GCN Circular 2417
Subject
SGR1806-20 bursts on 031008. Helicon detection and small error box.
Date
2003-10-10T13:39:04Z (22 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
R. Aptekar, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks on
behalf of Konus-Wind and Helicon/Coronas-F teams,
T. Cline and K. Hurley, on behalf of the Ulysses and Konus GRB team,
Helicon-Coronas-F also observed two SGR bursts (GCN 2414, 2415),
first at 03:27:04:070 UT (12424.070 s) and second one at 03:27:56:172 UT
(12476.172s).
Konus-Wind - Helicon-Coronas-F triangulation gives the
annulus centered at RA(2000) = 344.822 deg, Dec(2000) = 0.740 deg, and
radius of 74.130 +/- 0.292 deg (3 sigma) (the distance between Wind and
Coronas-F was only 1 light second).
This annulus intersects the Ulysses-Konus annulus (GCN 2414) to
form two error boxes, one of which may be eliminated by the Konus
ecliptic latitude response. The resulting error box has an approximate
area of 40 sq. arcmin. Its coordinates are:
RA(2000) DEC(2000)
ERROR BOX CENTER: 272.106 -20.647
ERROR BOX CORNER1: 271.897 -21.447
ERROR BOX CORNER2: 272.310 -19.793
ERROR BOX CORNER3: 272.317 -19.850
ERROR BOX CORNER4: 271.905 -21.505
This error box includes the position of SGR 1806-20.
The first burst contains a precursor with a duration ~0.100 s and a main
pulse which had a duration ~0.110 s (total duration 0.210 s).
The second burst had a duration of approximately 0.380 s .
The spectrum of the first burst can be well-described by OTTB model
dN/dE ~ E^-1 exp(-E/E0) with E0 = 13.4 +/- 0.7 keV.
The fluences are:
13-200 keV 25-100 keV
1st burst: 3.15 x 10^-6 erg/cm2 1.3 x 10^-6 erg/cm2
2nd burst: 1.7 x 10^-6 erg/cm2 7.0 x 10^-7 erg/cm2
The peak fluxes are:
1st burst: 4.0 x 10^-5 erg/cm2 s (over 0.008 s)
2nd burst: 1.5 x 10^-5 erg/cm2 s (over 0.064 s)