GCN Circular 6944
Adria C. Updike, Brian Donehew, Paul Jay Searcy, Ernest Garrison, and Dieter H. Hartmann report (on behalf of the Clemson GRB Follow-Up Team): We observed the field of GRB 071018 (GCN 6932, Krimm et al.) beginning 1.05 days after the trigger under good weather conditions. We obtained 69 minutes of R-band images at high airmass. Upon comparison to the sources identified by Xin et al. (GCN 6936), we find a magnitude of 20.5 � 0.15 for OT candidate #1. We note that this is brighter than the magnitude reported by Xin et al. half a day earlier, so this may indeed be a variable source. We also note a source in SDSS images at the location of GCN 6936 OT candidate #2. At the locations of the XRT error circles (GCN 6943, Beardmore et al.), we detect no new sources down to a limiting magnitude of 20.8 in the R band. Calibration to the USNO B1.0 catalog was done relative to 10 field stars. We would like to thank Liping Xin for providing a finder chart and additional information on their observations. We also acknowledge the help of Kenneth Rumstay (Valdosta U). This message may be cited.