TITLE:   GCN CIRCULAR
NUMBER:  11048
SUBJECT: GRB 100805A: ROTSE-III Optical Limits
DATE:    10/08/05 04:56:08 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship@umich.edu>

S. B. Pandey (U Mich) and W. Zheng (U Mich), report on behalf of the ROTSE
collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
100805A (Swift trigger 430957; Hoversten , E. A., GCN 11047), producing
images beginning 6.2 s after the GCN notice time. An automated response
took the first image at 04:13:39.2 UT, 50.9 s after the burst, under fair
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 or at the Swift/UVOT position, for both
single images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 16.1-17.3; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
04:13:39.2   04:13:44.2         5     16.1           50.9       N
04:14:59.3   04:19:41.7       282     18.0          131.0       Y