Cosmic voids: a novel probe to shed light on our Universe

TL;DR

Cosmic voids are under-explored regions that offer unique opportunities to investigate fundamental physics like dark energy, neutrinos, and modified gravity through their sensitivity to diffuse components and distinctive observables.

Contribution

This paper highlights the potential of cosmic voids as a novel probe for cosmology, emphasizing their sensitivity to new physics and the need for dedicated large-area surveys.

Findings

Void observables can effectively test dark energy and modified gravity.

Upcoming surveys can exploit voids to gain new cosmological insights.

Void studies complement traditional high-density region analyses.

Abstract

Cosmic voids, the less dense patches of the Universe, are promising laboratories to extract cosmological information. Thanks to their unique low density character, voids are extremely sensitive to diffuse components such as neutrinos and dark energy, and represent ideal environments to study modifications of gravity, where the effects of such modifications are expected to be more prominent. Robust void-related observables, including for example redshift-space distortions (RSD) and weak lensing around voids, are a promising way to chase and test new physics. Cosmological analysis of the large-scale structure of the Universe predominantly relies on the high density regions. Current and upcoming surveys are designed to optimize the extraction of cosmological information from these zones, but leave voids under-exploited. A dense, large area spectroscopic survey with imaging capabilities is ideal to exploit the power of voids fully. Besides helping illuminate the nature of dark energy, modified gravity, and neutrinos, this survey will give access to a detailed map of under-dense regions, providing an unprecedented opportunity to observe and study a so far under-explored galaxy population.