Voids in the Cosmic Web as a probe of dark energy
  The formation of large voids in the Cosmic Web from the initial adiabatic
cosmological perturbations of space-time metric, density and velocity of matter
is investigated in cosmological model with the dynamical dark energy
accelerating expansion of the Universe. It is shown that the negative density
perturbations with the initial radius of about 50 Mpc in comoving to the
cosmological background coordinates and the amplitude corresponding to the
r.m.s. temperature fluctuations of the cosmic microwave background lead to the
formation of voids with the density contrast up to $-$0.9, maximal peculiar
velocity about 400 km/s and the radius close to the initial one. An important
feature of voids formation from the analyzed initial amplitudes and profiles is
establishing the surrounding overdensity shell. We have shown that the ratio of
the peculiar velocity in units of the Hubble flow to the density contrast in
the central part of a void does not depend or weakly depends on the distance
from the center of the void. It is also shown that this ratio is sensitive to
the values of dark energy parameters and can be used to find them based on the
observational data on mass density and peculiar velocities of galaxies in the
voids.
