{
  "bibcode": "2008GCN..8344....1R",
  "body": "J. L. Racusin (PSU), W. H. Baumgartner (GSFC/UMBC), P. J. Brown (PSU),\nD. N. Burrows (PSU), P. A. Evans (U Leicester), D. Grupe (PSU),\nS. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),\nJ. A. Kennea (PSU), V. La Parola (INAF-IASFPA),\nF. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),\nJ. P. Osborne (U Leicester), A. M. Parsons (GSFC),\nM. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester),\nG. Tagliaferri (INAF-OAB), T. N. Ukwatta (GSFC/GWU) and\nL. Vetere (PSU) report on behalf of the Swift Team:\n\nAt 19:58:09 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 081008 (trigger=331093).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 279.987, -57.464 which is \n   RA(J2000) = 18h 39m 57s\n   Dec(J2000) = -57d 27' 50\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a double-peaked\nstructure with a duration of about 150 sec.  The peak count rate\nwas ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 19:59:36.5 UT, 87.1 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 279.9587, -57.4312 which is equivalent to:\n   RA(J2000)  = 18h 39m 50.08s\n   Dec(J2000) = -57d 25' 52.3\"\nwith an uncertainty of 5.3 arcseconds (radius, 90% containment). This\nlocation is 130 arcseconds from the BAT onboard position, within the\nBAT error circle. No event data are yet available to determine the\ncolumn density using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 150 seconds with the White (160-650 nm)\nfilter starting 96 seconds after the BAT trigger. There is a candidate\nafterglow in the rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t18:39:50.11 = 279.9588\n  DEC(J2000) = -57:25:52.3  = -57.4312\nwith a 1-sigma error radius of about 1.6 arc sec. This position is 0.3 arcseconds\nfrom the center of the XRT error circle. The estimated magnitude is 15.0 with a\n1-sigma error of about 0.5 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.10. \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": 8344,
  "createdOn": 1223496770000,
  "email": "kennea@astro.psu.edu",
  "subject": "GRB 081008: Swift detection of a burst with optical afterglow",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>",
  "eventId": "GRB 081008"
}