[vsnet-grb-info 21945] Konus-Wind observation of GRB 190329A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24044
SUBJECT: Konus-Wind observation of GRB 190329A
DATE:    19/04/03 12:52:21 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, bright GRB 190329A
(IPN  triangulation: Hurley et al., GCN Circ. 24029;
CALET-GBM detection: Yamaoka et al., GCN Circ. 24033)
triggered Konus-Wind at T0=22905.458 s UT (06:21:45.458).

The burst light curve shows two separated multi-peaked emission
episodes. The first episode starts at ~T0-0.3 s and
has a duration of ~2 s; the second starts at ~T0-10.3 s
and has a duration of ~8 s.
The emission is seen up to ~3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190329_T22905/

As observed by Konus-Wind, the burst
had a fluence of 2.20(-0.14,+0.16)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+11.168 s,
of 1.31(-0.16,+0.16)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+15.104 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.15(-0.08,+0.09)
and Ep = 345(-39,+50) keV (chi2 = 73/65 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 73/64 dof).

The spectrum near the maximum count rate
(measured from T0+8.448 to T0+15.104 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
with  alpha = -1.01(-0.11,+0.11)
and Ep = 252(-24,+30) keV (chi2 = 80/67 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.1
(chi2 = 80/66 dof).

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