Mitigating Internal Instrument Coupling for 21 cm Cosmology. II. A Method Demonstration with the Hydrogen Epoch of Reionization Array
Mitigating Internal Instrument Coupling for 21 cm Cosmology. II. A Method Demonstration with the Hydrogen Epoch of Reionization Array
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DOI：
10.3847/1538-4357/ab5e8a
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发表时间：
2019-09
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通讯作者：
N. Kern;A. Parsons;J. Dillon;A. Lanman;Adrian Liu;P. Bull;A. Ewall-Wice;Zara Abdurashidova;J. Aguirre;P. Alexander;Z. Ali;Yanga Balfour;A. Beardsley;G. Bernardi;J. Bowman;R. Bradley;Jacob Burba;C. Carilli;Carina Cheng;D. DeBoer;M. Dexter;E. D. L. Acedo;N. Fagnoni;Randall Fritz;S. Furlanetto;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;P. Plante;Telalo Lekalake;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Eunice Matsetela;A. Mesinger;Mathakane Molewa;M. Morales;Tshegofalang Mosiane;S. Murray;A. Neben;Nipanjana Patra;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;P. Sims;Craig H. Smith;A. Syce;N. Thyagarajan;P. Williams;Haoxuan Zheng
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作者：
N. Kern;A. Parsons;J. Dillon;A. Lanman;Adrian Liu;P. Bull;A. Ewall-Wice;Zara Abdurashidova;J. Aguirre;P. Alexander;Z. Ali;Yanga Balfour;A. Beardsley;G. Bernardi;J. Bowman;R. Bradley;Jacob Burba;C. Carilli;Carina Cheng;D. DeBoer;M. Dexter;E. D. L. Acedo;N. Fagnoni;Randall Fritz;S. Furlanetto;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;P. Plante;Telalo Lekalake;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Eunice Matsetela;A. Mesinger;Mathakane Molewa;M. Morales;Tshegofalang Mosiane;S. Murray;A. Neben;Nipanjana Patra;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;P. Sims;Craig H. Smith;A. Syce;N. Thyagarajan;P. Williams;Haoxuan Zheng
本文对再电离阵列（HERA）氢历元第一期的内反射和交叉耦合系统进行了研究。在一篇配套论文中，我们概述了这种系统的数学形式，并提出了建模和从数据中删除它们的算法。在这项工作中，我们将这些技术应用于HERA第一个观测季节的数据作为方法演示。数据显示，如果不移除，将阻碍在0.2 h−1 Mpc−1 < < 0.5 h−1 Mpc−1范围内检测目标再电离纪元（EoR）视线模式的21 cm功率谱。特别是，我们在原始自相关中发现了不可忽略的光谱结构的证据，这些自相关与EoR窗口重叠，并暗示了复杂的仪器效应。通过对单晚数据的系统建模，我们发现我们可以在功率谱中恢复到集成噪声底，在EoR窗口中获得106功率（mK2单位）的动态范围，相对于明亮的银河系前景信号。未来更深入的集成工作将有助于确定这些系统是否可以继续降低到EoR水平。在未来的观测季节，HERA将升级模拟和数字硬件，以更好地在现场控制这些系统。
We present a study of internal reflection and cross-coupling systematics in Phase I of the Hydrogen Epoch of Reionization Array (HERA). In a companion paper, we outlined the mathematical formalism for such systematics and presented algorithms for modeling and removing them from the data. In this work, we apply these techniques to data from HERA’s first observing season as a method demonstration. The data show evidence for systematics that, without removal, would hinder a detection of the 21 cm power spectrum for the targeted Epoch of Reionization (EoR) line-of-sight modes in the range 0.2 h−1 Mpc−1 < < 0.5 h−1 Mpc−1. In particular, we find evidence for nonnegligible amounts of spectral structure in the raw autocorrelations that overlaps with the EoR window and is suggestive of complex instrumental effects. Through systematic modeling on a single night of data, we find we can recover these modes in the power spectrum down to the integrated noise floor, achieving a dynamic range in the EoR window of 106 in power (mK2 units) with respect to the bright galactic foreground signal. Future work with deeper integrations will help determine whether these systematics can continue to be mitigated down to EoR levels. For future observing seasons, HERA will have upgraded analog and digital hardware to better control these systematics in the field.