面向就地 21 cm 射电计的电路建模
摘要
最近的天文学实验，特别是旨在探测微弱红移全球 21 cm 氢线 (深度 < ~200 mK, z > 7.5) 的实验，施加了严苛的射电计校准要求。在本工作中，我们提出了一套用于电路建模和参数推断的框架，以强化这些校准管道。该新方法使能够就地表征原本不可测的系统性误差，采用以物理为导向的模型。频率主义与贝叶斯技术相结合，用于支持迭代建模、稳健参数估计和详细不确定性量化的管道。该框架应用于 REACH 望远镜，此处对 radio signal paths 因组件老化或环境效应而产生的精确校正至关重要。我们发展了 REACH 校准源的电路模型，目标是预测通常从实验室测量中获得的源温度校正。通过采用卷积代价函数拟合模型至测量数据，获得的 RMS 残差不糅于 -37 dB。然而，贝叶斯推断揭示，所得温度校正可因反射系数退化、测量噪声以及模型误差而产生 1~2 K 级别的不确定性。为对抗此问题，我们采用实验室测量得到的后验分布作为更新的先验，从而将校正不确定性降低至 75 mK。最终，该框架为动态地对宇宙学全局 21 cm 射电天文学中系统非理想性随时间演化进行因应，满足日益提升的精度需求。
引用
@article{arxiv.2603.15072,
title = {Circuit Modeling for In Situ 21 cm Radiometer Calibration},
author = {Gary Vincent Charles Allen and Saurabh Pegwal and Dirk de Villiers and Dominic Anstey and Kaan Artuc and Harry Bevins and Gianni Bernardi and Martin Bucher and Steve Carey and Jean Cavillot and Ricardo Chiello and Adele Chu and Wessel Croukamp and John Cumner and Ardash Dash and Saswata Dasgupta and Eloy de Lera Acedo and Jiten Dhandha and Aleksandra Dragovic and John Ely and Anastasia Fialkov and Thomas Gessey-Jones and Will Handley and Christian Kirkham and Girish Kulkarny and Samuel Leeney and Alessio Magro and Daan Meerburg and Shikhar Mittal and Daniel Molnar and Rohan Patel and Joe Pattison and Carla Pieterse and Jonathan Pritchard and Gabriella Rajpoot and Nima Razavi-Ghods and Daniel Robins and Ian Roque and Anchal Saxena and Killian Scheutwinkel and Paul Scott and Emma Shen and Peter Sims and Marta Spinelli and Jiacong Zhu},
journal= {arXiv preprint arXiv:2603.15072},
year = {2026}
}
备注
29 pages, 16 figures, 2 tables, authored by the REACH collaboration, Preprint of an article submitted for consideration in Journal of Astronomical Instrumentation \c{opyright} 2026 copyright World Scientific Publishing Company https://www.worldscientific.com/worldscinet/jai