{
  "bibcode": "2022GCN.31749....1B",
  "body": "D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester),\nK.L. Page (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo\n(INAF-OAB), M.G. Bernardini (INAF-OAB), J.A. Kennea (PSU) and P.A.\nEvans (U. Leicester) report on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nSwift/BAT-GUANO-detected burst GRB 220310C, collecting 4.6 ks of Photon\nCounting (PC) mode data between T0+102.8 ks and T0+120.2 ks. \n\nFour 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 1:\n  RA (J2000.0):  289.9580  =  19:19:49.91\n  Dec (J2000.0): +40.2093  =  +40:12:33.3\n  Error: 7.9 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (4.4 +/- 1.2)e-3 ct s^-1\t \n  Distance: 344 arcsec from Swift/BAT-GUANO position.\n  Flux: (9.6 +/- 2.7)e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 2:\n  RA (J2000.0):  290.2354  =  19:20:56.50\n  Dec (J2000.0): +40.3333  =  +40:19:59.9\n  Error: 7.6 arcsec (radius, 90% conf.)\n  Count-rate: (3.7 [+1.4, -1.1])e-3 ct s^-1   \n  Distance: 539 arcsec from Swift/BAT-GUANO position.\n  Flux: (1.39 [+0.51, -0.42])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 3:\n  RA (J2000.0):  290.1544  =  19:20:37.05\n  Dec (J2000.0): +40.2064  =  +40:12:23.0\n  Error: 6.3 arcsec (radius, 90% conf.)\n  Count-rate: (1.92 [+0.98, -0.76])e-3 ct s^-1\t \n  Distance: 288 arcsec from Swift/BAT-GUANO position.\n  Flux: (4.2 [+2.2, -1.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 4:\n  RA (J2000.0):  289.8727  =  19:19:29.46\n  Dec (J2000.0): +40.2572  =  +40:15:26.0\n  Error: 6.4 arcsec (radius, 90% conf.)\n  Count-rate: (1.41 [+0.96, -0.69])e-3 ct s^-1\t \n  Distance: 540 arcsec from Swift/BAT-GUANO position.\n\nThe results of the XRT-team automatic analysis of the XRT observations,\nincluding a position-specific upper limit calculator, are available at\nhttps://www.swift.ac.uk/ToO_GRBs/00021483.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 31749,
  "createdOn": 1647125155000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 220310C: Swift-XRT observations",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 220310C"
}