A method to search for strong galaxy-galaxy lenses in optical imaging surveys

TL;DR

This paper introduces a semi-automated, multi-parameter method for identifying strong galaxy-galaxy lenses in optical surveys, demonstrated on the Deep Lens Survey data, leading to the discovery of lens candidates.

Contribution

The paper presents a novel shape-based search technique utilizing third-order moments to detect strong lenses in optical imaging surveys.

Findings

Applied method to the Deep Lens Survey data

Detected multiple strong galaxy-galaxy lens candidates

Simulated arc properties using real galaxy data from HST fields

Abstract

We present a semi-automated method to search for strong galaxy-galaxy lenses in optical imaging surveys. Our search technique constrains the shape of strongly lensed galaxies (or arcs) in a multi-parameter space, which includes the third order (octopole) moments of objects. This method is applied to the Deep Lens Survey (DLS), a deep ground based weak lensing survey imaging to $R\sim26$. The parameter space of arcs in the DLS is simulated using real galaxies extracted from deep HST fields in order to more accurately reproduce the properties of arcs. Arcs are detected in the DLS using a pixel thresholding method and candidate arcs are selected within this multi-parameter space. Examples of strong galaxy-galaxy lens candidates discovered in the DLS F2 field (4 square degrees) are presented.