Mitigating calibration errors from mutual coupling with time-domain filtering of 21 cm cosmological radio observations

ABSTRACT The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionization (EoR). This has led to the construction of low-frequency radio interferometric arrays, such as the Hydrogen Epoch of Reionization Array (HERA), aimed at systematically mapping this emission for the first time. Precision calibration, however, is a requirement in 21 cm radio observations. Due to the spatial compactness of HERA, the array is prone to the effects of mutual coupling, which inevitably lead to non-smooth calibration errors that contaminate the data. When unsmooth gains are used in calibration, intrinsically spectrally smooth foreground emission begins to contaminate the data in a way that can prohibit a clean detection of the cosmological EoR signal. In this paper, we show that the effects of mutual coupling on calibration quality can be reduced by applying custom time-domain filters to the data prior to calibration. We find that more robust calibration solutions are derived when filtering in this way, which reduces the observed foreground power leakage. Specifically, we find a reduction of foreground power leakage by 2 orders of magnitude at $k_\parallel \approx 0.5$ h Mpc$^{-1}$.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-10-07
DOI
https://doi.org/10.1093/mnras/stae2303
Citations
6
Primary Topic
Radio Astronomy Observations and Technology
Type
article
Field-Weighted Citation Impact
1.99

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article

Mitigating calibration errors from mutual coupling with time-domain filtering of 21 cm cosmological radio observations

Bradley Marero, Eloy de Lera Acedo, Hans Nuwegeld, Tashalee S. Billings et al.
6 citations
Monthly Notices of the Royal Astronomical Society
Radio Astronomy Observations and Technology
1.99
article

Mitigating calibration errors from mutual coupling with time-domain filtering of 21 cm cosmological radio observations

Bradley Marero, Eloy de Lera Acedo, Hans Nuwegeld, Tashalee S. Billings, S Choudhuri, James Robnett, Scott Dynes, Hertzog L. Bester, Piyanat Kittiwisit, Mário G. Santos, Ntsikelelo Charles, D. Riley, Eva Rath, M. F. Morales, Ziyaad Halday, Abhik Ghosh, Sukhdeep Singh, A Liu, Joseph Stephen 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, John E. Kerrigan, T. Cox, Deepthi Gorthi, Nicholas S. Kern, Michael J. Wilensky, Matthew Kolopanis, Zachary E. Martinot, Pieter van Wyngaarden, Ruby Byrne, Robert Pascua, Haimei Zheng, A. T. Josaitis, James Aguirre, Steven R. Furlanetto, Andrei Mesinger, Peter K. G. Williams, Jacqueline N. Hewitt, B. J. Hazelton, A P Beardsley, Aaron R. Parsons, Kingsley Gale‐Sides, Justin Ely, O. Smirnov, Lindsay M. Berkhout, N Mohamed-Hinds, Kai Chen, Ying Qin, Steven Carey, Kathryn Rosie, L R McBride, Mark Dexter, R. Fritz, Dave MacMahon, J. D. Bowman
article en
6 citations

Abstract

ABSTRACT The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionization (EoR). This has led to the construction of low-frequency radio interferometric arrays, such as the Hydrogen Epoch of Reionization Array (HERA), aimed at systematically mapping this emission for the first time. Precision calibration, however, is a requirement in 21 cm radio observations. Due to the spatial compactness of HERA, the array is prone to the effects of mutual coupling, which inevitably lead to non-smooth calibration errors that contaminate the data. When unsmooth gains are used in calibration, intrinsically spectrally smooth foreground emission begins to contaminate the data in a way that can prohibit a clean detection of the cosmological EoR signal. In this paper, we show that the effects of mutual coupling on calibration quality can be reduced by applying custom time-domain filters to the data prior to calibration. We find that more robust calibration solutions are derived when filtering in this way, which reduces the observed foreground power leakage. Specifically, we find a reduction of foreground power leakage by 2 orders of magnitude at $k_\parallel \approx 0.5$ h Mpc$^{-1}$.

Monthly Notices of the Royal Astronomical SocietyVol. 534(4)
Australian National University (AU), Raman Research Institute (IN), 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 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), North-West University (ZA), Université Paris-Saclay (FR), Brown University (US), University of Manchester (GB), Institut d'Astrophysique Spatiale (FR), Istituto di Radioastronomia di Bologna (IT), South African Radio Astronomy Observatory (ZA), Center for Astrophysics Harvard & Smithsonian (US), 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 Aeronautics and Space Administration, Canadian Institute for Advanced Research, McGill University, Space Telescope Science Institute, National Research Foundation, Ministero degli Affari Esteri e della Cooperazione Internazionale, Ministero dell'Università e della Ricerca, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council
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Openalex Percentile: Top 14%
Radio Astronomy Observations and Technology
1.99
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