{
  "bibcode": "2016GCN.20145....1B",
  "body": "A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC),\nA. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),\nK. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)\nreport on behalf of the Swift Team:\n\nAt 03:32:33 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 161108A (trigger=721234).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 180.784, +24.869 which is \n   RA(J2000) = 12h 03m 08s\n   Dec(J2000) = +24d 52' 09\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex\nstructure with a duration of about 30 sec.  The peak count rate\nwas ~800 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 03:33:53.5 UT, 80.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source located at RA, Dec 180.78748,\n24.86801 which is equivalent to:\n   RA(J2000)  = 12h 03m 09.00s\n   Dec(J2000) = +24d 52' 04.8\"\nwith an uncertainty of 3.7 arcseconds (radius, 90% containment). This\nlocation is 11 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 1.79\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nThe initial flux in the 2.5 s image was 8.63e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 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 100% 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\n0.02. \n\nBurst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). \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": 20145,
  "createdOn": 1478576986000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 161108A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 161108A"
}