论文标题
电离阵列氢时代的冗余基线校准
Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
论文作者
论文摘要
在21 cm的宇宙学中，精度校准是将中性氢信号与非常明亮但光谱平滑的天体物理前景分离的关键。电源阵列（HERA）的氢时代是一种专门用于21 cm宇宙学的干涉仪，目前在南非正在建造，被设计为在很大程度上使用相同的干涉模式的重复测量的自相连进行校准。该技术被称为“冗余 - 基线校准”，可以在校准问题中解决大多数内部自由度。但是，它假设在天线元件上，将相同的原代光束精确放在冗余网格上。在这项工作中，我们回顾了算法的详细实现，从而实现了冗余 - 基线校准，并通过HERA数据报告结果。我们量化了现实世界中非差额的影响，以及它们如何与理想化的场景进行比较，在这些方案中，冗余测量仅在其噪声实现中有所不同。最后，我们研究了非差额如何在我们的校准解决方案中产生虚假的时间结构 - 在数据和模拟中，以及为缓解该结构的策略。
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.
