[vsnet-grb-info 19510] Konus-Wind observation of GRB 170604A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21247
SUBJECT: Konus-Wind observation of GRB 170604A
DATE:    17/06/11 15:27:18 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long GRB 170604A (Swift-BAT trigger #736407: Page et al.,
GCN 21191; Stamatikos et al., GCN 21195; T0(BAT)=17:08:50.402 UT)
was detected by Konus-Wind (KW) in the waiting mode.

The light curve shows a single peak with a duration of ~30 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)-16.155 s to T0(BAT)+10.341 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.31(-0.20,+0.26) and Ep = 220(-48,+72) keV.
The energy fluence for this time interval is (1.03 ± 0.13)x10^-5
erg/cm2, and the peak energy flux, measured on a 2.944 s scale from
T0(BAT)+1.509 s is (6.9 ± 0.13)x10^-7 erg/cm2/s, both in the
20 keV-10 MeV range.

Assuming the redshift z=1.329 (Izzo et al., GCN 21197)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70, we estimate the burst
isotropic energy release E_iso to (4.7 ± 0.6)x10^52 erg,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, to 512(-112,+168) keV.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB170604A/

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