{
  "bibcode": "2009GCN..9368....1B",
  "body": "A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the\nSwift-XRT team :\n\nWe have analysed 4.5 ks of XRT data for GRB 090515 (Beardmore et\nal. GCN Circ. 9356), from 70 s to 11.5 ks after the BAT trigger. The\ndata comprise 132 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode.  The enhanced XRT position for this\nburst was given by Osborne et al. (GCN Circ. 9367).\n\nInitially, the light curve follows a shallow decay from a rate of 30\ncount s^-1 (at T+70 s), with a decay index of 0.59, out to\napproximately T+245 s. The count rate then drops by a factor of\n~250 in the next ~70 s (i.e. suggesting a decay index in excess of 10\nat this time). The burst is no longer detected beyond the first orbit\nto a 3 sigma count rate upper limit of 0.0058 count s^-1 (from T+5.7\nto T+11.5 ks).\n\nA spectrum formed from the WT mode data (from T+70 to T+195 s) can be\nfitted with an absorbed power-law with a photon spectral index of\n1.88 +/- 0.14. The best-fitting absorption column is (6.1 +3.0 -2.8) x\n10^20 cm^-2, in excess of the Galactic value of 1.9 x 10^20 cm^-2\n(Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV\nflux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.1\nx 10^-11) erg cm^-2 count^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00352108.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 9368,
  "createdOn": 1242413907000,
  "email": "apb@star.le.ac.uk",
  "subject": "GRB 090515: Swift-XRT refined analysis",
  "submitter": "Andy Beardmore at U Leicester  <apb@star.le.ac.uk>",
  "eventId": "GRB 090515"
}