TITLE: GCN CIRCULAR NUMBER: 38671 SUBJECT: GRB 241223A: Swift-XRT observations DATE: 24/12/25 16:42:10 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> B. Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Ferro (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM-detected burst GRB 241223A, collecting 2.2 ks of Photon Counting (PC) mode data between T0+20.5 ks and T0+99.8 ks. No X-ray sources have been detected at the position of the GOTO optical source (GCN Circ. 38655). The 3-sigma upper limit in the field ranges from ~0.005 to ~0.006 ct s^-1, corresponding to a 0.3-10 keV observed flux of 2.0e-13 to 2.5e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021749. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38671. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...