TITLE: GCN CIRCULAR NUMBER: 13356 SUBJECT: GRB 120603A: Suzaku WAM observation of the prompt emission DATE: 12/06/06 08:15:54 GMT FROM: Makoto Tashiro at Saitama U/Swift T. Yasuda, M. S. Tashiro, Y. Terada, W. Iwakiri, K. Takahara, M. Asahina, S. Kobayashi, A. Sakamoto, H. Ueno (Saitama U.), M. Akiyama, N. Ohmori, M. Yamauchi (Univ. of Miyazaki), K. Yamaoka, 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.), 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 IPN localized GRB 120603A (IPN; Golenetskii et al., GCN 13353, Konus-Wind; Golenetskii et al., GCN 13354) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2012-06-03 10:32:9.80 UT (=T0). The observed light curve shows a single peak with a duration (T90) of about 0.19 seconds. The fluence in 100 - 1000 keV was 5.49 (+1.15/-4.79) x10^-7 erg/cm^2. The 1-s peak flux was 1.19 (+0.20/-0.94) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 0.70 (+0.81/-1.17), and Epeak 580 (+285/-203) keV (chi^2/d.o.f. = 16/14). All the quoted errors are at statistical 90% confidence level 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