{
  "bibcode": "2015GCN.18631....1P",
  "body": "K. L. Page (U Leicester), S. D. Barthelmy (GSFC) and\nJ. R. Cummings (NASA/UMBC) report on behalf of the Swift Team:\n\nAt 08:49:04 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a possible source(trigger=664610).  Swift slewed immediately to the target. \nThe BAT on-board calculated location is \nRA, Dec 184.205, +17.599, which is \n   RA(J2000)  =  12h 16m 49s\n   Dec(J2000) = +17d 35' 55\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is typical for image triggers, there is nothing\nsignificant in the real-time TDRSS light curve.  This is a 5.9 sigma trigger. \n\nThe XRT began observing the field at 08:51:23.6 UT, 139.1 seconds after\nthe BAT trigger. No source was detected in the 2.5-s promptly available\nimage. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of 144 seconds with the White filter\nstarting 143 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\n0.04. \n\nWe note that this is a low significance trigger (5.9 sigma); part of the\nsub-threshold program within BAT.  Given that the initial XRT exposure\ndid not produce a source (time-on-target was only 2.9 min), it is unlikely\nthat this source is real, but we can not rule it out at this time.  We will have\nto wait for more data in the next orbit. \n\nBurst Advocate for this burst is K. L. Page (klp5 AT leicester.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": 18631,
  "createdOn": 1448183703000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 664610: is unlikely a GRB",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>"
}