GCN Circular 19733
Subject
Konus-Wind observation of short GRB 160726A
Event
Date
2016-07-26T14:14:21Z (10 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, 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 GRB 160726A (Swift/BAT detection: Starling et al., GCN 19731;
Fermi GBM observation: Hamburg et al., GCN 19732)
triggered Konus-Wind at T0=5645.315 s UT (01:34:05.315).
The light curve shows a short pulse with a total duration is ~0.2 s.
The emission is seen up to ~2 MeV.
As observed by Konus-Wind, the burst had a fluence of
(1.5 �� 0.5)x10^-6 erg/cm2 and a 16-ms peak energy flux,
measured from T0+0.016, of (1.1 �� 0.3)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).
The spectrum of the burst (measured from T0 to T0+0.128 s)
is best fit in the 20 keV - 2 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.65(-0.47,+0.71),
and the peak energy Ep = 424(-163,+389) keV,
chi2 = 19.5/20 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with only an upper limit on beta of -1.8,
chi2 = 19.5/19 dof.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160726_T05645/
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.