We present optical and near–infrared spectroscopic observations of the optical Einstein ring 0047–2808 .
We detect both [ OIII ] lines \lambda \lambda 4959 , 5007 near \sim 2.3 \mu , confirming the redshift of the lensed source as z = 3.595 .
The Ly \alpha line is redshifted relative to the [ OIII ] line by 140 \pm 20 { km s ^ { -1 } } .
Similar velocity shifts have been seen in nearby starburst galaxies .
The [ OIII ] line is very narrow , 130 { km s ^ { -1 } } FWHM .
If the ring is the image of the centre of a galaxy the one-dimensional stellar velocity dispersion \sigma = 55 { km s ^ { -1 } } is considerably smaller than the value predicted by Baugh et al .
( 1998 ) for the somewhat brighter Lyman–break galaxies .
The Ly \alpha line is significantly broader than the [ OIII ] line , probably due to resonant scattering .
The stellar central velocity dispersion of the early–type deflector galaxy at z = 0.485 is 250 \pm 30 { km s ^ { -1 } } .
This value is in good agreement both with the value predicted from the radius of the Einstein ring ( and a singular isothermal sphere model for the deflector ) , and the value estimated from the D _ { n } - \sigma relation .