{
  "body": "J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri\n(INAF-OAR), T. Sbarrato (INAF-OAB), M. A. Williams (PSU), S. Dichiara\n(PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.\nLeicester) and P.A. Evans (U. Leicester) reports on behalf of the\nSwift-XRT team:\n\nWe have analysed 4.5 ks of XRT data for the SVOM/ECLAIRs-detected burst\nGRB 250328A (SVOM trigger sb25032803), from 3.2 ks to 190.2 ks after\nthe  SVOM/ECLAIRs trigger. The data are entirely in Photon Counting\n(PC) mode. We find an uncatalogued fading X-ray source. Using 1975 s of\nPC mode data and 2 UVOT images, we find an enhanced XRT position (using\nthe XRT-UVOT alignment and matching UVOT field sources to the USNO-B1\ncatalogue): RA, Dec = 215.95979, +25.93224 which is equivalent to:\n\nRA (J2000): 14h 23m 50.35s\nDec(J2000): +25d 55' 56.1\"\n\nwith an uncertainty of 4.4 arcsec (radius, 90% confidence). This\nposition is 3.1 arcmin from the SVOM/ECLAIRs position and 1.6 arcsec\nfrom the IR/optical afterglow candidate (Schneider et al., GCN 39919;\nSchneider et al., GCN 39920; Li et al., GCN 39923; Li et al, GCN 39936;\nKumar et al., GCN 39946).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=0.67 (+0.24, -0.18).\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00019661.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "createdOn": 1743413580294,
  "bibcode": "2025GCN.39967....1O",
  "eventId": "GRB 250328A",
  "submittedHow": "email",
  "subject": "GRB 250328A: Swift-XRT refined Analysis",
  "circularId": 39967
}