The Size Distribution of Void Filaments in a LCDM Cosmology

TL;DR

This paper investigates the size distribution of mini-filaments in cosmic voids using Millennium Run data, revealing a universal, redshift-insensitive distribution that could serve as a new cosmological probe.

Contribution

It introduces a novel analysis of void filament sizes using MST-based identification, deriving an analytic universal distribution function across redshifts.

Findings

Void filament size distribution is nearly universal and redshift-independent.

Distribution follows a power-law at small sizes and exponential decay at large sizes.

Proposes void filament distribution as a cosmological probe.

Abstract

The size distribution of mini-filaments in voids has been derived from the Millennium Run halo catalogs at redshifts z=0,0.5,1 and 2. It is assumed that the primordial tidal field originated the presence of filamentary substructures in voids and that the void filaments have evolved only little, keeping the initial memory of the primordial tidal field. Applying the filament-finding algorithm based on the minimal spanning tree (MST) technique to the Millennium voids, we identify the mini-filaments running through voids and measure their sizes at each redshift. Then, we calculate the comoving number density of void filaments as a function of their sizes in the logarithmic interval and determine an analytic fitting function for it. It is found that the size distribution of void mini-filaments in the logarithmic interval has an almost universal shape, insensitive to the redshift: In the short-size section it is well approximated as a power-law, while in the long-size section it decreases exponentially. We expect that the universal size distribution of void filaments may provide a useful cosmological probe without resorting to the rms density fluctuations.