  We developed a theoretical model able to give a common origin to the
correlations between the mass of supermassive black holes and the mass,
velocity dispersion, kinetic energy and momentum parameter of the corresponding
host galaxies. Our model is essentially based on the transformation of the
angular momentum of the interstellar material, which falls into the black hole,
into the angular momentum of the radiation emitted in this process. In this
framework, we predict the existence of a relation of the form $M_bh \propto R_e
\sigma^3$, which is confirmed by the experimental data and can be the starting
point to understand the other popular scaling laws too.
