{
  "bibcode": "2012GCN.13223....1L",
  "body": "O.M. Littlejohns (U. Leicester), A. Melandri (INAF-OAB), B. Sbarufatti\n(INAF-OAB/PSU), G. Stratta (ASDC), D.N. Burrows (PSU), J.A. Kennea\n(PSU), M.C. Stroh (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester) and V.D'Elia report on behalf of the Swift-XRT team:\n\nWe have analysed 4.5 ks of XRT data for GRB 120403B (D'Elia  et al. GCN\nCirc. 13203), from 920 s to 8.9 ks after the  BAT trigger. The data are\nentirely in Photon Counting (PC) mode. The enhanced XRT position for\nthis burst was given by Goad et al. (GCN. Circ 13205).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=0.80 (+0.15, -0.14).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.2 (+/-0.3). The\nbest-fitting absorption column is  2.2 (+0.9, -0.8) x 10^21 cm^-2, in\nexcess of the Galactic value of 9.5 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 3.5 x 10^-11 (5.8 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.2 (+0.9, -0.8) x 10^21 cm^-2\nGalactic foreground: 9.5 x 10^20 cm^-2\nExcess significance: 2.5 sigma\nPhoton index:\t     2.2 (+/-0.3)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00519256.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 13223,
  "createdOn": 1333616705000,
  "email": "pae9@star.le.ac.uk",
  "subject": "GRB 120403B: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@star.le.ac.uk>",
  "eventId": "GRB 120403B"
}