[vsnet-grb-info 2473] Possible resuming of the SGR 1806-20 activity

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4310
SUBJECT: Possible resuming of the SGR 1806-20 activity
DATE:    05/12/03 14:37:11 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks
on behalf of Konus-Wind, and
T. Cline on behalf of the Konus-Wind team,

Two SGR-like events were detected recently by the Konus-Wind.

The first one triggered the Konus-Wind on December 1 at 35965.468 s UT 
(09:59:25.468) . It had a duration ~3.6 sec,
a fluence  ~2.0x10^-5 erg/cm2, a peak flux ~1.2x10^-5 erg/cm2 s
(both in 20-200 keV range).
The time-integrated spectrum of the burst is well fit by the OTTB
spectral model:
dN/dE ~ E^{-1} exp(-E/kT) with kT = 19.7 ± 0.6 keV,
which is typical for SGR 1806-20.

The second one occurred on December 3 at 32626.087 s UT (09:03:46.087)
(only ~5 hours ago). It had an unusual long initial pulse
with a duration ~9 sec followed by at least 9 weaker short bursts during 
the 229 sec of the Konus-Wind trigger record. So, this event can be 
classified as a burst series. The Konus-Wind spectral data for this 
event will be available in a day.

The Konus ecliptic latitude response indicates
that the source of these bursts is near the ecliptic plane.
There were no solar flares at these times according to the GOES data.

We suppose, that these events are originated from SGR 1806-20.
But now we can not exclude the other possibilities.

Further analysis using the data from other instruments will clarify
this issue.