We report the discovery of a Lyman \alpha emitting galaxy at z = 6.518 .
The single line was found in the 43 arcmin ^ { 2 } VLT/FORS field by slitless spectroscopy limited to the atmospheric window at \lambda \sim 9100 Å ( sampling Ly \alpha at 6.4 < z < 6.6 ) .
Its counterpart is undetected in a deep I band image and the line has an asymmetric appearance in a deeper follow-up spectrum .
There are no plausible line identifications except for Ly \alpha with a flux of 1.9 \times 10 ^ { -17 } erg cm ^ { -2 } s ^ { -1 } and rest frame equivalent width > 80 Å .
The lower limit to the star formation rate density at z = 6.5 derived from our complete sample is 5 \times 10 ^ { -4 } M _ { \odot } yr ^ { -1 } Mpc ^ { -3 } , consistent with measurements in the Subaru Deep Field and Hubble Ultra Deep Field but approximately ten times higher than in the Large Area Lyman Alpha survey .
This Ly \alpha emitter is among the very small sample of highest redshift galaxies known .