[vsnet-grb-info 19061] Konus-Wind observation of GRB 170202A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20604
SUBJECT: Konus-Wind observation of GRB 170202A
DATE:    17/02/05 14:32:27 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 170202A (Swift-BAT trigger #736407: Racusin et al.,
GCN 20575; Barthelmy et al., GCN 20596; T0(BAT)=18:28:02.373 UT)
was detected by Konus-Wind (KW) in the waiting mode.

The light curve shows a double-peaked with a duration of ~30 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)+0.907 s to T0(BAT)+30.347 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.16(-0.34,+0.59) and Ep = 247(-86,+166) keV.
The energy fluence (20 keV-10 MeV) for this time interval
is (5.9 ± 1.4)x10^-6 erg/cm2.

Assuming the redshift z=3.645 (de Ugarte Postigo et al., GCN 20584)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the burst isotropic energy release E_iso to ~1.7x10^53 erg
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, to ~1150 keV.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB170202A/

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