{
  "bibcode": "2011GCN.11865....1P",
  "body": "C. Pagani (U. Leicester) and T. N. Ukwatta (MSU) report on behalf of\nthe Swift-XRT team:\n\nWe have analysed 6.8 ks of XRT data for GRB 110402A (Ukwatta  et al.\nGCN Circ. 11857), from 552 s to 24.7 ks after the  BAT trigger. The\ndata are entirely in Photon Counting (PC) mode. The enhanced XRT\nposition for this burst was given by Beardmore et al. (GCN. Circ\n11860).\n\nThe late-time light curve (from T0+6.4 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.3 (+/-0.4).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.31 (+0.25, -0.27). The\nbest-fitting absorption column is  10.0 (+2.9, -5.6) x 10^20 cm^-2, in\nexcess of the Galactic value of 1.6 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 3.3 x 10^-11 (4.8 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     10.0 (+2.9, -5.6) x 10^20 cm^-2\nGalactic foreground: 1.6 x 10^20 cm^-2\nExcess significance: 2.9 sigma\nPhoton index:\t     2.31 (+0.25, -0.27)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00450545.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11865,
  "createdOn": 1301743067000,
  "email": "cp232@star.le.ac.uk",
  "subject": "GRB 110402A: Swift-XRT refined Analysis",
  "submitter": "Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>",
  "eventId": "GRB 110402A"
}