An improved method for polarimetric image restoration in interferometry
An improved method for polarimetric image restoration in interferometry
复制标题
干涉测量中偏振图像恢复的改进方法
DOI：
10.1093/mnras/stw1377
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发表时间：
2016
影响因子：
4.8
通讯作者：
M. Johnston
中科院分区：
文献类型：
--
作者：
L. Pratley;M. Johnston
干涉射电天文学数据需要通过去卷积过程来解释傅立叶平面中有限覆盖的影响。在过去的40年里，这个过程，被称为“清洗”，几乎完全是单独对所有斯托克斯参数进行的，就好像它们是独立的标量图像一样。然而，在这里，我们证明的情况下，线性极化$\mathcal{P}$，这种方法未能正确地考虑复杂的矢量性质，导致在一个过程中，这是依赖于轴下进行反卷积。我们在这里提出了一种改进的方法，“广义复杂的清洁”，它正确地占复矢量性质的偏振发射，是不变的旋转下的反卷积轴。我们使用两个澳大利亚望远镜紧凑阵列数据集测试标准和复杂的清洁版本的Hogbom和SDI清洁算法。我们表明，在一般情况下，复杂的清洁版本的每个算法产生更准确的清洁组件，更少的虚假检测和更低的计算成本，由于减少迭代比目前的方法。特别是，我们发现，复杂的SDI CLEAN产生最好的结果与标准的CLEAN算法和其他复杂的CLEAN算法相比，扩散极化源。考虑到移动到宽视场，高分辨率偏振成像与未来的望远镜，如平方公里阵列，我们建议，广义复杂的清洁应采用反卷积方法为所有未来的偏振调查，特别是复杂版本的SDI清洁应使用。
Interferometric radio astronomy data require the effects of limited coverage in the Fourier plane to be accounted for via a deconvolution process. For the last 40 years this process, known as `cleaning', has been performed almost exclusively on all Stokes parameters individually as if they were independent scalar images. However, here we demonstrate for the case of the linear polarisation $\mathcal{P}$, this approach fails to properly account for the complex vector nature resulting in a process which is dependant on the axis under which the deconvolution is performed. We present here an improved method, `Generalised Complex CLEAN', which properly accounts for the complex vector nature of polarised emission and is invariant under rotations of the deconvolution axis. We use two Australia Telescope Compact Array datasets to test standard and complex CLEAN versions of the Hogbom and SDI CLEAN algorithms. We show that in general the Complex CLEAN version of each algorithm produces more accurate clean components with fewer spurious detections and lower computation cost due to reduced iterations than the current methods. In particular we find that the Complex SDI CLEAN produces the best results for diffuse polarised sources as compared with standard CLEAN algorithms and other Complex CLEAN algorithms. Given the move to widefield, high resolution polarimetric imaging with future telescopes such as the Square Kilometre Array, we suggest that Generalised Complex CLEAN should be adopted as the deconvolution method for all future polarimetric surveys and in particular that the complex version of a SDI CLEAN should be used.
影响因子：
6.5
作者：
van Haarlem, M. P.;Wise, M. W.;van Zwieten, J.
通讯作者：
van Zwieten, J.