TITLE: GCN CIRCULAR NUMBER: 16649 SUBJECT: Swift Trigger 607945: possible noise event in the direction of NGC2559 DATE: 14/08/01 12:36:41 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), L. M. Z. Hagen (PSU), A. Melandri (INAF-OAB) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 12:02:51 UT, the Swift Burst Alert Telescope (BAT) triggered on a location near NGC 2559 (trigger=607945). Swift did not slew because of Sun constraint. The BAT on-board calculated location is RA, Dec 124.350, -27.332 which is RA(J2000) = 08h 17m 24s Dec(J2000) = -27d 19' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, there is nothing to be seen in the real-time TDRSS lightcurve. Further, this is a sub-threshold trigger (because of the spatial coincidence with the galaxy in the on-board catalog) and as such of low confidence. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 05:34 UT on 2014 August 22. There will thus be no XRT or UVOT data for this trigger before this time. This was a low significance BAT trigger in the direction of NGC 2559. Since the field is Sun constrained there will be no XRT or UVOT data to further ascertain the nature of the trigger, which is likely the result of a noise fluctuation.