Testing the local-void alternative to dark energy using galaxy pairs

TL;DR

This paper tests the local-void hypothesis as an alternative to dark energy by analyzing galaxy pair orientations, finding that such models are inconsistent with multiple cosmological observations and are statistically ruled out.

Contribution

It introduces a novel method using galaxy pair orientations to test the local-void model against the Copernican principle, providing strong observational constraints.

Findings

Void models cannot simultaneously fit supernova, CMB, and galaxy pair data.

Results rule out local-void models at 4σ confidence level.

Supports the Copernican principle as the correct cosmological assumption.

Abstract

The possibility that we live in a special place in the universe, close to the center of a large, radially inhomogeneous void, has attracted attention recently as an alternative to dark energy or modified gravity to explain the accelerating universe. We show that the distribution of orientations of galaxy pairs can be used to test the Copernican principle that we are not in a central or special region of Universe. The popular void models can not fit both the latest type Ia supernova, cosmic microwave background data and the distribution of orientations of galaxy pairs simultaneously. Our results rule out the void models at the $4\sigma$ confidence level as the origin of cosmic acceleration and favor the Copernican principle.