{
  "bibcode": "2011GCN.12612....1S",
  "body": "E. Sonbas (GSFC/USRA/Adiyaman Univ.), W. H. Baumgartner (GSFC/UMBC),\nA. P. Beardmore (U Leicester), D. N. Burrows (PSU),\nS. Campana (INAF-OAB), N. Gehrels (NASA/GSFC),\nS. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),\nK. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU),\nC. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the\nSwift Team:\n\nAt 13:37:28 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 111204A (trigger=509018).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 336.641, -31.395 which is \n   RA(J2000) = 22h 26m 34s\n   Dec(J2000) = -31d 23' 41\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a double-peaked\nstructure with a duration of about 80 sec.  The peak count rate\nwas ~400 counts/sec (15-350 keV), at ~50 sec after the trigger. \n\nThe XRT began observing the field at 13:40:08.0 UT, 159.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 336.62912, -31.37514 which is\nequivalent to:\n   RA(J2000)  = 22h 26m 30.99s\n   Dec(J2000) = -31d 22' 30.5\"\nwith an uncertainty of 3.8 arcseconds (radius, 90% containment). This\nlocation is 80 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 consistent with the Galactic value of 1.08\nx 10^20 cm^-2 (Kalberla et al. 2005). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 143 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 34% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.01. \n\nBurst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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.)\n\n[GCN OPS NOTE(04dec11): Per author's request, the contact address for ES\nhas been changed to edasonbas@yahoo.com .]",
  "circularId": 12612,
  "createdOn": 1323006644000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 111204A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 111204A"
}