Issue |
A&A
Volume 646, February 2021
|
|
---|---|---|
Article Number | A84 | |
Number of page(s) | 21 | |
Section | Numerical methods and codes | |
DOI | https://doi.org/10.1051/0004-6361/202039258 | |
Published online | 12 February 2021 |
Comparison of classical and Bayesian imaging in radio interferometry
Cygnus A with CLEAN and resolve
1
Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
e-mail: parras@mpa-garching.mpg.de
2
Ludwig-Maximilians-Universität München (LMU), Geschwister-Scholl-Platz 1, 80539 München, Germany
3
Technische Universität München (TUM), Boltzmannstr. 3, 85748 Garching, Germany
4
South African Radio Astronomy Observatory, 2 Fir Street, Black River Park, Observatory (North Gate entrance) 7925, South Africa
5
Department of Physics and Electronics, Rhodes University, Grahamstown 6140, South Africa
6
National Radio Astronomy Observatory, PO Box O, Socorro, NM 87801, USA
Received:
26
August
2020
Accepted:
1
December
2020
CLEAN, the commonly employed imaging algorithm in radio interferometry, suffers from a number of shortcomings: In its basic version, it does not have the concept of diffuse flux, and the common practice of convolving the CLEAN components with the CLEAN beam erases the potential for super-resolution; it does not output uncertainty information; it produces images with unphysical negative flux regions; and its results are highly dependent on the so-called weighting scheme as well as on any human choice of CLEAN masks for guiding the imaging. Here, we present the Bayesian imaging algorithm resolve , which solves the above problems and naturally leads to super-resolution. We take a VLA observation of Cygnus A at four different frequencies and image it with single-scale CLEAN, multi-scale CLEAN, and resolve. Alongside the sky brightness distribution, resolve estimates a baseline-dependent correction function for the noise budget, the Bayesian equivalent of a weighting scheme. We report noise correction factors between 0.4 and 429. The enhancements achieved by resolve come at the cost of higher computational effort.
Key words: techniques: interferometric / methods: statistical / methods: data analysis / instrumentation: interferometers
© P. Arras et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Open Access funding provided by Max Planck Society.
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