{
  "bibcode": "2015GCN.17986....1E",
  "body": "P. A. Evans (U Leicester), A. Y. Lien (GSFC/UMBC) and\nK. L. Page (U Leicester) report on behalf of the Swift Team:\n\nAt 06:59:05 UT, the Swift Burst Alert Telescope (BAT) triggered on a\nmarginal significance peak in an non-rate-triggered image \n(trigger=647642). Swift slewed immediately to the event. \nThe BAT on-board calculated location is \nRA, Dec 161.248, +55.989 which is \n   RA(J2000) = 10h 45m 00s\n   Dec(J2000) = +55d 59' 22\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty). As is usual with an image trigger, \nthe available BAT light curve shows no significant structure. \n\nThe XRT began observing the field at 07:01:44.1 UT, 158.9 seconds after\nthe BAT trigger. No source was detected in 822 s of promptly downlinked\ndata. \n\nUVOT took a finding chart exposure of 145 seconds with the White filter\nstarting 163 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\n0.01. \n\nBecause this is a marginal significance detection of a peak in a \nnon-rate-triggered image, with no corresponding source in the XRT \ndata, we believe that this is noise fluctuation and not an \nastrophysical source.",
  "circularId": 17986,
  "createdOn": 1435821572000,
  "email": "klp5@leicester.ac.uk",
  "subject": "Swift Trigger 647642 is probably not an astrophysical source",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>"
}