TITLE: GCN CIRCULAR NUMBER: 13873 SUBJECT: GRB 121011A Suzaku WAM observation of the prompt emission DATE: 12/10/16 08:58:49 GMT FROM: Masanori Ohno at Hiroshima U K. Takaki, Y. Hanabata, T. Kawano, R. Nakamura, Y. Tanaka, M. Ohno, Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), H. Ueno, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda, M. Asahina, S. Kobayashi, A. Sakamoto, Y. Ishida, S. Sugimoto (Saitama U.), M. Akiyama, N. Ohmori, E. Mochinaga, M. Yamauchi (Univ. of Miyazaki) Y. E. Nakagawa (Waseda U.), K. Yamaoka, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The long GRB 121011A (Swift/BAT trigger #535764; Racusin et al., GCN 13845; Fermi-LAT detection: Ohno et al., GCN 13777) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 11:15:30.264 UT (=T0). The observed light curve shows a single peak structure starting at T0-10 s, ending at T0+30 s with the total duration (T90) is about 31 seconds. The fluence of main pulse in 100 - 1000 keV was 4.70 (-0.15, +0.10) x 10^-6 erg/cm^2 The 1-s peak flux measured at T0-1.0 s was 0.41 (-0.31, +0.29) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-10 s to T0+30 s is well fitted by by a single power-law with a photon index of 1.61 (-0.14, +0.18) (chi^2/d.o.f = 20.4/25). 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