{
  "bibcode": "2011GCN.11968....1M",
  "body": "V. Mangano (INAF-IASFPA) and B. Sbarufatti (INAF OAB/INAF IASFPA)\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 3.5 ks of XRT data for GRB 110422A (Mangano  et al.\nGCN Circ. 11957), from 804 s to 12.7 ks after the  BAT trigger. The\ndata comprise 394 s in Windowed Timing (WT) mode (the first 9 s were\ntaken while Swift was slewing) with the remainder in Photon Counting\n(PC) mode. The enhanced XRT position for this burst was given by Evans\net al. (GCN. Circ 11965).\n\nThe light curve can be modelled with an initial power-law decay with an\nindex of alpha=1.02 (+/-0.03), followed by a break at T+7585 s to an\nalpha of 2.2 (+0.5, -0.4).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.99 (+/-0.09). The\nbest-fitting absorption column is  1.94 (+0.26, -0.24) x 10^21 cm^-2,\nin excess of the Galactic value of 4.2 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 2.13 (+0.11, -0.10)\nand a best-fitting absorption column of 2.28 (+0.31, -0.29) x 10^21\ncm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.9 x 10^-11 (6.3 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.28 (+0.31, -0.29) x 10^21 cm^-2\nGalactic foreground: 4.2 x 10^20 cm^-2\nExcess significance: 12.8 sigma\nPhoton index:\t     2.13 (+0.11, -0.10)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00451901.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11968,
  "createdOn": 1303558040000,
  "email": "vanessa@ifc.inaf.it",
  "subject": "GRB 110422A: Swift-XRT refined Analysis",
  "submitter": "Vanessa Mangano at INAF-IASFPA  <vanessa@ifc.inaf.it>",
  "eventId": "GRB 110422A"
}