Marginal evidence for cosmic acceleration from Type Ia supernovae

TL;DR

This paper critically examines the evidence for cosmic acceleration from Type Ia supernovae data, finding that the data are more consistent with a constant expansion rate than previously believed.

Contribution

It provides a rigorous statistical analysis of supernova data, challenging the prevailing view of cosmic acceleration based on earlier interpretations.

Findings

Data are consistent with a constant expansion rate

Re-evaluation of supernova corrections reduces evidence for acceleration

Supports alternative explanations for supernova observations

Abstract

The "standard" model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these "standardisable candles" indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.