[vsnet-grb-info 18405] Konus-Wind observation of GRB 160822A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19853
SUBJECT: Konus-Wind observation of GRB 160822A
DATE:    16/08/24 11:37:30 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova at mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, 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 160822A
(Fermi GBM detection: Hamburg et al., GCN Circ. 19845;
IPN triangulation: Svinkin et al., GCN Circ. 19852)
triggered Konus-Wind at T0=58061.153 s UT (16:07:41.153).

The burst light curve shows a single pulse
which starts at T0-0.016 s with a total duration of 0.03 s.
The emission is seen up to ~10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160822_T58061/

As observed by Konus-Wind, the burst
had a fluence of 7.60(-1.87,+5.46)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.006 s,
of 3.95(-1.40,+4.02)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.59 (-0.75,+1.34)
and Ep = 599 (-222,+2249) keV (chi2 = 11/14 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 11/13 dof)

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