M-sigma relation
= M-sigma relation
{c}
{title2=$M_{\rm BH}\propto\sigma^\alpha$}
The M-sigma relation is an empirical correlation between <supermassive black hole> mass and the stellar <velocity dispersion> of its host's spheroidal component. A commonly used rough parametrization has exponent near four, but the normalization, exponent, scatter, and selection effects depend on the observed sample. It is distinct from the <black-hole--bulge mass relation>.