[vsnet-grb-info 12787] GRB 121225B: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14138
SUBJECT: GRB 121225B: Suzaku WAM observation of the prompt emission
DATE:    13/01/09 05:46:16 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

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
(Waseda U.),
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:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html