{
  "bibcode": "2009GCN.10125....1V",
  "body": "L. Vetere and E. A. Hoversten (PSU) report on behalf of the Swift-XRT  \nteam:\n\nWe have analysed 1.4 ks of XRT data for GRB 091102 (Hoversten et al.  \nGCN Circ.\n10117), from 988 s to 19 ks after the BAT trigger. The data are  \nentirely in\nPhoton Counting (PC) mode. The enhanced XRT position has already been  \ndetermined\nby Kennea et al. (GCN Circ. 10120).\n\nThe PC light curve shows a steep drop at 1.3 ks after the BAT trigger  \nwith a\ndecay index of alpha=2.9 +/- 0.6.\n\nA spectrum formed from the PC mode data can be fitted with an absorbed  \npower-law\nwith a photon spectral index of 2.0 (+0.8, -0.6). The best-fitting  \nabsorption\ncolumn is 2.4 (+2.5, -1.3) x 10^21 cm^-2, consistent with the Galactic  \nvalue of\n1.1 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed  \n(unabsorbed)\n0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x  \n10^-11\n(6.3 x 10^-11) erg cm^-2 count^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00374598.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 10125,
  "createdOn": 1257229410000,
  "email": "vetere@astro.psu.edu",
  "subject": "GRB 091102: Swift-XRT refined analysis",
  "submitter": "Loredana Vetere at PSU  <vetere@astro.psu.edu>",
  "eventId": "GRB 091102"
}