{
  "bibcode": "2008GCN..7532....1P",
  "body": "M. Perri and G. Stratta (ASDC) report on behalf of the Swift XRT team:\n\nWe have analysed the first 3 orbits of Swift XRT data of the BAT GRB\n080328 (Perri et al., GCN Circ. 7525). The data consist of 151 s in\nWindowed Timing (WT) mode, from  T+108s to T+259s, and of\n6.9 ks in Photon Counting (PC) mode thereafter.\n\nThe best XRT position is the UVOT-enhanced position reported by\nBeardmore et al. (GCN Circ. 7527).\n\nThe early 0.3-10 keV X-ray light curve in WT mode shows a rapid decay.\nStarting from T+260s up to T+13.7ks the curve is well fit by a broken\npower-law model with decay indices alpha1=-0.57 (+0.09) (-0.06),\nalpha2=-1.10 (+/-0.05) and a temporal break at (1.7+/-0.3) ks.\n\nThe WT X-ray spectrum is well fit by an absorbed power-law model\nwith a photon index of 2.1 (+/-0.1), a column density of\n(4.2+/-0.4)e21 cm**-2 and an average observed 0.3-10 keV flux\nof 9.3e-10 erg/cm**2/s. The PC X-ray spectrum during the first orbit,\nfrom  T+260s to T+2106s, is also well fit by an absorbed power-law\nmodel with a photon index of 2.2 (+/-0.1) and a column density of\n(5.0+/-0.6)e21 cm**-2. The observed 0.3-10 keV flux for this spectrum\nis 1.5e-10 erg/cm**2/s. We note the Galactic column density in the\ndirection of the source is 3.4e21 cm**-2.\n\nAssuming the X-ray emission continues to decline at the same rate, we\npredict a 0.3-10 keV XRT count rate of 0.03 count/s at T+24hr, which\ncorresponds to an observed 0.3-10 keV flux of about\n1.4e-12 erg/cm**2/s.\n\nThis circular is an official product of the Swift XRT Team.",
  "circularId": 7532,
  "createdOn": 1206731217000,
  "email": "perri@asdc.asi.it",
  "subject": "GRB 080328: Swift XRT refined analysis",
  "submitter": "Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>",
  "eventId": "GRB 080328"
}