The photo shows the quasar known under the name J03.13. It is the seventh extragalactic gravitational lens candidate to be discovered at the European Southern Observatory (ESO, La Silla). Its visual magnitude is 17.2 and the redshift is 2.545, corresponding to a distance of about 10 billion light-years. At the upper left (A) is the directly observed image of J03.13, as seen on a CCD frame with 3 min exposure and taken in red light (R-filter) with the SUSI direct camera attached to the ESO New Technology Telescope (NTT) in February 1994.
It clearly reveals the elongated shape, caused by the superposition of two images very near each other. In (B), the stronger of the two has been subtracted with an advanced image processing algorithm, based on the scaling of stellar profiles elsewhere in the frame. In (C), the fainter component has been removed, and in (D) the subtraction of both leaves no residual, indicating that there are no further detectable components of the quasar image. The intensity ratio between the two images is 1:7.
ESO
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