A New Approach to Identifying the Most Powerful Gravitational Lensing Telescopes

TL;DR

This paper introduces a new optical data-based method to identify the most powerful gravitational lensing fields by selecting lines of sight with high luminosity from luminous red galaxies, which correlate with large mass concentrations.

Contribution

The authors develop and apply a novel selection technique using LRG luminosities from SDSS to find optimal gravitational lensing fields, outperforming known clusters in total luminosity.

Findings

Identified 200 high-luminosity LRG fields likely containing massive structures.

Confirmed LRG luminosity correlates with mass concentrations.

Selected fields are 2-3 times more luminous than typical strong-lensing clusters.

Abstract

The best gravitational lenses for detecting distant galaxies are those with the largest mass concentrations and the most advantageous configurations of that mass along the line of sight. Our new method for finding such gravitational telescopes uses optical data to identify projected concentrations of luminous red galaxies (LRGs). LRGs are biased tracers of the underlying mass distribution, so lines of sight with the highest total luminosity in LRGs are likely to contain the largest total mass. We apply this selection technique to the Sloan Digital Sky Survey and identify the 200 fields with the highest total LRG luminosities projected within a 3.5' radius over the redshift range 0.1 < z < 0.7. The redshift and angular distributions of LRGs in these fields trace the concentrations of non-LRG galaxies. These fields are diverse; 22.5% contain one known galaxy cluster and 56.0% contain multiple known clusters previously identified in the literature. Thus, our results confirm that these LRGs trace massive structures and that our selection technique identifies fields with large total masses. These fields contain 2-3 times higher total LRG luminosities than most known strong-lensing clusters and will be among the best gravitational lensing fields for the purpose of detecting the highest redshift galaxies.