[vsnet-grb-info 5238] GRB 071010B: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6931
SUBJECT: GRB 071010B: Suzaku WAM observation of the prompt emission
DATE:    07/10/18 02:57:14 GMT
FROM:    Masanori Ohno at Hiroshima U  <ohno at hirax7.hepl.hiroshima-u.ac.jp>

C. Kira, M. Ohno, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
Y. Terada, T. Tamagawa (RIKEN), K. Yamaoka, Y. E. Nakagawa,
S. Sugita (Aoyama Gakuin U.), M. Tashiro, 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 long GRB 071010B (Swift/BAT trigger #293795;
C. B. Markwardt et al., GCN 6871, 6877)
was triggered by the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 2007-10-10 20:45:49 UT (=T0).
The observed light curve shows a single FRED-like peak,
starting at T0-3s, ending  at T0+10s, with a duration (T90) of about 5 seconds.
There is no signal corresponding to the pre-trigger pulse and the weak soft tail
detected by the Swift/BAT (GCN Report 92.1) and the Konus-Wind (GCN 6879)
in the WAM energy band (50-5000 keV).

The fluence in 100 - 1000 keV was (1.8 +/- 0.3)*10^-6 erg/cm^2.
The 1-s peak flux measured from T0+1s was 1.1 +/- 0.3 photons/cm^2/s in the same
energy range.

Preliminary result shows that the time-averaged spectrum from T0-3s to
T0+10s is well fitted by a single power-law with a photon index
of 3.2 (-0.5, +0.7) (chi^2/d.o.f = 6/8 ).

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