Local dark energy in the Sculptor Filament of galaxies

TL;DR

This study models the Sculptor Filament of galaxies using N-body simulations, revealing that local dark energy dominates its outer regions, causing accelerated expansion and a linear velocity-distance relation similar to the Hubble law.

Contribution

It introduces a model incorporating local dark energy effects into the dynamics of the Sculptor Filament, highlighting its role in filament expansion and velocity relations.

Findings

Dark energy dominates the outer parts of the filament.

The filament expands with acceleration due to dark energy.

The velocity-distance relation depends on dark energy density.

Abstract

Two dozens of different mass galaxies observed at distances less than 10 Mpc from the Local Group are organized in the elongated structure known as the Sculptor Filament. We use recent Hubble Space Telescope data on local galaxies to study the dynamical structure and evolutionary trends of the filament. An N-body computer model, which reproduces its observed kinematics, is constructed under the assumption that the filament is embedded in the universal dark energy background. In the model, the motions of the filament members are controlled by their mutual gravity attraction force and the anti-gravity repulsion force produced by the local dark energy. It is found that the dark energy repulsion dominates the force field of the outer parts of the filament. Because of this, the filament expands and its expansion proceeds with acceleration. The dark energy domination increases with cosmic time and introduces to the filament the linear velocity--distance relation with the universal time-rate ("the Hubble constant") that depends asymptotically on the dark energy density only.