Sigma-D relation
= Sigma-D relation
{wiki=Sigma-D_relation}
The Sigma-D relation, also known as the \\(\\Sigma-D\\) relation or the \\(\\Sigma-D\\) correlation, is a concept in astrophysics and cosmology that describes a relationship between the surface density of galaxies (or their stellar components) and their dynamical properties, particularly their rotational velocity or other measures of mass distribution.