Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae

TL;DR

This paper proposes a minimal void model to explain supernovae and WMAP data without dark energy, suggesting large-scale inhomogeneities could mimic cosmic acceleration and align with multiple cosmological observations.

Contribution

It introduces a minimal void scenario with specific parameters that can account for supernovae and WMAP data without dark energy, and discusses its consistency with other measurements.

Findings

Void model fits supernovae data

Void model consistent with WMAP data

Potential observable signatures of the void scenario

Abstract

It is now a known fact that if we happen to be living in the middle of a large underdense region, then we will observe an "apparent acceleration", even when any form of dark energy is absent. In this paper, we present a "Minimal Void" scenario, i.e. a "void" with minimal underdensity contrast (of about -0.4) and radius (~ 200-250 Mpc/h) that can, not only explain the supernovae data, but also be consistent with the 3-yr WMAP data. We also discuss consistency of our model with various other measurements such as Big Bang Nucleosynthesis, Baryon Acoustic Oscillations and local measurements of the Hubble parameter, and also point out possible observable signatures.