The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry
The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry
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DOI：
10.1007/s10686-017-9563-0
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发表时间：
2017-01
影响因子：
3
通讯作者：
Nipanjana Patra;A. Parsons;D. DeBoer;N. Thyagarajan;A. Ewall-Wice;G. Hsyu;Tsz Kuk Leung;C. Day;E. Lera Acedo;J. Aguirre;P. Alexander;Z. Ali;A. Beardsley;J. Bowman;R. Bradley;C. Carilli;Carina Cheng;J. Dillon;G. Fadana;N. Fagnoni;Randall Fritz;S. Furlanetto;B. Glendenning;B. Greig;J. Grobbelaar;B. Hazelton;D. Jacobs;A. Julius;M. Kariseb;S. Kohn;A. Lebedeva;Telalo Lekalake;Adrian Liu;A. Loots;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Nathan Mathison;Eunice Matsetela;A. Mesinger;M. Morales;A. Neben;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;R. Sell;Craig H. Smith;A. Syce;Max Tegmark;P. Williams;Haoxuan Zheng
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文献类型：
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作者：
Nipanjana Patra;A. Parsons;D. DeBoer;N. Thyagarajan;A. Ewall-Wice;G. Hsyu;Tsz Kuk Leung;C. Day;E. Lera Acedo;J. Aguirre;P. Alexander;Z. Ali;A. Beardsley;J. Bowman;R. Bradley;C. Carilli;Carina Cheng;J. Dillon;G. Fadana;N. Fagnoni;Randall Fritz;S. Furlanetto;B. Glendenning;B. Greig;J. Grobbelaar;B. Hazelton;D. Jacobs;A. Julius;M. Kariseb;S. Kohn;A. Lebedeva;Telalo Lekalake;Adrian Liu;A. Loots;D. MacMahon;Lourence Malan;Cresshim Malgas;M. Maree;Z. Martinot;Nathan Mathison;Eunice Matsetela;A. Mesinger;M. Morales;A. Neben;Samantha Pieterse;J. Pober;N. Razavi-Ghods;J. Ringuette;J. Robnett;K. Rosie;R. Sell;Craig H. Smith;A. Syce;Max Tegmark;P. Williams;Haoxuan Zheng
由于仪器响应的光谱结构是当前试图检测来自再电离时期（EoR）的红移21 cm信号的实验的限制因素。测量红移21厘米EoR功率谱的延迟谱方法的最新进展引起了人们对天线频率响应对进行这种具有挑战性的测量的可行性的影响的新的关注。延迟谱方法提供了可以直接测量的仪器的时域响应与21 cm EoR实验可获得的功率谱模式之间的某种直接关系。在本文中，我们推导出天线反射系数（S11）测量矢量网络分析仪（VNA）和延迟空间中的额外前景污染的程度之间的显式关系。在这个数学框架的光，我们研究的原型天线元件，将构成氢时代的再电离阵列（HERA）在100和200 MHz之间的色度。这些反射测量相对于电磁模拟表现出额外的结构，但我们发现，即使没有任何进一步的设计改进，这样的天线元件将支持测量的spatialkmodes与视线分量的k ε> 0.2hMpc− 1。我们还发现，当与用于红移21 cm功率谱的最佳二次估计的强大的逆协方差加权方法相结合时，HERA原型元件可以成功地测量空间模式下的功率谱，如低ask λ> 0.1hMpc− 1。这项工作是一个重要的一步，了解HERA天线元件，并强调了一个简单的方法来表征仪器响应，为未来的实验设计，以检测21厘米EoR功率谱。
Spectral structures due to the instrument response is the current limiting factor for the experiments attempting to detect the redshifted 21 cm signal from the Epoch of Reionization (EoR). Recent advances in the delay spectrum methodology for measuring the redshifted 21 cm EoR power spectrum brought new attention to the impact of an antenna’s frequency response on the viability of making this challenging measurement. The delay spectrum methodology provides a somewhat straightforward relationship between the time-domain response of an instrument that can be directly measured and the power spectrum modes accessible to a 21 cm EoR experiment. In this paper, we derive the explicit relationship between antenna reflection coefficient (S11) measurements made by a Vector Network Analyzer (VNA) and the extent of additional foreground contaminations in delay space. In the light of this mathematical framework, we examine the chromaticity of a prototype antenna element that will constitute the Hydrogen Epoch of Reionization Array (HERA) between 100 and 200 MHz. These reflectometry measurements exhibit additional structures relative to electromagnetic simulations, but we find that even without any further design improvement, such an antenna element will support measuring spatialkmodes with line-of-sight components ofk∥> 0.2hMpc− 1. We also find that when combined with the powerful inverse covariance weighting method used in optimal quadratic estimation of redshifted 21 cm power spectra the HERA prototype elements can successfully measure the power spectrum at spatial modes as low ask∥> 0.1hMpc− 1. This work represents a major step toward understanding the HERA antenna element and highlights a straightforward method for characterizing instrument response for future experiments designed to detect the 21 cm EoR power spectrum.