{
  "bibcode": "2013GCN.15311....1P",
  "body": "C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A.\nMaselli  (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), V.\nMangano (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester)\nand  report on behalf of the Swift-XRT team: report on behalf of the\nSwift-XRT team:\n\nWe have analysed 9.1 ks of XRT data for GRB 131004A,  from 79 s to 34.7\nks after the  BAT trigger. The data are entirely in Photon Counting\n(PC) mode.  the light curve is consistent with a constant source of\nmean count rate 7.4e-02 ct/sec. A power-law fit gives an index of 0.1\n(+2.0, -1.6).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.16 (+0.27, -0.26). The\nbest-fitting absorption column is  3.1 (+1.0, -0.9) x 10^21 cm^-2, in\nexcess of the Galactic value of 7.0 x 10^20 cm^-2 (Kalberla et al.\n2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.9 x 10^-11 (6.8 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     3.1 (+1.0, -0.9) x 10^21 cm^-2\nGalactic foreground: 7.0 x 10^20 cm^-2\nExcess significance: 4.7 sigma\nPhoton index:\t     2.16 (+0.27, -0.26)\n\nIf the light curve continues to decay with a power-law decay index of\n0.1, the count rate at T+24 hours will be 0.029 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x\n10^-12 (1.9 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/00573190.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 15311,
  "createdOn": 1380974045000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 131004A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 131004A"
}