# Voids in the Cosmic Web as a probe of dark energy

## TL;DR

This paper investigates how large voids in the Cosmic Web form within a universe with dynamical dark energy, highlighting their potential as probes for understanding dark energy parameters through galaxy velocities and densities.

## Contribution

It demonstrates that void properties and their velocity-density ratios are sensitive to dark energy parameters, offering a new method to constrain dark energy models.

## Key findings

- Void formation is influenced by initial perturbations with specific amplitudes.
- The velocity-to-density contrast ratio in voids is weakly dependent on distance from the center.
- This ratio is sensitive to dark energy parameters, enabling their estimation from observations.

## Abstract

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.