A VLT colour image of the optical Einstein ring 0047-2808 ?

The optical Einstein ring 0047 2808 was imaged by the VLT UT1 during the science verification programme. The ring is the image of a high-redshift z =3 :595 star- forming galaxy, with strong Ly emission at 5589 ˚ A, gravita- tionally lensed by a massive early-type galaxy at z =0 :485. Relative to earlier NTT data the high signal-to-noise ratio of the VLT Ly narrow-band image allows much improved con- straints to be placed on the surface-brightness profile of the source and on the mass, leading to a measured mass-to-light ratio of M=LB 13 h for the deflector galaxy. We have com- bined the VLT B-band and Ly narrow-band images with a K-band image obtained at UKIRT to produce a deep colour image of the system.