TITLE: GCN CIRCULAR NUMBER: 42193 SUBJECT: GRB 251007B: Swift/UVOT Upper Limits DATE: 25/10/10 18:00:23 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18@psu.edu> GRB 251007B: Swift/UVOT Upper Limits M. H. Siegel (PSU) and A. Melandri (INAF-OAR) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251007B 152 s after the BAT trigger (Melandri et al., GCN Circ. 42147). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ 42159) 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 152 302 147 >19.8 u_FC 311 561 246 >19.1 white 152 5220 220 >19.9 v 641 4360 220 >19.2 b 567 5181 236 >20.3 u 311 4975 462 >19.5 w1 691 4770 216 >19.8 m2 665 4565 216 >19.5 w2 616 810 39 >18.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.786 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42193. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...