Investigating mutual coupling in the hydrogen epoch of reionization array and mitigating its effects on the 21-cm power spectrum

ABSTRACT Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum, but some k-modes remain systematics-dominated. Mutual coupling is a major systematic that must be overcome in order to detect the 21-cm signal, and simulations that reproduce effects seen in the data can guide strategies for mitigating mutual coupling. In this paper, we analyse 12 nights of data from the Hydrogen Epoch of Reionization Array and compare the data against simulations that include a computationally efficient and physically motivated semi-analytic treatment of mutual coupling. We find that simulated coupling features qualitatively agree with coupling features in the data; however, coupling features in the data are brighter than the simulated features, indicating the presence of additional coupling mechanisms not captured by our model. We explore the use of fringe-rate filters as mutual coupling mitigation tools and use our simulations to investigate the effects of mutual coupling on a simulated cosmological 21-cm power spectrum in a ‘worst case’ scenario where the foregrounds are particularly bright. We find that mutual coupling contaminates a large portion of the ‘EoR Window’, and the contamination is several orders-of-magnitude larger than our simulated cosmic signal across a wide range of cosmological Fourier modes. While our fiducial fringe-rate filtering strategy reduces mutual coupling by roughly a factor of 100 in power, a non-negligible amount of coupling cannot be excised with fringe-rate filters, so more sophisticated mitigation strategies are required.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-06-27
DOI
https://doi.org/10.1093/mnras/staf1012
Citations
6
Primary Topic
Gyrotron and Vacuum Electronics Research
Type
article
Field-Weighted Citation Impact
7.48

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article

Investigating mutual coupling in the hydrogen epoch of reionization array and mitigating its effects on the 21-cm power spectrum

Bradley Marero, Hans Nuwegeld, Tashalee S. Billings, S Choudhuri et al.
6 citations
Monthly Notices of the Royal Astronomical Society
Gyrotron and Vacuum Electronics Research
7.48
article

Investigating mutual coupling in the hydrogen epoch of reionization array and mitigating its effects on the 21-cm power spectrum

Bradley Marero, Hans Nuwegeld, Tashalee S. Billings, S Choudhuri, James Robnett, Scott Dynes, Piyanat Kittiwisit, Mário G. Santos, Yin-Zhe Ma, D. Riley, Eva Rath, M. F. Morales, Ziyaad Halday, Abhik Ghosh, A Liu, Joseph S. Dillon, R. Baartman, Zuhra Abdurashidova, Aaron Ewall‐Wice, Jacob Burba, Dara Storer, G. Bernardi, Nico Eksteen, Philip Bull, Tong-Ming Huang, Peter Sims, David R. DeBoer, J. Hickish, Mathakane Molewa, Cresshim Malgas, Lourence Malan, B. K. Gehlot, B Nikolic, Hugh Garsden, Tina Adams, Steven Murray, N. Razavi‐Ghods, Adam Lanman, Keith Malgas, Nipanjana Patra, Hilton Swarts, Adélie Gorce, Jianrong Tan, Daniel Jacobs, Alec Josaitis, John E. Kerrigan, T. Cox, Deepthi Gorthi, Nicholas S. Kern, Michael J. Wilensky, Matthew Kolopanis, Paul La Plante, Saurabh Singh, Nicolas Fagnoni, Zachary E. Martinot, Pieter van Wyngaarden, Ruby Byrne, Robert Pascua, Haimei Zheng, James Aguirre, Steven R. Furlanetto, Andrei Mesinger, Peter K. G. Williams, Jacqueline N. Hewitt, B. J. Hazelton, Judd D. Bowman, A P Beardsley, Kuan‐Fu Chen, Aaron R. Parsons, Kingsley Gale‐Sides, Justin Ely, Lindsay M. Berkhout, N Mohamed-Hinds, Ying Qin, Steven Carey, Kathryn Rosie, L R McBride, Mark Dexter, R. Fritz, Dave MacMahon
article en
6 citations

Abstract

ABSTRACT Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum, but some k-modes remain systematics-dominated. Mutual coupling is a major systematic that must be overcome in order to detect the 21-cm signal, and simulations that reproduce effects seen in the data can guide strategies for mitigating mutual coupling. In this paper, we analyse 12 nights of data from the Hydrogen Epoch of Reionization Array and compare the data against simulations that include a computationally efficient and physically motivated semi-analytic treatment of mutual coupling. We find that simulated coupling features qualitatively agree with coupling features in the data; however, coupling features in the data are brighter than the simulated features, indicating the presence of additional coupling mechanisms not captured by our model. We explore the use of fringe-rate filters as mutual coupling mitigation tools and use our simulations to investigate the effects of mutual coupling on a simulated cosmological 21-cm power spectrum in a ‘worst case’ scenario where the foregrounds are particularly bright. We find that mutual coupling contaminates a large portion of the ‘EoR Window’, and the contamination is several orders-of-magnitude larger than our simulated cosmic signal across a wide range of cosmological Fourier modes. While our fiducial fringe-rate filtering strategy reduces mutual coupling by roughly a factor of 100 in power, a non-negligible amount of coupling cannot be excised with fringe-rate filters, so more sophisticated mitigation strategies are required.

Monthly Notices of the Royal Astronomical SocietyVol. 541(2)
Australian National University (AU), California Institute of Technology (US), American Astronomical Society (US), Centre National de la Recherche Scientifique (FR), Space Science Institute (US), University of Nevada, Las Vegas (US), Scuola Normale Superiore (IT), University of Cape Town (ZA), University of California, Los Angeles (US), University of Washington (US), Rhodes University (ZA), University of Cambridge (GB), Indian Institute of Technology Madras (IN), Stellenbosch University (ZA), National Radio Astronomy Observatory (US), Université Paris-Saclay (FR), Brown University (US), University of Manchester (GB), Bridge University (SS), Institut d'Astrophysique Spatiale (FR), Istituto di Radioastronomia di Bologna (IT), South African Radio Astronomy Observatory (ZA), Center for Astrophysics Harvard & Smithsonian (US), University of Washington Applied Physics Laboratory (US), Astronomical Observatory (RS), McGill University (CA), Arizona State University (US), Winona State University (US), Massachusetts Institute of Technology (US), University of Pennsylvania (US), University of the Western Cape (ZA), University of California, Berkeley (US)
National Science Foundation, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Massachusetts Institute of Technology, Canadian Institute for Advanced Research, McGill University, Space Telescope Science Institute, European Commission, National Research Foundation, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council
Openalex Percentile: Top 3%
Gyrotron and Vacuum Electronics Research
7.48
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