A Bayesian approach to high fidelity interferometric calibration − II: demonstration with simulated data
A Bayesian approach to high fidelity interferometric calibration − II: demonstration with simulated data
复制标题
高保真度干涉校准的贝叶斯方法 — II：用模拟数据进行演示
DOI：
10.1093/mnras/stac1749
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发表时间：
2022
影响因子：
4.8
通讯作者：
Sievers, Jonathan L.
中科院分区：
文献类型：
--
作者：
Sims, Peter H.;Pober, Jonathan C.;Sievers, Jonathan L.
在随附的一篇论文中，我们提出了一种用于减少干涉定标中天空模型不完备性的数学形式--bayescal。本文介绍了用类HERA六角密集冗余阵列，对定标天空模型的优先已知分量的三个假设完备度，用贝叶斯定标方法来定标全斯托克斯模拟观测的简并增益参数。我们比较了贝叶斯定标方案和那些通过仅用定标天空模型的一个优先已知分量来定标简并增益参数而恢复的定标方案，无论是否在增益幅度解上施加物理激励的先验，以及对于要定标的基线长度范围的两种选择。我们发现，在杂散增益幅度波动中，Bayscaler提供的校准解决方案的功率比使用替代方法针对相同数据集得出的校准解决方案低4个数量级，并且在数据可访问的整个光谱尺度上，在∼107和∼1010之间比平均简并增益幅度小4个数量级。此外，我们发现，在仅建模的场景中，Bayscalale具有足够高保真的校准解决方案，可以在大光谱尺度(k∥≲0.15hMpc−1)上无偏恢复21厘米功率谱。在所有其他情况下，在所研究的完备性制度中，这些标度是受污染的。
In a companion paper, we presentedbayescal, a mathematical formalism for mitigating sky-model incompleteness in interferometric calibration. In this paper, we demonstrate the use ofbayescalto calibrate the degenerate gain parameters of full-Stokes simulated observations with a HERA-like hexagonal close-packed redundant array, for three assumed levels of completeness of thea prioriknown component of the calibration sky model. We compare thebayescalcalibration solutions to those recovered by calibrating the degenerate gain parameters with only thea prioriknown component of the calibration sky model both with and without imposing physically motivated priors on the gain amplitude solutions and for two choices of baseline length range over which to calibrate. We find thatbayescalprovides calibration solutions with up to 4 orders of magnitude lower power in spurious gain amplitude fluctuations than the calibration solutions derived for the same data set with the alternate approaches, and between ∼107and ∼1010times smaller than in the mean degenerate gain amplitude, on the full range of spectral scales accessible in the data. Additionally, we find that in the scenarios modelled onlybayescalhas sufficiently high fidelity calibration solutions for unbiased recovery of the 21-cm power spectrum on large spectral scales (k∥≲ 0.15hMpc−1). In all other cases, in the completeness regimes studied, those scales are contaminated.