Unfolding the Hierarchy of Voids

TL;DR

This paper introduces a hierarchical framework for identifying and analyzing cosmic voids using a generalized watershed approach, revealing the multi-scale structure of the universe's large-scale voids.

Contribution

It presents a novel Hierarchical Void Finder that extends the watershed method to capture the hierarchical nature of cosmic voids across multiple scales.

Findings

Successfully applied to cosmological simulations

Revealed the nested structure of voids

Demonstrated potential for large-scale structure analysis

Abstract

We present a framework for the hierarchical identification and characterization of voids based on the Watershed Void Finder. The Hierarchical Void Finder is based on a generalization of the scale space of a density field invoked in order to trace the hierarchical nature and structure of cosmological voids. At each level of the hierarchy, the watershed transform is used to identify the voids at that particular scale. By identifying the overlapping regions between watershed basins in adjacent levels, the hierarchical void tree is constructed. Applications on a hierarchical Voronoi model and on a set of cosmological simulations illustrate its potential.