[vsnet-grb-info 16978] Konus-Wind observation of GRB 150906B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18259
SUBJECT: Konus-Wind observation of GRB 150906B
DATE:    15/09/08 18:12:45 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at 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 150906B
(IPN triangulation:  Hurley, et al., GCN 18258)
triggered Konus-Wind at 31340.560 s UT (08:42:20.560).

The KW light curve shows a single, multi-peaked pulse
with a duration of ~2 s.
The emission is visible up to ~10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150906_T31340/

As observed by Konus-Wind, the burst had a fluence
of 2.8(-0.2,+0.2)x10^-5 erg/cm2, and a 16-ms peak flux,
measured from T0+1.488 s, of 2.9(-0.3,+0.3)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -0.43(-0.11,+0.12),
and the peak energy Ep = 928(-95,+111) keV,
chi2 = 93/94 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with an upper limit on beta of -2.8

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.