{
  "bibcode": "2008GCN..8057....1R",
  "body": "J. L. Racusin (PSU), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU),\nN. Gehrels (NASA/GSFC), D. Grupe (PSU),\nS. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),\nC. Pagani (PSU), D. M. Palmer (LANL), M. C. Stroh (PSU) and\nT. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:\n\nAt 23:20:14 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080804 (trigger=319016).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 328.701, -53.195 which is \n   RA(J2000)  =  21h 54m 48s\n   Dec(J2000) = -53d 11' 40\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows multiple overlapping\npeaks with a duration of about 20 sec.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 23:21:53.7 UT, 99.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 328.66583, -53.18532 which\nis equivalent to:\n   RA(J2000)  = 21h 54m 39.80s\n   Dec(J2000) = -53d 11' 07.2\"\nwith an uncertainty of 3.0 arcseconds (radius, 90% containment). This\nlocation is 83 arcseconds from the BAT onboard position, within the BAT\nerror circle. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of\n1.63e+20 cm^-2 (Kalberla et al. 2005). \n\nThe initial flux in the 2.5 s image was 5.50e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of nominal 100 seconds with the White\n(160-650 nm) filter starting 109 seconds after the BAT trigger. There is a\ncandidate afterglow in the list of sources generated on-board at\n  RA(J2000)  =  21:54:40.2 = 328.6675\n  DEC(J2000) = -53:11:05   = -53.18472\nwith a 1-sigma error radius of about 1.0 arc sec. The estimated white\nmagnitude is 16.8 with a 1-sigma error of about 0.5 mag. No correction\nhas been made for a Galactic extinction corresponding to a reddening of\n0.02 mag along the line of sight. \n\nBurst Advocate for this burst is J. L. Racusin (racusin AT astro.psu.edu). \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": 8057,
  "createdOn": 1217893047000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 080804: Swift detection of a burst with optical afterglow",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 080804"
}