{
  "bibcode": "2012GCN.14073....1B",
  "body": "A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), O.M.\nLittlejohns (U. Leicester), V. Mangano (INAF-IASFPA), A. Melandri\n(INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), J.A. Kennea (PSU), M.C. Stroh\n(PSU), D.N. Burrows (PSU) and D. Grupe report on behalf of the\nSwift-XRT team:\n\nWe have analysed 9.1 ks of XRT data for GRB 121212A (Grupe  et al. GCN\nCirc. 14064),  from 81 s to 19.3 ks after the  BAT trigger. The data\nare entirely in Photon Counting (PC) mode. The enhanced XRT position\nfor this burst was given by Beardmore et al. (GCN. Circ 14066).\n\nThe late-time light curve (from T0+5.3 ks) can be modelled with  a\npower-law decay with a decay index of alpha=0.80 (+/-0.24).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.48 (+0.17, -0.16). The\nbest-fitting absorption column is  2.2 (+/-0.4) x 10^21 cm^-2, in\nexcess of the Galactic value of 3.7 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 3.1 x 10^-11 (6.2 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.2 (+/-0.4) x 10^21 cm^-2\nGalactic foreground: 3.7 x 10^20 cm^-2\nExcess significance: 7.7 sigma\nPhoton index:\t     2.48 (+0.17, -0.16)\n\nIf the light curve continues to decay with a power-law decay index of\n0.80, the count rate at T+24 hours will be 0.011 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.3 x\n10^-13 (6.6 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/00541371.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14073,
  "createdOn": 1355339165000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 121212A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 121212A"
}