{
  "bibcode": "2007GCN..6056....1G",
  "body": "O. Godet, K. Page, P. Evans, J. Osborne (U. Leicester), D. N. Burrows\n(PSU) report on behalf of the Swift XRT team:\n\nWe analysed the first 5 orbits of XRT data from GRB 070129 (from T0+140s\nto T0+24749s).  An 11ks photon counting (PC) mode image provides a\nrefined XRT position:\n\nRA(J2000) = 02h 28m 00.83s\nDec(J2000) = +11d 41' 05.1''\n\nwith an uncertainty of 3.6 arcsec (90% containment). This position is\nwithin the BAT error circle and is 2.5 arcsec away from the on-board XRT\nposition quoted in Godet et al. (GCN 6053) and includes the latest XRT\nboresight correction. We note that our error circle includes the\nposition of the source reported in Malesani et al. 2007 (GCN 070129). \n\nThe BAT triggered on a precursor and saw the main burst around T0+380s.\nThe XRT started to observe the field 140s after the BAT trigger (T0).\nThe X-ray light curve shows the main burst consisting of several X-ray\nflares from T0+140s to T0+700s, followed by a steep decay to T0+1200s\nand then a flatter decay (so far to T0+24749s). This flatter decay can\nbe fitted by a single power-law with a decay slope of alpha = 0.33\n+0.09/-0.10.\n\nThe Windowed Timing (WT) data correspond to the main burst, which shows\nstrong spectral evolution.  An absorbed power-law fit of the WT data\n(first orbit) from T+140s to T+792s gives a photon index of 1.81+/-0.03\nand an absorption value of (2.1 +/-0.1)e21 cm**-2, compared to the\nGalactic value of 8.4e20 cm**-2 in the burst direction.  The error are\ngiven at a 90% confidence level.  The spectrum of the PC data from T0\n+795s to T0+24749s can be fit by an absorbed power-law with Gamma = 2.39\n+0.22/-0.19 and an absorption value of (1.6 +/-0.5)e21 cm**-2.\n\nIf the burst continues decaying at the current rate (alpha = 0.33) we\nestimate an XRT count rate of 0.042 counts/s at T0 + 24hr, which\ncorresponds to an observed 0.3-10.keV flux of 2.5e-12 ergs cm**-2 s**-1\nand an unabsorbed flux of 2.9e-12 ergs cm**-2 s**-1.\n\nThis circular is an official product of the Swift XRT Team.",
  "circularId": 6056,
  "createdOn": 1170160056000,
  "email": "og19@star.le.ac.uk",
  "subject": "GRB 070129: Swift-XRT Refined Analysis",
  "submitter": "Olivier Godet at U.of Leicester  <og19@star.le.ac.uk>",
  "eventId": "GRB 070129"
}