GCN Circular 8906
Subject
Konus-Wind observation of GRB 090217
Date
2009-02-18T20:01:46Z (16 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:
The long GRB 090217 (Fermi/GBM trigger 256539404/ 090217206: von
Kienlin, GCN 8902) localized by Fermi/LAT (Ohno et al., GCN 8903) and
IPN (Mitrofanov et al., GCN 8905)
triggered Konus-Wind at T0=17804.799 s UT (04:56:44.799) .
As observed by Konus-Wind the burst
had a fluence of 3.13(-0.30, +0.35)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+4.592 s
of 4.72(-0.81, +0.86)x10^-6 erg/cm2/s
(both in the 20 keV - 4 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+24.832 s) is well fitted (in the 20 keV - 4 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.87(-0.14, +0.15),
and Ep = 534(-78, +105) keV (chi2 = 71.5/73 dof).
Fitting by GRB (Band) model yields:
the low-energy photon index alpha = -0.80(-0.16, +0.18),
the high energy photon index beta < -2.19,
the peak energy Ep = 480(-82, +120) keV (chi2 = 70.0/72 dof).
All the quoted errors are at the 90% confidence level.