[vsnet-grb-info 19071] Konus-Wind observation of GRB 170205A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20614
SUBJECT: Konus-Wind observation of GRB 170205A
DATE:    17/02/06 16:19:11 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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

The long-duration GRB 170205A
(Swift-BAT detection: Troja et al., GCN Circ. 20603),
triggered Konus-Wind at T0=45549.824 s UT (12:39:09.824).

The burst light curve shows a double-peaked structure which
started at ~T0-32 s and had a total duration of ~56 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170205_T45549/

As observed by Konus-Wind, the burst
had a fluence of 1.22(-0.20,+0.24)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0-0.220 s,
of 3.29(-1.62,+1.99)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+24.832 s)
is best fit in the 20 keV - 10 MeV range
by a power law with spectral index = -2.19(-0.12,+0.13)
(chi2 = 58/69 dof).
Fitting this spectrum by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields
alpha = -1.75 (-0.24,+0.62) and
an upper limit on Ep of 75 keV (chi2 = 56/68 dof).
For the CPL model, the burst fluence is
6.2(-0.8,+1.4)x10^-6 erg/cm2,
and the 64-ms peak flux is 1.8(-0.8,+2.8)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

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