{
  "bibcode": "2008GCN..7737....1P",
  "body": "K.L. Page (U. Leicester) and S.T. Holland (CRESST/USRA/GSFC) report on \nbehalf of the Swift-XRT team:\n\nWe have analysed the first five orbits of data obtained for GRB 080516 \n(Holland et al., GCN Circ. 7733), covering 11.5 ks of Photon Counting (PC) \nmode data. The UVOT-enhanced XRT position was given by Beardmore et al. in \nGCN Circ. 7735.\n\nThe light-curve begins relatively flat, with a decay of alpha ~ 0.36 +/- \n0.17, until around 4800 seconds after the trigger, at which point the \nslope steepens to 1.04 +0.20/-0.18. \n\nThe first five orbits of PC data can be modelled with an absorbed \npower-law, with Gamma = 2.7 +/- 0.4 and total NH = (1.3 +/- 0.3)x10^22 \ncm^-2, considerably in excess of the Galactic value of 3.22x10^21 cm^-2. \nUsing the relation in Grupe et al. (2007, ApJ, 133, 2216), this implies an \nestimated upper limit on the redshift of the burst of z<1.0. There is no \nevidence for spectral evolution across the temporal break. The observed \n(unabsorbed) flux over this time interval (90-2.5x10^4 s after the \ntrigger) is 2.38x10^-12 (1.06x10^-11) erg cm^-2 s^-1. The counts to \nobserved flux conversion is 5.8x10^-11 erg cm^-2 count^-1.\n\nIf the light-curve continues to decay at alpha ~ 1.04, the count rate at \n24 hours is predicted to be 3.7x10^-3 count s^-1, corresponding to an \nobserved flux of 2.1x10^-13 erg cm^-2 s^-1.\n\nThis is an official product of the Swift-XRT team.",
  "circularId": 7737,
  "createdOn": 1210936092000,
  "email": "kpa@star.le.ac.uk",
  "subject": "GRB 080516: Swift-XRT Team refined analysis",
  "submitter": "Kim Page at U.of Leicester  <kpa@star.le.ac.uk>",
  "eventId": "GRB 080516"
}