[vsnet-grb-info 7502] GRB 090324: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9061
SUBJECT: GRB 090324: Suzaku WAM observation of the prompt emission
DATE:    09/03/31 17:50:35 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka at phys.aoyama.ac.jp>

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

The long GRB 090324 localized by SuperAGILE (Feroci et al., GCN 9029) 
triggered the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 02:47:17.604 UT (=T0).
The observed light curve shows a double-peaked structure starting at
T0-1s, with a duration (T90) of about 70 seconds. We note that the
second peak starting around T0+50s corresponds to the FRED-like pulse
observed by SuperAGILE.
The fluence in 100 - 1000 keV was 8.8(-2.4, +1.0)x10^-6 erg/cm^2. The
1-s peak flux measured from T0+59s was 0.99(-0.12, +0.05) photons/cm^2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s
to T0+89s is well fitted by a single power-law with a photon index
of  2.0(-0.2, +0.3) (chi^2/d.o.f = 10.1/13).