Charles, N.Kern, N. S.Pascua, R.Bernardi, G.Bester, L.Smirnov, O.Acedo, E. D.L.Abdurashidova, Z.Adams, T.Aguirre, J. E.Baartman, R.Beardsley, A. P.Berkhout, L. M.Billings, T. S.Bowman, J. D.Bull, P.Burba, J.Byrne, R.Carey, S.Chen, K.Choudhuri, S.Cox, T.DeBoer, D. R.Dexter, M.Dillon, J. S.Dynes, S.Eksteen, N.Ely, J.Ewall-Wice, A.Fritz, R.Furlanetto, S. R.Gale-Sides, K.Garsden, H.Gehlot, B. K.Ghosh, A.Gorce, A.Gorthi, D.Halday, Z.Hazelton, B. J.Hewitt, J. N.Hickish, J.Huang, T.Jacobs, D. C.Josaitis, A.Kerrigan, J.Kittiwisit, P.Kolopanis, M.Lanman, A.Liu, A.Qin, Y.2025-05-312025-05-310035-8711WOS:001339748900012http://www.scopus.com/inward/record.url?scp=85207334679&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733755927The 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|| approximate to 0 . 5 h Mpc(-1).This work was supported in part by the Italian Ministry of Foreign Affairs and International Cooperation, grant number ZA23GR03. GB acknowledges support from the Ministry of Universities and Research (MUR) through the PRIN project 'Optimal inference from radio images of the epoch of reionization'. NK acknowledges support from NASA through the NASA Hubble Fellowship grant #HST-HF2-51533.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. MGS acknowledges support from the South African Radio Astronomy Observatory and National Research Foundation (grant no. 84156). OMS's research was supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation (grant No. 81737). AL and RP acknowledge support from the Trottier Space Institute, the Canadian Institute for Advanced Research (CIFAR) Azrieli Global Scholars program, a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant, a NSERC/Fonds de recherche du Quebec-Nature et Technologies NOVA grant, the Canada 150 Research Chairs Program, the Sloan Research Fellowship, and the William Dawson Scholarship at McGill.15enPublisher Copyright: © 2024 The Author(s).Cosmology: dark ages, reionization, first starsCosmology: observationsInstrumentation: interferometersMethods: data analysis2024-10-2110.1093/mnras/stae230385207334679