{
  "bibcode": "2008GCN..7988....1M",
  "body": "F. E. Marshall (NASA/GSFC), A. P. Beardmore (U Leicester),\nD. N. Burrows (PSU), P. A. Evans (U Leicester),\nN. Gehrels (NASA/GSFC), C. Gronwall (PSU), C. Guidorzi (INAF-OAB),\nS. T. Holland (CRESST/USRA/GSFC), V. Mangano (INAF-IASFPA),\nP. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),\nK. L. Page (U Leicester), D. M. Palmer (LANL),\nD. Perez (U Leicester), M. Perri (ASDC), B. Preger (ASDC),\nP. Romano (INAF-IASFPA), M. Stamatikos (NASA/ORAU),\nR. L. C. Starling (U Leicester), T. N. Ukwatta (GSFC/GWU),\nP. A. Ward (MSSL-UCL) and H. Ziaeepour (UCL-MSSL) report on behalf of\nthe Swift Team:\n\nAt 10:25:16 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080721 (trigger=317508).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 224.471, -11.712 which is \n   RA(J2000) = 14h 57m 53s\n   Dec(J2000) = -11d 42' 43\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed at least 4 peaks\nstructure with a duration of about 35 sec.  The peak count rate\nwas ~19k counts/sec (15-350 keV), at ~0 sec after the trigger,\nduring the second peak. \n\nThe XRT began observing the field at 10:27:04.1 UT, 107.2 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 224.4899, -11.7242 which is equivalent to:\n   RA(J2000)  = 14h 57m 55.9s\n   Dec(J2000) = -11d 43' 27.3\"\nwith an uncertainty of 4.7 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 nominal 100 seconds with the White\n(160-650 nm) filter starting 180 seconds after the BAT trigger. There is a\ncandidate afterglow in the list of sources generated on-board at\n  RA(J2000)  =  14:57:55.8 = 224.48268\n  DEC(J2000) = -11:43:25   = -11.72361\nwith a 1-sigma error radius of about 1.0 arc sec. The estimated white\nmagnitude is 14.6 with a 1-sigma error of about 0.01 mag. No correction\nhas been made for Galactic extinction. \n\nBurst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). \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": 7988,
  "createdOn": 1216636965000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 080721: Swift detection of a burst with a bright optical counterpart.",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 080721"
}