[vsnet-grb-info 5492] GRB 071227: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7158
SUBJECT: GRB 071227: Suzaku WAM observation of the prompt emission
DATE:    08/01/10 11:58:10 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

K. Onda, M. Tashiro, Y. Terada, 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.), K. Yamaoka, Y. E. Nakagawa,
S. Sugita (Aoyama Gakuin U.), T. Tamagawa (RIKEN),
T. Enoto, R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo),
M. Yamauchi, E. Sonoda, 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 short GRB 071227 (Swift/BAT trigger #299787; Sato et al.,
GCN 7148; Sakamoto et al., GCN 7156) triggered
the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 2007-12-27 20:13:47.71 UT (=T0).

The observed light curve shows a multi-peaked structure
with a duration (T90) of about 1.5 seconds.
The fluence in 100 - 1000 keV was (1.3 ± 0.2)*10^-6 erg/cm^2.
The 1-s peak flux measured from T0-1s was
2.1 (+0.1, -0.1) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+1s is well fitted by a single power-law with a photon index
of 1.2 (+0.2, -0.2) (chi^2/d.o.f = 18.5/17).

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