Speaker
Description
Chromatic instrumental response is a major source of foreground leakage in 21-cm Epoch-of-Reionization measurements. We explore a conceptual scaled-array strategy in which antenna coordinates are scaled with observing frequency so that, in the WODEN simulations, the frequency-normalised uvw sampling is common across channels to numerical precision. This removes one source of instrumental chromaticity and provides a controlled testbed for foreground separation.
Using point-source foregrounds plus an EoR-like signal, together with image-domain and visibility-domain diagnostics, we test this idea with several scaled-array configurations. The current results show successful narrow-band visibility-domain recovery: the foreground-only high-delay residual is strongly suppressed, while the recovered total delay power remains close to the EoR-only control. Image-domain recovery is more fragile, and poorer-PSF layouts require denser spectral sampling or give weaker recovery.
These early tests suggest that common-uv sampling could be a useful foreground-control component for future low-frequency EoR experiments, provided PSF quality, beam chromaticity, layout precision, and thermal-noise averaging requirements are controlled. I will present the simulation setup, the main recovery tests, and the remaining feasibility questions.