{
  "body": "S. Dichiara (PSU), K.L. Page (U. Leicester), J.A. Kennea (PSU), \nP. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi  \n(INAF-IASFPA) , M. A. Williams (PSU), J.P. Osborne (U. Leicester), \nA.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports \non behalf of the Swift-XRT team:\n\nWe have analysed 1.8 ks of XRT data for GRB 250510A, from 10.2 ks to\n20.8 ks after the  SVOM/ECLAIRs trigger. The data are entirely in\nPhoton Counting (PC) mode.  \n\nWithin the SVOM/ECLAIRs 90% C.L. error region (GCN #40415) we detect \nthe EP-FXT source EPF_J185624.8+181937 (GCN#40420) at RA, Dec =\n284.10364, +18.3267 which is equivalent to:\n\nRA (J2000): 18h 56m 24.87s\nDec (J2000): +18d 19′ 36.0″\n\nwith an uncertainty of 5.7 arcsec (radius, 90% confidence).\nThe source has a mean count rate of 7.3e-03 ct/sec and a flux of 3.2 \n(+1.3, -1.1) ×  10^-13 erg cm^-2 s^-1 (0.3-10 keV); we note that this \nposition is also consistent with a known 2MASS source, \n2MASS J18562485+1819380. \n\nNo other X-ray sources have been detected. The 3-sigma upper limit in \nthe field ranges  from ~4.4e-03 to ~1.0e-02 ct s^-1, corresponding to a \n0.3-10 keV observed flux of 1.9e-13 to 4.4e-13 erg cm^-2 s^-1 (assuming \na typical GRB spectrum).\n\nThe results of the XRT-team automatic analysis are available at\nhttps://www.swift.ac.uk/SVOM/SVOM_FIELD00016/.\n\nThis circular is an official product of the Swift-XRT team.",
  "createdOn": 1746896091313,
  "submittedHow": "web",
  "format": "text/plain",
  "subject": "GRB 250510A: Swift-XRT observations",
  "circularId": 40423,
  "eventId": "GRB 250510A",
  "submitter": "Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu>",
  "bibcode": "2025GCN.40423....1D"
}