Dark matter scaling relations

We investigate the structure of dark matter halos by means of the kinematic s of a very large sample of spiral galaxies of all luminosities. The observ ed rotation curves show a universal profile which is the sum of an exponent ial thin disk term and a spherical halo term with a flat density core. We f ind that the Burkert profile proposed to describe the dark matter halo dens ity distribution of dwarf galaxies also provides an excellent mass model fo r the dark halos around disk systems up to 100 times more massive. Moreover , we find that spiral dark matter core densities rho(0) and core radii r(0) lie in the same scaling relation rho(0) = 4.5 x 10(-2)(r(0)/kpc)(-2/3) M. pc(-3) of dwarf galaxies with core radii up to 10 times smaller. At the hig hest masses rho(0) decreases with r(0) faster than the -2/3 power law, impl ying a lack of objects with disk masses greater than 10(11) M. and central densities greater than 1.5 x 10(-2)(r(0)/kpc)(-3) M. pc(-3) that can be exp lained by the existence of a maximum mass of about 2 x 10(12) M. for a halo hosting a spiral galaxy.