TITLE:   GCN CIRCULAR
NUMBER:  23869
SUBJECT: Konus-Wind observation of GRB 190204A
DATE:    19/02/04 19:23:03 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

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

The long-duration GRB 190204A
(Swift detection: Lien et al., GCN Circ. 23852;
MAXI/GSC detection: Oeda et al., GCN Circ. 23854;
AstroSat CZTI detection: Khanam et al., GCN Circ. 23856)
triggered Konus-Wind at T0=20755.832 s UT (05:45:55.832).

The burst light curve shows a multipeaked structure
started at ~T0-1 s with a total duration of ~49 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 5.31(-0.51,+0.53)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+8.288 s,
of 2.17(-0.28,+0.29)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+17.408 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.88(-0.07,+0.08),
the high energy photon index beta = -2.43(-0.30,+0.18),
the peak energy Ep = 308(-30,+33) keV
(chi2 = 76/98 dof).

The spectrum near the maximum count rate
(measured from T0+7.680 to T0+9.472 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.85(-0.07,+0.08),
the high energy photon index beta = -2.70(-0.58,+0.25),
the peak energy Ep = 387(-39,+46) keV
(chi2 = 69/66 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190204_T20755/

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