GCN Circular 5837
Subject
Konus-Wind and Konus-A observations of GRB 061121
Date
2006-11-22T18:00:35Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind and Konus-A teams report:
The second, brightest pulse of the long GRB 061121 (Swift-BAT trigger
#239899: Page et al., GCN 5823; Fenimore et al., GCN 5831)
triggered Konus-Wind at T0=55412.445 s UT(15:23:32.445).
The first pulse which triggered Swift-BAT was detected
by Konus-Wind in the waiting mode.
The Konus-Wind spectrum integrated over the main episode of emission
(from T0 to T0+21.504 s) can be fitted (in the 20 keV - 5 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha) * exp(-(2-alpha)*E/Ep)
with alpha = 1.32(-0.05, +0.04)
and Ep = 606(-72, +90) keV (chi2 = 95/75 dof).
The fluence of this part is 5.67(-0.50, +0.30)x10^-5 erg/cm2
and the 64-ms peak flux measured from T0+12.960 s
1.28(-0.19, +0.16)x10^-5 erg/cm2/s
(both in the 20 keV - 5 MeV range).
The fluence of the precursor is estimated as ~10^-6 erg/cm2,
so the total burst fluence equals to the
fluence of the main episode in the limits of its uncertainty.
Assuming z = 1.314 (Bloom, Perley, and Chen, GCN 5826)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.3, Omega_\Lambda = 0.7,
the isotropic bolometric energy release is E_iso ~2.5x10^53 erg, and
the maximum bolometric luminosity is (L_iso)_max ~1.3x10^53 erg/s.
All the quoted errors are at the 90% confidence level.
The GRB 061121 also triggered Konus-A at T0=55350.15 s UT
(15:22:10.15) (so Konus-A triggered on the precursor).
The Konus-A instrument has been operating onboard Cosmos-2421 spacecraft
since June 25, 2006. The instrument consists of 3 NaI(Tl) detectors
200 mm in diameter and 50 mm in height with beryllium entrance windows.
It is designed to study temporal and spectral characteristics
of gamma-ray bursts in the wide energy range from 10 keV up to 10 MeV.
The Konus-Wind and Konus-A light curves of this GRB are available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB061121_T55412/