GCN Circular 5426
Subject
GRB060806 is similar to previous activity of SGR1806-20
Event
Date
2006-08-09T10:21:45Z (20 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S.Golenetskii, D.Frederiks, V.Pal'shin, R.Aptekar, T.Cline
and E.Mazets on behalf of the Konus-Wind team report:
The soft gamma-ray event 060806 related to SGR1806-20
(Hurley et al., GCN 5416, 5419) is of great interest,
However it hardly can be defined as unique for SGR1806-20,
all of the main features of this event were also observed earlier.
In 2006 SGR1806-20 renewed its activity in the middle of July.
Until now it has emitted about 20 soft bursts.
Date UT, s Instrument/Spacecraft
Konus-Wind Konus-A (Cosmos-2421)
060717 50457 yes yes
060717 57178 yes no
060718 11636 yes no
640718 64171 no yes
060718 69585 yes yes
060721 61862 yes no
060728 30102 no yes
060729 76209 yes no
060731 27269 yes yes
060806 21037 yes yes
060806 51824 yes no
060807 3806 yes no
060807 5881 yes yes
060807 34982 yes no
060807 83305 yes no
060808 16377 yes no
The GRB060806 composes a cluster of 6 separate bursts
similar to clusters observed in 2004 on October 5, December 24 and 25.
Energy spectra of all bursts in the table are identical,
revealing the same value of kT = 20 +/- 0.5 keV.
What is more, the last burst in the cluster, wich lasts for
~30 s and exhibits three broad pulses separated by
time intervals of ~7.55 s, strikingly resembles the light curve
of the soft burst from SGR 1806-20 occured on December 3, 2005.
This burst also starts a quick growing spike followed by
a long tail with two broad if less pronounced peaks of periodic pulsations.
Date Duration Fluence Fmax kT
sec erg cm-2 erg cm-2 s-1 keV
060806 30.8 2.4x10-4 4.7x10-5 20
051203 22 1.6x10-4 3.4x10-5 20
A comparative chart of the two events lightcurves one can find at:
http://www.ioffe.ru/LEA/SGR/060806/0806-060806-051203.jpg