GCN Circular 13258
Subject
GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval
Date
2012-04-23T22:37:04Z (12 years ago)
From
James Wren at LANL <jwren@nis.lanl.gov>
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