K.Yamaoka, S.Sugita (Aoyama Gakuin U.), M.Ohno, T.Takahashi,
T.Asano, T.Uehara, Y.Fukazawa (Hiroshima U.), Y.Terada, T.Tamagawa,
M.Suzuki (RIKEN), K.Abe, K.Onda, M.Suzuki, M.Tashiro (Saitama U.),
S.Hong (Nihon U.) K.Nakazawa, T.Takahashi (ISAS/JAXA), T.Enoto,
R.Miyawaki, K.Kokubun (Univ. of Tokyo)
on behalf of the Suzaku HXD-II team report:
The bright, long burst, GRB 060813 (Swift-BAT trigger #224364;
Morettim et al., GCN5442; Cummings et al. GCN 5443), triggered
the Suzaku Wideband All-sky Monitor (WAM) which covers an energy
range of 50 keV - 5 MeV at 22:50:24.295 (UT).
The observed prompt emission exhibits a single-peaked lightcurve
with a duration (T90) of 6.1 seconds.
The fluence in 100 - 1000 keV was (1.0 +/- 0.1)X10^-6 erg/cm2.
The 1-s peak flux was 5.6 +/- 0.2 photons/cm2/s
in the same energy range.
Preliminary result shows that the time-averaged spectrum
is well-fitted by a power law with an exponential
cutoff having the following parameters:
alpha = 0.93 +- 0.31,
E0 = 229 (+82, -53) keV, and
Epeak = 248 +- 20 keV.
All the quoted errors are at statistical 90% confidence level,
not included in the systematic errors.
Further detailed analyses are in progress.