{
  "bibcode": "2008GCN..7674....1G",
  "body": "GRB 080503: Swift-XRT refined analysis\n\n\nC. Guidorzi & J. Mao (INAF-OAB) report on behalf of the Swift-XRT team:\n\nThe Swift-XRT began observing GRB 080503 (trigger=310785, Mao et\nal., GCN Circ. 7665) in Window Timing mode, 81 s after the BAT\ntrigger. The enhanced XRT position was given in Goad et al.\n(GCN Circ. 7669).\n\nThe light curve from 81 s to 13.2 ks can be modelled with\nthe combination of an exponential with\na power law taking over at late time, with the following\nbest-fitting parameters: e-folding time= (72 � 4) s, power-law\nindex alpha= 2.2 (-1.1, +0.6). The chisq/dof=202/151 is due to\nshort-term variability superposed to the model.\n\nThe WT mode spectrum spanning from 81 to 282 s can be fit by a\npower-law model, with a photon index of 1.27 � 0.03 and column\ndensity consistent with the average Galactic column density in\nthis direction of 5.6e20 cm^-2.\nThe PC mode spectrum, starting from 282 s and totalling 6.3 ks\nof exposure, is fit with a power law with a photon index of 2.45+/-0.25\nand no evidence for any additional column density with respect\nto the Galactic one.\nThe corresponding observed (unabsorbed) 0.3-10 keV flux is 2.9e-12\n(3.9e-12) erg cm^-2 s^-1.\n\nIf the burst continues to decay at the same rate, we predict an\nXRT count rate of 1.7e-6 count/s at T+24 hours, which corresponds\nto an observed 0.3-10 keV flux of approximately 4e-17 erg cm^-2 s^-1.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 7674,
  "createdOn": 1209855164000,
  "email": "jirong.mao@brera.inaf.it",
  "subject": "GRB080503 XRT refined analysis",
  "submitter": "Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>",
  "eventId": "GRB 080503"
}