SDSS J0246-0825: A New Gravitationally Lensed Quasar from the Sloan Digital Sky Survey

Naohisa Inada, Scott Burles, Michael D. Gregg, Robert H. Becker, Paul L. Schechter, Daniel J. Eisenstein, Masamune Oguri, Francisco J. Castander, Patrick B. Hall, David E. Johnston, Bartosz Pindor, Gordon T. Richards, Donald P. Schneider, Richard L. White, J. Brinkmann, Alexander S. Szalay, Donald G. York

Published 2005-06-27Version 1

We report the discovery of a new two-image gravitationally lensed quasar, SDSS J024634.11-082536.2 (SDSS J0246-0825). This object was selected as a lensed quasar candidate from the Sloan Digital Sky Survey (SDSS) by the same algorithm that was used to discover other SDSS lensed quasars (e.g., SDSS J0924+0219). Multicolor imaging with the Magellan Consortium's Walter Baade 6.5-m telescope and the spectroscopic observations using the W. M. Keck Observatory's Keck II telescope confirm that SDSS J0246-0825 consists of two lensed images ($\Delta{\theta}=$1\farcs04) of a source quasar at z=1.68. Imaging observations with the Keck telescope and the Hubble Space Telescope reveal an extended object between the two quasar components, which is likely to be a lensing galaxy of this system. From the absorption lines in the spectra of quasar components and the apparent magnitude of the galaxy, combined with the expected absolute magnitude from the Faber-Jackson relation, we estimate the redshift of the lensing galaxy to be z=0.724. A highly distorted ring is visible in the Hubble Space Telescope images, which is likely to be the lensed host galaxy of the source quasar. Simple mass modeling predicts the possibility that there is a small (faint) lensing object near the primary lensing galaxy.