S. Sugimoto, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda,
K. Takahara, M. Asahina, S. Kobayashi, A. Sakamoto,
Y. Ishida,H. Ueno, (Saitama U.),
M. Akiyama, N. Ohmori, E. Mochinaga, M. Yamauchi (Univ. of Miyazaki),
K. Yamaoka, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. Hanabata, T. Kawano, K. Takaki, R. Nakamura, Y.Tanaka, M. Ohno,
Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), Y. E. Nakagawa
Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The long, IPN localized GRB 121225B (K. Hurley et al., GCN 14103) was
detected by the the Suzaku Wide-band All-sky Monitor (WAM) which covers
an energy range of 50 keV - 5 MeV at 10:01:03.165 UT (=T0).
The observed light curve shows double-peaked structure starting at
T0-16s, ending at T0+70s with a duration (T90) of about 53 seconds. The
fluence in 100 - 1000 keV was 4.80(+0.19/-0.25)x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+9s was 8.50 photons/cm^2/s in the
same energy range.
Preliminary result shows that the time-averaged spectrum from T0-16s to
T0+70s is well fitted by a single power-law with a photon index of
2.17(+0.07/-0.07) (chi^2/d.o.f = 32.8/30).
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves with 1-sec time resolution for this burst are appeared at: