TITLE: GCN CIRCULAR NUMBER: 15423 SUBJECT: GRB 131030A: P60 observations DATE: 13/11/01 00:48:58 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report on behalf of a larger collaboration: We observed the afterglow of GRB 131030A (GCN 15402, Troja et al.) with the robotic Palomar 60-inch telescope in the g, r, i, and z filters. Three exposures of 180 seconds each were acquired in each filter at four separate epochs starting at 5.09, 6.63, 8.12, and 9.65 hours after the Swift trigger, respectively. The light curve in these bands shows a steady power-law decline with decay index alpha~0.95, similar to that reported by RATIR over the same timescale (GCN 15420, Littlejohns et al.) Photometry from the first epoch (calibrated relative to SDSS) yields: t_mid(d) exp(s) filter magnitude 0.21434 3x180 g = 19.14 +/- 0.02 0.21912 3x180 r = 18.81 +/- 0.02 0.22391 3x180 i = 18.61 +/- 0.03