{
  "bibcode": "2020GCN.26961....1B",
  "body": "A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne\n(U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi\t(INAF-IASFPA) ,\nM. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU) and B.\nSbarufatti report on behalf of the Swift-XRT team:\n\nWe have analysed 6.1 ks of XRT data for GRB 200131A (Sbarufatti et al.\nGCN Circ. 26953), from 61 s to 17.4 ks after the  BAT trigger. The data\ncomprise 249 s in Windowed Timing (WT) mode (the first 5 s were taken\nwhile Swift was slewing) with the remainder in Photon Counting (PC)\nmode. The enhanced XRT position for this burst was given by Goad et al.\n(GCN Circ. 26956). We cannot determine at the present time whether the\nsource is fading.\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.83 (+0.04, -0.03). The\nbest-fitting absorption column is  consistent with the Galactic value\nof 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has\na photon index of 1.81 (+0.15, -0.14) and a best-fitting absorption\ncolumn of 2.3 (+0.6, -0.4) x 10^21 cm^-2. The counts to observed\n(unabsorbed) 0.3-10 keV flux conversion factor deduced from this\nspectrum  is 4.0 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.3 (+0.6, -0.4) x 10^21 cm^-2\nGalactic foreground: 1.8 x 10^21 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.81 (+0.15, -0.14)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00953689.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 26961,
  "createdOn": 1580547316000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 200131A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 200131A"
}