[vsnet-grb-info 10691] GRB 110705A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12114
SUBJECT: GRB 110705A: Suzaku WAM observation of the prompt emission
DATE:    11/07/08 13:19:27 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro at phy.saitama-u.ac.jp>

T. Yasuda, Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara (Saitama U.),
T. Uehara, Y. Hanabata, T. Takahashi, M. Mizuno, M. Ohno, Y. Fukazawa
(Hiroshima U.), S. Sugita (Nagoya U.), K. Yamaoka (Aoyama Gakuin U.),
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), N.
Ohmori, M. Akiyama, M. Yamauchi (Univ.of Miyazaki), Y. Urata, P. Tsai,
C-J. Chuang (NCU), K. Nakazawa, K. Makishima (Univ.of Tokyo), on behalf
of the Suzaku WAM team, report:

The short GRB 110705A (Fermi Gamma-Ray Burst Monitor trigger 331529833,
GCN12108; von Kienlin et al.) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at
03:37:11.933 UT (=T0).

The observed light curve shows double-peaked structure starting at
T0+0.008s, ending at T0+0.258s with a duration (T90) of about 0.25
seconds. The fluence in 100 - 1000 keV was
2.31(+0.10/-0.13) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0
was 4.24 (+0.19/-0.20) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0 to
T0+1s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha of
0.30 (+0.18/-0.10), and Epeak of 1030 (+139/-113) keV
(chi^2/d.o.f. = 45/53).

All the quoted errors are at statistical 90% confidence level.

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html