{
  "bibcode": "2021GCN.31010....1D",
  "body": "S. Dichiara (PSU), B. Sbarufatti (PSU), K.L. Page (U. Leicester), A.P.\nBeardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini\n(INAF-OAB), E. Ambrosi\t(INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp\n(PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT\nteam:\n\nSwift-XRT has performed follow-up observations of the\nFermi/LAT-detected burst GRB 211018A (Arimoto et al. GCN Circ. 30943),\ncollecting 4.4 ks of Photon Counting (PC) mode data between T0+304.3 ks\nand T0+340.2 ks. \n\nFive 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. We notice that Source 2 and Source 4 are consistent with\ncatalogued quasars at redshift z = 0.64 and z=1.09, respectively. \nDetails of these sources are given below:\n\nSource 1:\n  RA (J2000.0):  19.5986  =  01:18:23.66\n  Dec (J2000.0): -3.6511  =  -03:39:04.1\n  Error: 6.1 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (2.68 [+1.16, -0.92])e-3 ct s^-1\t \n  Distance: 338 arcsec from Fermi/LAT position.\n  Flux: (9.3 [+4.0, -3.2])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 2:\n  RA (J2000.0):  19.5656  =  01:18:15.74\n  Dec (J2000.0): -3.3800  =  -03:22:48.2\n  Error: 5.1 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (9.6 [+3.9, -3.1])e-3 ct s^-1   \n  Distance: 884 arcsec from Fermi/LAT position.\n\nSource 3:\n  RA (J2000.0):  19.4544  =  01:17:49.06\n  Dec (J2000.0): -3.6662  =  -03:39:58.4\n  Error: 7.2 arcsec (radius, 90% conf.)\n  Count-rate: (3.6 [+1.4, -1.1])e-3 ct s^-1   \n  Distance: 835 arcsec from Fermi/LAT position.\n  Flux: (1.85 [+0.70, -0.56])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\n\nSource 4:\n  RA (J2000.0):  19.5576  =  01:18:13.83\n  Dec (J2000.0): -3.7295  =  -03:43:46.2\n  Error: 3.2 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (6.6 +/- 1.6)e-3 ct s^-1\t \n  Distance: 636 arcsec from Fermi/LAT position.\n  Flux: (1.70 +/- 0.40)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 5:\n  RA (J2000.0):  19.6548  =  01:18:37.16\n  Dec (J2000.0): -3.6066  =  -03:36:23.9\n  Error: 8.0 arcsec (radius, 90% conf.)\n  Count-rate: (2.46 [+1.08, -0.85])e-3 ct s^-1\t \n  Distance: 84 arcsec from Fermi/LAT position.\n  Flux: (5.3 [+2.3, -1.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)\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/00021463.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 31010,
  "createdOn": 1635281976000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 211018A: Swift-XRT observations",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 211018A"
}