Effects of voids on the reconstruction of the equation of state of Dark Energy

TL;DR

This paper investigates how cosmic voids influence the accuracy of reconstructing dark energy's equation of state, revealing that voids can significantly affect results depending on data selection and combination.

Contribution

It quantifies the impact of cosmic voids on dark energy equation of state reconstruction and assesses how data combination mitigates this effect.

Findings

Void effects can be comparable to other errors in supernova data analysis.

Including BAO and CMB data reduces void impact but does not eliminate it.

Void effects induce errors larger than a percent in $w$ reconstruction.

Abstract

We quantify the effects of the voids known to exist in the Universe upon the reconstruction of the dark energy equation of state $w$. We show that the effect can start to be comparable with some of the other errors taken into account when analysing supernova data, depending strongly upon the low redshift cut-off used in the sample. For the supernova data alone, the error induced in the reconstruction of $w$ is much larger than the percent level. When the Baryonic Acoustic Oscillations and the CMB data are included in the fit, the effect of the voids upon the determination of $w$ is much lessened, but is not much smaller than some of the other errors taken into consideration when performing such fits.