[vsnet-grb-info 5098] SGR1806-20: Swift-BAT detection of enhanced activity

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6804
SUBJECT: SGR1806-20: Swift-BAT detection of enhanced activity
DATE:    07/09/19 21:29:28 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU),
G. Sato (GSFC/ISAS) and M. Stamatikos (NASA/ORAU) report on behalf of
the Swift Team:

At 20:45:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located the SGR 1806-20 (trigger=291587).  We note that the initial
GCN Notice went out with a dual identification of this source (both
SGR 1900+14 and SGR 1806-20).  This is due to a mismatch error
in the catalog numbers used between the on-board and ground catalogs
for this source.  The real identification is SGR 1806-20.  We also
note that because of a star tracker loss-of-lock error, the flight
position is 10 arcmin off the true position. 
The BAT light curve shows a large initial spike of ~190,000 counts/sec
with an ~2 sec FWZM, followed by 4 smaller spikes: ~2000 cnts/sec
at ~T+3 sec, 10,000 cnts/sec at ~T+5 sec, 50,000 cnts/sec at ~T+14 sec,
and 30,000 cnts/sec at ~T+18 sec. 

Swift-BAT, and other space instruments (e.g. Konus-WIND
and Konus-A, Suzaku-WAM, IBAS, and SuperAGILE) have been
detecting elevated activity from this source over the
past few days. 

Notably, earlier today (at 16:01:12 UT, Trigger #291566)
a 50,000 counts/second burst (250 times the flux of 
the Crab) was detected by BAT,  which made it the 
third largest SGR 'baby' burst (excluding activity 
related to the superburst) imaged by the Swift mission.  
The new Trigger #291587 burst reported here is much larger.