{
  "bibcode": "2011GCN.11999....1P",
  "body": "K.L. Page (U. Leicester) and M. Stamatikos (OSU/NASA/GSFC) report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 8.2 ks of XRT data for GRB 110503A (Stamatikos  et al.\nGCN Circ. 11991), from 166 s to 28.4 ks after the  BAT trigger. The\ndata comprise 1.1 ks in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Goad et al. (GCN. Circ 11992).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=1.059 (+/-0.013).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.86 (+/-0.04). The\nbest-fitting absorption column is  2.2 (+/-0.6) x 10^21 cm^-2, at a\nredshift of 1.613, in addition to the Galactic value of 2.6 x 10^20\ncm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index\nof 2.01 (+/-0.08) and a best-fitting absorption column of 2.4 (+/-1.0)\nx 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 3.7 x 10^-11 (4.3 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 2.6 x 10^20 cm^-2\nIntrinsic column:    2.4 (+/-1.0) x 10^21 cm^-2 at z=1.613\nPhoton index:\t     2.01 (+/-0.08)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00452685.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11999,
  "createdOn": 1304492438000,
  "email": "kpa@star.le.ac.uk",
  "subject": "GRB 110503A: Swift-XRT refined Analysis",
  "submitter": "Kim Page at U.of Leicester  <kpa@star.le.ac.uk>",
  "eventId": "GRB 110503A"
}