{
  "bibcode": "2008GCN..8566....1M",
  "body": "J. Mao, C. Guidorzi (INAF-OAB) and R. Margutti (Univ. Bicocca & \nINAF-OAB) report on behalf of the Swift XRT team:\n\nWe have analysed the first 4 orbits of Swift-XRT data obtained for GRB \n081127 (Mao et al., GCN Circ. 8560), covering from 128 to 219 s in \nWindowed Timing (WT) and from 220 s to 19.5 ks in Photon Counting (PC) \nmode data, respectively. The net exposures are 90 s and 9.4 ks for the \nWT and PC modes data, respectively.  The UVOT-enhanced XRT position was \ngiven by Beardmore et al. in GCN Circ. 8565.\n\nThe light curve shows an inital steep decay of index 5.6 until 420 s, \nthen it shows a shallow decay with index of 0.6. After 13.3 ks the \nlightcurve shows a decay with an index of about 2.0. The WT spectrum can \nbe fit with an absorbed power-law model with a photon index of 4.2 +- \n0.2 and an absorbing\nequivalent hydrogen column density is (2.8 +- 0.3)e21 cm^-2, which is \nlarger than the Galactic one, 6.7e20 cm^-2 (Kalberla et al.  2005). The \nobserved (unabsorbed) 0.3-10 keV flux is 3.7(4.5)e-10 erg cm^-2  s^-1. \nThe PC spectrum can be fit with an absorbed power-law model with a \nphoton index of 2.3 +- 0.3 with an absorbing equivalent hydrogen column \ndensity compatible with the Galactic value.\n\nIf the light curve continues to decay with an index of 2.0, the count \nrate 24 hours after the burst will be 2.9e-4 c/s, corresponding to an \nabsorbed flux of 9.9e-15 erg cm^-2 s^-1.\n\nThis is an official product of the Swift-XRT team.",
  "circularId": 8566,
  "createdOn": 1227807776000,
  "email": "jirong.mao@brera.inaf.it",
  "subject": "GRB 081127: Swift-XRT refined analysis",
  "submitter": "Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>",
  "eventId": "GRB 081127"
}