{
  "bibcode": "2012GCN.13687....1L",
  "body": "O.M. Littlejohns (U. Leicester), V. D'Elia (ASDC), A. Maselli \n(INAF-IASFPA), V. Mangano (INAF-IASFPA), D.N. Burrows (PSU), J.A.\nKennea (PSU), M.C. Stroh (PSU), J.P. Osborne (U. Leicester), K.L. Page\n(U. Leicester) and A.P. Beardmore report on behalf of the Swift-XRT\nteam:\n\nWe have analysed 10 ks of XRT data for GRB 120819A (Beardmore  et al.\nGCN Circ. 13681), from 159 s to 23.0 ks after the  BAT trigger. The\ndata comprise 67 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 13684).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=1.75 (+0.12, -0.09).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.7 (+/-0.4). The\nbest-fitting absorption column is  3.3 (+2.0, -1.5) x 10^21 cm^-2, in\nexcess of the Galactic value of 8.9 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 4.2 x 10^-11 (6.0 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the WT-mode spectrum is thus:\nTotal column:\t     3.3 (+2.0, -1.5) x 10^21 cm^-2\nGalactic foreground: 8.9 x 10^20 cm^-2\nExcess significance: 2.6 sigma\nPhoton index:\t     1.7 (+/-0.4)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00531428.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 13687,
  "createdOn": 1345441624000,
  "email": "pae9@star.le.ac.uk",
  "subject": "GRB 120819A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@star.le.ac.uk>",
  "eventId": "GRB 120819A"
}