TITLE: GCN CIRCULAR NUMBER: 42298 SUBJECT: GRB 251013C: Swift/UVOT Detection DATE: 25/10/15 19:54:12 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18@psu.edu> M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251013C 0.4 ks after the Fermi/SVOM trigger (GCN Circ. 42221, Rakotondrainibe et al., GCN Circ. 42222). A bright source consistent with the XRT position (Evans et al., GCN Circ. 42232) and optical counterpart (Palmerio et al., GCN Circ. 42223, Perez-Garcia et al., GCN Circ. 42225; Konno et al., GCN Circ. 42226; Masi et al., GCN Circ. 42228; Moskvitin, GCN Circ. 42230; Gompertz et al., GCN Circ. 42231; Garnavich, GCN Circ. 42240; Watson et al., GCN Circ. 42241) is detected in the UVOT exposures. The preliminary UVOT position is: RA (J2000) = 23:03:20.55 = 345.83562 (deg.) Dec (J2000) = -00:12:36.9 = -0.21024 (deg.) with an estimated uncertainty of 0.42 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 u 480 5581 1785 15.22+/-0.03 white 129831 141519 2753 21.66+/-0.20 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.045 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42298. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...