[vsnet-grb-info 25425] Konus-Wind observation of GRB 200327A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27525
SUBJECT: Konus-Wind observation of GRB 200327A
DATE:    20/04/10 13:15:13 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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

The short-duration GRB 200327A
(Fermi-GBM detection: The Fermi GBM Team, GCN Circ. 27458;
Veres and Meegan, GCN Circ. 27466;
AGILE-MCAL detection: Ursi, et al., GCN Circ. 27461;
IPN triangulation: Svinkin et al., GCN Circ. 27463)
triggered Konus-Wind at T0=75409.744 s UT (20:56:49.744).

The burst light curve shows a double-peaked structure
which starts at ~T0-0.1 s and has a total duration of ~0.2 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200327_T75409/

As observed by Konus-Wind, the burst
had a fluence of 2.32(-0.67,+0.82)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.016 s,
of 2.45(-1.16,+1.37)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 - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.56(-0.36,+0.52)
and Ep = 1323(-545,+961) 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 < -2
(chi2 = 11/13 dof).

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