An exquisite gravitational arc with a radius of 2 \farcs 1 has been discovered around the z = 0.938 field elliptical galaxy CFRS03.1077 during HST observations of Canada-France Redshift Survey ( CFRS ) fields .
Spectroscopic observations of the arc show that the redshift of the resolved lensed galaxy is z = 2.941 .
This gravitational lens-source system is well-fitted using the position angle and ellipticity derived from the visible matter distribution and an isothermal mass profile with a mass corresponding to \sigma = 387 \pm 5 km s ^ { -1 } .
Surprisingly , given the evidence for passive evolution of elliptical galaxies , this is in good agreement with an estimate based on the fundamental plane for z = 0 ellipticals .
This , perhaps , indicates that this galaxy has not shared in the significant evolution observed for average elliptical galaxies at z \sim 1 .
A second elliptical galaxy with similar luminosity from the CFRS survey , CFRS 14.1311 at z = 0.807 , is also a lens but in this case the lens model gives a much smaller mass-to-light ratio , i.e. , it appears to confirm the expected evolution .
This suggests that this pair of field elliptical galaxies may have very different evolutionary histories , a significant result if confirmed .
Clearly , CFRS03.1077 demonstrates that these “ Einstein rings ” are powerful probes of high redshift galaxies .