Aliasing from Galactic Plane Setting in Widefield Radio Interferometry

Abstract

Measurements with widefield radio interferometers often include the near-infinite gradient between the sky and the horizon. This causes aliasing inherent to the measurement itself, and is purely a consequence of the Fourier basis. For this reason, the horizon is often attenuated by the instrumental beam down to levels deemed inconsequential. However, this effect is enhanced via our own Galactic plane as it sets over the course of a night. We show all-sky simulations of the Galactic plane setting in a radio interferometer in detail for the first time. We then apply these simulations to the Murchison Widefield Array to show that a beam attenuation of 0.1% is not sufficient in some precision science cases. We determine that the noise statistics of the residual data image are drastically more Gaussian with aliasing removal, and explore consequences in simulation for cataloging of extragalactic sources and 21 cm Epoch of Reionization detection via the power spectrum.

10 pages, 3 figures, published in ApJ

References in corpus (12)

• The Epoch of Reionization Window: I. Mathematical Formalism
• Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations
• Fast Holographic Deconvolution: a new technique for precision radio interferometry
• First Season MWA Phase II EoR Power Spectrum Results at Redshift 7
• The impact of interference excision on 21-cm Epoch of Reionization power spectrum analyses
• The FHD/$\mathbf{\epsilon }$ppsilon Epoch of Reionization Power Spectrum Pipeline
• Radio Source Extraction with ProFound
• On the use of temporal filtering for mitigating galactic synchrotron calibration bias in 21 cm reionization observations
• The Role of the Instrumental Response in 21 cm EoR Power Spectrum Gridding Analyses
• Investigating the Contribution of Extended Radio Sources to the Epoch of Reionisation Power Spectrum
• Skew spectrum and smoothed skewness of 21-cm signals from epoch of reionization
• The Impact of ionization Morphology and X-ray Heating on the Cosmological 21cm Skew Spectrum

Cited by in corpus (1)

• Diffuse radio sky models using large scale shapelets