Kinematics of Spiral galaxies as a Portal to the Nature of Dark Matter

Abstract

The gravitational field of Spiral galaxies is well traced by their rotation curves. Only recently it has become of extreme interest that the latter form a family ruled by two parameters of the {\it luminous} component: the disk length-scale $R_D$ and the magnitude $M_I$. This evidence is so strong and consequential that it must be taken as the starting point for the investigation on the issue of the dark matter in galaxies. The emerging fact is that structural quantities deeply rooted in the luminous components, like the disk length scales are found to tightly correlate with structural quantities deeply rooted in the dark component, like the DM halo core radii. This unexpected evidence may strongly call for a shift of paradigm with respect to the current Cold collisionless Dark Matter one.