Citation:
Date Published:
June 1, 2005Abstract:
We report on the discovery of a fifth lensed image in the largeseparation lensed quasar system SDSS J1004 + 4112. A faint point sourcelocated 0.''2 from the center of the brightest galaxy in the lensingcluster was detected in images taken with the Advanced Camera forSurveys (ACS) and the Near Infrared Camera and Multi-Object Spectrometer(NICMOS) on the Hubble Space Telescope. The flux ratio between the pointsource and the brightest lensed component in the ACS image is similar tothat in the NICMOS image. The location and brightness of the pointsource are consistent with lens model predictions for a lensed image. Wetherefore conclude that the point source is likely to be a fifth lensedimage of the source quasar. In addition, the NICMOS image reveals thelensed host galaxy of the source quasar, which can strongly constrainthe structure of the lensing critical curves, and thereby the massdistribution of the lensing cluster.