{
  "bibcode": "2007GCN..6388....1G",
  "body": "D. Grupe, J. Racusin, & C. Pagani (PSU) report on behalf of the Swift/XRT team\n\nWe have analyzed the first three orbits of GRB 070508 (Grupe et al., GCN 6383) \nwith total observing times of 1.3 ks in Windowed Timing mode and 1.3 ks in \nPhoton Counting mode in the Swift XRT.\nThe Photon Counting mode image of the third orbit provides a refined XRT \nposition at RA, DEC= 312.7993, -78.3848, which is\n\nRA(J2000) = 20h 51m 11.84s\nDec(J2000) = -78d 23' 05.4\"\n\nwith an error of 5.6\" (90% confidence). This position is 2.6\" away from the \npreliminary XRT position reported in GCN 6383 and 1.9\" from the optical \nposition given in GCN 6386 (Berger & Burgasser).\n\nThe XRT observations in Windowed Timing more started at the end of a flare and \nboth Windowed timing and Photon Counting mode display the rapid decay of the \nafterglow with a decay slope of 1.15+/-0.11 measured from the PC data. The \nprediction 24h after the burst is a 0.3-10.0 keV flux of 3.2e-12 ergs/s/cm2 \nor about 0.04 XRT counts/s.\n\nThe Windowed Timing mode data can be fitted by a single power law with a \nphoton index Gamma=2.05+-0.04 and an absorption column density of \nNH=(3.8+/-0.2)e21cm-2. The Galactic absorption density in the direction of \nthe burst is 8.60e20cm-2 (Dickey & Lockman, 1990). The PC data are consistent \nwith this result. According to the relation given in Grupe et al. (2007, AJ, \n133, 2216) the excess absorption suggests that the burst has a redshift of \nless than 2.6.\n\nThis circular is an official product of the Swift XRT team.",
  "circularId": 6388,
  "createdOn": 1178628119000,
  "email": "pagani@astro.psu.edu",
  "subject": "GRB 070508: Swift-XRT refined analysis",
  "submitter": "Claudio Pagani at PSU/Swift-XRT  <pagani@astro.psu.edu>",
  "eventId": "GRB 070508"
}