{
  "bibcode": "2009GCN..9086....1Z",
  "body": "H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), D. N. Burrows (PSU),\nN. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara),\nS. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),\nC. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),\nP. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL),\nK. L. Page (U Leicester), D. M. Palmer (LANL) and\nB. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:\n\nAt 15:56:30 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 090404 (trigger=348428).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 239.218, +35.500 which is \n   RA(J2000) = 15h 56m 52s\n   Dec(J2000) = +35d 29' 59\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multiply-peaked\nstructure with a duration of about 80 sec and possible activity \nout to T+100 sec.  The peak count rate was ~3500 counts/sec \n(15-350 keV), at ~17 sec after the trigger. \n\nThe XRT began observing the field at 15:57:57.8 UT, 87.3 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 239.2351, +35.5173 which is equivalent to:\n   RA(J2000)  = 15h 56m 56.42s\n   Dec(J2000) = +35d 31' 02.2\"\nwith an uncertainty of 5.0 arcseconds (radius, 90% containment). This\nlocation is 79 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 96 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.02. \n\nBurst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). \nPlease contact the BA by email if you require additional information\nregarding Swift followup of this burst. In extremely urgent cases, after\ntrying the Burst Advocate, you can contact the Swift PI by phone (see\nSwift TOO web site for information: http://www.swift.psu.edu/too.html.)",
  "circularId": 9086,
  "createdOn": 1238861278000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090404: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090404"
}