{
  "circularId": 39232,
  "eventId": "GRB 250207B",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "createdOn": 1739020926384,
  "subject": "GRB 250207B: Swift-XRT observations",
  "bibcode": "2025GCN.39232....1D",
  "submittedHow": "email",
  "body": "A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB),\nJ.A. Kennea (PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P.\nBeardmore (U. Leicester), J.P. Osborne (U. Leicester) and P.A. Evans\n(U. Leicester) reports on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the MAXI-detected\nburst GRB 250207B in a series of observations tiled on the sky.  The\ntotal exposure time is\t1.5 ks, distributed over 6 tiles; the maximum\nexposure at a single sky location in the tiling was 540 s. The data\nwere collected between T0+51.2 ks and T0+53.6 ks, and are entirely in\nPhoton Counting (PC) mode. \n\nNo X-ray sources have been detected. The 3-sigma upper limit in the\nfield (not including the regions where the tiles overlap) ranges from\n~0.0e+00 to ~5.5e-01 ct s^-1, corresponding to a 0.3-10 keV observed\nflux of 0.0e+00 to 2.2e-11 erg cm^-2 s^-1 (assuming a typical GRB\nspectrum).\n\nThe results of the XRT-team automatic analysis of the tiled XRT\nobservations, including a position-specific upper limit calculator, are\navailable at https://www.swift.ac.uk/xrt_products/TILED_GRB00131.\n\nThis circular is an official product of the Swift-XRT team.\n\n"
}