SDSS J090334.92+502819.2: A New Gravitational Lens


Johnston DE, Richards GT, Frieman JA, Keeton CR, Strauss MA, Knapp GR, Becker RH, White RL, Johnson ET, Ma Z, et al. SDSS J090334.92+502819.2: A New Gravitational Lens. The Astronomical Journal. 2003;126 :2281-2290.

Date Published:

November 1, 2003


We report the discovery of a new gravitationally lensed quasar from theSloan Digital Sky Survey, SDSS J090334.92+502819.2. This object wastargeted for SDSS spectroscopy as a luminous red galaxy, but manualexamination of the spectrum showed the presence of a quasar at z~=3.6 inaddition to a red galaxy at z=0.388, and the SDSS image showed a secondpossible quasar image nearby. Follow-up imaging and spectroscopyconfirmed the lensing hypothesis. In images taken at the AstrophysicalResearch Consortium 3.5 m telescope, two quasars are separated by 2.8"the lensing galaxy is clearly seen and is blended with one of the quasarimages. Spectroscopy taken at the Keck II telescope shows that thequasars have identical redshifts of z~=3.6, and both show the presenceof the same broad absorption line-like troughs. We present simple lensmodels that account for the geometry and magnifications. The lens galaxylies near two groups of galaxies and may be a part of them. The modelssuggest that the groups may contribute considerable shear that has astrong effect on the lens configuration.