{
  "bibcode": "2014GCN.15926....1P",
  "body": "K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. Maselli \n(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),\nJ.A. Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), A.P. Beardmore\n(U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 6.4 ks of XRT data for GRB 140304A (Evans  et al. GCN\nCirc. 15915),  from 81 s to 23.1 ks after the  BAT trigger. The data\ncomprise 42 s in Windowed Timing (WT) mode with the remainder in Photon\nCounting (PC) mode. The enhanced XRT position for this burst was given\nby Beardmore et al. (GCN Circ. 15925). The late-time light curve (from\nT0+5.2 ks) is consistent with a constant source of mean count rate\n1.1e+00 ct/sec. A power-law fit gives an index of 0.2 (+/-0.7).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.00 (+0.15, -0.14). The\nbest-fitting absorption column is  9.8 (+3.4, -3.1) x 10^20 cm^-2, in\nexcess of the Galactic value of 6.0 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 3.6 x 10^-11 (4.6 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     9.8 (+3.4, -3.1) x 10^20 cm^-2\nGalactic foreground: 6.0 x 10^20 cm^-2\nExcess significance: 2.0 sigma\nPhoton index:\t     2.00 (+0.15, -0.14)\n\nIf the light curve continues to decay with a power-law decay index of\n0.2, the count rate at T+24 hours will be 0.024 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.7 x\n10^-13 (1.1 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00590206.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 15926,
  "createdOn": 1393988224000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 140304A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 140304A"
}