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GCN Circular 19874

Subject
Swift Trigger 710022 is very likely noise
Date
2016-08-27T08:28:59Z (8 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), D. Malesani (DARK/NBI and DTU Space) and
K. L. Page (U Leicester) report on behalf of the Swift Team:

At 07:36:39 UT, the Swift Burst Alert Telescope (BAT) triggered on noise in
the image domain near the known source IGR18027-2016 (trigger=710022). 
Swift executed a delayed slewed to the location.  The BAT on-board calculated
location is RA, Dec 183.074, -67.689, which is 
   RA(J2000)  =  12h 12m 18s
   Dec(J2000) = -67d 41' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  This is an image trigger and as such, there is nothing
significant in the real-time light curve. Given the weak significance (5.9 sigma)
near a known source, it is very unlikely that this is a valid trigger. Final
determination will be made when the full data set is downlinked. 

The XRT began observing the field at 08:05:33.4 UT, 1734.3 seconds
after the BAT trigger. No source was detected in 451 s of promptly
downlinked data. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 1736 seconds after the BAT trigger. There is no candidate afterglow 
in the rapidly available 2.7'x2.7' sub-image.
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