{
  "eventId": "GRB 250527B",
  "subject": "GRB 250527B: Swift-XRT observations",
  "body": "J.A. Kennea (PSU), D.N. Burrows (PSU), M.A. Williams (PSU), A.P.\nBeardmore (U. Leicester), J.P. Osborne (U. Leicester), B. Sbarufatti\n(INAF-OAB), C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB) 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 250527B in a series of observations tiled on the sky.  The\ntotal exposure time is\t3.5 ks, distributed over 12 tiles; the maximum\nexposure at a single sky location in the tiling was 620 s. The data\nwere collected between T0+57.5 ks and T0+65.2 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~0.02 to ~0.05 ct s^-1, corresponding to a 0.3-10 keV observed flux of\n9.2e-13 to 2.0e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum).\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_GRB00136.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "createdOn": 1748511000916,
  "circularId": 40570,
  "bibcode": "2025GCN.40570....1K",
  "submittedHow": "email",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>"
}