The Hubble stream near a massive object: the exact analytical solution
  for the spherically-symmetric case
  The gravitational field of a massive object (for instance, of a galaxy group
or cluster) disturbs the Hubble stream, decreasing its speed. Dependence
$v(r_0)$ of the radial velocity of the stream from the present-day radius $r_0$
can be directly observed and may provide valuable information about the cluster
properties. We offer an exact analytical relationship $v(r_0)$ for a
spherically-symmetric system.
