Supernovae data and perturbative deviation from homogeneity

TL;DR

This paper demonstrates that small spherically symmetric perturbations in a dust-dominated universe can mimic cosmic acceleration observed in supernova data without requiring dark energy, by fitting the magnitude-redshift relation.

Contribution

It shows that perturbative deviations from homogeneity can account for supernova observations typically attributed to dark energy, challenging the need for non-perturbative models.

Findings

Perturbations can produce apparent acceleration consistent with supernova data.

Small gravitational potential perturbations suffice to fit the magnitude-redshift relation.

Perturbed FRW models are equivalent to certain Lemaître-Tolman-Bondi models along the light cone.

Abstract

We show that a spherically symmetric perturbation of a dust dominated $\Omega=1$ FRW universe in the Newtonian gauge can lead to an apparent acceleration of standard candles and provide a fit to the magnitude-redshift relation inferred from the supernovae data, while the perturbation in the gravitational potential remains small at all scales. We also demonstrate that the supernovae data does not necessarily imply the presence of some additional non-perturbative contribution by showing that any Lemaitre-Tolman-Bondi model fitting the supernovae data (with appropriate initial conditions) will be equivalent to a perturbed FRW spacetime along the past light cone.