{
  "bibcode": "2012GCN.12971....1B",
  "body": "D.N. Burrows (PSU), O.M. Littlejohns (U. Leicester), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester), G. Stratta (ASDC), P. D'Avanzo\n(INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), M.C. Stroh (PSU) and\nC.A. Swenson report on behalf of the Swift-XRT team:\n\nWe have analysed 6.3 ks of XRT data for GRB 120219A (Swenson  et al.\nGCN Circ. 12964), from 118 s to 51.3 ks after the  BAT trigger. The\ndata comprise 667 s in Windowed Timing (WT) mode (the first 9 s were\ntaken while Swift was slewing) with the remainder in Photon Counting\n(PC) mode. The enhanced XRT position for this burst was given by Goad\net al. (GCN. Circ 12967).\n\nThe light curve can be modelled with an initial power-law decay with an\nindex of alpha=3.25 (+0.11, -0.10), followed by a break at T+444 s to\nan alpha of 1.64 (+0.15, -0.14).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 3.25 (+0.16, -0.14). The\nbest-fitting absorption column is  2.25 (+0.26, -0.24) x 10^21 cm^-2,\nin excess of the Galactic value of 3.5 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 2.11 (+0.14, -0.11)\nand a best-fitting absorption column consistent with the Galactic\nvalue. The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.4 x 10^-11 (3.8 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     0 (+3.4, -0) x 10^20 cm^-2\nGalactic foreground: 3.5 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     2.11 (+0.14, -0.11)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00515375.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 12971,
  "createdOn": 1329723603000,
  "email": "pae9@star.le.ac.uk",
  "subject": "GRB 120219A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@star.le.ac.uk>",
  "eventId": "GRB 120219A"
}