New Statistical Perspective to The Cosmic Void Distribution

TL;DR

This paper introduces a new statistical model for cosmic void size distribution using a 3-parameter log-normal function derived from the Cosmic Void Catalog, revealing potential links between voids and galaxy mass distributions.

Contribution

It presents a novel, parameter-free log-normal void probability function directly from observational data, linking void size distribution to galaxy mass distribution and nonlinear cosmic mechanisms.

Findings

Void size distribution fits a 3-parameter log-normal model.

Void and galaxy mass distributions show similar shapes.

Possible evidence of nonlinear mechanisms influencing both voids and galaxies.

Abstract

In this study, we obtain the size distribution of voids as a 3-parameter redshift independent log-normal void probability function (VPF) directly from the Cosmic Void Catalog (CVC). Although many statistical models of void distributions are based on the counts in randomly placed cells, the log-normal VPF that we here obtain is independent of the shape of the voids due to the parameter-free void finder of the CVC. We use three void populations drawn from the CVC generated by the Halo Occupation Distribution (HOD) Mocks which are tuned to three mock SDSS samples to investigate the void distribution statistically and the effects of the environments on the size distribution. As a result, it is shown that void size distributions obtained from the HOD Mock samples are satisfied by the 3-parameter log-normal distribution. In addition, we find that there may be a relation between hierarchical formation, skewness and kurtosis of the log-normal distribution for each catalog. We also show that the shape of the 3-parameter distribution from the samples is strikingly similar to the galaxy log-normal mass distribution obtained from numerical studies. This similarity of void size and galaxy mass distributions may possibly indicate evidence of nonlinear mechanisms affecting both voids and galaxies, such as large scale accretion and tidal effects. Considering in this study all voids are generated by galaxy mocks and show hierarchical structures in different levels, it may be possible that the same nonlinear mechanisms of mass distribution affect the void size distribution.