A tomographic test of cosmological principle using the JLA compilation of type Ia supernovae

TL;DR

This study tests the cosmological principle by analyzing supernova data for anisotropies across different redshifts, finding no significant deviations and constraining anisotropic amplitude very tightly.

Contribution

It introduces a redshift tomographic method to detect anisotropies in supernova data, providing stringent constraints on deviations from isotropy.

Findings

No significant anisotropy detected in supernova data.

Anisotropic amplitude constrained to less than a few thousandths at 95% confidence.

Method effectively tests the cosmological principle across redshift bins.

Abstract

We test the cosmological principle by fitting a dipolar modulation of distance modulus and searching for an evolution of this modulation with respect to cosmological redshift. Based on a redshift tomographic method, we divide the Joint Light-curve Analysis compilation of supernovae of type Ia into different redshift bins, and employ a Markov-Chain Monte-Carlo method to infer the anisotropic amplitude and direction in each redshift bin. However, we do not find any significant deviations from the cosmological principle, and the anisotropic amplitude is stringently constrained to be less than a few thousandths at $95\%$ confidence level.