GCN Circular 20570

GRB 170131A detected in Swift/BAT ground processing

David Palmer (LANL), on behalf of the Swift team, reports:

At 23:15:13 UT on 2017-01-31, the Swift Burst Alert Telescope (BAT) 
detected a marginal peak in a rate-triggered image (Swift Trigger #736107).
Because it was below the image significance threshold, it did not yield a GRB 
follow-up.  However, ground analysis shows that it is at the same location 
as a Fermi/GBM trigger (#507597304).  KONUS/WIND also reported a trigger
at the same time.

The BAT on-board calculated location is 
RA, Dec 341.447, 64.006, which is 
 RA(J2000)  =  22h 45m 55s
 Dec(J2000) = +64d 00' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a ~30 s long
FRED structure starting at ~T-20 (consistent with the Fermi/GBM
trigger time) superimposed with a ~5 second peak near the BAT
trigger time.  The peak count rate was ~3000 counts/sec (15-350 keV),
at ~3 sec after the BAT trigger. 

A Swift ToO observation has been scheduled.