O universo está em expansão, pero no mucho!

terça-feira, outubro 25, 2016

Marginal evidence for cosmic acceleration from Type Ia supernovae

J. T. Nielsen, A. Guffanti & S. Sarkar

Scientific Reports 6, Article number: 35596 (2016)

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Received: 21 July 2016 Accepted: 03 October 2016 Published online: 21 October 2016

Source/Fonte: Planck Mission


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.


We thank the JLA collaboration for making their data and software public and M. Betoule for making the corrections we suggested to the catalogue. This work was supported by the Danish National Research Foundation through the Discovery Center at the Niels Bohr Institute and the award of a Niels Bohr Professorship to S.S.

Author information


Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen 2100, Denmark

J. T. Nielsen & S. Sarkar

Dipartimento di Fisica, Università degli Studi di Torino, via P. Giuria 1, I-10125 Torino, Italy

A. Guffanti

Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UK

S. Sarkar


All authors participated in the analysis and in the writing of the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to S. Sarkar.

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