{
  "bibcode": "2012GCN.14045....1M",
  "body": "A. Maselli (INAF-IASFPA), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),\nJ. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),\nC. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),\nD. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU)\nand E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:\n\nAt 21:59:11 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 121209A (trigger=540964).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 326.801, -8.244 which is \n   RA(J2000)  =  21h 47m 12s\n   Dec(J2000) = -08d 14' 39\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows multiple peaks\nwith a total duration of about 60 sec.  The peak count rate\nwas ~3300 counts/sec (15-350 keV), at ~20 sec after the trigger. \n\nThe XRT began observing the field at 22:00:43.3 UT, 92.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 326.78917, -8.23262 which is equivalent\nto:\n   RA(J2000)  = 21h 47m 09.40s\n   Dec(J2000) = -08d 13' 57.4\"\nwith an uncertainty of 3.9 arcseconds (radius, 90% containment). This\nlocation is 58 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 (3.81 x\n10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.8\n(+2.58/-2.19) x 10^21 cm^-2 (90% confidence). \n\nUVOT data is not yet available. \n\nBurst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.it). \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": 14045,
  "createdOn": 1355090942000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 121209A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 121209A"
}