Voids in the distribution of galaxies and the Cosmological constant

TL;DR

This paper investigates how the cosmological constant influences the formation of large-scale voids in galaxy distribution, revealing nonlinear effects on void expansion and potential methods to distinguish universe geometries.

Contribution

It introduces a covariant Newtonian approach to model spherical void evolution considering the cosmological constant, highlighting its nonlinear impact on void growth and universe geometry.

Findings

Void expansion is significantly affected by the cosmological constant.

Maximum growth rate of voids occurs at redshift z~1.7.

Void behavior can distinguish between open and closed universe models.

Abstract

With the motivation in mind to evaluate the contribution of the cosmological constant $\Lambda$ on the foam like patterns formation process in the distribution of galaxies, we investigate the Newtonian dynamics of a spherical void embedded in an uniform medium which undergoes a Hubble expansion. We use a covariant approach for deriving the evolution with time of the shell (S) acting as a boundaries condition for the inside and outside media. As a result, with the usual values for the cosmological parameters, S expands with a huge initial burst that freezes up to matching Hubble flow. With respect to Friedmann comoving frame, its magnification increases nonlinearly with $\Lambda$, with a maximal growth rate at redshift $z\sim 1.7$. The velocity field inside S shows an interesting feature which enables us to disentangle a spatially closed from open universe. Namely, the void region are swept out in the first case, what can be interpreted as a stability criterion.