[en] GRAVITATIONAL LENSES ; RADIO GALAXIES ; VISIBLE SPECTRUM ; CHARGE COUPLED DEVICES ; RADIO EMISSION ; RED SHIFT ; ELLIPTICAL GALAXIES
[en] Deep optical imaging and spectroscopy have been obtained for the well known radio Einstein ring MG1131 + 0456 with the ESO/NTT. The direct CCD frames show a red emission excess at the exact location of the radio ring. Subsequent subtraction of the lensing galaxy, assumed to be an elliptical galaxy, results in the detection of an optical ring which is strikingly similar to the radio ring. Gravitational lensing models, including source reconstruction, predicts that the source is likely a radio-galaxy for which both the optical and extended radio emissions are sufficiently distorted by the foreground lensing galaxy as to produce a nearly complete ring. The present spectroscopy and broad band photometry suggest that the lensing galaxy has a spectral energy distribution typical of a nonevolved elliptical, tentatively at z of 0.85. The radio-galaxy associated with the radio-ring is likely to be an elliptical at larger redshift, tentatively of 1.13.