RXTE spectrum of the Coma cluster

The Coma cluster was observed for similar or equal to 90 ks by the PCA and HEXTE instruments aboard the RXTE satellite. Our analysis of the measuremen ts clearly indicates that in addition to the main thermal emission from hot intracluster gas at kT similar or equal to 7.5 keV, a second spectral comp onent is required to best-fit the data. If this component is thermal, its t emperature is similar or equal to 4.7 keV, and it contributes similar or eq ual to 20% of the total flux. The second spectral component can also be des cribed by a power-law, probabaly due to Compton scattering of relativistic electrons by the CMB. A Compton origin of the nonthermal component implies that the volume-averaged magnetic field in the central region of Coma is B similar or equal to 0.2 mu G, and the energy density of the emitting electr ons is similar to 8 X 10(-14) erg cm(-3).