TITLE: GCN CIRCULAR NUMBER: 10186 SUBJECT: GRB 091117A: Suzaku WAM observation of the prompt emission DATE: 09/11/22 07:30:19 GMT FROM: Hidenori Hayasi at Miyazaki U H. Hayashi, N. Ohmori, A. Daikyuji,E. Sonoda, K. Kono, K. Noda, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki) T. Sugasahara, M. Tashiro, Y. Terada, A. Endo, K. Onda, W. Iwakiri (Saitama U.), S. Sugita(Nagoya U.), K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Ohmori, A. Daikyuji, E. Sonoda, K. Kono, H. Hayashi, K. Noda, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki), N. Vasquez (Tokyo Tech.), Y. Urata, H.M Lin (NCU), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report The short GRB 091117A (Swift/BAT Detected in ground analysis ; Cummings et al., GCN 10171) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2009-11-17 17:44:25.253 UT (=T0). The observed light curve shows a single peak starting at T0 s, ending at T0+1 s with a duration (T90) of about 0.4 seconds. The fluence in 100 - 1000 keV was 1.54 (-0.26/+0.25) x10^-6 erg/cm^2. The 1-s peak flux measured from T0 s was 2.78 (-0.30,+0.37) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 s to T0+1 s is well fitted by a single power-law with a photon index of 1.29 (-0.13,+0.13) (chi^2/d.o.f. = 42/33). 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