{
  "bibcode": "2012GCN.14057....1M",
  "body": "V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nM. M. Chester (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester),\nN. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU),\nA. Maselli (INAF-IASFPA), K. L. Page (U Leicester),\nB. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU),\nE. Sonbas (NASA/GSFC/Adiyaman Univ.), R. L. C. Starling (U Leicester)\nand E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:\n\nAt 13:47:02 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 121211A (trigger=541200).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 195.544, +30.161 which is \n   RA(J2000)  =  13h 02m 11s\n   Dec(J2000) = +30d 09' 40\"\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 180 sec.  The peak count rate\nwas ~800 counts/sec (15-350 keV), at ~1 sec after the trigger. \n\nThe XRT began observing the field at 13:48:32.3 UT, 89.5 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 195.5332, 30.1489 which is equivalent to:\n   RA(J2000)  = +13h 02m 7.97s\n   Dec(J2000) = +30d 08' 56.0\"\nwith an uncertainty of 4.8 arcseconds (radius, 90% containment). This\nlocation is 55 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 96 seconds after the BAT trigger. There is a candidate afterglow in\nthe list of sources generated on-board at\n  RA(J2000)  =\t13:02:08.01 = 195.53339\n  DEC(J2000) = +30:08:54.9  =  30.14858\nwith a 90%-confidence error radius of about 1.10 arc sec. This position is 1.3\narc sec. from the center of the XRT error circle. The estimated magnitude is\n18.49. No correction has been made for the expected extinction corresponding to\nE(B-V) of 0.01. \n\nBurst Advocate for this burst is V. Mangano (vanessa 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": 14057,
  "createdOn": 1355234452000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 121211A: Swift detection of a burst with an optical counterpart",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 121211A"
}