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GCN Circular 8833

AXP 1E1547.0-5408 activity with SGR bursts
2009-01-22T02:25:39Z (15 years ago)
David Palmer at LANL <>
C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL),
M. Stamatikos (NASA/ORAU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 01:32:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located the known Anomalous X-Ray Pulasr AXP 1E1547.0-5408
(trigger=340573).  Swift could not slew to this burst due to Earth
limb constraint.  The BAT on-board calculated location is 
RA, Dec 237.705, -54.320 which is 
   RA(J2000) = 15h 50m 49s
   Dec(J2000) = -54d 19' 10"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed the typical short
(<128 ms) spike of a Soft Gamma Repeater.  The peak count rate
was ~30,000 counts/sec (15-350 keV), at ~0 sec after the trigger. 
There are additional similar bursts visible in the light curve
at T-40 and T+160 seconds. 

In addition at least 4 similar bursts had been seen by the Fermi
GBM in the previous hour. 

An additional burst triggered BAT at T+37 minutes (Trigger 340578)
which showed a multiple peak structure with a maximum count
rate of 170,000 counts/s. 

SGR bursts from this source were last seen in early October 2008. 

XRT and UVOT will observe this source when it emerges from Earth limb
constraint at 02:23 UT.
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