Gaussian Processes for Systematic Mitigation for Global 21-cm Cosmology Experiments
Christian Kirkham (University of Cambridge)Cambridge Fluids Network - fluids-related seminars21 February 2024 1:15pmThe Hoyle Lecture Theatre + Zoom Radio observations of the neutral hydrogen signal from the Cosmic Dawn and Epoch of Reionisation have helped to provide constraints on the properties of the first stars and galaxies. Since this global 21-cm cosmological signal from the Cosmic Dawn is effectively constant on observing timescales and since effects resulting from systematics will vary with time, the effects of these systematics can be mitigated without the need for a model of the systematic. In this talk I will present a method to account for unmodelled time-varying systematics in 21-cm radio cosmology experiments using a Gaussian process method to account for correlations between time bins in a fully Bayesian way. I will finally present a further method using Gaussian process regression to calculate a mean fit to the residuals over time, providing a basis for producing a model of the time-varying systematic.