TITLE: GCN CIRCULAR NUMBER: 18692 SUBJECT: GRB151215A: P60 Optical Afterglow Candidate DATE: 15/12/15 03:50:49 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko (NASA/GSFC) reports on behalf of a larger collaboration: We have imaged the location of GRB151215A (Gibson et al., GCN 18691) with the robotic Palomar 60 inch telescope. Observations began at 3:07 UT (~ 6 minutes after the BAT trigger) and were obtained in the r', i', and z' filters. Just outside the XRT error circle, we find a fading source at (J2000.0) coordinates: RA: 06:14:20.22 Dec: +35:30:57.2 Using calibration from nearby point sources, we find the object fades from i' = 17.47 +/- 0.05 mag at 3:07 UT to 18.58 +/- 0.15 mag at 3:24 UT. Thus, we believe this quite likely to be the optical afterglow of GRB151215A. Further observations are planned.