[vsnet-grb-info 10647] GRB 110604A: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12075
SUBJECT: GRB 110604A: Suzaku WAM observation of the prompt emission
DATE:    11/06/16 10:16:24 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori at astro.miyazaki-u.ac.jp>

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

The bright GRB 110604A (IPN and Swift/BAT ; Barthelmy et al., GCN 12063) 
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy
range of 50 keV - 5 MeV at 14:49:42 UT (=T0).

The observed light curve shows a multi-peaked structure starting at
T0-13s, ending at T0+31s with a duration (T90) of about 27 seconds. There 
is a possible precursor at T0-13s with a duration of about 1 second. The
fluence in 100 - 1000 keV was 1.96 (-0.12, +0.10) x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+2s was 7.68 (-0.98, +0.75) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum including the precursor
from T0-13s to T0+31s is well fitted by a single power-law with a photon index
of 2.49 (-0.15, +0.17) (chi^2/d.o.f = 14.0/15).
All the quoted errors are at statistical 90% confidence level.

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