Context : We present the results from the analysis of long Suzaku observations ( 149 ks and 122 ks for XIS and HXD , respectively ) of the most X-ray luminous galaxy cluster , RX J1347.5–1145 , at z = 0.451 .

Aims : In order to understand the gas physics of a violent cluster merger , we study physical properties of the hot ( \sim 20 keV ) gas clump in the south-east ( SE ) region discovered previously by the Sunyaev–Zel ’ dovich ( SZ ) effect observations .
Using the hard X-ray data , a signature of non-thermal emission is also explored .

Methods : We perform single as well as multi temperature fits to the Suzaku XIS spectra .
Then the Suzaku XIS and HXD , and the Chandra ACIS-I data are fit jointly to examine the properties of the hot gas component in the SE region .
Finally , we look for non-thermal emission in the Suzaku HXD data .

Results : The single-temperature model fails to reproduce the 0.5–10 keV continuum emission and Fe-K lines measured by XIS simultaneously .
The two-temperature model with a very hot component improves the fit , although the XIS data can only give a lower bound on the temperature of the hot component .
We detect the hard X-ray emission in the Suzaku HXD data above the background in the 12–40 keV band at the 9 \sigma level ; however , the significance becomes marginal when the systematic error in the background estimation is included .
With the joint analysis of the Suzaku and Chandra data , we determine the temperature of the hot gas in the SE region to be 25.3 ^ { +6.1 } _ { -4.5 } ( statistical ; 90 % CL ) ^ { +6.9 } _ { -9.5 } ( systematic ; 90 % CL ) keV , which is in an excellent agreement with the previous joint analysis of the SZ effect in radio and the Chandra X-ray data .
This is the first time that the X-ray analysis alone gives a good measurement of the temperature of the hot component in the SE region , which is made possible by Suzaku ’ s unprecedented sensitivity over the wide X-ray band .
These results strongly indicate that RX J1347.5–1145 has undergone a recent , violent merger .
The spectral analysis shows that the SE component is consistent with being thermal .
We find the 3 \sigma upper limit on the non-thermal flux , F < 8 \times 10 ^ { -12 } ~ { } { erg s ^ { -1 } cm ^ { -2 } } in the 12–60 keV band , which provides a limit on the inverse Compton scattering of relativistic electrons off the CMB photons .
Combining this limit with a recent discovery of the radio mini halo in this cluster at 1.4 GHz , which measures the synchrotron radiation , we find a lower limit on the strength of the intracluster magnetic field B > 0.007 ~ { } { \mu G } .

Conclusions :