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