{
  "bibcode": "2016GCN.20101....1B",
  "body": "S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC),\nD. Malesani (DARK/NBI and DTU Space), K. L. Page (U Leicester),\nD. M. Palmer (LANL) and T. N. Ukwatta (LANL) report on behalf of the\nSwift Team:\n\nAt 17:11:02 UT, the Swift Burst Alert Telescope (BAT) triggered on noise near to\nNGC 5023 (trigger=718919).  Swift slewed immediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 197.822, +43.936, which is \n   RA(J2000)  =  13h 11m 17s\n   Dec(J2000) = +43d 56' 09\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is typical for image triggers, there is nothing\nvisible in the real-time telemetry light curve.  We do not believe this trigger\nis astrophysical -- it is very likely to be a noise trigger. \n\nThe XRT began observing the field at 17:13:14.8 UT, 131.9 seconds after\nthe BAT trigger. No source was detected in 270 s of promptly downlinked\ndata. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 135 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 25% of\nthe BAT 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\nBAT 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\nBAT selected this trigger based on its proximity to the\ndirection to a known nearby galaxy, despite its low significance (5.8 sigma). \n\nBased on the lack of a corresponding rate increase in BAT and the\nnon-detection by XRT of any counterpart, we believe that this event\nis a statistical fluctuation in the image.",
  "circularId": 20101,
  "createdOn": 1477243574000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 718919 is not an astrophysical event.",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>"
}