[vsnet-grb-info 22745] Konus-Wind observation of GRB 190613B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24844
SUBJECT: Konus-Wind observation of GRB 190613B
DATE:    19/06/17 18:30:10 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. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 190613B
(Swift-BAT detection: D'Ai et al., GCN Circ. 24807;
Fermi-GBM observation: Bissaldi et al., GCN Circ. 24814;
Insight-HXMT/HE detection: Luo et al., GCN Circ. 24829)
triggered Konus-Wind at T0=38825.774 s UT (10:47:05.774).

The burst light curve shows a single pulse
which starts at ~T0-2.6 s and has a total duration of ~4 s.
The emission is seen up to ~3 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.48(-0.79,+1.29)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.544 s,
of 2.65(-1.10,+1.54)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.93(-0.53,+0.83)
and Ep = 277(-107,+331) keV (chi2 = 82/72 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.8
(chi2 = 82/71 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190613_T38825/

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