TITLE:   GCN CIRCULAR
NUMBER:  2693
SUBJECT: Very bright burst detected from SGR 1806-20
DATE:    04/09/04 09:25:41 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R.
Vanderspek, J. Villasenor, G. Crew, N. Butler, J.G.  Jernigan, F.
Martel, G. Prigozhin, A. Dullighan, J. Braga, R.  Manchanda, G.
Pizzichini, Y.  Shirasaki, C. Graziani, M. Matsuoka, T.  Tamagawa, T.
Sakamoto, A.  Yoshida, E. Fenimore, M. Galassi, T.  Donaghy, C.
Barraud, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB
team, and

K. Hurley on behalf of the IPN team report:

A very bright SGR burst was detected by Konus-Wind on August 28
at 42581.338 s UT.
This burst also triggered HETE at 42569.952 s UT (H3514).
We have triangulated it to an annulus centered at
RA(2000) = 317.135 deg, Decl(2000) = -17.624 deg,
whose radius is 42.448 +/- 1.601 deg (3 sigma).
As this annulus includes the position of SGR 1806-20
and Konus ecliptic latitude response indicates
that the burst source lays near ecliptic plane,
we believe that SGR 1806-20 is the source of this event.

As observed by Konus-Wind, the burst had a duration of 0.7 s, a
fluence  ~4.0x10^-5 erg/cm^2, and  a peak flux ~1x10^-4 erg/cm^2 s
(both in 20-200 keV range).

The value of the spectral parameter kT for an OTTB spectral model
(dN/dE ~ E^{-1} exp(-E/kT)) was 26 keV.

This burst is the brightest one from this SGR detected
so far by Konus-Wind. It is stronger, than the burst on 040825
(GCN 2665) by a factor of about 1.7 in fluence
and peak flux.