TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4480 SUBJECT: GRB 060111: ROTSE-III Optical Limits DATE: 06/01/11 05:12:43 GMT FROM: Fang Yuan at ROTSE F. Yuan (U Mich), W. Rujopakarn (U Mich), E.S. Rykoff (U Mich), S.A. Yost (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, responded to GRB 060111 (Swift trigger 176818), producing images beginning 5 s after the GCN notice time. An automated response took the first image at 04:23:23.2 UT, 17.1 s after the burst, under twilight conditions. We took 10 5-sec eposures before the individual images were saturated due to twilight. 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 and particularly at the XRT position, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 13.4-13.8; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 04:23:23.2 04:23:28.2 5 13.4 17.1 N 04:23:23.2 04:25:31.0 127.8 14.5 17.1 Y