[vsnet-grb-info 21984] Konus-Wind observation of GRB 190404B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24083
SUBJECT: Konus-Wind observation of GRB 190404B
DATE:    19/04/09 16:28:57 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova at mail.ioffe.ru>

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

The long GRB 190404B which triggered MAXI/GSC at 12:24:20 UT
(MAXI/GSC detection: Nakajima et al., GCN 24048;
CALET Gamma-Ray Burst Monitor detection: Nakahira et al., GCN 24055)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows a single multi-peaked emission episode
started at ~T0(MAXI)-7.4 s with a total  duration of ~85.4 s.

As observed by Konus-Wind, the burst had a fluence of
5.57(-1.00,+1.34)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(MAXI)+51.5 s, of 1.09(-0.20,+0.26)x10^-7 erg/cm2/s
(both in the 20 - 1200 keV energy range).

Fitting the K-W 3-channel time-integrated spectrum
(from ~T0(MAXI)-7.4 s to ~T0(MAXI)+78.0 s) in the 20 keV - 1.2 MeV range
by a power law with exponential cutoff model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields
alpha = -1.64(-0.36,+3.80),
and Ep =80(-39,+33) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB190404B/