Effects of model incompleteness on the drift-scan calibration of radio telescopes
Effects of model incompleteness on the drift-scan calibration of radio telescopes
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模型不完备性对射电望远镜漂移扫描定标的影响
DOI：
10.1093/mnras/stab2072
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发表时间：
2021
影响因子：
4.8
通讯作者：
Alexander, Paul
中科院分区：
文献类型：
--
作者：
Gehlot, Bharat K;Jacobs, Daniel C;Bowman, Judd D;Mahesh, Nivedita;Murray, Steven G;Kolopanis, Matthew;Beardsley, Adam P;Abdurashidova, Zara;Aguirre, James E;Alexander, Paul
精确的校准对探测来自宇宙黎明和再电离时代（z = 30-6）的中性氢红移21厘米信号的实验提出了挑战。在干涉测量和全局信号实验中，系统校准是误差的主要来源。虽然许多方面的校准已被研究，这两种类型的仪器之间的重叠得到较少的关注。我们研究了HERA碟形天线和EDGES型天线对总功率测量的天空校准，以了解自相关在校准干涉仪中的作用和天空在校准总功率仪器中的作用。使用模拟，我们研究了各种情况下，如时变增益，不完整的天空校准模型，和主波束模型。我们发现时间增益漂移、天空模型不完整和波束不准确会导致接收器增益幅度和接收器温度估计的偏差。在某些情况下，这些偏差混合波束和天空之间的光谱结构，导致光谱可变增益误差。将校正方法应用于HERA和EDGES数据，通过更标准的方法，我们发现与校正的一致性很好。虽然仪器增益是一致的光束和天空的误差类似的规模模拟，接收器温度显示出显着的偏离预期值。虽然我们表明，它是可能的，以部分减轻偏差，由于模型的不准确性，将时间依赖性增益模型在校准，校准产品上产生的误差更大，更相关。完全解决这些偏差将需要更精确的天空和初级波束模型。
Precision calibration poses challenges to experiments probing the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn and Epoch of Reionization (z∼ 30–6). In both interferometric and global signal experiments, systematic calibration is the leading source of error. Though many aspects of calibration have been studied, the overlap between the two types of instruments has received less attention. We investigate the sky based calibration of total power measurements with a HERA dish and an EDGES-style antenna to understand the role of autocorrelations in the calibration of an interferometer and the role of sky in calibrating a total power instrument. Using simulations we study various scenarios such as time variable gain, incomplete sky calibration model, and primary beam model. We find that temporal gain drifts, sky model incompleteness, and beam inaccuracies cause biases in the receiver gain amplitude and the receiver temperature estimates. In some cases, these biases mix spectral structure between beam and sky resulting in spectrally variable gain errors. Applying the calibration method to the HERA and EDGES data, we find good agreement with calibration via the more standard methods. Although instrumental gains are consistent with beam and sky errors similar in scale to those simulated, the receiver temperatures show significant deviations from expected values. While we show that it is possible to partially mitigate biases due to model inaccuracies by incorporating a time-dependent gain model in calibration, the resulting errors on calibration products are larger and more correlated. Completely addressing these biases will require more accurate sky and primary beam models.
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DOI：
10.3847/0004-637x/818/2/139
发表时间：
2016-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
C. Trott;B. Pindor;P. Procopio;R. Wayth;D. Mitchell;B. McKinley;S. Tingay;N. Barry;A. Beardsley;G. Bernardi;J. Bowman;F. Briggs;R. Cappallo;P. Carroll;A. D. Oliveira-Costa;J. Dillon;A. Ewall-Wice;L. Feng;L. Greenhill;B. Hazelton;J. Hewitt;N. Hurley-Walker;M. Johnston-Hollitt;D. Jacobs;D. Kaplan;Hs. Kim;E. Lenc;J. Line;A. Loeb;C. Lonsdale;M. Morales;E. Morgan;A. Neben;N. Thyagarajan;D. Oberoi;A. Offringa;S. Ord;S. Paul;J. Pober;T. Prabu;J. Riding;N. Shankar;S. Sethi;K. Srivani;R. Subrahmanyan;I. Sullivan;Max Tegmark;R. Webster;A. Williams;C. Williams;C. Wu;J. Wyithe
通讯作者：
C. Trott;B. Pindor;P. Procopio;R. Wayth;D. Mitchell;B. McKinley;S. Tingay;N. Barry;A. Beardsley;G. Bernardi;J. Bowman;F. Briggs;R. Cappallo;P. Carroll;A. D. Oliveira-Costa;J. Dillon;A. Ewall-Wice;L. Feng;L. Greenhill;B. Hazelton;J. Hewitt;N. Hurley-Walker;M. Johnston-Hollitt;D. Jacobs;D. Kaplan;Hs. Kim;E. Lenc;J. Line;A. Loeb;C. Lonsdale;M. Morales;E. Morgan;A. Neben;N. Thyagarajan;D. Oberoi;A. Offringa;S. Ord;S. Paul;J. Pober;T. Prabu;J. Riding;N. Shankar;S. Sethi;K. Srivani;R. Subrahmanyan;I. Sullivan;Max Tegmark;R. Webster;A. Williams;C. Williams;C. Wu;J. Wyithe
射电天文天线的主波束效应 – II. MeerKAT L 波段波束建模
DOI：
10.1093/mnras/stab104
发表时间：
2019
期刊：
arXiv: Instrumentation and Methods for Astrophysics
影响因子：
--
作者：
K. Asad;J. Girard;M. de Villiers;T. Ansah;K. Iheanetu;O. Smirnov;M. G. Santos;R. Lehmensiek;J. Jonas;D. I. L. de Villiers;K. Thorat;B. Hugo;S. Makhathini;G. Józsa;S. Sirothia
通讯作者：
S. Sirothia
404 Mc/s频率背景辐射的调查
影响因子：
4.8
作者：
I. Pauliny;J. Shakeshaft
通讯作者：
J. Shakeshaft
宽带天线和光谱仪的绝对校准，用于精确的天噪声温度测量
影响因子：
1.6
作者：
A. Rogers;J. Bowman
通讯作者：
J. Bowman
原位测量 HERA 主光束：方法和初步结果
DOI：
10.3847/1538-4357/ab9634
发表时间：
2020
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Nunhokee, Chuneeta D.;Parsons, Aaron R.;Kern, Nicholas S.;Nikolic, Bojan;Pober, Jonathan C.;Bernardi, Gianni;Carilli, Chris L.;Abdurashidova, Zara;Aguirre, James E.;Alexander, Paul
通讯作者：
Alexander, Paul