[vsnet-grb-info 16045] Konus-Wind observation of GRB 150118C

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17327
SUBJECT: Konus-Wind observation of GRB 150118C
DATE:    15/01/20 22:15:51 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 150118C
(IPN triangulation: Golenetskii et al., GCN Circ. 17324)
triggered Konus-Wind at T0=80075.206 s UT (22:14:35.206).

The burst light curve shows a single pulse with a duration ~0.1 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150118_T80075/

As observed by Konus-Wind, the burst
had a fluence of 6.2(-1.2,+1.5)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.020 s,
of 1.3(-0.4,+0.5)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 = -0.91 (-0.44,+0.56)
and Ep = 286 (-94,+204) keV (chi2 = 8/13 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 = 8/12 dof)

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