{
  "bibcode": "2006GCN..5652....1G",
  "body": "D. Grupe (PSU) and Caryl Gronwall (PSU) report on behalf of the Swift team\n\nWe report on an update of the Swift XRT and UVOT observations\nof GRB 060729 (Grupe et al., GCN 5365). The afterglow is still\ndetectable in X-rays at a level of 1e-3 counts/s in the Swift\nXRT (5e-14 ergs/s/cm2). The late-time decay slope is 1.29+/-0.03.\nAssuming this decay slope continues, we expect the afterglow to\nbe still detectable in the XRT until the end of December 2006.\nWe plan to follow the afterglow as long as possible.\nCurrently we are at day 61 after the burst, which is the\nlongest period Swift has ever followed and detected an\nafterglow in X-rays.\n\nIn the UVOT the afterglow was still visible in all 6 filters\nuntil 9 days after the burst. In UV W1 the afterglow was\ndetectable until 2006-August-29 (31 days after the burst).\nwe still obtain a 3.9 sigma detection at a level of 22.8+/-0.3\nmag. We calculated the following late-time flux decay slopes in\nthe 6 UVOT filters:\n\nV:    1.11+/-0.14\nB:    0.98+/-0.07\nU:    1.40+/-0.08\nUVW1: 1.29+/-0.03\nUVM2: 1.45+/-0.07\nUVW2: 1.38+/-0.04\n\nThese values are slightly different than what has been reported\nearlier by Grupe (2006, GCN Circ. 5432). However, our new\nlight curves contain more data than what was available earlier.\n\nAssuming the power law decay continues without a break in the\noptical, our extrapolation of the light curves show that the\nafterglow will be visible at the beginning of October with\nV=24.0 mag, B=23.4 mag, U=24.0 mag. At this level a detection\nof the afterglow is still feasible for a large southern telescope.\nWe, therefore, encourage everybody again who has access to one\nof the large southern telescopes to follow this afterglow in V,\nB, and U in order to search for a break in the light curves.\n\n\nThis circular is an official product of the Swift XRT Team.",
  "circularId": 5652,
  "createdOn": 1159534578000,
  "email": "grupe@astro.psu.edu",
  "subject": "GRB 060729: An update on the late-time Swift observations",
  "submitter": "Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>",
  "eventId": "GRB 060729"
}