[vsnet-grb-info 5560] GRB 080123 : Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7223
SUBJECT: GRB 080123 : Suzaku WAM observation of the prompt emission
DATE:    08/01/28 13:12:19 GMT
FROM:    Takeshi Uehara at Hiroshima U  <uehara at hirax7.hepl.hiroshima-u.ac.jp>

T. Uehara, M. Ohno, T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.),
T. Tamagawa (RIKEN), K. Yamaoka, Y. E. Nakagawa,
S. Sugita (Aoyama Gakuin U.), M. Tashiro, Y. Terada, Y. Urata, A. Endo,
K. Onda, M. Suzuki, N. Kodaka, K. Morigami (Saitama 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 short GRB 080123 (Swift/BAT trigger #301578 ; Ukwatta et al., GCN 7203)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 2008-01-22 04:21:57 UT (=T0).

The observed light curve shows a double-peaked structure 
starting at T0 s, ending at T0+0.4 s with a duration (T90) of about 0.40 seconds. 
The fluence in 100 - 1000 keV was 3.1 (+/- 0.5) x 10^-7 erg/cm^2.
The 1-s peak flux measured from T0 s was 1.2 (+/- 0.2) photons/cm^2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0 s to
T0+0.5 s is well fitted by a single power-law with a photon index
of 1.22 (+0.21, -0.52) (chi^2/d.o.f = 10/13).

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