HERA主波束的原位测量：方法论与初步结果
天体物理仪器与方法
2020-07-08 v1 宇宙学与河外天体物理
摘要
21厘米宇宙学中的核心挑战是将宇宙学信号与明亮前景分离。许多分离技术依赖于对天空和仪器响应（包括天线主波束）的准确认知。对于诸如氢再电离时代阵列\citep[HERA, ][]{DeBoer2017}这类不动的漂移扫描望远镜，主波束表征尤为困难，因为标准波束校准流程不适用\citep{Cornwell2005}，且现有技术需要在望远镜分辨率下准确的源星表。我们提出了\citet{Pober2012}方法的扩展，其利用波束对称性创建重叠的源轨迹网络，从而打破源通量密度与波束响应之间的简并并允许二者同时估计。我们利用HERA早期观测拟合了仪器的波束响应，发现对于高信噪比的源，我们的结果在相对于峰值增益功率低至-20 dB的层面上与电磁模拟吻合良好。此外，我们构建了一个包含90个源的源星表，在151 MHz下通量密度低至1.4 Jy。
引用
@article{arxiv.2005.12174,
title = {Measuring HERA's primary beam in-situ: methodology and first results},
author = {Chuneeta D. Nunhokee and Aaron R. Parsons and Nicholas S. Kern and Bojan Nikolic and Jonathan C. Pober and Gianni Bernardi and Chris L. Carilli and Zara Abdurashidova and James E. Aguirre and Paul Alexander and Zaki S. Ali and Yanga Balfour and Adam P. Beardsley and Tashalee S. Billings and Judd D. Bowman and Richard F. Bradley and Jacob Burba and Carina Cheng and David R. DeBoer and Matt Dexter and Eloy de~Lera~Acedo and Joshua S. Dillon and Aaron Ewall-Wice and Nicolas Fagnoni and Randall Fritz and Steve R. Furlanetto and Kingsley Gale-Sides and Brian Glendenning and Deepthi Gorthi and Bradley Greig and Jasper Grobbelaar and Ziyaad Halday and Bryna J. Hazelton and Jacqueline N. Hewitt and Daniel C. Jacobs and Austin Julius and Joshua Kerrigan and Piyanat Kittiwisit and Saul A. Kohn and Matthew Kolopanis and Adam Lanman and Paul La~Plante and Telalo Lekalake and Adrian Liu and David MacMahon and Lourence Malan and Cresshim Malgas and Matthys Maree and Zachary E. Martinot and Eunice Matsetela and Andrei Mesinger and Mathakane Molewa and Miguel F. Morales and Tshegofalang Mosiane and Abraham R. Neben and Nipanjana Patra and Samantha Pieterse and Nima Razavi-Ghods and Jon Ringuette and James Robnett and Kathryn Rosie and Peter Sims and Craig Smith and Angelo Syce and Nithyanandan Thyagarajan and Peter K. ~G. Williams and Haoxuan Zheng},
journal= {arXiv preprint arXiv:2005.12174},
year = {2020}
}
备注
22 pages, 22 figures, accepted for publication in ApJ