{
  "bibcode": "2014GCN.16510....1P",
  "body": "K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. Melandri\n(INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), P. D'Avanzo (INAF-OAB), M.C.\nStroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A.P. Beardmore (U.\nLeicester) and D. Kocevski report on behalf of the Swift-XRT team:\n\nWe have analysed 7.5 ks of XRT data for GRB 140703A (Kocevski  et al.\nGCN Circ. 16503),  from 104 s to 39.2 ks after the  BAT trigger. The\ndata comprise 126 s in Windowed Timing (WT) mode (the first 7 s were\ntaken while Swift was slewing) with the remainder in Photon Counting\n(PC) mode. The enhanced XRT position for this burst was given by Goad\net al. (GCN Circ. 16506).\n\nThe light curve can be modelled with a series of power-law decays. The\ninitial decay index is alpha=0.1 (+1.5, -1.6). At T+120 s  the decay\nsteepens to an alpha of 6.8 (+0.4, -0.3). The light curve breaks again\nat T+158 s to a decay with alpha=5.1 (+/-0.4),\tand  again at T+319 s s\nto alpha=0.1 (+0.6, -0.4),  before a final break at T+7413 s s after\nwhich the decay index is 1.56 (+0.14, -0.13).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.84 (+0.08, -0.07). The\nbest-fitting absorption column is  5.2 (+/-0.6) x 10^22 cm^-2, at a\nredshift of 3.14, in addition to the Galactic value of 1.3 x 10^21\ncm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index\nof 1.82 (+/-0.09) and a best-fitting absorption column of 5.4 (+8.0,\n-5.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV\nflux conversion factor deduced from this spectrum  is 3.8 x 10^-11 (4.6\nx 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 1.3 x 10^21 cm^-2\nIntrinsic column:    5.4 (+8.0, -5.4) x 10^21 cm^-2 at z=3.14\nPhoton index:\t     1.82 (+/-0.09)\n\nIf the light curve continues to decay with a power-law decay index of\n1.56, the count rate at T+24 hours will be 0.022 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.4 x\n10^-13 (1.0 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/00603243.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 16510,
  "createdOn": 1404399123000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 140703A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 140703A"
}