[vsnet-grb-info 12443] GRB 120923A: RAPTOR Early Afterglow Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13818
SUBJECT: GRB 120923A: RAPTOR Early Afterglow Limits
DATE:    12/09/25 23:45:36 GMT
FROM:    James Wren at LANL  <jwren at 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 follow-up observations
of Swift trigger 534402 (Yershov, et al., GCN 13796).  Our narrow-field
instruments in Los Alamos, NM, began imaging at 05:17:43.06 UT, 96.8 s after
the Swift BAT trigger.  We do not detect the optical counterpart (Levan,
et al., GCN 13802) in any of our images.  The following table summarizes some
of our early observations.  Our unfiltered images are calibrated to the
USNO-B1 r-band.  The start time is seconds since the BAT trigger time.  The
magnitude limit is the 3-sigma detection threshold.

T-Start    Exp-Time   Mag-Limit
----------------------------------
96.82      5.9        17.3
106.83     5.4        17.6
143.24     5.4        17.5
161.53     5.1        17.5
181.82     10.1       18.2
220.22     10.4       18.1
284.22     10.9       18.1