TITLE: GCN CIRCULAR NUMBER: 13045 SUBJECT: GRB 120311B: Faulkes Telescope North observations DATE: 12/03/12 08:58:55 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB), F. Virgili (LJMU), J. Japeli (U. Ljubljana) on behalf of a larger collaboration report: "The 2-m Faulkes Telescope North robotically followed up GRB 120311B (Swift trigger 517489, Marshall et al., GCN Circ 13038) 200 sec after the GRB trigger time. Within the enhanced XRT error circle (Osborne et al., GCN Circ. 13042) we do not detect any object in R and i' filters down to the following limits: Mid time from Exposure Filter Magnitude GRB (hr) (s) ---------------------------------------------------------- 0.29 240 R > 20.5 0.39 220 i' > 20.3 ---------------------------------------------------------- Values are calibrated against nearby USNOB-1 field stars.