GCN Circular 2831
Subject
Summary of the recent bursts from SGR 1806-20
Date
2004-11-04T14:12:33Z (20 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
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:
SGR 1806-20 remains in the active state. Since the last SGR burst
041017, listed in GCN 2823, Konus-Wind and Helicon-Coronas-F have
detected seven SGR-like bursts in the trigger mode. Two of them were
also detected by INTEGRAL SPI-ACS.
The most recent intense SGR burst was detected by Helicon-Coronas-F
today (041104) at 04:17:08.929 UT. Konus-Wind data aren't available
yet.
The following table summarizes the bursts:
Date Time, Instr* Duration, Fluence, Peak Flux, kT**
s UT s (20-200 keV) (20-200 keV) keV
ergs/cm2 ergs/cm2 s
-----------------------------------------------------------------------
041026 76305.409 K 0.54 3.0E-6 2.4E-5 21.4+/-1.2
041027 35196.737 K 0.55 5.0E-6 2.6E-5 18.6+/-1.1
041029 22099.384 K 0.16 2.5e-6 3.4E-5 17.7+/-1.3
041031(a) 57535.834 H 0.056 4.7e-7 1.2e-5 17.8+/-1.6
041031 61900.552 K, I 0.70 1.2e-5 4.4e-5 18.9+/-0.6
041102(b) 26875.713 K 0.19 1.1e-5 9.9e-5 22.6+/-1.2
041104(c) 15428.929 H, I 1.6 1.9e-5 2.0e-5 21.8+/-0.5
------------------------------------------------------------------------
* - the intrument, which detected the burst:
K = Konus-Wind
H = Helicon-Coronas-F
I = INTEGRAL SPI-ACS
** - the last column contains the values of spectral parameter kT
for the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT)
(a) - this burst was also observed by Konus-Wind in the
background mode. Estimated time delay is consistent with
SGR 1806-20 position.
(b) - this burst was also observed by Helicon-Coronas-F in the
background mode. Estimated time delay is consistent with
SGR 1806-20 position.
(c) - We have triangulated it to Coronas-INTEGRAL annulus centered at
RA(2000) = 225.846 deg, Decl(2000) = 44.432 deg,
whose radius is 77.4 � 4.0 deg (3 sigma).
The center line of this annulus passes 0.02 degrees from
the position of SGR 1806-20.
The Konus-Wind ecliptic latitude response indicates
that the source of the remaining bursts is near ecliptic plane,
so we suppose, that they are also originated from SGR 1806-20.
The peak flux of the burst on 041102 was nearly the same as
the peak flux of the brighest burst detected by Konus-Wind
from SGR 1806-20 on 040828 (GCN 2693).