Analysis of the Redshift Lens Probability Distribution Method in Constraining Cosmological Parameters
Hafiz Indra Arwinata (a*) and Anton Timur Jaelani (b,c,d)

a) Astronomy Master Program, FMIPA, Institut Tekologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia
*) handranata13[at]gmail.com
b) Astronomy Research Group and Bosscha Observatory, FMIPA, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia
c) U-CoE AI-VLB, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia
d) University Center of Excellence for Space Science, Technology and Innovation, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia

Abstract

The flat \(\Lambda\)CDM model, as the standard model of cosmology, faces a significant challenge due to the Hubble tension arising from discrepancies between measurements of the early and late universe. Gravitational lensing serves as an effective tool for constraining cosmological parameters due to its independence from the cosmic microwave background (CMB) and the distance ladder. This study investigates the effectiveness of the lens redshift probability distribution method in constraining cosmological parameters. This method assumes a simple and isolated gravitational lens system represented by the singular isothermal sphere (SIS) model. The peak of the lens redshift probability depends on the velocity dispersion function (VDF) of the galaxy, the cosmological model, and the cosmological parameters. We constrain the cosmological parameters of the specific cosmological model by adopting VDF values from references and employing a sample of galaxy-scale gravitational lenses. Variations in VDF values do not affect the constraints of cosmological parameters. However, the constraints are significantly influenced by the distribution of the Einstein radius within the data. This distribution should reflect the actual distribution of gravitational lensing systems in the universe. Using this method, future improvements in the quality and quantity of gravitational lens data are expected to tighten the constraints on cosmological parameters.

Keywords: gravitational lensing, cosmological parameters, lens redshift probability

Topic: Galaxies and Cosmology