How Cold Dark Matter Theory Explains Milgrom's Law

Abstract

Milgrom noticed the remarkable fact that the gravitational effect of dark matter in galaxies only becomes important where accelerations are less than about 10^{-8} cm s^{-2} ~ cH_0. This forms the basis for his Modified Newtonian Dynamics (MOND), an alternative to particle dark matter. However, any successful theory of galactic dynamics must account for Milgrom's Law. We show how Milgrom's Law comes about in the Cold Dark Matter (CDM) theory of structure formation.

Version accepted for publication in ApJ Letters; shortened intro; + discussion on collapsed baryon fraction