M. Tashiro, K. Abe, K. Onda, Y. Sato, M. Suzuki, Y. Urata (Saitama U.),
M. Ohno, T. Takahashi, T. Asano, T. Uehara, Y. Fukazawa (Hiroshima U.),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), T. Enoto, R. Miyawaki,
K. Kokubun, K. Makishima (Univ. of Tokyo), K. Nakazawa, T. Takahashi
(ISAS/JAXA), M. Suzuki, Y. Terada, T. Tamagawa (RIKEN),
S. Hong (Nihon U.), on behalf of the Suzaku WAM team report:
The bright, long burst, GRB 060904A (Swift-BAT trigger #227996;
D. Grupe et al., GCN 5502; Krimm et al., GCN 5516), triggered
the Suzaku Wideband All-sky Monitor (WAM) which covers an energy
range of 50 keV - 5 MeV at 01:04:09.040 (UT).
The three little peaks and following large peak (GCN 5502) are
clearly seen in the light curve observed with the WAM.
The T90 duration was ~79 seconds.
The fluence in 100 - 1000 keV was 8.66(-4.19 +0.39)x10-6 erg/cm2,
while the 1-s peak flux was 2.07(-1.12 +0.09) photons/cm2/s in the
same energy range.
Preliminary result shows that the time-averaged spectrum is
well described with a single power-law model with the energy index
of 1.16 (-0.18 0.20).
All the quoted errors are at statistical 90% confidence level,
in which systematic errors are not included.