On the Abundance of Extreme Voids

TL;DR

This paper develops a theoretical framework using extreme-value statistics to predict the size of the largest cosmic voids, comparing predictions with simulations and observations to test void models.

Contribution

It introduces a novel application of extreme-value statistics to cosmic voids, providing a new method to evaluate void abundance models against data.

Findings

Simple void models require ad hoc parameters to match extreme-void data.

Extreme-void distributions serve as a new test for void abundance theories.

The framework links void size predictions to cosmological parameters.

Abstract

Cosmic voids have been shown to be an effective probe of cosmology, complementary to galaxy clusters. In this work, we present a simple theoretical framework for predicting of the size of the largest voids expected within a given redshift and volume. Our model is based on the exact extreme-value statistics which has previously been successfully applied to massive galaxy clusters. We implement our formalism using the void-abundance models and compare the extreme-void predictions to simulations and observations. We find that the simplest void models can only explain the extreme-void abundance with ad hoc parameter adjustments. We argue that extreme-void distributions should be used as an additional test on theories of void abundance.