TITLE: GCN CIRCULAR NUMBER: 5666 SUBJECT: GRB 060930: ROTSE-III Optical Limits DATE: 06/09/30 12:48:59 GMT FROM: Heather Swan at U.of Michigan/ROTSE H. Swan (U. Michigan), W. Rujopakarn (U. Arizona), S.A. Yost (U. Michigan), E.S. Rykoff (U. Michigan), B. E. Schaefer (Louisiana State), report on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 060930 (Integral trigger 3503), producing images beginning 6.3 s after the GCN notice time. An automated response took the first image at 09:05:08.3 UT, 44.1 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 80 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 15.8-17.1; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 09:05:08.3 09:05:13.3 5 15.8 44.1 N 09:05:08.3 09:07:44.3 156 17.1 44.1 Y