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

Understand

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.