TITLE: GCN CIRCULAR NUMBER: 13655 SUBJECT: GRB 120816A: ROTSE-III Optical Limits DATE: 12/08/16 20:18:36 GMT FROM: Weikang Zheng at U.of Michigan W. Zheng (U Mich), W. Rujopakarn (Steward), T. Guver (Sabanci University), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, automatically responded to GRB 120816A (Swift trigger 531223; Page et al., GCN 13654). An automated response took the first image at 19:23:18.6 UT, 285 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 50 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; however, we are limited as the field is severely crowded. Individual images have limiting magnitudes ranging from 13.9-15.1; we set the following specific limits. start UT end UT t_exp(s) mlim Coadd? ---------------------------------------------------- 19:23:18.6 19:23:23.6 5 13.9 N 19:23:45.6 19:23:50.6 5 14.2 N 19:24:13.1 19:24:18.1 5 14.3 N 19:25:34.5 19:25:54.5 20 14.8 N 19:35:05.4 19:40:22.7 600 15.1 Y