GCN Circular 12367
S. B. Cenko (UC Berkeley), N. R. Tanvir (Leicester), E. O. Ofek (Caltech / Weizmann Institute), K. Wiersema (Leicester), A. J. Levan (Warwick), and P. E. Nugent (LBNL): As part of the Palomar Transient Factory (PTF), we have imaged the location of the afterglow candidate (GCN 12364, GCN 12365) of the IPN GRB 110918A (GCN 12357) with the robotic Palomar 48 inch telescope. Images began at 8:49 UT (dt ~ 35.4 hours after the burst trigger time) in the PTF R-band. Comparing our images with those obtained by the INT approximately six hours earlier (GCN 12365), we find the optical candidate has faded by 0.45 +/- 0.13 mag. The observed variability thus confirms that this object is the afterglow of GRB 110918A. Though with large uncertainties, the inferred power-law decay slope (alpha ~ 2.1) is quite steep for this period after the trigger.