{
  "bibcode": "2011GCN.11541....1S",
  "body": "B. Sbarufatti (INAF-OAB/IASFPA) reports on behalf of the Swift-XRT\nteam:\n\nWe have analysed 6.2 ks of XRT data for GRB 110106B (Sbarufatti  et al.\nGCN Circ. 11525), from 339 s to 30.3 ks after the  BAT trigger. The\ndata comprise 24 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Beardmore et al. (GCN. Circ 11532).\n\nThe light curve can be modelled with a series of power-law decays. The\nlight curve initially rises, with an index alpha=-1.5 (+0.0, -1.3). At\nT+470 s it breaks to an alpha of 0.64 (+/-0.07) before breaking again\nat T+14354 s to a final decay with index alpha=1.6 (+1.0, -0.5).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.20 (+/-0.16). The\nbest-fitting absorption column is  2.08 (+0.44, -0.22) x 10^21 cm^-2,\nin excess of the Galactic value of 2.4 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 3.8 x 10^-11 (6.1 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.08 (+0.44, -0.22) x 10^21 cm^-2\nGalactic foreground: 2.4 x 10^20 cm^-2\nExcess significance: 15.4 sigma\nPhoton index:\t     2.20 (+/-0.16)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00441676.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11541,
  "createdOn": 1294413145000,
  "email": "boris.sbarufatti@brera.inaf.it",
  "subject": "GRB 110106B: Swift-XRT refined Analysis",
  "submitter": "Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti@brera.inaf.it>",
  "eventId": "GRB 110106B"
}