Speaker
Description
"Detecting the redshifted H I 21-cm signal from the Cosmic Dawn and Epoch of Reionization requires exquisite control over propagation effects that distort low-frequency radio measurements before they reach the interferometer. In this talk, I will discuss how plasma-induced refraction, scattering and frequency-dependent path distortions, arising from both the terrestrial ionosphere and astrophysical plasma media, can bias precision 21-cm observables if not carefully modelled and mitigated.
Drawing on my ongoing research in radiative transfer through magnetised plasma including refraction and scattering of radio waves in the solar corona, I will outline a unified physical framework to understand ray bending, angular broadening and spectral mode-mixing in low-frequency radio propagation. I will highlight conceptual parallels between solar-coronal propagation and line-of-sight plasma effects relevant for EoR experiments particularly their impact on foreground chromaticity, calibration stability and power-spectrum contamination.
The talk will emphasise how propagation effects couple to instrumental response, potentially leaking foreground power into the EoR window, and how forward modelling via ray-based or wave-optics approaches can complement existing calibration and foreground-mitigation pipelines. I will also discuss prospects for incorporating physically motivated plasma models into end-to-end simulations and parameter-inference frameworks for SKA-Low.
Finally, I will outline how multi-frequency diagnostics and cross-correlations with external datasets can help disentangle propagation-induced systematics from cosmological signals. This work aims to contribute toward improving robustness in 21-cm measurements and strengthening SKA-Low readiness by bridging plasma physics, radiative transfer and observational cosmology."
