[vsnet-grb-info 19246] Konus-Wind observation of GRB 170320A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20935
SUBJECT: Konus-Wind observation of GRB 170320A
DATE:    17/03/23 11:06:28 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova at mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, intense GRB 170320A
(IPN Triangulation: Hurley et al., GCN 20927;
POLAR Observation: Zhao et al., GCN 20934)
triggered Konus-Wind at T0=13359.957 s UT (03:42:39.957).

The burst light curve shows a multipeaked structure with a total
duration of ~30 s.
The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.87(-0.30,+0.34)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+0.592 s,
of 1.01(-0.19,+0.20)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+35.072 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.35(-0.15,+0.21),
the high energy photon index beta = -2.41(-0.46,+0.22),
the peak energy Ep = 111(-22,+23) keV,
chi2 = 99/97 dof.

The spectrum near the peak count rate
(measured from T0 to T0+2.304 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.52(-0.17,+0.20),
the high energy photon index beta = -2.21(-0.18,+0.13),
the peak energy Ep = 178(-24,+29) keV,
chi2 = 79/69 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170320_T13359/

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