GCN Circular 10119
Subject
GRB 091102: ROTSE-III Optical Limits
Date
2009-11-02T15:34:52Z (15 years ago)
From
Brad Schaefer at LSU <schaefer@grb.phys.lsu.edu>
B. E. Schaefer (Louisiana State), F. Yuan (U Mich), S. B. Pandey (U Mich),
report on behalf of the ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to
GRB 091102 (Swift trigger 374598; Hoversten et al., GCN 10117), producing
images beginning 5.8 s after the GCN notice time. An automated response
took the first image at 14:35:04.8 UT, 26.5 s after the burst, under fair
conditions with occassional thin clouds and a bright Full Moon 96 degrees
away. We took 10 5-sec, 10 20-sec and 100 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. No XRT position is available. Individual images have
limiting magnitudes ranging from 13.7-16.0; we set the following specific
limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
14:35:04.8 14:35:09.8 5 14.6 26.5 N
14:35:04.8 14:37:16.8 50 15.5 26.5 Y
14:37:25.9 14:42:08.0 282 16.6 167.6 Y