{
  "bibcode": "2006GCN..5502....1G",
  "body": "D. Grupe (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nM. M. Chester (PSU), N. Gehrels (NASA/GSFC),\nS. T. Holland (GSFC/USRA), S. D. Hunsberger (PSU),\nJ. A. Kennea (PSU), H. A. Krimm (GSFC/USRA),\nC. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC),\nD. M. Palmer (LANL), M. Stamatikos (NASA/ORAU) and M. C. Stroh (PSU)\nreport on behalf of the Swift Team:\n\nAt 01:03:21 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 060904 (trigger=227996).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA,Dec 237.743, +44.966 {15h 50m 58s, +44d 57' 57\"} (J2000)\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows 3 little peaks\nstarting out and then a large peak at T+55 sec and a total burst duration\nof about 85 sec.  The peak count rate was ~9000 counts/sec (15-350 keV),\nat ~55 sec after the trigger. \n\nThe XRT began observing the field at 01:04:27 UT, 66 seconds after the\nBAT trigger. XRT found a bright, fading, uncatalogued X-ray source\nlocated at RA(J2000) = 15h 50m 54.9s, Dec(J2000) = +44d 59' 07.8\", with an\nestimated uncertainty of 5.4 arcseconds (90% confidence radius). \nThis location is 79 arcseconds from the BAT on-board position, within\nthe BAT error circle. The initial flux in the 0.1s image was\n2.7e-08 erg/cm2/s (0.2-10 keV). \n\nUVOT took a finding chart exposure of 100 seconds with the White\n(160-650 nm) filter starting 75 seconds after the BAT trigger. No\nafterglow candidate has been found in the initial data products. The\n2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical\n3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the\nlist of sources generated on-board covers 100% of the XRT error\ncircle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to\nE(B-V) of 0.02.",
  "circularId": 5502,
  "createdOn": 1157332879000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 060904: Swift detection of a bright burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 060904"
}