Understanding the nature of the soft excess in AGN with Simbol-X

The nature of the soft excess and the origin of the spectral shape seen in AGNs are still highly debated. Two different physical models can explain most of the spectral complexities observed in the 0.2-10 keV energy band. One involves a strong reflection component from the innermost parts of an accretion disc, the other a high column density of ionized absorbing material moving at relativistic speed. These two models are degenerate at energies below 10 keV, but predict a distinctively different behaviour at higher energies. It is shown here how, with Simbol-X, it will be possible to disentangle the two scenerios observing the spectral shape of AGNs at energies above 10 keV.