We present results from a narrow-band optical survey of a contiguous area of 1.95 deg ^ { 2 } , covered by the Cosmic Evolution Survey ( COSMOS ) .
Both optical narrow-band ( \lambda _ { c } = 8150 Å and \Delta \lambda = 120 Å ) and broad-band ( B , V , g ^ { \prime } , r ^ { \prime } , i ^ { \prime } , and z ^ { \prime } ) imaging observations were performed with the Subaru prime-focus camera , Suprime-Cam on the Subaru Telescope .
We provide the largest contiguous narrow-band survey , targetting Ly \alpha emitters ( LAEs ) at z \approx 5.7 .
We find a total of 119 LAE candidates at z \sim 5.7 .
Over the wide-area covered by this survey , we find no strong evidence for large scale clustering of LAEs .
We estimate a star formation rate ( SFR ) density of \sim 7 \times 10 ^ { -4 } M _ { \odot } yr ^ { -1 } Mpc ^ { -3 } for LAEs at z \approx 5.7 , and compare it with previous measurements .