Is there evidence for cosmic acceleration?

January 30, 2017
3:00pm to 4:00pm

IFT Seminar Room/Red Room

Theoretical Physics, general interest
Subir Sarkar
University of Oxford and Niels Bohr Institute

IFT Seminar Room/Red Room


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.