[vsnet-grb-info 20357] Konus-Wind observation of GRB 180223A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22453
SUBJECT: Konus-Wind observation of GRB 180223A
DATE:    18/02/26 11:22:09 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 180223A (IPN Triangulation: Hurley et al., GCN 22451)
triggered Konus-Wind at T0=22171.045 s UT (06:09:31.045)

The burst light curve shows a bright, multi-peaked structure,
which started at ~T0-20 s and peaked at ~T0+30 s.
The total duration of the burst is ~200 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(8.9 ± 1.0)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+30.912, of (1.0 ± 0.1)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+62.464 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.00 (-0.10,+0.12),
the high energy photon index beta = -2.31 (-0.32,+0.18),
the peak energy Ep = 284 (-31,+33) keV,
chi2 = 83/97 dof.

The spectrum near the peak count rate (measured from T0+24.832
to T0+38.656 s) is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.95 (-0.09,+0.10),
the high energy photon index beta = -2.44 (-0.40,+0.21),
the peak energy Ep = 310 (-37,+43) keV,
chi2 = 98/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180223_T22171/

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.