On the distribution of collisionless particles in local potential well
  The distribution of collisionless particles with infinite motion in the presence of a local potential well is discussed. Such distribution is important for interpretation of results of dark matter searches. The relationship n/v=const, where n and v are respectively number density and velocity of particles, is derived for particles crossing a local potential well. The limits of application of this relationship are specified. 
K. Belotsky, M. Khlopov