Hydrogen Epoch of Reionization Array (HERA)
Hydrogen Epoch of Reionization Array (HERA)
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DOI：
10.1088/1538-3873/129/974/045001
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发表时间：
2017-04-01
影响因子：
3.5
通讯作者：
Zheng, Haoxuan
中科院分区：
文献类型：
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作者：
DeBoer, David R.;Parsons, Aaron R.;Zheng, Haoxuan
氢再电离时代阵列（HERA）是一个分阶段实验，旨在测量整个宇宙再电离过程中原始星系际介质（IGM）的21厘米发射（z = 6-12），并探索我们宇宙黎明的早期时代（z类似于30））。在这些时期，早期的恒星和黑洞加热并电离了IGM，引入了21 cm发射的波动。HERA的目的是表征21厘米功率谱的演变，以限制再电离的时间和形态，第一个星系的性质，大尺度结构的演变，以及早期的热源。HERA的全套仪器将是一台位于南非的350个元件的干涉仪，由14米抛物面碟形天线组成，从50至250兆赫进行观测。目前，19个盘子已经部署在现场，接下来的18个正在建设中。HERA已被指定为SKA前体仪器。在本文中，我们总结了HERA的科学背景，并提供其关键科学成果的预测。在回顾了前景缓解的最新技术水平后，我们使用延迟谱技术来激励HERA仪器的高水平性能要求。接下来，我们介绍HERA仪器设计沿着确保HERA满足其性能要求的子系统规格。最后，我们总结了项目的进度和现状。最后，我们建议，鉴于前景污染的现实，当前一代21厘米仪器正在接近其灵敏度极限。HERA旨在提供灵敏度和精确度，以在经过验证的前景过滤技术的基础上提供其主要科学，同时开发新的减法技术来解锁新的功能。这一结果将是实现21厘米宇宙学广泛认可的科学潜力的重要一步。
The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization (z = 6-12), and to explore earlier epochs of our Cosmic Dawn (z similar to 30). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14 m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.