Evolution of Energy and Power Spectra in XTE J1650-500 with BeppoSAX

We show preliminary results of a comparative spectral and timing analysis of the Galactic Black Hole XTE J1650-500, using data from BeppoSAX. A clear relation is present between the evolution of energy spectra and power spectra. The central frequency of a given QPO is increasing with the softening of the energy spectra. This is consistent with the following picture: the spectral evolution from Hard to Soft is occurring together with a decreasing of the dimension of the Comptonizing corona. This also implies that the effect of bulk inflow vs thermal Comptonization is increasing its importance during the softening of the source.