{
  "bibcode": "2009GCN..8875....1B",
  "body": "A.P. Beardmore, K.L. Page (U. Leicester), S.R. Oates (UCL-MSSL) report on\nbehalf of the Swift-XRT team.\n\nThe Swift-XRT started observing the BAT GRB 090201 (trigger #341749,\nOates et al., GCN circ. 8865) at 18:47:33 UT, 3.65ks after the trigger.\nThe UVOT-enhanced X-ray position has been reported in Beardmore et al.\n(GCN Circ. 8872).\n\nUsing 14.5ks of photon counting mode data taken from T+3.65ks to T+39.2ks\nafter the trigger, we find the X-ray light curve can be described by a\nbroken powerlaw, with initial decay slope of 0.64 +0.17 -0.15, break time\nof 7.2 +2.1 -1.5 ks and final decay slope of 1.45 +/- 0.11.\n\nThe spectrum spanning the same interval can be fit by an absorbed\npowerlaw, with a photon index of 2.20 +/- 0.10 and column density of\n4.78 +/- 0.42 x 10^21 cm^-2, compared with the Galactic column of 4.9\nx 10^20 cm^-2 in the direction of the burst. The observed (unabsorbed)\n0.3-10 keV flux is (1.00 +/- 0.06) x 10^-11 [(2.02+/-0.12) x 10^-11]\nerg cm^-2 s^-1.\n\nAssuming the decay continues at the same rate, we  predict a count rate\nof 0.017 count/s 1 day after the trigger, which corresponds to an observed\n0.3-10 keV flux of 7.4e-13 erg cm^-2 s^-1.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 8875,
  "createdOn": 1233573124000,
  "email": "apb@star.le.ac.uk",
  "subject": "GRB 090201: Swift-XRT refined analysis",
  "submitter": "Andy Beardmore at U Leicester  <apb@star.le.ac.uk>",
  "eventId": "GRB 090201"
}