Ian Hothi — Exploring the Epoch of Reionization with Scattering Transforms

Exploring the Epoch of Reionization with Scattering Transforms

Abstract (assisted by AI): This presentation explores the Epoch of Reionization (EoR), a key period in the history of the Universe when the intergalactic medium transitioned from neutral to ionized, using 21 cm hydrogen emission as a probe. Since current radio interferometers face significant challenges in detecting this faint signal due to foreground contamination, instrumental effects, and systematic errors, the presentation introduces scattering transforms as a way to extract information beyond the conventional power spectrum, particularly the non-Gaussian features of the 21 cm signal. It presents the development of a three-dimensional scattering transform tailored to EoR lightcones, designed to capture the signal’s key characteristics and support future foreground separation methods. The results show that this approach can reproduce the statistical properties of simulated lightcones and provide a foundation for separating the cosmological signal from foregrounds. The presentation also introduces a 2+1D scattering transform that combines spatial information with redshift evolution to improve cosmological parameter inference. Using simulations from 21cmFAST, this method achieves tighter parameter constraints than traditional power-spectrum statistics, even in the presence of substantial instrumental noise. Overall, scattering transforms offer a promising framework for analysing 21 cm observations, improving our understanding of the Epoch of Reionization and enabling more informative constraints on the physical processes that shaped the early Universe.