TITLE: GCN CIRCULAR NUMBER: 40423 SUBJECT: GRB 250510A: Swift-XRT observations DATE: 25/05/10 16:54:51 GMT FROM: Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu> S. Dichiara (PSU), K.L. Page (U. Leicester), J.A. Kennea (PSU), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. A. Williams (PSU), J.P. Osborne (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 1.8 ks of XRT data for GRB 250510A, from 10.2 ks to 20.8 ks after the SVOM/ECLAIRs trigger. The data are entirely in Photon Counting (PC) mode. Within the SVOM/ECLAIRs 90% C.L. error region (GCN #40415) we detect the EP-FXT source EPF_J185624.8+181937 (GCN#40420) at RA, Dec = 284.10364, +18.3267 which is equivalent to: RA (J2000): 18h 56m 24.87s Dec (J2000): +18d 19′ 36.0″ with an uncertainty of 5.7 arcsec (radius, 90% confidence). The source has a mean count rate of 7.3e-03 ct/sec and a flux of 3.2 (+1.3, -1.1) × 10^-13 erg cm^-2 s^-1 (0.3-10 keV); we note that this position is also consistent with a known 2MASS source, 2MASS J18562485+1819380. No other X-ray sources have been detected. The 3-sigma upper limit in the field ranges from ~4.4e-03 to ~1.0e-02 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.9e-13 to 4.4e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/SVOM/SVOM_FIELD00016/. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/40423. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...