Sky Survey (SDSS) and other surveys, considering a singular isothermal ellipsoid (SIE) model for galactic potentials as well as improved new measurements of the velocity dispersion function of galaxies based on the SDSS DR5 data and recent semi-analytical modeling of galaxy formation, to constrain two dark energy models ($\Lambda$CDM and constant $w$) under a flat universe assumption. We find that the current lens redshift data give a relatively weak constraint on the model parameters. However, by combing the redshift data with the baryonic acoustic oscillation peak and the comic macrowave background data, we obtain more stringent results, which show that the flat $\Lambda$ CDM model is still included at 1$\sigma$.