SDSS J133401.39+331534.3: A New Subarcsecond Gravitationally Lensed Quasar

TL;DR

This paper reports the discovery and detailed analysis of a new gravitationally lensed quasar system with subarcsecond separation, demonstrating the effectiveness of adaptive optics in studying strong lens systems.

Contribution

It presents the first confirmed gravitational lens system SDSS J133401.39+331534.3 with precise astrometry using laser guide star adaptive optics, and discusses the influence of nearby galaxies on lens modeling.

Findings

Two-image lens system with 0.833 arcsecond separation.

Lens galaxy redshift estimated at 0.557.

Nearby bright galaxy likely affects lens potential.

Abstract

The quasar SDSS J133401.39+331534.3 at z = 2.426 is found to be a two-image gravitationally lensed quasar with the image separation of 0.833. The object is first identified as a lensed quasar candidate in the Sloan Digital Sky Survey Quasar Lens Search, and then confirmed as a lensed system from follow-up observations at the Subaru and University of Hawaii 2.2-meter telescopes. We estimate the redshift of the lensing galaxy to be 0.557 based on absorption lines in the quasar spectra as well as the color of the galaxy. In particular, we observe the system with the Subaru Telescope AO188 adaptive optics with laser guide star, in order to derive accurate astrometry, which well demonstrates the usefulness of the laser guide star adaptive optics imaging for studying strong lens systems. Our mass modeling with improved astrometry implies that a nearby bright galaxy $\sim 4"$ apart from the lensing galaxy is likely to affect the lens potential.