GCN Circular 18360
Subject
Konus-Wind observation of GRB 150922A
Date
2015-09-23T13:09:30Z (9 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team, report:
The short-duration, hard-spectrum GRB 150922A
(IPN triangulation: Golenetskii et al., GCN 18357;
Fermi GBM detection: Roberts et al., GCN 18358)
triggered Konus-Wind at T0=20250.916 s UT (05:37:30.916).
The burst light curve shows a multipeak structure
with a total duration of ~0.16 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150922_T20250/
As observed by Konus-Wind, the burst
had a fluence of 7.94(-1.93,+2.25)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.008 s,
of 1.34(-0.52,+0.59)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.17(-0.66,+1.10)
and Ep = 393(-132,+222) keV (chi2 = 11/13 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2
(chi2 = 11/12 dof)
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.