TITLE: GCN CIRCULAR NUMBER: 41799 SUBJECT: GRB 250910A / EP250910a: Swift-XRT afterglow detection DATE: 25/09/11 16:29:52 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of GRB 250910A. We searched for X-ray sources in 1.2 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 1.2 ks, obtained between T0+29.5 ks and T0+30.7 ks. An uncatalogued X-ray source is detected and is believed to be the afterglow. Using 1195 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 39.80164, -39.69498 which is equivalent to: RA (J2000): 02h 39m 12.39s Dec(J2000): -39d 41' 41.9" with an uncertainty of 8.4 arcsec (radius, 90% confidence). This source is consistent with the position reported by EP/FXT (Liu et al., GCN 41776) and with the optical/NIR source detected with VLT (Schneider et al., GCN 41794) and SVOM/VT (Li et al., GCN 41798). We cannot determine at the present time whether the source is fading. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/03000083. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/SVOM/SVOM_FIELD00036. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/41799. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...