[vsnet-grb-info 11697] GRB 120316A : Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13088
SUBJECT: GRB 120316A : Suzaku WAM observation of the prompt emission
DATE:    12/03/23 07:51:49 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata at hep01.hepl.hiroshima-u.ac.jp>

Y. Hanabata, T. Uehara, T. Kawano, K. Takaki, M. Mizuno, M. Ohno,
Y. Fukazawa (Hiroshima U.), W. Iwakiri, M. Tashiro, Y. Terada,
T. Yasuda, K. Takahara, M. Asahina, S. Kobayashi, A. Sakamoto (Saitama 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), C-J. Chuang, Y. Urata, P. Tsai (NCU), 
K. Nakazawa, K. Makishima (Univ. of Tokyo), 
on behalf of the Suzaku WAM team, report:

The long GRB 120316A (GBM trigger 353549464; Fermi-LAT detection:
Zheng & Akerlof, GCN 13070; IPN localization: Hurley at al., GCN 13073) 
was detected by the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 00:11:02 UT (=T0).

The observed light curve shows a multi-peaked structure starting at T0,
ending at T0+28 s with a duration (T90) of about 24 seconds. The
fluence in 100 - 1000 keV was 1.79 (-0.49, +0.07) x 10^-5 erg/cm^2. The
1-s peak flux measured from T0+21 s was 2.75 (-1.02, +0.31)
photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from 
T0 to T0+28 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.44 (-0.61, +0.89),
the high-energy photon index beta: -2.63 (-0.58, +0.31),
and the peak energy Epeak: 530 (-76, +89) keV (chi^2/d.o.f = 12.6/12).

Due to the brightness of this burst, a 3% systematic error was added
for low energy channels. All the quoted errors are at statistical 90%
confidence level.

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