{
  "bibcode": "2016GCN.20164....1G",
  "body": "S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo\n(INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N.\nBurrows (PSU) and P.A. Evans (U. Leicester) report on behalf of the\nSwift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nFermi/LAT-detected burst GRB 161109A (Desiante et al. GCN Circ. 20155)\nin a series of observations tiled on the sky. The total exposure time\nis 4.1 ks, distributed over 5 tiles; the maximum exposure at a single\nsky location was 2.9 ks. The data were collected between T0+40.4 ks and\nT0+63.6 ks, and are entirely in Photon 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 2:\n  RA (J2000.0):  157.9051  =  10:31:37.24\n  Dec (J2000.0): +61.8845  =  +61:53:04.4\n  Error: 3.7 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (6.1 [+3.2, -2.4])e-3 ct s^-1   \n  Distance: 244 arcsec from Fermi/LAT position.\n\nSource 5:\n  RA (J2000.0):  157.9726  =  10:31:53.43\n  Dec (J2000.0): +61.9393  =  +61:56:21.6\n  Error: 6.4 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (6.6 [+2.6, -2.1])e-3 ct s^-1   \n  Distance: 471 arcsec from Fermi/LAT position.\n\nSource 6:\n  RA (J2000.0):  158.0653  =  10:32:15.66\n  Dec (J2000.0): +61.6754  =  +61:40:31.5\n  Error: 6.9 arcsec (radius, 90% conf.)\n  Count-rate: (6.8 [+3.1, -2.4])e-3 ct s^-1   \n  Distance: 635 arcsec from Fermi/LAT position.\n  Flux: (2.01 [+0.91, -0.70])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nThree 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 http://www.swift.ac.uk/xrt_products/TILED_GRB00060.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 20164,
  "createdOn": 1478764839000,
  "email": "antonino.dai@ifc.inaf.it",
  "subject": "GRB 161109A: Swift-XRT observations",
  "submitter": "Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>",
  "eventId": "GRB 161109A"
}