[vsnet-grb-info 10750] GRB 110709B : Suzaku WAM observation of the prompt emission

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12172
SUBJECT: GRB 110709B : Suzaku WAM observation of the prompt emission
DATE:    11/07/19 01:12:55 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori at astro.miyazaki-u.ac.jp>

N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), M. Ohno,
Y. Hanabata, T. Uehara, T. Takahashi, M. Mizuno, Y. Fukazawa (Hiroshima U.), 
K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.), T. Yasuda, Y. Terada, 
M. Tashiro, W. Iwakiri, K. Takahara (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 long GRB110709B (Swift/BAT trigger #456967, GCN 12122 ; Cummings et al.,) 
triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 21:32:44.453 UT (=T0).

The observed light curve shows multiple peaks starting at T0-10 s, ending
at T0+40 s, with a duration (T90) of about 48 seconds. The fluence in
100 - 1000 keV was 1.53 (-0.16, +0.29) x 10^-5 erg/cm^2. The 1-s peak
flux measured from T0+25.5 s was 1.70 (-0.43, +0.30) photons/cm^2/s in the
same range.

Preliminary result shows that the time-averaged spectrum from
T0-12 s to T0+40 s is well fitted by a power-law with exponential cutoff model:
 dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
 alpha       0.61 (-1.16, +0.95), and
 Epeak       286 (-80, +41) keV (chi^2/d.o.f. = 12.6/14).

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