[vsnet-grb-info 7524] Konus-Wind observation of GRB 090401B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9083
SUBJECT: Konus-Wind observation of GRB 090401B
DATE:    09/04/03 11:35:30 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at 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 090401B (Swift-BAT trigger #348152: Schady et al., 
GCN 9066; Stamatikos et al., GCN 9068) triggered Konus-Wind at 
T0=30922.964 s UT (08:35:22.964).

The burst light curve shows a multipeaked structure with a duration of
~11 s. There is a hint of an extended soft emission.

As observed by Konus-Wind the burst
had a fluence of 6.25(-0.75, +0.78)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+6.576 s
of 4.63(-0.86, +0.87)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+16.996 s) is well fitted (in the 20 keV - 10 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.78(-0.09, +0.11),
the high energy photon index beta = -2.14(-0.23, +0.15),
the peak energy Ep = 409(-60, +66) keV (chi2 = 61.8/85 dof).

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/GRB090401_T30922/