TITLE:   GCN CIRCULAR
NUMBER:  9479
SUBJECT: GRB 090528B: Suzaku WAM observation of the prompt emission 
DATE:    09/06/02 11:09:48 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata@hep01.hepl.hiroshima-u.ac.jp>

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

The long GRB 090528B (Fermi-GBM trigger 265206153 / 090528516;
von Kienlin et al., GCN9447) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 12:22:29.849 UT (=T0).

The observed light curve shows a bright multi-peaked structure
starting at T0-5 s, ending at T0+60 s, and very weak emission is seen
up to T0+120 s. The total T90 duration is about 77 seconds.

The fluence in 100 - 1000 keV was 3.08 (-0.16, +0.14) x10^-5 erg/cm2.
The 1-s peak flux measured from T0+11s was 3.53 (-0.32, +0.27)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-5 s
to T0+120 s is fitted by a single power-law with a photon index of
2.00 (-0.10, +0.11) (chi^2/d.o.f = 32.1/20).

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html