GCN Circular 19410
A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester), S. B. Cenko (NASA/GSFC), D. Perley (DARK) report on behalf of a larger collaboration: We observed the field of Fermi/LAT GRB 160509A (Longo et al. GCN 19403) with the Gemini North telescope on Mauna Kea, beginning at 14:45 UT during morning twilight, approximately 5.75 hr post-burst. Consistent with the refined X-ray afterglow position reported by Kennea et al. (GCN 19408) we detect a faint source with preliminary magnitudes of r=23.52+/-0.15, z=21.35+/-0.30 (calibrated via SDSS stars in the field). We cannot make any statement about the variability of this source at the present time. The position of the source is 20:47:00.93 +76:06:29.2 (J2000), accurate to about 0.5" in each coordinate. The fairly red r-z colour could be explained if the burst was at a high redshift of z=5-6, or alternatively at a more moderate redshift with some extinction in the host galaxy. We acknowledge the rapid response of the Gemini staff, in obtaining these observations.