{
  "bibcode": "2012GCN.13919....1P",
  "body": "K.L. Page (U. Leicester) and R. L. C. Starling (U Leicester) report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 9.4 ks of XRT data for GRB 121028A (Starling  et al.\nGCN Circ. 13913), from 139 s to 48.8 ks after the  BAT trigger. The\ndata are entirely in Photon Counting (PC) mode. The enhanced XRT\nposition for this burst was given by Evans et al. (GCN. Circ 13918).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=0.87 (+/-0.07).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.63 (+0.26, -0.25). The\nbest-fitting absorption column is  4.8 (+1.7, -1.4) x 10^21 cm^-2, in\nexcess of the Galactic value of 2.5 x 10^21 cm^-2 (Kalberla et al.\n2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 5.6 x 10^-11 (7.9 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     4.8 (+1.7, -1.4) x 10^21 cm^-2\nGalactic foreground: 2.5 x 10^21 cm^-2\nExcess significance: 2.6 sigma\nPhoton index:\t     1.63 (+0.26, -0.25)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00536897.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 13919,
  "createdOn": 1351496399000,
  "email": "klp5@leicester.ac.uk",
  "subject": "GRB 121028A: Swift-XRT refined Analysis",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>",
  "eventId": "GRB 121028A"
}