TITLE:   GCN CIRCULAR
NUMBER:  41172
SUBJECT: Swift detection of the Soft Gamma Repeater PSR J1647-4552
DATE:    25/07/26 23:21:53 GMT
FROM:    David Palmer at LANL <palmer@lanl.gov>

S. Dichiara (PSU), R. Gupta (NASA GSFC) and D. M. Palmer (LANL) report
on behalf of the Neil Gehrels Swift Observatory Team:

At 2025-07-26 22:49:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located Soft Gamma Repeater (SGR) PSR J1647-4552 (trigger=1337165).
For this previously-known source, Swift is configured to
NOT automatically slew to the location.
The BAT on-board calculated location is 
RA, Dec 251.779, -45.871 which is 
   RA(J2000) = 16h 47m 07s
   Dec(J2000) = -45d 52' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  This position is within 34 arcseconds of the
SGR catalogued location.  The BAT light curve showed a single spike
structure (at the 64 ms resolution of the immediately-available lightcurve)
with a duration of about 128 ms sec.  The peak count rate
was ~2700 counts/sec (15-350 keV), at ~0 sec after the trigger.

There have been 12 previous detections of bursts from this source by BAT,
most recently in Feb 2020.  The detections have come singly or
in clusters of 2-3 within minutes to hours.