On the importance of high redshift intergalactic voids

TL;DR

This paper analyzes high-redshift intergalactic flux voids using hydrodynamical simulations and observations, confirming their consistency with LCDM cosmology and exploring their relation to the underlying matter distribution.

Contribution

It provides a detailed comparison of flux voids between simulations and observations, and models their connection to the three-dimensional matter density field.

Findings

Flux void distribution matches LCDM predictions.

Simulation parameters significantly affect void statistics.

Framework established for linking flux voids to matter distribution.

Abstract

We investigate the properties of one--dimensional flux ``voids'' (connected regions in the flux distribution above the mean flux level) by comparing hydrodynamical simulations of large cosmological volumes with a set of observed high--resolution spectra at z ~ 2. After addressing the effects of box size and resolution, we study how the void distribution changes when the most significant cosmological and astrophysical parameters are varied. We find that the void distribution in the flux is in excellent agreement with predictions of the standard LCDM cosmology, which also fits other flux statistics remarkably well. We then model the relation between flux voids and the corresponding one--dimensional gas density field along the line--of--sight and make a preliminary attempt to connect the one--dimensional properties of the gas density field to the three--dimensional dark matter distribution at the same redshift. This provides a framework that allows statistical interpretations of the void population at high redshift using observed quasar spectra, and eventually it will enable linking the void properties of the high--redshift universe with those at lower redshifts, which are better known.