GCN Circular 17660

Subject
Konus-Wind observation of GRB 150330A
Event
Date
2015-04-02T08:02:27Z (11 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, very bright GRB 150330A
(Fermi-GBM detection: Stanbro, GCN 17568Loading...
 
 
IPN triangulation: Hurley et al., GCN 17659Loading...
 
 )
triggered Konus-Wind at T0=71538.572 s UT (19:52:18.572).

The light curve starts with a double-peaked pulse
lasting from ~T0 to ~T0+10 s followed by a bright
multi-peaked structure from ~T0+97 s to ~T0+195 s.
The emission is seen up to ~15 MeV.

As observed by Konus-Wind, the burst had a fluence
of 2.1(-0.2,+0.2)x10^-4 erg/cm2, and a 64-ms peak flux,
measured from T0+130.560 s, of 3.4(-0.1,+0.1)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+194.560 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 = -0.96 (-0.07,+0.07),
the high energy photon index beta = -2.16 (-0.11,+0.08),
the peak energy Ep = 222 (-20,+21) keV,
chi2 = 85/97 dof.

The spectrum near the peak count rate (measured from T0+129.536
to T0+131.072 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 = -0.72 (-0.09,+0.09),
the high energy photon index beta = -1.98 (-0.08,+0.06),
the peak energy Ep = 341 (-44,+52) keV,
chi2 = 107/96 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150330_T71538/

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