{
  "bibcode": "2016GCN.18986....1O",
  "body": "J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia\n(ASDC), A. D'Ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley\n(PSU), J.A. Kennea (PSU), C. Pagani (U. Leicester) and P. D'Avanzo\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 10 ks of XRT data for GRB 160203A (D'Avanzo et al. GCN\nCirc. 18979), from 122 s to 33.8 ks after the  BAT trigger. The data\ncomprise 7 s in Windowed Timing (WT) mode (taken while Swift was\nslewing), with the remainder in Photon Counting (PC) mode. The enhanced\nXRT position for this burst was given by Osborne et al. (GCN Circ.\n18983).\n\nThe late-time light curve (from T0+4.9 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.15 (+0.24, -0.23).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.76 (+0.23, -0.22). The\nbest-fitting absorption column is  1.5 (+2.6, -1.5) x 10^22 cm^-2, at a\nredshift of 3.52, in addition to the Galactic value of 7.4 x 10^20\ncm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)\n0.3-10 keV flux conversion factor deduced from this spectrum  is 3.8 x\n10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 7.4 x 10^20 cm^-2\nIntrinsic column:    1.5 (+2.6, -1.5) x 10^22 cm^-2 at z=3.52\nPhoton index:\t     1.76 (+0.23, -0.22)\n\nIf the light curve continues to decay with a power-law decay index of\n1.15, the count rate at T+24 hours will be 2.8 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x\n10^-13 (1.2 x 10^-13) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00672525.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 18986,
  "createdOn": 1454510574000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 160203A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 160203A"
}