{
  "bibcode": "2012GCN.13583....1P",
  "body": "C. Pagani (U. Leicester) and J. L. Racusin (NASA/GSFC) report on behalf\nof the Swift-XRT team:\n\nWe have analysed 4.4 ks of XRT data for GRB 120803B (Racusin  et al.\nGCN Circ. 13566), from 79 s to 17.5 ks after the  BAT trigger. The data\ncomprise 31 s in Windowed Timing (WT) mode with the remainder in Photon\nCounting (PC) mode. The enhanced XRT position for this burst was given\nby Goad et al. (GCN. Circ 13571).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=1.25 (+0.07, -0.06).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.2 (+/-0.4). The\nbest-fitting absorption column is  8.5 (+4.7, -2.8) x 10^21 cm^-2,\nconsistent with the Galactic value of 5.7 x 10^21 cm^-2 (Kalberla et\nal. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 8.4 x 10^-11 (1.1 x\n10^-10) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     8.5 (+4.7, -2.8) x 10^21 cm^-2\nGalactic foreground: 5.7 x 10^21 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.2 (+/-0.4)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00529606.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 13583,
  "createdOn": 1344121714000,
  "email": "cp232@star.le.ac.uk",
  "subject": "GRB 120803B: Swift-XRT refined Analysis",
  "submitter": "Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>",
  "eventId": "GRB 120803B"
}