Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum
Nicolas Fagnoni, Eloy de Lera Acedo, David R. DeBoer, Zara Abdurashidova, James E. Aguirre, Paul Alexander, Zaki S. Ali, Yanga Balfour, Adam P. Beardsley, Giann… 展开作者
Nicolas Fagnoni, Eloy de Lera Acedo, David R. DeBoer, Zara Abdurashidova, James E. Aguirre, Paul Alexander, Zaki S. Ali, Yanga Balfour, Adam P. Beardsley, Gianni Bernardi, Tashalee S. Billings, Judd D. Bowman, Richard F. Bradley, Phil Bull, Jacob Burba, Chris L. Carilli, Carina Cheng, Matt Dexter, Joshua S. Dillon, Aaron Ewall-Wice, Randall Fritz, Steve 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, Alec Josaitis, Austin Julius, Nicholas S. Kern, Joshua Kerrigan, Honggeun Kim, Piyanat Kittiwisit, Saul A. Kohn, Matthew Kolopanis, Adam Lanman, Paul La Plante, Telalo Lekalake, Adrian Liu, David MacMahon, Lourence Malan, Cresshim Malgas, Matthys Maree, Zachary E. Martinot, Eunice Matsetela, Juan Mena Parra, Andrei Mesinger, Mathakane Molewa, Miguel F. Morales, Tshegofalang Mosiane, Abraham R. Neben, Bojan Nikolic, Aaron R. Parsons, Nipanjana Patra, Samantha Pieterse, Jonathan C. Pober, Nima Razavi-Ghods, James Robnett, Kathryn Rosie, Peter Sims, Craig Smith, Angelo Syce, Nithyanandan Thyagarajan, Peter K. G. Williams, Haoxuan Zheng
The detection of the Epoch of Reionization (EoR) delay power spectrum using a "foreground avoidance method" highly depends on the instrument chromaticity. The systematic effects induced by the radio-telescope spread the foreground signal in the delay domain, which contaminates the EoR window theoretically observable. Applied to the Hydrogen Epoch of Reionization Array (HERA), this paper combines detailed electromagnetic and electrical simulations in order to model the chromatic effects of the instrument, and quantify its frequency and time responses. In particular, the effects of the analogue receiver, transmission cables, and mutual coupling are included. These simulations are able to accurately predict the intensity of the reflections occurring in the 150-m cable which links the antenna to the back-end. They also show that electromagnetic waves can propagate from one dish to another one through large sections of the array due to mutual coupling. The simulated system time response is attenuated by a factor $10^{4}$ after a characteristic delay which depends on the size of the array and on the antenna position. Ultimately, the system response is attenuated by a factor $10^{5}$ after 1400 ns because of the reflections in the cable, which corresponds to characterizable ${k_\parallel}$-modes above 0.7 $h\;\rm{Mpc}^{-1}$ at 150 MHz. Thus, this new study shows that the detection of the EoR signal with HERA Phase I will be more challenging than expected. On the other hand, it improves our understanding of the telescope, which is essential to mitigate the instrument chromaticity.
Characterizing Signal Loss in the 21 cm Reionization Power Spectrum: A Revised Study of PAPER-64
再电离时代（EoR）是我们宇宙历史上一个未知的时代，在此期间，第一批恒星和星系的诞生导致了星系际介质中中性氢的电离。有许多实验通过追踪中性氢的21厘米线来研究EoR。由于这种信号非常微弱，难以分离，因此开发最大限度地提高灵敏度并抑制数据中污染物的分析技术至关重要。还必须了解不同分析方法之间的权衡及其对功率谱估计的影响。具体而言，随着HERA可预见的未来的统计功率谱检测，了解某些分析选择如何导致EoR信号丢失变得越来越重要。在本文中，我们专注于与功率谱估计的信号损失。我们使用玩具模型和唐纳德C的64元件配置所取的数据来描述这种损失的起源。Backer Precision Array for Probing the Epoch of Reionization（贝克精密阵列探测再电离时代）特别是，我们强调如何详细的调查信号损失导致修订，更高的21厘米功率谱上限从PAPER-64。此外，我们总结了与功率谱误差估计，以前无法解释的错误。我们专注于一个子集的PAPER-64数据在本文中，修订的功率谱限制的PAPER实验中提出了即将发表的论文Kolopanis等。并取代先前发表的PAPER分析结果。
Detection of Cosmic Structures using the Bispectrum Phase. II. First Results from Application to Cosmic Reionization Using the Hydrogen Epoch of Reionization Array
The Tracking Tapered Gridded Estimator for the 21-cm power spectrum from the Murchison Widefield Array (MWA) drift scan observations -- III. Improved upper limits at $z = 8.2$ from multiple pointings
Indian Institute of Technology Madras（印度马德拉斯理工学院）；Indian Institute of Technology Kharagpur（印度克拉格普尔理工学院）；University of the Western Cape（西开普大学）；Raman Research Institute（拉曼研究所）
