TITLE: GCN CIRCULAR NUMBER: 11033 SUBJECT: GRB 100802A: ROTSE-III Optical Limits DATE: 10/08/02 06:29:52 GMT FROM: Shashi Bhushan Pandey at ROTSE S. B. Pandey (U Mich), H. Flewelling (IfA/Hawaii), W. Zheng (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 100802A (Swift trigger 430603; Troja, E., GCN 11031), producing images beginning 9.1 s after the GCN notice time. An automated response took the first image at 05:46:10.1 UT, 27.9 s after the burst, and during the gamma-ray emission, 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 the XRT error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 15.3-17.6; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 05:46:10.1 05:46:15.1 5 15.3 27.9 N 05:47:30.9 05:52:12.0 281 18.2 108.7 Y