We report the discovery of two doubly imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+ 433217.6, at redshifts of 1.838 and 1.789, and with image separations of 2″.86 and 2″.90, respectively. The objects were selected as lens candidates from the Sloan Digital Sky Survey (SDSS). Based on the identical nature of the spectra of the two quasars in each pair and the identification of the lens galaxies, we conclude that the objects are gravitational lenses. The lenses are complicated; in both systems there are several galaxies in the fields very close to the quasars, in addition to the lens galaxies themselves. The lens modeling implies that these nearby galaxies contribute significantly to the lens potentials. On larger scales, we have detected an enhancement in the galaxy density near SDSS J100128.61+502756.9. The number of lenses with image separation of ∼3″ in the SDSS already exceeds the prediction of simple theoretical models based on the standard Λ-dominated cosmology and observed velocity function of galaxies.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science