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arXiv 2602.21739astro-ph.GA
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800-1088 MHz和1296-1440 MHz范围内QU拟合行为的稳健分析

A Robust Analysis of QU-fitting Behavior for 800-1088 MHz and 1296-1440 MHz

The Australian National University（澳大利亚国立大学）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；SKA Observatory（平方公里阵列望远镜观测站）；ATNF, CSIRO Space & Astronomy（CSIRO空间与天文天体物理部澳方天文台）；National Astronomical Observatory of Japan（日本国立天文台）；Radboud University（拉德堡德大学）；University of Calgary（卡尔加里大学）
Lindsey Oberhelman, Cameron L. Van Eck, N. M. McClure-Griffiths, Yik Ki Ma, Alec J. M. Thomson, Jason M. Price, Shinsuke Ideguchi, Craig S. Anderson, Marijke Ha… 展开作者

Lindsey Oberhelman, Cameron L. Van Eck, N. M. McClure-Griffiths, Yik Ki Ma, Alec J. M. Thomson, Jason M. Price, Shinsuke Ideguchi, Craig S. Anderson, Marijke Haverkorn, Denis Leahy, Takuya Akahori, Jennifer West

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AI总结：

本文研究了800-1088 MHz和1296-1440 MHz频率范围内QU拟合的有效性，发现贝叶斯因子在模型选择中表现更优，并探讨了模型区分性的边界条件。

摘要：

QU拟合是一种强大的工具，用于将光谱极化无线电连续观测与物理模型联系起来，从而估计银河系、星系团和无线电喷流中的磁场。我们对ASKAP POSSUM调查频率范围（800-1088 MHz和1296-1440 MHz）内QU拟合的有效性和局限性进行了全面研究，并扩展到其他光谱极化无线电观测。我们模拟了不同的物理极化源：法拉第简单模型、Burn板模型、内部湍流、外部湍流和双组分模型，在POSSUM频率下评估其观测退化性和拟合准确性。我们的结果突显了可靠拟合的模型依赖性，并确定了特定参数空间区域，其中模型选择，因此介质特征的表征变得模糊。对于QU拟合，我们发现使用边缘似然计算的贝叶斯因子在模型选择中优于传统使用的好度拟合度量，如贝叶斯信息准则（BIC）、Akaike信息准则（AIC）和卡方检验。我们提供了经验关系，以界定模型区分性不可能的边界。最后，我们评估了QU拟合恢复模型参数及其相关不确定性的准确性，从而评估其正确表征法拉第旋转介质在法拉第深度空间中点和扩展源中的能力。

英文摘要：

QU-fitting is a powerful tool for interpreting spectro-polarimetric radio continuum observations by linking them to physical models, enabling estimates of the magnetic fields in, for example, the Milky Way, galaxy clusters, and radio jets. We present a comprehensive investigation into the effectiveness and limitations of QU-fitting within the ASKAP POSSUM survey frequency ranges (800-1088 MHz and 1296-1440 MHz) with projections to other spectro-polarimetric radio observations. We simulate different physical polarization sources: Faraday simple, Burn slab, internal turbulence, external turbulence, and two-component models in the POSSUM frequencies, and assess their observational degeneracies and fit accuracies. Our results highlight the model-dependent nature of reliable fitting and identify specific regions of parameter space where model selection, and therefore characterization of the physical medium, becomes ambiguous. For QU-fitting we find the Bayes factor, computed using the marginal likelihood, outperforms more traditionally used goodness-of-fit metrics such as Bayesian Information Criterion (BIC), Akaike Information Criterion (AIC), and chi-squared for model selection. We provide empirical relationships to delineate the boundaries where model distinguishability is impossible. Finally, we evaluate how accurately QU-fitting recovers model parameters and their associated uncertainties, thereby assessing its ability to correctly characterize the Faraday-rotating medium in both point and extended sources in Faraday depth space.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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