{
  "bibcode": "2009GCN..9341....1G",
  "body": "D. Grupe (PSU) and E. Hoversten (PSU) report on behalf of the Swift- \nXRT team:\n\nWe have analysed  XRT data for GRB090510 (Hoversten et al. GCN Circ.  \n9331) up to\n25ks after the burst\nbeginning 94.1 s after the BAT trigger. The data comprise 200 s in  \nWindowed\nTiming (WT) mode and 9.7 ks in Photon Counting (PC) mode.\nThe enhanced XRT position for this burst was given by Goad et al.\n(GCN. Circ 9339).\n\nThe light curve can be modelled with a broken power-law decay with an\nindex of alpha=0.77+/-0.05, followed by a break at T+1470+/-160 s to\nan alpha of 2.16 (+0.17, -0.14).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.57+/-0.08 with an\nabsorption column consistent with the Galactic\nvalue of 1.66 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum\nis consistent with this result.\n\n\nIf the light curve continues to decay with a power-law decay index of  \n2.16,\nthe count rate at T+24 hours will be 1.3e-4 counts/s, corresponding to  \nan\nobserved  0.3-10 keV flux of 6.1 x 10^-15 erg cm^-2 s^-1.\n\n\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00351588.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 9341,
  "createdOn": 1241970062000,
  "email": "grupe@astro.psu.edu",
  "subject": "GRB 090510: Swift XRT refined analysis",
  "submitter": "Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>",
  "eventId": "GRB 090510"
}