Skip to main content

Precision Cosmological Parameters

Final Report Summary - COSMOPARS (Precision Cosmological Parameters)

The project aimed to measurements of the microwave background fluctuations to provide precise measurements of key quantities such as the dark matter and dark energy densities of the Universe and its expansion rate, as well as providing precision tests of any new physics that may have happened before the Big Bang. Using data from the Planck satellite we were able to measure the parameters to percent-level accuracy, giving a sharp test of consistency for the simplest standard cosmological model (which still appears to be remarkably successful!). We developed novel analysis techniques to efficiently capture all the statistical uncertainties, and developed a series of numerical codes that have been widely used for the analysis of other data.

The project also aimed to establish new methods to measure the integrated mass in the universe by using gravitational lensing of the microwave background. Gravitational lensing causes small distortions of the light from the Big Bang caused by matter. We devised new powerful methods to extract this signal from the data, and used data from the Planck satellite to provide the best maps of the lensing effect over the full sky. Our new techniques will be particularly powerful with new more sensitive data, such as from the Simons Observatory currently being built in Chile.