Analysing the impact of far-out sidelobes on the imaging performance of the SKA-LOW telescopeReport as inadecuate


Analysing the impact of far-out sidelobes on the imaging performance of the SKA-LOW telescope


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Publication Date: 2017-03

Journal Title: Monthly Notices of the Royal Astronomical Society

Publisher: Oxford University Press

Volume: 465

Issue: 3

Pages: 3680-3692

Language: English

Type: Article

This Version: VoR

Metadata: Show full item record

Citation: Mort, B., Dulwich, F., Razavi-Ghods, N., Acedo, E., & Grainge, K. (2017). Analysing the impact of far-out sidelobes on the imaging performance of the SKA-LOW telescope. Monthly Notices of the Royal Astronomical Society, 465 (3), 3680-3692. https://doi.org/10.1093/mnras/stw2814

Abstract: The Square Kilometre Array’s Low Frequency instrument (SKA-LOW) will operate in the undersampled regime for most of the frequency band where grating lobes pose particular challenges. To achieve the expected level of sensitivity for SKA-LOW, it is particularly important to understand how interfering sources in both near and far side-lobes of the station beam affect the imaging performance. In this study, we discuss options for station designs, and adopting a random element layout, we assess its effectiveness by investigating how sources far from the main lobe of the station beam degrade images of the target field. These sources have the effect of introducing a noise-like corruption to images, which is called the far sidelobe confusion noise (FSCN). Using $\tiny{OSKAR}$, a software simulator accelerated using graphics processing units, we carried out end-to-end simulations using an all-sky model and telescope configuration representative of the SKA-LOW instrument. The FSCN is a function of both the station beam and the interferometric point spread function, and decreases with increasing observation time until the coverage of the aperture plane no longer improves. Using apodization to reduce the level of near-in sidelobes of the station beam had a notable improvement on the level of the FSCN at low frequencies. Our results indicate that the effects of picking up sources in the sidelobes are worse at low frequencies, where the array is less sparse.

Keywords: instrumentation: interferometers, techniques: interferometric, telescopes

Sponsorship: This work used the Wilkes GPU cluster at the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc., NVIDIA and Mellanox, and part funded by STFC with industrial sponsorship from Rolls Royce and Mitsubishi Heavy Industries.

Embargo Lift Date: 2100-01-01

Identifiers:

External DOI: https://doi.org/10.1093/mnras/stw2814

This record's URL: https://www.repository.cam.ac.uk/handle/1810/262875



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Author: Mort, BDulwich, F Razavi-Ghods, NAcedo, EDLGrainge, K

Source: https://www.repository.cam.ac.uk/handle/1810/262875



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