[vsnet-grb-info 5669] GRB 080204: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7326
SUBJECT: GRB 080204: Suzaku WAM observation of the prompt emission
DATE:    08/02/22 11:19:24 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

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

The IPN localized GRB 080204 (Golenetskii et al., GCN 7256)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers
an energy range of 50 keV - 5 MeV at 13:56:32 UT (=T0).
The observed light curve shows a multi-peaked structure,
starting at T0-1s, ending at T0+10s, with a duration (T90) of about
4.8seconds. The fluence in 100 - 1000 keV was 1.0(+0.1,-0.1)x10^-5
erg/cm^2. The 1-s peak flux measured from T0+3s was
3.9(+0.2,-0.9)photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0+0s to T0+10s is well fitted by a power-law with exponential cutoff model:
    dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
    alpha       0.8(+0.2,-0.3), and
    Epeak       990(+350,-205) keV (chi^2/d.o.f. = 25.0/24).

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 available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html