Characterize primary-beam sidelobe effects on foreground cleaning

Characterize the impact of MeerKAT primary-beam sidelobes on interferometric HI observations and on foreground cleaning with the Generalised Visibility Internal Linear Combination method.

Background

The simulations approximate the MeerKAT primary beam with a circular Gaussian. Although this describes the main lobe adequately, the actual MeerKAT beam contains secondary peaks, or sidelobes, around the main lobe.

The effect of these sidelobes on the simulated observations and on the performance of foreground-cleaning methods is not analyzed in the paper and remains an explicit subject for subsequent work.

References

Although the main lobe of the primary beam fits well to a Gaussian profile, MeerKAT's primary beam has secondary peaks surrounding the main lobe, named sidelobes. We defer a detailed analysis of the impact of sidelobes on such observations and their effect on foreground cleaning to future work.

— Generalised Visibility ILC: a new foreground mitigation strategy for interferometric HI intensity mapping in the low-redshift Universe  (2609.19276 - Ruiz-Granda et al., 16 Sep 2026) in Section 2.4, subsection “Instrument”