SDSS J092455.87+021924.9: An Interesting Gravitationally Lensed Quasar from the Sloan Digital Sky Survey


Inada N, Becker RH, Burles S, Castander FJ, Eisenstein D, Hall PB, Johnston DE, Pindor B, Richards GT, Schechter PL, et al. SDSS J092455.87+021924.9: An Interesting Gravitationally Lensed Quasar from the Sloan Digital Sky Survey. The Astronomical Journal. 2003;126 :666-674.

Date Published:

August 1, 2003


We report the discovery of a new gravitationally lensed quasar from theSloan Digital Sky Survey, SDSS J092455.87+021924.9 (SDSS J0924+0219).This object was selected from among known SDSS quasars by an algorithmthat was designed to select another known SDSS lensed quasar (SDSSJ1226-0006A,B). Five separate components, three of which are unresolved,are identified in photometric follow-up observations obtained with theMagellan Consortium's 6.5 m Walter Baade Telescope at Las CampanasObservatory. Two of the unresolved components (designated A and B) areconfirmed to be quasars with z=1.524; the velocity difference is lessthan 100 km s-1 according to spectra taken with the W. M.Keck Observatory's Keck II Telescope at Mauna Kea, Hawaii. A thirdstellar component, designated C, has the colors of a quasar withredshift similar to components A and B. The maximum separation of thepoint sources is 1.78". The other two sources, designated G and D, areresolved. Component G appears to be the best candidate for the lensinggalaxy. Although component D is near the expected position of the fourthlensed component in a four-image lens system, its properties are notconsistent with being the image of a quasar at z~1.5. Nevertheless, theidentical redshifts of components A and B and the presence of componentC strongly suggest that this object is a gravitational lens. Ourobservations support the idea that a foreground object reddens thefourth lensed component and that another unmodeled effect (such asmicro- or millilensing) demagnifies it, but we cannot rule out thepossibility that SDSS J0924+0219 is an example of the relatively rareclass of ``three-component'' lens systems.