  We present the results of a Suzaku study of the Arches cluster. A high S/N
spectrum in the 3-12 keV band was obtained with the XIS. We found that the
spectrum consists of a thermal plasma, a hard power-law tail, and two Gaussian
lines. The plasma component (kT~2.2 keV) is established from the presence of
CaXIX and FeXXV K alpha lines as well as the absence of FeXXVI K alpha line.
The two Gaussian lines represent the K alpha and beta lines from iron at lower
ionization stages. Both the line centers and the intensity ratio of these two
lines are consistent with the neutral iron. The hard power-law tail (index~0.7)
was found to have no pronounced iron K edge feature. In comparison with the
published Chandra spectra, we conclude that the thermal component is from the
ensemble of point-like sources plus thermal diffuse emission concentrated at
the cluster center, while the Gaussian and the hard tail components are from
the non-thermal diffuse emission extended in a larger scale. In the
band-limited XIS images, the distribution of the 7.5-10.0 keV emission
resembles that of the 6.4 keV emission. This strongly suggests that the
power-law emission is related to the 6.4 and 7.1 keV lines in the underlying
physics. We discuss two ideas to explain both the hard continuum and the lines:
(1) X-ray photoionization that produces fluorescence lines and the Thomson
scattering continuum and (2) non-thermal electron impact ionization of iron
atoms and bremsstrahlung continuum. But whichever scenario is adopted, the
photon or particle flux from the Arches cluster is too low to account for the
observed line and continuum intensity.
