TITLE: GCN CIRCULAR NUMBER: 14310 SUBJECT: GRB 130310A : Suzaku WAM observation of the prompt emission DATE: 13/03/15 10:55:37 GMT FROM: Masanori Ohno at Hiroshima U T. Kawano, M. Ohno, Y. Hanabata, Y. Tanaka, R. Nakamura, K. Takaki, Y. Fukazawa (Hiroshima U.), A. Sakamoto, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda, K. Takahara, M. Asahina, S. Kobayashi, H. Ueno (Saitama U.), M. Akiyama, N. Ohmori, M. Yamauchi (Univ. of Miyazaki), Y. E. Nakagawa (Waseda 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 bright short GRB (Fermi-LAT detection ; Guiriec et al., GCN14282; Sbarufatti et al., GCN 14288) triggered by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 20:09:45 UT (=T0). The observed light curve shows a single peak structure starting at T0 s, ending at T0+1 s with a duration (T90) of about 0.3 seconds. The fluence in 100 - 1000 keV was 7.78 (-1.13, +2.72) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0 s was 14.34(-1.37,+2.30) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 to T0+1 s is well fitted by GRB Band model: the low-energy photon index alpha: -1.13 (-0.25, +0.16), beta : -2.07 (-0.32, +0.19) and the peak energy Epeak: 1000 (-442, +639) keV (chi^2/d.o.f = 43.2/44). All the quoted errors are at statistical 90% confidence level. The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html