[vsnet-grb-info 6708] GRB 080925: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8309
SUBJECT: GRB 080925: Suzaku WAM observation of the prompt emission
DATE:    08/10/03 01:10:38 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka at phys.aoyama.ac.jp>

T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, 
K. Yamaoka (Aoyama Gakuin U.),  M. Ohno, M. Kokubun, M. Suzuki, 
T. Takahashi (ISAS/JAXA), Y.E. Nakagawa, T. Tamagawa (RIKEN), 
T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.),
M. Tashiro, Y. Terada, Y. Urata, A. Endo, K. Onda, 
N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.),
E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori (Univ. of Miyazaki),
S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report:

The long GRB080925 (Fermi-GBM triggered ; Goldstein et al., GCN 
8291) triggered the the Suzaku Wide-band  All-sky Monitor (WAM) 
which covers an energy range of 50 keV - 5 MeV at 18:35:56.853
UT (=T0). 

The observed light curve shows a multi-peaked structure (peaks at 
T0+1s, T0+5s, and T0+14s) with a duration (T90) of about 15 seconds. 
The fluence in 100 - 1000 keV was 7.3(+0.3, -0.2) X 10^-6 erg/cm^2. 
The 1-s peak flux measured from T0+5s was 2.8 photons/cm^2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-10s 
to T0+20s is well fitted by a single power-law with a photon index 
of 2.33(+0.16/-0.18) (chi^2/d.o.f = 36.0/42) in the 150-1000 keV 
energy band. All the quoted errors are at statistical 90% confidence 
level, in which the systematic uncertainties are not included.

The light curves for this burst are availabel at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trg/grb_table.html