Redundant-baseline calibration of the hydrogen epoch of reionization array
Redundant-baseline calibration of the hydrogen epoch of reionization array
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DOI：
10.1093/mnras/staa3001
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发表时间：
2020-03
影响因子：
4.8
通讯作者：
J. Dillon;Max E. Lee;Z. Ali;A. Parsons;Naomi Orosz;C. Nunhokee;P. Plante;A. Beardsley;N. Kern;Zara Abdurashidova;J. Aguirre;P. Alexander;Yanga Balfour;G. Bernardi;T. Billings;J. Bowman;R. Bradley;P. Bull;Jacob Burba;S. Carey;C. Carilli;Carina Cheng;D. DeBoer;M. Dexter;E. D. L. Acedo;J. Ely;A. Ewall-Wice;N. Fagnoni;Randall Fritz;S. Furlanetto;K. Gale-Sides;B. Glendenning;Deepthi Gorthi;B. Greig;J. Grobbelaar;Ziyaad Halday;B. Hazelton;J. Hewitt;J. Hickish;D. Jacobs;A. Julius;Joshua Kerrigan;P. Kittiwisit;S. Kohn;M. Kolopanis;A. Lanman;Telalo Lekalake;David Lewis;Adrian Liu;Yin-Zhe Ma;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Eunice Matsetela;A. Mesinger;Mathakane Molewa;M. Morales;Tshegofalang Mosiane;S. Murray;A. Neben;B. Nikolic;R. Pascua;Nipanjana Patra;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;Mário G. Santos;P. Sims;Craig H. Smith;A. Syce;Max Tegmark;N. Thyagarajan;P. Williams;Haoxuan Zheng
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作者：
J. Dillon;Max E. Lee;Z. Ali;A. Parsons;Naomi Orosz;C. Nunhokee;P. Plante;A. Beardsley;N. Kern;Zara Abdurashidova;J. Aguirre;P. Alexander;Yanga Balfour;G. Bernardi;T. Billings;J. Bowman;R. Bradley;P. Bull;Jacob Burba;S. Carey;C. Carilli;Carina Cheng;D. DeBoer;M. Dexter;E. D. L. Acedo;J. Ely;A. Ewall-Wice;N. Fagnoni;Randall Fritz;S. Furlanetto;K. Gale-Sides;B. Glendenning;Deepthi Gorthi;B. Greig;J. Grobbelaar;Ziyaad Halday;B. Hazelton;J. Hewitt;J. Hickish;D. Jacobs;A. Julius;Joshua Kerrigan;P. Kittiwisit;S. Kohn;M. Kolopanis;A. Lanman;Telalo Lekalake;David Lewis;Adrian Liu;Yin-Zhe Ma;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Eunice Matsetela;A. Mesinger;Mathakane Molewa;M. Morales;Tshegofalang Mosiane;S. Murray;A. Neben;B. Nikolic;R. Pascua;Nipanjana Patra;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;Mário G. Santos;P. Sims;Craig H. Smith;A. Syce;Max Tegmark;N. Thyagarajan;P. Williams;Haoxuan Zheng
在21厘米宇宙学中，精确校准是将中性氢信号从非常明亮但光谱平滑的天体物理前景中分离出来的关键。氢时代再电离阵列（HERA）是一个专门用于21厘米宇宙学的干涉仪，目前正在南非建造，其设计主要是利用相同干涉仪模式重复测量的自洽性进行校准。这种技术称为冗余基线校准，解决了校准问题中的大部分内部自由度。然而，它假设天线元件具有精确放置在冗余网格上的相同的主波束。在这项工作中，我们审查的算法，使冗余基线校准和报告结果与HERA数据的详细实施。我们量化现实世界中的非冗余的影响，以及它们如何比较的理想化的情况下，冗余的测量不同，只有在他们的噪声实现。最后，我们研究了非冗余如何在我们的校准解决方案中产生虚假的时间结构-无论是在数据中还是在模拟中-并提出了缓解这种结构的策略。
In 21-cm cosmology, precision calibration is key to the separation of the neutral hydrogen signal from very bright but spectrally smooth astrophysical foregrounds. The Hydrogen Epoch of Reionization Array (HERA), an interferometer specialized for 21-cm cosmology and now under construction in South Africa, was designed to be largely calibrated using the self-consistency of repeated measurements of the same interferometric modes. This technique, known as redundant-baseline calibration resolves most of the internal degrees of freedom in the calibration problem. It assumes, however, on antenna elements with identical primary beams placed precisely on a redundant grid. In this work, we review the detailed implementation of the algorithms enabling redundant-baseline calibration and report results with HERA data. We quantify the effects of real-world non-redundancy and how they compare to the idealized scenario in which redundant measurements differ only in their noise realizations. Finally, we study how non-redundancy can produce spurious temporal structure in our calibration solutions – both in data and in simulations – and present strategies for mitigating that structure.