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arXiv 1003.2307astro-ph.IMphysics.data-anstat.AP
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Radio Telescope阵列的基波成像极限

Fundamental Imaging Limits of Radio Telescope Arrays

Stefan J. Wijnholds, Alle-Jan van der Veen

摘要:

射电天文图像的保真度通常通过实际经验来评估,即使用经验法则,尽管某些方面和情况已经得到了严格的处理。在本文中,我们提出了一个数学框架,能够描述射电天文成像问题的基本限制。虽然数据模型假设一个单一的快照观察,即在时间和频率的变化不考虑,这个框架是足够的一般性,允许扩展到综合观察。使用统计信号处理和线性代数的工具,我们讨论了成像和反卷积问题的易处理性,噪声在地图中的重新分配的成像和反卷积过程中,由于传播的校准误差和热噪声的图像值的协方差和易处理的自校准源的数量的上限。图像值的协方差和易处理源的数量的组合确定在成像过程中可实现的有效噪声基底。有效噪声提供比动态范围更好的品质因数,因为它包括噪声的空间变化。我们的研究结果提供了通过设计阵列来提高成像性能的方法。

英文摘要:

The fidelity of radio astronomical images is generally assessed by practical experience, i.e. using rules of thumb, although some aspects and cases have been treated rigorously. In this paper we present a mathematical framework capable of describing the fundamental limits of radio astronomical imaging problems. Although the data model assumes a single snapshot observation, i.e. variations in time and frequency are not considered, this framework is sufficiently general to allow extension to synthesis observations. Using tools from statistical signal processing and linear algebra, we discuss the tractability of the imaging and deconvolution problem, the redistribution of noise in the map by the imaging and deconvolution process, the covariance of the image values due to propagation of calibration errors and thermal noise and the upper limit on the number of sources tractable by self calibration. The combination of covariance of the image values and the number of tractable sources determines the effective noise floor achievable in the imaging process. The effective noise provides a better figure of merit than dynamic range since it includes the spatial variations of the noise. Our results provide handles for improving the imaging performance by design of the array.

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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