Probing Backreaction Effects with Supernova Data

TL;DR

This paper investigates how inhomogeneities in the universe affect the measurement of the Hubble constant using supernova data, exploring the significance of backreaction effects on cosmological observations.

Contribution

It provides an analysis of backreaction effects on Hubble constant measurements using supernova data and compares observational results with theoretical predictions.

Findings

Backreaction effects can influence Hubble constant measurements.

The size of the averaging volume impacts the magnitude of backreaction effects.

Comparison shows partial agreement between observations and theory.

Abstract

As the Einstein equations are non-linear, spatial averaging and temporal evolution do not commute. Therefore, the evolution of the averaged universe is affected by inhomogeneities. It is, however, highly controversial how large these cosmological backreaction effects are. We use the supernova data of the Constitution set up to a redshift of 0.1 in order to analyse to what extent the measurement of the Hubble constant is affected. The size of the effect depends on the size of the volume that is averaged over. The observational results are then compared to the theory of the backreaction mechanism.