{
  "bibcode": "2006GCN..5212....1P",
  "body": "M. J. Page (UCL-MSSL), A. J. Blustin (UCL-MSSL),\nJ. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC),\nO. Godet (U Leicester), J. A. Kennea (PSU), K. M. McLean (LANL/UTD),\nK. L. Page (U Leicester), G. Sato (GSFC/JSPS/USRA) and\nM. Stamatikos (NASA/ORAU) report on behalf of the Swift Team:\n\nAt 18:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 060604 (trigger=213486).  Swift slewed immediately to the \nburst.  The BAT on-board calculated location is \nRA,Dec 337.242, -10.905 {22h 28m 58s, -10d 54' 17\"} (J2000)\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single FRED\npeak with a duration of about 8 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 18:20:48 UT, 109 seconds after the\nBAT trigger. XRT found a variable, uncatalogued X-ray source\nlocated at RA(J2000) = 22h 28m 54.9s, Dec(J2000) = -10d 55' 03.0\", with an\nestimated uncertainty of 4.7 arcseconds (90% confidence radius). \nDuring the first 100s of data, the source shows bright flaring activity. \nThis location is 65 arcseconds from the BAT on-board position, within\nthe BAT error circle. The initial flux in the 2.5s image was\n2.9e-09 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 117 seconds after the BAT trigger. There\nis a candidate afterglow in the rapidly available 2.7'x2.7' sub-image\nat (RA,DEC) (J2000) of (337.2292,-10.9155) or\n(22h28m55.01s,-10o54'55.8\")  with a 1-sigma error radius of about 0.6\narc sec. This position is 7.2 arc sec. from the center of the XRT\nerror circle. The estimated magnitude is 18.0 with a 1-sigma error of\nabout 0.5 mag. No correction has been made for the expected extinction\ncorresponding to E(B-V) of  0.04.",
  "circularId": 5212,
  "createdOn": 1149446778000,
  "email": "kennea@astro.psu.edu",
  "subject": "GRB 060604: Swift detection of a burst with possible optical counterpart",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>",
  "eventId": "GRB 060604"
}