TITLE: GCN CIRCULAR NUMBER: 43105 SUBJECT: GRB 251214B: Swift/UVOT Detection DATE: 25/12/15 05:01:50 GMT FROM: Paul Kuin at MSSL <npkuin@gmail.com> N.P.M. Kuin (MSSL/UCL) and R. Eyles-Ferris (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251214B 64 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 43089). A source consistent with the XRT position Evans et al. GCN Circ. 43098) is detected in the initial UVOT exposures. There were early reports of the optical afterglow from Zhe Kang et al. (GCN Circ. 43093) and S.Y. Fu et al. (GCN Circ. 43097). The preliminary UVOT position is: RA (J2000) = 22:00:50.53 = 330.21053 (deg.) Dec (J2000) = -09:09:46.4 = -9.16290 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 64 214 147 17.21 +/- 0.03 v 606 800 39 17.09 +/- 0.17 b 532 724 39 18.08 +/- 0.17 u 277 527 246 17.76 +/- 0.08 w1 655 1472 97 >18.9 m2 630 1447 97 >20.3 w2 582 5213 136 >19.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.039 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/43105. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...