Fundamental Limitations on the Calibration of Redundant 21 cm Cosmology Instruments and Implications for HERA and the SKA
Fundamental Limitations on the Calibration of Redundant 21 cm Cosmology Instruments and Implications for HERA and the SKA
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DOI：
10.3847/1538-4357/ab107d
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发表时间：
2018-11
期刊：
影响因子：
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通讯作者：
R. Byrne;M. Morales;B. Hazelton;Wenyang Li;N. Barry;A. Beardsley;R. Joseph;J. Pober;I. Sullivan;C. Trott
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文献类型：
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作者：
R. Byrne;M. Morales;B. Hazelton;Wenyang Li;N. Barry;A. Beardsley;R. Joseph;J. Pober;I. Sullivan;C. Trott
精确的仪器校准是21厘米宇宙学实验成功的关键。校准中未减轻的误差会污染再电离时期（EoR）信号，从而妨碍检测。巴里等人描述了一类由校准到不完整天空模型而出现的固有误差;然而，天空模型中的误差是否影响冗余阵列的校准还不清楚。在本文中，我们表明，冗余校准是容易受到错误的天空模型的不完整性，即使在完美的天线定位和相同的波束的限制。这些误差处于可以压倒EoR信号并阻止在关键功率谱模式中的检测的水平。最后，我们提出了误差缓解策略与氢时代的再电离阵列和平方公里阵列的影响。
Precise instrument calibration is critical to the success of 21 cm cosmology experiments. Unmitigated errors in calibration contaminate the Epoch of Reionization (EoR) signal, precluding a detection. Barry et al. characterized one class of inherent errors that emerge from calibrating to an incomplete sky model; however, it has been unclear if errors in the sky model affect the calibration of redundant arrays. In this paper, we show that redundant calibration is vulnerable to errors from sky model incompleteness even in the limit of perfect antenna positioning and identical beams. These errors are at a level that can overwhelm the EoR signal and prevent a detection in crucial power spectrum modes. Finally, we suggest error mitigation strategies with implications for the Hydrogen Epoch of Reionization Array and the Square Kilometre Array.