{
  "bibcode": "2016GCN.20073....1E",
  "body": "P.A. Evans (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo\n(INAF-OAB), V. D'Elia (ASDC), T.G.R. Roegiers (PSU), L.M. McCauley\n(PSU), J.A. Kennea (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U.\nLeicester) and E. Troja report on behalf of the Swift-XRT team:\n\nWe have analysed 7.6 ks of XRT data for GRB 161017A (Troja et al. GCN\nCirc. 20064), from 51 s to 46.2 ks after the  BAT trigger. The data\ncomprise 595 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 Beardmore\net al. (GCN Circ. 20067).\n\nThe late-time light curve (from T0+4.5 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.04 (+/-0.06).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.656 (+/-0.019). The\nbest-fitting absorption column is  7.5 (+/-0.7) x 10^21 cm^-2, at a\nredshift of 2.013, in addition to the Galactic value of 1.8 x 10^20\ncm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index\nof 1.99 (+0.10, -0.07) and a best-fitting absorption column of 4 (+20,\n-4) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 3.2 x 10^-11 (3.4 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 1.8 x 10^20 cm^-2\nIntrinsic column:    4 (+20, -4) x 10^20 cm^-2 at z=2.013\nPhoton index:\t     1.99 (+0.10, -0.07)\n\nIf the light curve continues to decay with a power-law decay index of\n1.04, the count rate at T+24 hours will be 0.042 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x\n10^-12 (1.4 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00718023.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 20073,
  "createdOn": 1476790032000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 161017A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 161017A"
}