Constraining the physics of the early Universe with CMB polarisation

Lead Research Organisation: University of Manchester
Department Name: Physics and Astronomy


Perhaps the most useful cosmological probe is the Cosmic Microwave Background (CMB). The
temperature anisotropies have been measured extremely well by the Planck satellite and this
has established the current concordance cosmological model. However, the CMB has not
been utilised fully yet: measurements of the CMB polarisation offer an opportunity to probe
the physical processes that occurred in the very early Universe. The linear polarisation signal
is decomposed into E-mode and B-mode contributions, where the detection of a B-mode
polarization signal on large angular scales would demonstrate the existence of primordial
gravitational waves. This would be indicative of inflation and provide a platform for exploring
physics at the Grand Unified Theory (GUT) energy scale. The detection of the B-mode signal
is thus a major goal of future CMB observations, such as the ground-based Simons array and
Simons Observatory, and the satellite LiteBIRD.
The polarisation signal of interest is faint and as such optimal observation strategy,
instrument design, and data-analysis is necessary. Spurious signals in the data that resemble
the B-mode signature can be generated by instrument and sky scanning imperfections, as
such these must be carefully accounted for. This project's aim is the optimisation of the
instrument design, scan strategy, and data analysis techniques for future CMB experiments
using analytic techniques and computer simulations


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Ade P (2019) The Simons Observatory: science goals and forecasts in Journal of Cosmology and Astroparticle Physics

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Lee Adrian (2019) The Simons Observatory in Bulletin of the American Astronomical Society

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Thomas D (2020) Controlling systematics in ground-based CMB surveys with partial boresight rotation in Monthly Notices of the Royal Astronomical Society

Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/R504956/1 01/10/2017 30/09/2021
1964068 Studentship ST/R504956/1 05/09/2017 30/09/2021 Nialh Mccallum