TITLE: GCN CIRCULAR NUMBER: 43145 SUBJECT: GRB 251215A: Swift/UVOT Upper LImits DATE: 25/12/16 18:52:06 GMT FROM: S. R. Oates at Lancaster University <samantha.oates@ucl.ac.uk> S. R. Oates (Lancaster U.) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251215A 32 ks after the Fermi/GBM trigger (Fermi GBM team, GCN Circ. 43104). No optical afterglow is found in the initial UVOT exposures. The UVOT exposures include the positions of XRT sources 2, 5, 6 and 8 (Osborne et al., GCN 43137). The positions of XRT sources 2, 6, and 8 are consistent with known USNO-B1 sources. No optical source is found consistent with XRT source 5. 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/3sigUL white 31995 49531 4297 >22.4 The magnitudes in the table are not corrected for the Galactic extinction due to the significant reddening of E(B-V) = 0.87 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/43145. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...