Cosmic voids in coupled dark energy cosmologies: the impact of halo bias

TL;DR

This study examines how coupled dark energy models influence cosmic void properties using simulations, highlighting the importance of tracer bias in using voids to distinguish cosmological models.

Contribution

It demonstrates that tracer bias significantly affects void properties and their utility in differentiating coupled dark energy from standard cosmology.

Findings

Coupled dark energy models show more large voids at low redshifts.

Void properties in dark matter differ from those in halo distributions.

Tracer bias impacts the effectiveness of voids as cosmological probes.

Abstract

In this work we analyse the properties of cosmic voids in standard and coupled dark energy cosmologies. Using large numerical simulations, we investigate the effects produced by the dark energy coupling on three statistics: the filling factor, the size distribution and the stacked profiles of cosmic voids. We find that the bias of the tracers of the density field used to identify the voids strongly influences the properties of the void catalogues, and, consequently, the possibility of using the identified voids as a probe to distinguish coupled dark energy models from the standard $\Lambda $CDM cosmology. In fact, on one hand coupled dark energy models are characterised by an excess of large voids in the cold dark matter distribution as compared to the reference standard cosmology, due to their higher normalisation of linear perturbations at low redshifts. Specifically, these models present an excess of large voids with $R_{eff}>20, 15, 12$ Mpc h^{-1}, at $z=0, 0.55, 1$, respectively. On the other hand, we do not find any significant difference in the properties of the void detected in the distribution of collapsed dark matter halos. These results imply that the tracer bias has a significant impact on the possibility of using cosmic void catalogues to probe cosmology.