TITLE: GCN CIRCULAR NUMBER: 13258 SUBJECT: GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval DATE: 12/04/23 22:37:04 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made observations of Swift trigger 520658 (Troja et al., GCN 13243). The burst location was within the field of our wide-field monitor located in Maui, HI, which began a 10 s integration of the location at 07:12:06.81 UT, 3.2 s after the Swift trigger time and during the gamma-ray emitting interval. The optical counterpart (Cucchiara, et al., GCN 13245, and Kuin et al., GCN 13248) was not detected above our 3-sigma limiting magnitude of 10.3 based on a comparison of our unfiltered image to the Tycho-2 V-band catalog. Our narrow-field instruments in Los Alamos, NM, began imaging at 07:12:55.49 UT, 51.8 s after the Swift trigger and 5.7 s after receiving the GCN packet. The initial 5 s exposure shows no counterpart to a 3-sigma limiting magnitude of 16.6 when compared to the USNO-B1 R-band. The following table gives a sample of our observations. The start time is given as the seconds between the start of the exposure and the initial Swift trigger time. start(s) exp(s) mag limit -------------------------------- -16.8 10.0 >10.3 3.2 10.0 >10.3 22.7 10.0 >10.3 51.8 5.0 >16.6 60.8 5.0 >16.9 149.8 10.0 >17.4 437.2 30.0 >17.9