Suzaku‐WAM, Konus‐Wind, and Swift‐BAT observations of the prompt emission of the highest redshift GRB 050904

We present the results of the highest redshift GRB 050904 from joint spectral analyses among Swift/BAT, Konus‐Wind and Suzaku‐WAM covering a wide energy range of 15–5000 keV. The peak energy was first measured at $338−93+168 keV,$ corresponding to $2465−678+1225 keV$ in the source frame. This is one of the highest value that has been ever meaured. The derived spectral and energetic parameters are consisitent with the Amati relation, but not with the Ghirlada relation. This implies that the circumburst density of this burst might be larger than the nominal value, as suggested by other wavelength observations. We also found that the burst could be an outlier in Yonetoku relation.