TITLE:   GCN CIRCULAR
NUMBER:  9050
SUBJECT: Konus-Wind observation of GRB 090328
DATE:    09/03/29 18:18:18 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The long bright GRB 090328 (Fermi-GBM trigger trigger 259925808 / 
GRB090328401) localized by Fermi-LAT (McEnery et al., GCN 9044; the LAT 
localization was confirmed by the IPN triangulation: Golenetskii et al., 
GCN 9049) triggered Konus-Wind at T0=34609.486 s UT (09:36:49.486).

The burst light curve shows a multipeaked structure with a duration of
~80 s. There is a hint of an extended soft emission.

As observed by Konus-Wind the burst
had a fluence of 9.25(-1.98, +1.63)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+20.064 s
of 1.22(-0.26, +0.25)x10^-5 erg/cm2/s
(both in the 20 keV - 8 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+72.960 s) is well fitted (in the 20 keV - 8 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -1.04(-0.10, +0.11),
the high energy photon index beta = -2.05(-0.90, +0.22),
the peak energy Ep = 592(-141, +237) keV (chi2 = 78.4/81 dof).


The spectrum of the most intense part
(from T0 to T0+23.808 s) is well fitted (in the 20 keV - 8 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.94 +/- 0.08,
the high energy photon index beta = -2.07(-0.36, +0.16),
the peak energy Ep = 600(-100, +147) keV (chi2 = 81.1/81 dof).
The fluence of this part is 7.48(-0.93, +0.83)x10^-5 erg/cm2 (in the 20 
keV - 8 MeV energy range).

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

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090328_T34609/