[vsnet-grb-info 5084] GRB 070911: Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6790
SUBJECT: GRB 070911: Suzaku WAM observation of the prompt emission
DATE:    07/09/15 05:02:46 GMT
FROM:    Yujin E. Nakagawa at Aoyama Gakuin U  <yujin at phys.aoyama.ac.jp>

Y. E. Nakagawa, K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. Terada,
T. Tamagawa (RIKEN), M. Ohno, T. Uehara, T. Takahashi, Y. Fukazawa,
C. Kira (Hiroshima U.),  M. Tashiro, Y. Urata, A. Endo, K. Onda,
M. Suzuki, N. Kodaka, K. Morigami (Saitama U.), T. Enoto, R. Miyawaki,
K. Nakawaza, 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 070911 (Swift/BAT trigger #290624 ; Krimm et al., GCN 6777;
Palmer et al., GCN 6778) triggered the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 2007-09-11 05:58:20 UT (=T0).

The observed light curve shows a multi-peaked structure lasting from T0-160s
to T0+120s, with a duration (T90) of about 182 seconds. The fluence in
100 - 2000 keV was 1.4 (+0.3, -0.3) * 10^-5 erg/cm^2. The 1-s peak flux
measured from T0+0s was 1.1 (+0.3, -0.2) photons/cm^2/s in the same energy
range.

Preliminary result shows that the time-averaged spectrum from T0-160s to 
T0+120s is well fitted by a single power-law with a photon index of
1.9 (+0.3, -0.4) (chi^2/d.o.f = 8.7/16).

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