[vsnet-grb-info 5474] GRB 071125: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7141
SUBJECT: GRB 071125: Suzaku WAM observation of the prompt emission
DATE:    07/12/05 01:19:16 GMT
FROM:    Masanori Ohno at Hiroshima U  <ohno at hirax7.hepl.hiroshima-u.ac.jp>

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), 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, S. Maeno, 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 bright, IPN localized GRB 071125 (Golenetskii et al., GCN 7136)
was detected by the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
 energy range of 50 keV - 5 MeV at 2007-11-25 13:56:42 UT (=T0).

The observed light curve shows a double-peaked structure in 1-sec
time resolution. The T90 duration  was about 6.0 seconds.
The fluence in 100 - 1000 keV was 5.8 (+0.4, -0.3) X 10^-5 erg/cm^2.
The 1-s peak flux measured from T0+1s was  32.9 (+1.0, -1.3)
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+12s is well fitted by a GRB Band model as follows.

the low-energy photon index alpha: -1.0 (+0.4, -0.3),
the high-energy photon index beta: -3.1 (+0.3, -0.6),
the break energy E0:      326 (+100, -92)  keV,
and the peak energy Epeak: 330 (+20, -20) keV (chi^2/d.o.f = 21/22).


All the quoted errors are at statistical 90% confidence level.
A 3% systematic error was added to each energy channel due to the
brightness of this GRB.

The light curves with 1-sec time resolution for this burst will be appeared at:

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


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