GCN Circular 12395
Subject
GRB 110928A: ROTSE-III Optical Limits
Date
2011-09-28T02:32:52Z (13 years ago)
From
Brad Schaefer at LSU <schaefer@grb.phys.lsu.edu>
B. E. Schaefer (Louisiana State), W. Zheng (U Mich), H. Flewelling (IfA/Hawaii), report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 110928A (Swift trigger 504215; Hoversten et al., GCN 12394), producing images beginning 7.1 s after the GCN notice time. An automated response took the first image at 01:52:39.1 UT, 67.3 s after the burst, under excellent conditions. We took 10 5-sec, 10 20-sec and 10 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma Swift/BAT error circle, for both single images and coadding into sets of 10; the field is not crowded. Individual images have limiting magnitudes ranging from 16.1-17.4; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
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01:52:39.1 01:52:44.1 5 16.1 67.3 N
01:52:39.1 01:54:26.8 107 17.5 67.3 Y