{
  "bibcode": "2008GCN..7362....1H",
  "body": "S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC),\nD. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),\nG. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester),\nN. Gehrels (NASA/GSFC), O. Godet (U Leicester),\nC. Guidorzi (INAF-OAB), S. D. Hunsberger (PSU), J. A. Kennea (PSU),\nV. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),\nA. Moretti (INAF-OAB), P. T. O'Brien (U Leicester),\nJ. P. Osborne (U Leicester), C. Pagani (PSU),\nK. L. Page (U Leicester), D. M. Palmer (LANL),\nD. Perez (U Leicester), P. Romano (INAF-IASFPA), G. Sato (GSFC/ISAS),\nM. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester) and\nE. Troja (U Leicester/INAF-IASFPA) report on behalf of the Swift\nTeam:\n\nAt 11:23:30 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080307 (trigger=305011).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 136.633, +35.168 which is \n   RA(J2000) = 09h 06m 32s\n   Dec(J2000) = +35d 10' 06\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a FRED\nstructure with a duration of at least 30 sec.  The peak count rate\nwas ~600 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 11:25:10.1 UT, 99.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright, fading\nuncatalogued X-ray source with an enhanced position: RA, Dec 136.62833,\n35.13866 which is equivalent to:\n   RA(J2000)  = 09h 06m 30.80s\n   Dec(J2000) = +35d 08' 19.2\"\nwith an uncertainty of 2.6 arcseconds (radius, 90% containment). This\nlocation is 106 arcseconds from the BAT onboard position, within the\nBAT error circle. No prompt spectrum is yet available to assess possible\nredshift constraints using X-ray spectroscopy and the nH-z relation\nfrom Grupe et al. (2007). \n\nThe initial flux in the 2.5 s image was 7.63e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)\nfilter starting 105 seconds after the BAT trigger. A possible fading source\nthat is not present in the DSS has been found in the initial data products at\n\n    RA(J2000.0) =  09:06:25.5\n   Dec(J2000.0) = +35:08:39\n\nwith an estimated uncertainty of 0.6 arcsec (radius, 90% confidence).  This\nsource is approximately 1 arcminute from the XRT position, which is too far\naway to be consistent with the X-ray source.  The estimated white magnitude\n is 19.6 +/- 0.1.  No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.03 mag. \n\nBurst Advocate for this burst is S. T. Holland (sholland 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": 7362,
  "createdOn": 1204891313000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 080307: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 080307"
}