{
  "body": "S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.\nBeardmore (U. Leicester), S. Campana (INAF-OAB), A. Melandri\n(INAF-OAR), T. Sbarrato (INAF-OAB), D.N. Burrows (PSU) 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 IPN-detected\nburst GRB 250804B in a series of observations tiled on the sky.  The\ntotal exposure time is\t3.3 ks, distributed over 3 tiles; the maximum\nexposure at a single sky location in the tiling was 2.2 ks. The data\nwere collected between T0+79.5 ks and T0+92.2 ks, and are entirely in\nPhoton Counting (PC) mode. \n\nThree uncatalogued X-ray sources have been detected, however none of\nthem is above the RASS limit or shows definitive signs of fading.\nTherefore, at the present time we cannot identify which, if any, is the\nafterglow. Details of these sources are given below:\n\nSource 5:\n  RA (J2000.0):  40.9795  =  02:43:55.09\n  Dec (J2000.0): -46.5917  =  -46:35:30.2\n  Error: 6.8 arcsec (radius, 90% conf.)\n  Count-rate: (6.1 [+3.1, -2.3])e-3 ct s^-1   \n  Distance: 1117 arcsec from IPN position.\n  Flux: (1.60 [+0.81, -0.62])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 6:\n  RA (J2000.0):  40.8694  =  02:43:28.64\n  Dec (J2000.0): -46.4818  =  -46:28:54.4\n  Error: 7.1 arcsec (radius, 90% conf.)\n  Count-rate: (9.6 [+4.0, -3.2])e-3 ct s^-1   \n  Distance: 1217 arcsec from IPN position.\n  Flux: (1.78 [+0.75, -0.59])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 7:\n  RA (J2000.0):  40.5489  =  02:42:11.74\n  Dec (J2000.0): -46.5143  =  -46:30:51.5\n  Error: 8.8 arcsec (radius, 90% conf.)\n  Count-rate: (8.8 [+4.8, -3.6])e-3 ct s^-1   \n  Distance: 924 arcsec from IPN position.\n  Flux: (3.0 [+1.6, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nFour catalogued sources were also detected.\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_GRB00138.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "createdOn": 1754403449155,
  "subject": "GRB 250804B: Swift-XRT observations",
  "submittedHow": "email",
  "circularId": 41239,
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "bibcode": "2025GCN.41239....1D",
  "eventId": "GRB 250804B"
}