[vsnet-grb-info 1945] Ongoing activity of SGR 1806-20: an intermediate burst 050811

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3784
SUBJECT: Ongoing activity of SGR 1806-20: an intermediate burst 050811
DATE:    05/08/12 11:29:07 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS
GRB team report:

A SGR-like burst 050811 triggered Konus-Wind
at 48952.617 s UT (13:35:52.617).
It was also detected by Integral SPI-ACS.
We have triangulated it to an annulus centered at
RA(2000) = 301.581 deg, Decl(2000) = -17.751 deg,
whose radius is 28.122 ± 1.686 deg (3 sigma).
As the center line of this annulus passes 0.23 degrees (0.41 sigma)
from the position of SGR 1806-20
and the Konus ecliptic latitude response indicates
that the source of the burst is near ecliptic plane,
we conclude that this burst originated from SGR 1806-20.

The burst had a duration of ~2.3 sec,
fluence (1.70± 0.17)10-5 erg/cm2,
and peak flux on 48-ms time scale (1.8 ± 0.1)10-5 erg/cm2 s
(both in 20-200 keV range).

The time-integrated spectrum of the burst is well fitted by the OTTB
spectral model:
dN/dE ~ E^{-1} exp(-E/kT),
with kT = 18.2 ± 0.6 keV.