What is the physical origin of all the structure in the Universe?

In the last decade, cosmology has undergone a revolution, becoming a precision science. Remarkably, uncertainties in the measurements of the constituents of the universe and its expansion history have been reduced from factors of a few to percent-precision in some cases. As a result, we have taken a census of the universe and learnt much about its evolution. The fossilized heat of the Big Bang, the cosmic microwave background (CMB), has been the foundation for the age of precision cosmology.

The CMB is a picture of the universe when it was less than 0.01% of its present age. It carries the almost unblemished signature of primordial fluctuations in the very early universe which, under the action of gravitational instability, grew into the remarkable variety of structures that fill the universe today. Given the extreme conditions at these early times, the CMB is our best hope of uncovering fingerprints of the physics operating at very high energy scales, inaccessible to Earth-bound particle accelerators.

Meanwhile, we are acquiring enormous volumes of data on the large scale structure (LSS) of the universe, the “scaffolding” of dark matter traced by galaxies. Galaxy surveys have huge potential to enhance our understanding of the primordial universe: the physical origin of the structure traced by galaxies is the same as that seen in the CMB, yet galaxy surveys sample different physical scales, at different epochs in the history of the universe. This complementary information, when combined with the CMB, can unlock the secrets of the origin of cosmic structure.

CMB data have thus far led the way in constraining early universe physics, and ESA’s Planck satellite is currently mapping the CMB at the highest precision ever achieved. However, next generation galaxy surveys – such as the Dark Energy Survey (DES), which saw first light in 2012 – will rival the CMB in their ability to unlock the secrets of the primordial universe.

CosmicDawn is a project funded by the European Research Council through the ERC Starting Grants scheme. Coordinated by Prof. Hiranya Peiris, the CosmicDawn Team are using the latest CMB and LSS data to rigorously test the theory of inflation, the dominant paradigm for the origin of cosmic structure, and to seek signatures of new physics that are likely to exist at these unexplored energies.

 In order to achieve these challenging goals, the CosmicDawn project combines theoretical modelling at the cutting edge of fundamental physics, advanced Bayesian and wavelet methods to extract reliable information from the data, and a deep understanding of data limitations and control of systematic errors. The CosmicDawn Team members have diverse backgrounds (in observational cosmology, theoretical physics, signal processing, and Bayesian inference) and work in interdisciplinary collaborations.

If you are interested in joining us, please check out the Vacancies page!