{
  "bibcode": "2008GCN..7427....1R",
  "body": "J. L. Racusin (PSU), N. Gehrels (NASA/GSFC),\nS. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),\nC. B. Markwardt (CRESST/GSFC/UMD), C. Pagani (PSU),\nD. M. Palmer (LANL) and M. Stamatikos (NASA/ORAU) report on behalf of\nthe Swift Team:\n\nAt 06:12:49 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080319B (trigger=306757).  Swift slewed immediately to\nthe burst. The BAT on-board calculated location is \nRA, Dec 217.926, +36.303 which is\n   RA(J2000) = 14h 31m 42s\n   Dec(J2000) = +36d 18' 10\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed one bright but\ncomplex peak with a duration of about 50 sec, with an extended tail.  \nThe peak count rate was ~70,000 counts/sec (15-350 keV), at ~20 sec \nafter the trigger. \n\nThe XRT began observing the field at 06:13:49.7 UT, 60.5 seconds after\nthe BAT trigger. XRT found a very bright fading, uncatalogued X-ray \nsource located at RA, Dec 217.9196, +36.3041 which is equivalent to:\n   RA(J2000)  = 14h 31m 40.7s\n   Dec(J2000) = +36d 18' 14.7\"\nwith an uncertainty of 4.7 arcseconds (radius, 90% containment). This\nlocation is 18 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to assess possible\nredshift constraints using X-ray spectroscopy and the nH-z relation\nfrom Grupe et al. (2007). \n\nUVOT took a finding chart exposure of 400 seconds with the V filter\nstarting  175 seconds after the BAT trigger. There is a candidate\nafterglow in the  rapidly available 2.7'x2.7' sub-image. This\nposition is consistent with  the XRT error circle, but the source is\nso bright that a precise UVOT position  is not possible due to\nsaturation effects. The estimated magnitude is 11.5 with a  1-sigma\nerror of about 0.5 mag. No correction has been made for the expected \nextinction of about 0.04 magnitudes. \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": 7427,
  "createdOn": 1205908346000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 080319B: Swift detection of an intense burst with a bright optical counterpart",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 080319B"
}