{
  "bibcode": "2016GCN.19171....1D",
  "body": "A. D'Ai (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nA. Y. Lien (GSFC/UMBC), A. Maselli (INAF-IASFPA),\nL. M. McCauley (PSU), D. M. Palmer (LANL),\nB. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU) and\nT. N. Ukwatta (LANL) report on behalf of the Swift Team:\n\nAt 02:37:15 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 160313A (trigger=678929).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 183.788, +57.293 which is \n   RA(J2000)  =  12h 15m 09s\n   Dec(J2000) = +57d 17' 34\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows several peaks\nwith a total duration of about 40 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~30 sec after the trigger. \n\nThe XRT began observing the field at 02:39:48.3 UT, 152.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 183.7969, 57.2840 which\nis equivalent to:\n   RA(J2000)  = 12h 15m 11.24s\n   Dec(J2000) = +57d 17' 02.3\"\nwith an uncertainty of 2.2 arcseconds (radius, 90% containment). This\nlocation is 36 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. No\nspectrum from the promptly downlinked event data is yet available to\ndetermine the column density. \n\nUVOT took a finding chart exposure of 150 seconds with the White\nfilter  starting 198 seconds after the BAT trigger. No credible\nafterglow candidate has  been found in the initial data products. The\n2.7'x2.7' sub-image covers 100% of  the XRT error circle. The typical\n3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the\nlist of sources  generated on-board covers 100% of the XRT error\ncircle. The list of sources is  typically complete to about 18 mag. No\ncorrection has been made for the  expected extinction corresponding to\nE(B-V) of 0.01. \n\nBurst Advocate for this burst is A. D'Ai (antonino.dai 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": 19171,
  "createdOn": 1457837560000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 160313A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 160313A"
}