{
  "bibcode": "2010GCN.11039....1R",
  "body": "A. Rowlinson (U. Leicester) and E. Troja (NASA/GSFC/ORAU) report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 10 ks of XRT data for GRB 100802A (Troja et al. GCN\nCirc. 11031), from 69 s to 24.0 ks after the BAT trigger. The data\ncomprise 804 s in Windowed Timing (WT) mode (the first 9 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 Evans et al.\n(GCN. Circ 11036).\n\nThe light curve can be modelled with an initial power-law decay with an\nindex of alpha=1.64 (+0.03, -0.03) and a flare peaking at 515 s which is\nconsistent with a BAT peak (Baumgartner et al. GCN Circ. 11035). At\nT+11500 s, the light curve breaks to a decay with alpha=0.06 (+0.26,\n-0.21).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.88 (+/-0.03). The\nbest-fitting absorption column is 1.93 (+/-0.09) x 10^21 cm^-2, in\nexcess of the Galactic value of 9.7 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 4.0 x 10^-11 (5.4 x 10^-11) erg\ncm^-2 count^-1. The PC mode spectrum can be fitted with an absorbed\npower-law with a photon spectral index of 2.21 (+0.23, -0.33). The\nbest-fitting absorption column is 1.39 (+0.82, -0.42) x 10^21 cm^-2, in\nexcess of the Galactic value. The counts to observed (unabsorbed) 0.3-10\nkeV flux conversion factor deduced from this spectrum is 3.5 x 10^-11\n(5.2 x 10^-11) erg cm^-2 count^-1.\n\nIf the light curve continues to decay with a power-law decay index of\n0.06, the count rate at T+24 hours will be 1.6 x 10^-2 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.6 x\n10^-13 (8.3 x 10^-13) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00430603.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11039,
  "createdOn": 1280770651000,
  "email": "bar7@star.le.ac.uk",
  "subject": "GRB 100802A: XRT refined analysis",
  "submitter": "Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>",
  "eventId": "GRB 100802A"
}