[vsnet-grb-info 6682] GRB080916A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8284
SUBJECT: GRB080916A: Suzaku WAM observation of the prompt emission
DATE:    08/09/23 14:59:42 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka at phys.aoyama.ac.jp>

M. Suzuki, M. Kokubun, M. Ohno, T. Takahashi (ISAS/JAXA), 
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), 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.),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), 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 GRB080916A (Swift/BAT trigger #324895; Ziaeepour et al., 
GCN 8237) was detected by the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 09:45:19.970 UT (=T0).
The observed light curve shows a single peak at T0+0 s, followed by a second 
 soft peak at ~T0+16 s with a total duration (T90) of about 20 seconds. 
The fluence in 100 - 500 keV was (2.57 +/- 0.32)x10^-6 erg/cm^2. 
The 1-s peak flux measured from T0+0 s was
1.54 (-0.12, +0.25) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-5s to 
T0+10s is fit by a single power-law with a photon index of 
1.58 +/- 0.29 (chi^2/d.o.f = 13.1/12) in 100 - 500 keV. 
All the quoted errors are at statistical 90% confidence level, in which 
the systematic uncertainties are not included.

The light curves with 1/64 sec time resolution for this burst are now 
available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html