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 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