{
  "bibcode": "2017GCN.21292....1G",
  "body": "S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai\n(INAF-IASFPA), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti\n(INAF-OAB/PSU) and R.L.C. Starling report on behalf of the Swift-XRT\nteam:\n\nWe have analysed 8.4 ks of XRT data for GRB 170705A (Starling et al.\nGCN Circ. 21289), from 62 s to 22.1 ks after the  BAT trigger. The data\ncomprise 424 s in Windowed Timing (WT) mode (the first 8 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. 21290).\n\nThe late-time light curve (from T0+4.6 ks) can be modelled with a\npower-law decay with a decay index of alpha=0.83 (+/-0.09).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.53 (+/-0.03). The\nbest-fitting absorption column is  8.4 (+1.1, -1.0) x 10^20 cm^-2, in\nexcess of the Galactic value of 1.5 x 10^20 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.87 (+0.09, -0.08)\nand a best-fitting absorption column of 1.29 (+0.26, -0.24) x 10^21\ncm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.6 x 10^-11 (4.5 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.29 (+0.26, -0.24) x 10^21 cm^-2\nGalactic foreground: 1.5 x 10^20 cm^-2\nExcess significance: 7.7 sigma\nPhoton index:\t     1.87 (+0.09, -0.08)\n\nIf the light curve continues to decay with a power-law decay index of\n0.83, the count rate at T+24 hours will be 0.11 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x\n10^-12 (5.0 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/00760064.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 21292,
  "createdOn": 1499250861000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 170705A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 170705A"
}