TITLE: GCN CIRCULAR NUMBER: 35233 SUBJECT: GRB 231129A: Swift/UVOT Upper Limits DATE: 23/11/30 13:17:20 GMT FROM: Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk> A. A. Breeveld (UCL-MSSL) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 231129A (Gropp et al., GCN circ. 35208; Mereghetti et al., GCN circ. 35209; Zhang et al., GCN circ. 35210) 120 s after the BAT trigger (Gropp et al., GCN Circ. 35208). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 35220) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 120 270 147 >20.5 white 120 4158 344 >20.8 v 4369 4568 197 >18.9 b 3753 3953 197 >19.4 u 333 5122 275 >19.9 w1 4780 4980 197 >18.8 m2 4574 4773 197 >18.9 w2 4164 4364 197 >19.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 1.164 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/35233. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...