TITLE: GCN CIRCULAR NUMBER: 13940 SUBJECT: GRB 121029A Suzaku WAM observation of the prompt emission DATE: 12/11/02 07:16:47 GMT FROM: Masanori Ohno at Hiroshima U W. Iwakiri, M. Tashiro, Y. Terada, T. Yasuda, M. Asahina, S. Kobayashi, A. Sakamoto, Y. Ishida, S. Sugimoto, H. Ueno(Saitama U.), M. Akiyama, N. Ohmori, E. Mochinaga, M. Yamauchi (Univ. of Miyazaki), Y. E. Nakagawa (Waseda U.), Y. Hanabata, T. Kawano, K. Takaki, R. Nakamura, Y.Tanaka, M. Ohno, Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya 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 121029A ( Fermi-GBM detection : von Kienlin et al., GCN 13925) was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 08:24:18 UT (=T0). The observed light curve shows multi-peaked structure starting at T0-2 s, ending at T0+20 s with a duration (T90) of about 15 seconds. The fluence in 100 - 1000 keV was 6.05 (-0.33, +0.29) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0+14 s was 4.63 (-0.42, +0.44) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2 s to T0+20 s is well fitted by a single power-law with a photon index of 2.76 (-0.21, +0.23) (chi^2/d.o.f = 6.9/14). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves with 1-sec time resolution for this burst will be appeared at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html