TITLE: GCN CIRCULAR NUMBER: 11976 SUBJECT: GRB 110422A: Suzaku WAM observation of the prompt emission DATE: 11/04/26 11:08:37 GMT FROM: Masanori Ohno at ISAS/JAXA W. Iwakiri, Y. Terada, M. Tashiro, K. Takahara, T. Yasuda (Saitama U.), T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.), N. Vasquez (Tokyo Tech.) K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA), S. Sugita (Nagoya U.), Y. E. Nakagawa (Waseda U.), N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The bright GRB 110422A (Swift/BAT trigger #451901 ; Mangano et al., GCN 11957; Palmer et al., GCN 11959) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 15:41:45 UT (=T0). The observed light curve shows a multi-peaked structure starting at T0-2s, ending at T0+35s with a duration (T90) of about 22 seconds. The fluence in 100 - 1000 keV was 3.60 (+/- 0.14) x10-5 erg/cm2. The 1-s peak flux measured from T0+18s was 14.5 (+/- 0.9) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2s to T0+35s is well fitted by a single power-law with a photon index of 2.83 (+/- 0.11) (chi2/d.o.f = 21.3/14). All the quoted errors are at statistical 90% confidence level. The light curves for this burst will be appeared at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html