Bayesian methods of astronomical source extraction
Bayesian methods of astronomical source extraction
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DOI：
10.1086/515393
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发表时间：
2007-06-01
影响因子：
4.9
通讯作者：
Oliver, Seb
中科院分区：
文献类型：
--
作者：
Savage, Richard S.;Oliver, Seb
我们提出了两种新的源提取方法，基于贝叶斯模型选择和使用贝叶斯信息准则。第一个是源检测滤波器，它能够同时检测点源并估计图像背景。第二种是先进的光度测量技术，可测量通量、位置（亚像素精度）、局部背景和点扩散函数。我们将源检测滤波器应用于模拟的 Herschel SPIRE 数据，并展示了该滤波器检测点源并同时估计图像背景的能力。我们使用光度测量方法来分析包含未知通量源、位置和点扩散函数的简单模拟图像；我们不仅准确地测量这些参数，而且还确定它们的不确定性（使用马尔可夫链蒙特卡罗采样）。该方法还表征了源的性质（区分点源和扩展源）。我们证明了包含额外先验知识的效果。点扩散函数的先验知识提高了通量测量的精度，而背景的先验知识只有很小的影响。在存在较高噪声水平的情况下，我们表明，即使源太微弱而无法直接检测到，先前的位置知识（例如可能来自另一个波段的强检测）也使我们能够准确测量源通量。这些方法被纳入 SUSSEXtractor 中，SUSSSEXtractor 是即将进行的 Akari 远红外勘测者全天勘测的源提取管道。它们还可以在免费提供的独立测试版工具中实现。
We present two new source extraction methods, based on Bayesian model selection and using the Bayesian information criterion. The first is a source detection filter, which is able to simultaneously detect point sources and estimate the image background. The second is an advanced photometry technique that measures the flux, position ( to subpixel accuracy), local background, and point-spread function. We apply the source detection filter to simulated Herschel SPIRE data and demonstrate the filter's ability to both detect point sources and simultaneously estimate the image background. We use the photometry method to analyze a simple simulated image containing a source of unknown flux, position, and point-spread function; we not only accurately measure these parameters but also determine their uncertainties (using Markov chain Monte Carlo sampling). The method also characterizes the nature of the source (distinguishing between a point source and an extended source). We demonstrate the effect of including additional prior knowledge. Prior knowledge of the point- spread function increases the precision of the flux measurement, while prior knowledge of the background has only a small impact. In the presence of higher noise levels, we show that prior positional knowledge (such as might arise from a strong detection in another wave band) allows us to accurately measure the source flux even when the source is too faint to be detected directly. These methods are incorporated in SUSSEXtractor, the source extraction pipeline for the forthcoming Akari Far-Infrared Surveyor all- sky survey. They are also implemented in a stand-alone, beta-version tool that is freely available.