{
  "bibcode": "2008GCN..8226....1B",
  "body": "A.P. Beardmore (U. Leicester) and P. Schady (MSSL-UCL) report on behalf\nof the Swift-XRT team :\n\nThe Swift-XRT started observing the field of GRB 080913 (trigger number \n324561, Schady et al., GCN Circ. 8217) at 2008-09-13 06:48:30 UT, 94 s\nafter the trigger. The best XRT position is the UVOT-enhanced position\nreported by Beardmore et al. (GCN Circ. 8219).\n\nThe X-ray light curve presently spans 5 orbits of photon counting mode\ndata from T+108 s to T+23 ks. The light curve shows a number of small\nflares in the first orbit, with the largest giving a factor of ~7 \nincrease in count rate at T+1.8 ks, on top of a power-law decay of \nindex 1.20 +0.16 -0.13.\n\nA 2.7 ks exposure X-ray spectrum from T+108 s to T+7.6 ks can be well \nfit by an absorbed power-law with a photon index of 1.69 +0.46 -0.41 \nand a column density consistent with the Galactic value of 3.2 x 10^20 cm^-2 \nin the direction of the burst.  The observed  0.3-10.0 keV flux is \n(3.2 +0.9 -1.6) x 10^-12 erg cm^-2 s^-1 which corresponds to an unabsorbed \nflux of (3.7 +1.6 -1.7) x 10^-12  erg cm^-2 s^-1. The count to flux \nconversion factor is 4.6 x 10^-11 erg cm^-2 count^-1.\n\nProviding the source continues to decay at the same rate, we predict a\ncount rate of 2.8 x 10^-4 count s^-1 at T+1 day.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 8226,
  "createdOn": 1221327012000,
  "email": "apb@star.le.ac.uk",
  "subject": "GRB 080913: Swift-XRT refined analysis",
  "submitter": "Andy Beardmore at U Leicester  <apb@star.le.ac.uk>",
  "eventId": "GRB 080913"
}