{
  "bibcode": "2013GCN.14577....1B",
  "body": "D.N. Burrows (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.\nLeicester), P.A. Evans (U. Leicester), G. Stratta (ASDC), P. D'Avanzo\n(INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), M.C. Stroh (PSU) and\nJ.K. Cannizzo report on behalf of the Swift-XRT team:\n\nWe have analysed 11 ks of XRT data for GRB 130505A (Cannizzo  et al.\nGCN Circ. 14563),  from 102 s to 29.4 ks after the  BAT trigger. The\ndata comprise 503 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Evans et al. (GCN. Circ 14569).\n\nThe late-time light curve (from T0+3.7 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.06 (+0.03, -0.04).\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 (+/-0.03). The\nbest-fitting absorption column is  10.0 (+/-0.7) x 10^20 cm^-2, in\nexcess of the Galactic value of 3.6 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 1.92 (+/-0.07) and a\nbest-fitting absorption column of 8.8 (+1.6, -1.5) x 10^20 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 3.8 x 10^-11 (4.7 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     8.8 (+1.6, -1.5) x 10^20 cm^-2\nGalactic foreground: 3.6 x 10^20 cm^-2\nExcess significance: 5.6 sigma\nPhoton index:\t     1.92 (+/-0.07)\n\nIf the light curve continues to decay with a power-law decay index of\n1.06, the count rate at T+24 hours will be 0.27 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x\n10^-11 (1.3 x 10^-11) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00555163.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14577,
  "createdOn": 1367786164000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 130505A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 130505A"
}