[vsnet-grb-info 24072] Trigger 933285: Swift detection of the brightest burst so far from SGR 1935+2154

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26171
SUBJECT: Trigger 933285: Swift detection of the brightest burst so far from SGR 1935+2154
DATE:    19/11/05 01:51:58 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU) and
D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 01:36:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a burst from SGR 1935+2154 (trigger=933285).  
Swift did not slew due to merit considerations. 
The BAT on-board calculated location is 
RA, Dec 293.753, +21.896 which is 
   RA(J2000) = 19h 35m 01s
   Dec(J2000) = +21d 53' 46"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 0.5 sec.  The peak count rate
was ~130,000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The BAT software is designed to automatically set the trigger of each
known source to twice the intensity seen with the previous trigger. 
Thus, each GCN notice for retriggering on the source indicates a burst
at least twice as bright as the previous burst.  

In this case, the burst is about 7x as bright as reported in GCN 26169. 
This is the brightest burst seen so far in the the current activation 
of this source.