{
  "bibcode": "2008GCN..8237....1Z",
  "body": "H. Ziaeepour (UCL-MSSL), L. Vetere (PSU),\nW. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),\nS. Campana (INAF-OAB), P. A. Evans (U Leicester), C. Gronwall (PSU),\nH. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),\nV. Mangano (INAF-IASFPA), J. Mao (INAF-OAB), S. R. Oates (UCL-MSSL),\nK. L. Page (U Leicester), D. M. Palmer (LANL), B. Preger (ASDC),\nP. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC),\nM. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester) and\nT. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:\n\nAt 09:45:20 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080916 (trigger=324895).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 336.302, -57.022 which is \n   RA(J2000) = 22h 25m 12s\n   Dec(J2000) = -57d 01' 17\"\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 60 sec.  The peak count rate\nwas ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 09:46:30.8 UT, 70.2 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 336.27802, -57.02190 which is\nequivalent to:\n   RA(J2000)  = 22h 25m 6.72s\n   Dec(J2000) = -57d 01' 18.8\"\nwith an uncertainty of 3.3 arcseconds (radius, 90% containment). This\nlocation is 46 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\n1.83e+20 cm^-2 (Kalberla et al. 2005). \n\nUVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)\nfilter starting 76 seconds after the BAT trigger. There is a candidate\nafterglow in the rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t22:25:06.19 = 336.2758\n  DEC(J2000) = -57:01:22.8  = -57.0230\nwith a 1-sigma error radius of about 0.5 arc sec. This position is 5.9 arc\nsec. from the center of the XRT error circle. The estimated magnitude is 18.3\nwith a 1-sigma error of about 0.5 mag. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.02. \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": 8237,
  "createdOn": 1221559433000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 080916: Swift detection of a burst with optical afterglow",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 080916"
}