{
  "bibcode": "2006GCN..4966....1F",
  "body": "A. D. Falcone (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nJ. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC),\nS. D. Hunsberger (PSU), J. A. Kennea (PSU) and D. M. Palmer (LANL)\nreport on behalf of the Swift Team:\n\nAt 03:06:08 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 060418 (trigger=205851).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA,Dec 236.420, -3.643 {15h 45m 41s, -03d 38' 35\"} (J2000)\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a broad smooth peak\nstarting at T-8 sec.  It decays almost to background, and then a bright\npeak at T+27 sec (FWHM ~3 sec).  There is possibly emission at T+130 sec. \nThe peak count rate was ~6000 counts/sec (15-350 keV), at ~27 sec\nafter the trigger. \n\nThe XRT began observing the field at 03:07:26 UT, 78 seconds after the\nBAT trigger. XRT found a bright, variable, uncatalogued X-ray source\nlocated at RA(J2000) = 15h 45m 42.8s, Dec(J2000) = -03d 38' 26.1\",\nwith an estimated uncertainty of 5.8 arcseconds (90% confidence\nradius). This location is 32 arcseconds from the BAT on-board\nposition, within the BAT error circle. The initial flux in the 0.1s\nimage was 1.6e-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 88 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 (236.4275,-3.6389) or\n(15h45m42.60s,-03o38'20.0\") with a 1-sigma error radius of about 0.5\narc sec. This position is 7.2 arc sec. from the center of the XRT\nerror circle. The estimated V magnitude is 14.5 with a 1-sigma error\nof about 0.5 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.22.",
  "circularId": 4966,
  "createdOn": 1145330583000,
  "email": "Scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow",
  "submitter": "Scott Barthelmy at NASA/GSFC  <Scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 060418"
}