Cosmology with voids

TL;DR

This paper explores how properties of cosmic voids can inform us about fundamental cosmological parameters, using simulations and analytical models to connect void characteristics with the universe's background parameters.

Contribution

It introduces a method combining analytical results with large-scale simulations to estimate cosmological parameters from void properties, considering the full phase-space distribution.

Findings

Large voids are consistent with the standard $\\Lambda$CDM model.

Void properties can estimate Hubble parameter, $\Omega_M$, and $\Omega_\Lambda$.

Simulations reach scales of ~3,000 $h^{-1}$Mpc for analysis.

Abstract

Voids are dominant features of the cosmic web. We revisit the cosmological information content of voids and connect void properties with the parameters of the background universe. We combine analytical results with a suite of large n-body realizations of large-scale structure in the quasilinear regime to measure the central density and radial outflow of voids. These properties, estimated from multiple voids that span a range of redshifts, provide estimates of the Hubble parameter, $\Omega_M$ and $\Omega_\Lambda$. The analysis assumes access to the full phase-space distribution of mass within voids, a dataset that is not currently observable. The observable properties of the largest void in the universe may also test models. The suite of large n-body realizations enables construction of lightcones reaching ~3,000 $h^{-1}$Mpc. Based on these lightcones, we show that large voids similar to those observed are expected in the standard $\Lambda$CDM model.