TITLE: GCN CIRCULAR NUMBER: 35475 SUBJECT: GRB 240102A: Swift/UVOT Upper Limits DATE: 24/01/03 15:38:51 GMT FROM: Alexander Belles at PSU <aub1461@psu.edu> A. Belles (PSU) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 240102A 113 s after the BAT trigger (Gropp et al., GCN Circ. 35461). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 35471) 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 135 285 147 >20.7 u_FC 294 544 246 >19.9 white 135 1196 353 >21.1 v 113 1246 90 >18.8 b 550 1172 58 >19.5 u 294 1314 299 >20.0 w1 676 1295 78 >19.0 m2 823 1270 58 >18.7 w2 600 1221 78 >19.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.176 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/35475. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...