{
  "bibcode": "2017GCN.22044....1B",
  "body": "A. P. Beardmore (U Leicester), A. A. Breeveld (UCL-MSSL),\nP. A. Evans (U Leicester), N. P. M. Kuin (UCL-MSSL),\nA. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf\nof the Swift Team:\n\nAt 08:33:58 UT, the Swift Burst Alert Telescope (BAT) triggered on a marginal\npeak in the image domain in the vicinity of a nearby galaxy (trigger=781740). \nSwift slewed immediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 10.633, +41.165 which is \n   RA(J2000) = 00h 42m 32s\n   Dec(J2000) = +41d 09' 54\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty). The BAT raw (non mask-weighted) light curve \nshows some periodic behavior with a ~ 10 s period, and a bright short \nspike at ~T0. The oscillation in the BAT light curve is caused by \nSwift J0243.6+6124. The full downloaded dataset will be required to determine \nwhether the short spike at T0 is due to Swift J0243.6+6124, another source, \nor noise fluctuation. \n\nThe XRT began observing the field at 08:35:13.0 UT, 74.3 seconds after\nthe BAT trigger. In 1.17 ks of promptly-downlinked data we find seven X-ray\nsources. One of these appears to be an artefact caused by optical loading,\nthe remaining sources are all known X-ray emitters, previously detected\nby Swift-XRT (see http://www.swift.ac.uk/1SXPS/Fields/90000007801/?refSource=1SXPS%20J004232.0%2B411314), \nand show no evidence for being in outburst. \n\nThis trigger occurred close to the galaxy NGC224 which is a bright\noptical source. Therefore, no UVOT data are available. \n\nGiven that this is a low significance detection in BAT (5.9 sigma) and\nthat there is no new source in the XRT data, it is likely that this is merely\na statistical fluctuation in the image and not an astrophysical\nsource, however we are awaiting the full dataset to confirm this.",
  "circularId": 22044,
  "createdOn": 1508750275000,
  "email": "klp5@leicester.ac.uk",
  "subject": "Swift Trigger 781740 is not a burst",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>"
}