Inflation science from the next generation Cosmic Microwave Background B-mode surveys

Our current best understanding of the origin of the universe envisages a rapid expansion phase, named cosmic inflation, occurring during the first trillionth of a second after the Big Bang and stretching primordial density ripples to cosmological scales. The most distinctive prediction of inflationary theories, which as of today is still lacking evidence from data, is the presence of a background of primordial gravitational waves (GWs) inducing a Cosmic Microwave Background (CMB) B-mode polarization pattern. This signal is however extremely weak and obscured by other sources of emission coming from our Galaxy, including thermal dust and synchrotron emission.

Many experiments are currently looking for primordial GWs with the CMB and more dedicated CMB B-mode surveys are being planned for the next decade. Here at Cardiff we work on CMB B-mode science for the ground-based Atacama Cosmology Telescope (ACT), Simons Observatory (SO) and CMB-S4 projects, and for the proposed LiteBIRD satellite mission. ACT is now observing with its 3rd-generation of receiver and will be overtaken by SO from 2021; CMB-S4 and LiteBIRD will operate from mid-to-late 2020s.

This project will focus on developing analysis strategies to separate the primordial CMB B-mode signal from foreground contaminants and on constraining inflationary models from GW data. This work will include the analysis of ACT data, pipeline construction and first data analysis of SO observations, and preparatory work for CMB-S4 and LiteBIRD.


The work requires expertise in Python, Fortran 90 or C.