{
  "bibcode": "2013GCN.14716....1M",
  "body": "A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), M.C. Stroh (PSU),\nD.N. Burrows (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), C.\nPagani (U. Leicester), A.P. Beardmore (U. Leicester), G. Stratta (ASDC)\nand V. D'Elia report on behalf of the Swift-XRT team:\n\nWe have analysed 9.0 ks of XRT data for GRB 130528A (D'Elia  et al. GCN\nCirc. 14711),  from 68 s to 22.8 ks after the  BAT trigger. The data\ncomprise 842 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Goad et al. (GCN. Circ 14714).\n\nThe late-time light curve (from T0+4.9 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.06 (+/-0.12).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.69 (+/-0.07). The\nbest-fitting absorption column is  3.6 (+/-0.3) x 10^21 cm^-2, in\nexcess of the Galactic value of 5.2 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 1.92 (+/-0.15) and a\nbest-fitting absorption column of 3.6 (+/-0.6) x 10^21 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 4.4 x 10^-11 (6.9 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     3.6 (+/-0.6) x 10^21 cm^-2\nGalactic foreground: 5.2 x 10^20 cm^-2\nExcess significance: 8.5 sigma\nPhoton index:\t     1.92 (+/-0.15)\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 0.013 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.7 x\n10^-13 (8.9 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/00556870.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14716,
  "createdOn": 1369803127000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 130528A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 130528A"
}