TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2692
SUBJECT: ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
DATE:    04/09/03 21:32:31 GMT
FROM:    Don Smith at U michigan  <dasmith@rotse2.physics.lsa.umich.edu>

Smith, D. A., Yost, S. A., & Rykoff, E. S. report on behalf of the ROTSE
collaboration:

ROTSE-IIIc at the H.E.S.S. site in Namibia responded automatically to the
INTEGRAL wakeup alert #1972.  The first exposure began at 18:18:34.6 (UTC),
approximately 8 s after the alert time stamp and 40 s after the burst time
reported by Gotz & Mereghetti (GCN Circ. 2691).  The ROTSE-IIIc system
automatically scheduled a series of exposures: 10 five-second images, 10
twenty-second images, and then a long series of sixty-second exposures.  As of
this writing, we have analyzed 82 images, and find no evidence for any variable
source within the updated offline error circle that is not in the USNO A2.0
catalog.  We estimate our unfiltered limiting magnitude to be roughly 15.1 in
the first two images, and then varying between 15.7 and 16.5 for all subsequent
images.  The field is extremely crowded relative to the ROTSE-IIIc PSF, which
greatly reduces sensitivity.  Co-adding ten frames does not significantly
improve the upper limits.