{
  "bibcode": "2012GCN.13101....1S",
  "body": "B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU),\nM.C. Stroh (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) and B.-B. Zhang report on behalf of the Swift-XRT team:\n\nWe have analysed 8.3 ks of XRT data for GRB 120324A (-B. Zhang\tet al.\nGCN Circ. 13090), from 81 s to 29.5 ks after the  BAT trigger. The data\ncomprise 160 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 13093).\n\nThe late-time light curve (from T0+4.7 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.04 (+/-0.07).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.12 (+/-0.10). The\nbest-fitting absorption column is  1.10 (+0.09, -0.08) x 10^22 cm^-2,\nin excess of the Galactic value of 4.5 x 10^21 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 2.07 (+/-0.14) and a\nbest-fitting absorption column of 1.18 (+0.13, -0.12) x 10^22 cm^-2.\nThe counts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 5.7 x 10^-11 (1.3 x 10^-10) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.18 (+0.13, -0.12) x 10^22 cm^-2\nGalactic foreground: 4.5 x 10^21 cm^-2\nExcess significance: 9.9 sigma\nPhoton index:\t     2.07 (+/-0.14)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00518507.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 13101,
  "createdOn": 1332612844000,
  "email": "pae9@star.le.ac.uk",
  "subject": "GRB 120324A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@star.le.ac.uk>",
  "eventId": "GRB 120324A"
}