TITLE: GCN CIRCULAR NUMBER: 41015 SUBJECT: GRB 250706B: Swift/UVOT Detection DATE: 25/07/07 18:35:19 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 250706B 12.5 ks after the SVOM/ECLAIRs trigger (Palmerio et al., GCN Circ. 40989). A source consistent with the XRT position (Ferro et al., GCN Circ. 40996) and the optical transient (Zhu et al., GCN Circ. 40991; Palmerio et al., GCN Circ. 40992; Romanov, GCN Circ. 40995) is detected in the UVOT exposures. The preliminary UVOT position is: RA (J2000) = 02:44:53.43 = 41.23097 (deg.) Dec (J2000) = -50:03:40.2 = -50.06116 (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 12471 18805 2023 16.49+/-0.03 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.026 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/41015. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...