Hydrodynamic Vacuum Sources of Dark Matter Self-Generation in
  Accelerated Universe without Big Bang
  We have obtained a generalization of the hydrodynamic theory of vacuum in the
context of general relativity. While retaining the Lagrangian character of
general relativity, the new theory provides a natural alternative to the view
that the singularity is inevitable in general relativity and in the theory of a
hot Universe. We show that the macroscopic source-sink motion of the ordinary
(dark) matter during production-absorption of particles by vacuum generates
polarization (determining the variability of the cosmological term in general
relativity). We have removed the well-known problems of the cosmological
constant by refining the physical nature of dark energy associated precisely
with this hydrodynamically initiated variability of the vacuum energy density.
A new exact solution of the modified general relativity equations that contains
no free (fitting) parameter (additional to thouse available in general
relativity) has been obtained. It corresponds to continuous and
metric-affecting production of ultralight dark matter particles out of vacuum,
with its density being retaned constant during the expansion of spatially flat
Universe. This solution is shown to be stable in the regime of cosmological
expansion untill Tmax about 38 billion years. After that time, the solution
becomes unstable and characterizes the inverse process of dark matter particles
absorption by the vacuum in the regime of contraction of the Universe. The
physical nature of dark matter particles is considered and their mass is
estimated. Good quantitative agreement of the indicated exact solution with
cosmological observations (SnIa, SDSS-BAO and recently found reduction of
acceleration of the expanding Universe) has been obtained.
