The distance duality relation: violations, constraints and biases

March 24, 2022
3:00pm to 4:00pm

Online on Zoom

Specialist level
Natalie Hogg
IPhT Paris-Saclay

Online on Zoom


We live in the era of precision cosmology, but how can we be sure that we are not losing out on accuracy and becoming susceptible to bias when striving for ever-greater precision in our cosmological measurements? To illustrate this question, in this talk I will present forecast BAO, SNIa and standard siren constraints on a violation of the strict relationship between luminosity and angular diameter distances, known as the distance duality relation (DDR). I will show how such constraints can be biased in the presence of a generic modified gravity model and how such a bias can be correctly accounted for in similar analyses. I will then go on to show how, in combination with Hubble's law, the distance duality relation can be used as a consistency check for beyond-LCDM cosmological models, revealing a 2σ discrepancy between the validity of the DDR and the latest Cepheid-calibrated SNIa measurement of H0.

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