{
  "bibcode": "2011GCN.12774....1L",
  "body": "A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), D. N. Burrows (PSU),\nS. Campana (INAF-OAB), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC),\nS. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),\nH. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),\nA. Melandri (INAF-OAB), J. L. Racusin (NASA/GSFC),\nP. Romano (INAF-IASFPA), E. Troja (NASA/GSFC/ORAU) and\nB.-B. Zhang (PSU) report on behalf of the Swift Team:\n\nAt 22:37:52 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 111229A (trigger=510736).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 76.282, -84.723, which is \n   RA(J2000)  =  05h 05m 08s\n   Dec(J2000) = -84d 43' 20\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows two or three peaks\nwith a total duration of about 25 sec.  The peak count rate\nwas ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger. \n\nThe XRT began observing the field at 22:39:15.5 UT, 83.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 76.2885, -84.7108 which\nis equivalent to:\n   RA(J2000)  = 05h 05m 09.25s\n   Dec(J2000) = -84d 42' 38.8\"\nwith an uncertainty of 2.5 arcseconds (radius, 90% containment). This\nlocation is 43 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://www.swift.ac.uk/sper.  We\ncannot determine whether the source is fading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (1.04 x\n10^21 cm^-2, Kalberla et al. 2005), with an excess column of 9.2\n(+7.65/-5.74) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White\nfilter  starting 87 seconds after the BAT trigger. No credible\nafterglow candidate has  been found in the initial data products. The\n2.7'x2.7' sub-image processing  failed because of no aspect solution. \nResults from the list of sources  generated on-board are not available\nat this time. A full analysis will not be possible until the full data\nset is downlinked. \n\nBurst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com). \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": 12774,
  "createdOn": 1325199319000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 111229A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 111229A"
}