TITLE: GCN CIRCULAR NUMBER: 14557 SUBJECT: GRB 130502B: Suzaku WAM observation of the prompt emission DATE: 13/05/04 15:15:48 GMT FROM: Makoto Tashiro at Saitama U/Swift T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto (Saitama U.), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri(RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report: The bright, long GRB 130502B (Fermi-GBM detection : von Kienlin and Younes, GCN 14530; Fermi-LAT detection : Kocevski et al., GCN 14532) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 07:51:15.113 UT (=T0). The observed light curve shows a multi-peaked structure starting at T0-2 s, ending at T0+34 s with a duration (T90) of about 24 seconds. The fluence in 100 - 1000 keV was 7.38 (+0.37/-0.29) x10-5 erg/cm^2. The 1-s peak flux measured from T0+22 s was 14.53 (-0.77/+0.73) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2 s to T0+34 s is well fitted by a GRB Band model as follows. the low-energy photon index alpha: -1.04 (+0.49/-0.36), the high-energy photon index beta: -2.73 (+0.10/-0.12), and the peak energy Epeak: 359 (+22/-33) keV (chi^2/d.o.f = 65.7/50). Due to the high flux of this burst, a 3% systematic error was added for low energy channels. All the errors are quoted at 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