{
  "bibcode": "2008GCN..7335....1C",
  "body": "J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC),\nP. A. Evans (U Leicester), O. Godet (U Leicester), C. Gronwall (PSU),\nS. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),\nS. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU),\nV. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),\nK. M. McLean (GSFC/UMD), A. Moretti (INAF-OAB),\nP. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),\nC. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),\nA. M. Parsons (GSFC), T. Sakamoto (NASA/UMBC), G. Sato (GSFC/ISAS),\nB. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU),\nR. L. C. Starling (U Leicester), G. Stratta (ASDC) and\nE. Troja (U Leicester/INAF-IASFPa) report on behalf of the Swift\nTeam:\n\nAt 17:04:59 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 080229 (trigger=304379).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 228.217, -14.712 which is \n   RA(J2000)  =  15h 12m 52s\n   Dec(J2000) = -14d 42' 43\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed three or four bright \npeaks with the brightest at ~T+40 sec with a duration of about 60 sec. \nThe peak count rate was ~7000 counts/sec (15-350 keV), at ~40 sec\nafter the trigger. \n\nThe XRT began observing the field at 17:06:29.9 UT, 90.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 228.21888,\n-14.70536 which is equivalent to:\n   RA(J2000)  = 15h 12m 52.53s\n   Dec(J2000) = -14d 42' 19.3\"\nwith an uncertainty of 2.7 arcseconds (radius, 90% containment). This\nlocation is 24 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\n8.97e+20 cm^-2 (Kalberla et al. 2005), so we cannot constrain the\nredshift at this time using the relation from Grupe et al. (2007). A\nsummary of the promptly downlinked data is given at\nhttp://www.swift.ac.uk/sper/304379/. \n\nThe initial flux in the 2.5 s image was 5.98e-09 erg cm^-2 s^-2 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 100 seconds with the White\n(160-650 nm) filter starting 100 seconds after the BAT trigger. A 400\nsecond image in V band was also taken 207 seconds after the trigger. \nNo afterglow candidate has been found in the either image. The\n2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical\n3-sigma upper limit has been about 18.5 mag in white and 18.0 in V. \nThe 8'x8' region for the list of sources generated on-board covers\n100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.15. There is a F0\nstar with R1~13.3 in the USNO catalog nearby the XRT position which\nappears in DSS images. \n\nBurst Advocate for this burst is J. K. Cannizzo (cannizzo 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": 7335,
  "createdOn": 1204306275000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 080229: Swift detection of a bright burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 080229"
}