A new gravitational lens from the MUSCLES survey: ULAS J082016.1+081216

TL;DR

This paper reports the discovery of a new gravitational lens system, ULAS J082016.1+081216, identified through combined SDSS and UKIDSS data, demonstrating the potential to expand the catalog of known quasar lenses.

Contribution

The study introduces a new method for identifying gravitational lenses using SDSS and UKIDSS data, increasing the potential for discovering more lenses with higher flux ratios and smaller separations.

Findings

Discovered a new gravitational lens with 2.3" separation and high flux ratio.

Identified the lens galaxy at redshift 0.803.

Confirmed the effectiveness of the SDSS-UKIDSS survey method for lens detection.

Abstract

We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3" and high (~6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new high-quality images from the UKIRT Deep Sky Survey (UKIDSS). The lensed quasar has a source redshift of 2.024, and we identify the lens galaxy as a faint red object of redshift 0.803+/-0.001. Three other objects from the UKIDSS survey, selected in the same way, were found not to be lens systems. Together with the earlier lens found using this method, the SDSS-UKIDSS lenses have the potential to significantly increase the number of quasar lenses found in SDSS, to extend the survey to higher flux ratios and lower separations, and to give greater completeness which is important for statistical purposes.