[vsnet-grb-info 6853] GRB 081025: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8445
SUBJECT: GRB 081025: Suzaku WAM observation of the prompt emission
DATE:    08/10/29 09:53:27 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata at hep01.hepl.hiroshima-u.ac.jp>

C. Kira, Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa(Hiroshima U.),
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),
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, K. Kono, H.Hayashi,
(Univ. of Miyazaki),S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report:

The long GRB 081025 (Copete et al., GCN 8409)
triggered the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 2008-10-25 08:23:07 UT (=T0).
The observed light curve shows a multi-peaked structure
starting at T0-0.5s, ending at T0+21.5s,
with a duration (T90) of about 22 seconds.
The fluence in 100 - 1000 keV was 3.8(-0.7, +0.5)*10^-06 erg/cm^2.
The 1-s peak flux measured from T0 was 1.5 +/- 0.2 photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-0.5s to
T0+21.5s is well fitted by a single power-law with a photon index
of 1.93 (-0.25, +0.29) (chi^2/d.o.f = 10/9).

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