{
  "bibcode": "2011GCN.12243....1W",
  "body": "C. A. Wolf (PSU) reports on behalf of the Swift-XRT team:\n\nWe have analysed 50 ks of XRT data for GRB 110726A (Wolf  et al. GCN\nCirc. 12196), from 47 s to 421.3 ks after the  BAT trigger. The data\ncomprise 1.3 ks in Windowed Timing (WT) mode (the first 4 s were taken\nwhile Swift was slewing) with the remainder in Photon Counting (PC)\nmode. The enhanced XRT position for this burst was given by Osborne et\nal. (GCN. Circ 12200).\n\nThe late-time light curve (from T0+4.1 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.26 (+0.16, -0.15).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.12 (+0.22, -0.21). The\nbest-fitting absorption column is  1.6 (+/-0.5) x 10^21 cm^-2, in\nexcess of the Galactic value of 5.6 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 2.15 (+0.12, -0.28)\nand a best-fitting absorption column of 9.6 (+3.9, -4.0) x 10^20 cm^-2.\nThe counts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 3.4 x 10^-11 (4.5 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     9.6 (+3.9, -4.0) x 10^20 cm^-2\nGalactic foreground: 5.6 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     2.15 (+0.12, -0.28)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00458059.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 12243,
  "createdOn": 1312374879000,
  "email": "cwolf@swift.psu.edu",
  "subject": "GRB 110726A: Swift-XRT refined Analysis",
  "submitter": "Chris Wolf at PSU  <cwolf@swift.psu.edu>",
  "eventId": "GRB 110726A"
}