{
  "bibcode": "2007GCN..6137....1R",
  "body": "J. L. Racusin (PSU), L. M. Barbier (NASA/GSFC),\nS. D. Barthelmy (GSFC), M. M. Chester (PSU),\nG. Cusumano (INAF-IASFPA), D. Grupe (PSU), J. A. Kennea (PSU),\nD. M. Palmer (LANL), R. L. C. Starling (U Leicester) and\nL. Vetere (PSU) report on behalf of the Swift Team:\n\nAt 20:27:58 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 070224 (trigger=261880).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 178.990, -13.340 which is \n   RA(J2000)  =  11h 55m 58s\n   Dec(J2000) = -13d 20' 23\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single peak\nwith a duration of about 25 sec.  The peak count rate\nwas ~500 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 20:30:21 UT, 143 seconds after the\nBAT trigger. XRT found a bright, fading, uncatalogued X-ray source\nlocated at RA, Dec 179.0257, -13.3294 which is\n   RA(J2000)  =  11h 56m 06.2s\n   Dec(J2000) = -13d 19' 46.0\"\nwith an uncertainty of 4.2 arcseconds (radius, 90% containment). \nThis location is 131 arcseconds from the BAT on-board position,\nwithin the BAT error circle. The initial flux in the 2.5s image\nwas 3.1e-10 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 153 seconds after the BAT trigger, and a\nfinding chart of nominal 400 seconds with the V filter starting 259\nseconds after the BAT trigger. No afterglow candidate has been found\nin the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. The 3-sigma upper limit in White at the XRT\nposition is 19.3 mag. The 8'x8' region for the list of sources\ngenerated on-board covers 100% of the XRT error circle. No correction\nhas been made for the expected extinction corresponding to E(B-V) of\n0.06.",
  "circularId": 6137,
  "createdOn": 1172350089000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 070224: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 070224"
}