GCN Circular 2823

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks
on behalf of Konus-Wind and Helicon/Coronas-F teams,

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:

Two bright SGR-like events were detected by Konus-Wind on
October 16 at 66284.062s UT and October 17 at 23771.551s UT.

Both events were also detected by INTEGRAL SPI-ACS,
Wind-INTEGRAL triangulation gives the following annuli:

The first event:
Alpha = 191.74323
Delta =-17.37563
Radius = 75.32431 +/-0.37658
The annulus passes 0.021 deg (0.17 sigma) from SGR 1806-20.

The second event:
Alpha = 191.85595
Delta =-16.48234
Radius = 75.45488 +/- 0.27746
The annulus passes 0.053 deg (0.57 sigma) from SGR 1806-20.

According to the Konus-Wind data the first event on 041016 had
a duration of 0.12 sec, fluence 6.4x10-6 erg cm-2, and peak flux
8.5x10-5 erg cm-2 s-1, both in 20-200 keV range.
OTTB fit gives parameter kT = 26.5 +/- 1.5 keV

The 041017 event had a duration of main pulse of 1.6 sec,
fluence 6.5x10-5 erg cm-2, and peak flux 6.7x10-5 erg cm-2 s-1, both in 
20-200 keV range. A considerable spectral evolution was observed,
OTTB fit gives the following values of kT during event:
------------------------------------
Time after trigger          kT
       sec                   keV
------------------------------------
0 - 0.256s              24.1 +/- 0.5
0.256 - 0.768s          20.4 +/- 0.5
0.768 - 1.6s            17.5 +/- 0.7
------------------------------------

Following the main pulse there were two weaker events
(times are given after the trigger), at +11.287 s (fluence ~2x10-7 erg
cm-2) and at +157.2s (fluence ~4.5x10-7 erg cm-2).