Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
Joshua S. Dillon, Max Lee, Zaki S. Ali, Aaron R. Parsons, Naomi Orosz, Chuneeta Devi Nunhokee, Paul La Plante, Adam P. Beardsley, Nicholas S. Kern, Zara Abduras… 展开作者
Joshua S. Dillon, Max Lee, Zaki S. Ali, Aaron R. Parsons, Naomi Orosz, Chuneeta Devi Nunhokee, Paul La Plante, Adam P. Beardsley, Nicholas S. Kern, Zara Abdurashidova, James E. Aguirre, Paul Alexander, Yanga Balfour, Gianni Bernardi, Tashalee S. Billings, Judd D. Bowman, Richard F. Bradley, Phil Bull, Jacob Burba, Steve Carey, Chris L. Carilli, Carina Cheng, David R. DeBoer, Matt Dexter, Eloy de Lera Acedo, John Ely, Aaron Ewall-Wice, Nicolas Fagnoni, Randall Fritz, Steven R. Furlanetto, Kingsley Gale-Sides, Brian Glendenning, Deepthi Gorthi, Bradley Greig, Jasper Grobbelaar, Ziyaad Halday, Bryna J. Hazelton, Jacqueline N. Hewitt, Jack Hickish, Daniel C. Jacobs, Austin Julius, Joshua Kerrigan, Piyanat Kittiwisit, Saul A. Kohn, Matthew Kolopanis, Adam Lanman, Telalo Lekalake, David Lewis, Adrian Liu, Yin-Zhe Ma, David MacMahon, Lourence Malan, Cresshim Malgas, Matthys Maree, Zachary E. Martinot, Eunice Matsetela, Andrei Mesinger, Mathakane Molewa, Miguel F. Morales, Tshegofalang Mosiane, Steven Murray, Abraham R. Neben, Bojan Nikolic, Robert Pascua, Nipanjana Patra, Samantha Pieterse, Jonathan C. Pober, Nima Razavi-Ghods, Jon Ringuette, James Robnett, Kathryn Rosie, Mario G. Santos, Peter Sims, Craig Smith, Angelo Syce, Max Tegmark, Nithyanandan Thyagarajan, Peter K. G. Williams, Haoxuan Zheng
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24 Pages, 19 Figures. Updated to match the accepted MNRAS version
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.
New Limits on Polarized Power Spectra at 126 and 164 MHz: Relevance to Epoch of Reionization Measurements
偏振前景发射是测量高红移21 cm HI再电离期涨落功率谱的一个潜在的污染源。使用Donald C。Backer精密阵列探测再电离时期（PAPER），我们提出了在两个频段，以126 MHz为中心的所有四个斯托克斯参数的观测功率谱的限制（$z=10.3$）和164 MHz（$z=7.66$）进行为期三个月的观测活动，部署32个天线，在$z=7.7$（Parsons et al 2014）和$7.5 < z < 10.5$（Jacobs et al 2014）中报告了非偏振功率谱结果。本文中的功率谱的处理方式与那些作品中的相同，并且没有显示出偏振功率的确定性检测。这种未检测到的现象似乎主要是由于电离层旋转测量波动对极化功率的抑制，这强烈影响了斯托克斯Q和U。我们能够证明，在Parsons等人2014年和Jacobs等人2014年报告的限值水平下，极化泄漏的净效应可以忽略不计。
