Scalable precision wide-field imaging in radio interferometry: I. uSARA validated on ASKAP data
Scalable precision wide-field imaging in radio interferometry: I. uSARA validated on ASKAP data
复制标题
无线电干涉测量中的可扩展精密宽视场成像：I. uSARA 在 ASKAP 数据上进行验证
DOI：
10.1093/mnras/stad1351
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发表时间：
2023
影响因子：
4.8
通讯作者：
Wilber A
中科院分区：
文献类型：
--
作者：
Wilber A
作为展示新成像框架的系列论文的第一部分，我们考虑了最近提出的用于宽视场、高分辨率、高动态范围、单色强度成像的无约束稀疏平均重加权分析（uSARA）优化算法。我们从澳大利亚平方公里阵列探路者（ASKAP）获得的真实无线电干涉观测中重建图像，并将这些结果与广泛使用的最先进的成像仪wclean进行比较。选定的领域来自ASKAP早期科学和进化宇宙地图（EMU）试点调查，包含几个复杂的射电源：合并星系团系统Abell 3391-95，合并星系团SPT-CL 2023-5535，以及许多延伸或弯曲尾巴的射电星系，包括x形射电星系PKS 2014-558和“跳舞的幽灵”，统称为PKS 2130-538。uSARA背后的现代框架利用并行化和自动化来解决低效应，并有效地计算测量算子，允许在单个ASKAP光束的全视场上进行宽视场重建（每个光束高达3.3°）。uSARA的精确能力产生的图像具有超分辨率和增强的漫射成分灵敏度，超过了传统的CLEAN算法，后者通常需要在这两种产量之间做出妥协。我们所得到的单色uSARA-ASKAP图像以非常高的分辨率（高达2.2弧秒）突出了扩展的漫射发射和紧凑的丝状发射，揭示了从未见过的结构。在这里，我们通过比较重建光源的形态、漫射通量的测量和光谱指数图与wclean图像获得的图像，来验证我们的uSARA-ASKAP图像。
As Part I of a paper series showcasing a new imaging framework, we consider the recently proposed unconstrained Sparsity Averaging Reweighted Analysis (uSARA) optimization algorithm for wide-field, high-resolution, high-dynamic range, monochromatic intensity imaging. We reconstruct images from real radio-interferometric observations obtained with the Australian Square Kilometre Array Pathfinder (ASKAP) and present these results in comparison to the widely used, state-of-the-art imagerWSClean. Selected fields come from the ASKAP Early Science and Evolutionary Map of the Universe (EMU) Pilot surveys and contain several complex radio sources: the merging cluster system Abell 3391-95, the merging cluster SPT-CL 2023-5535, and many extended, or bent-tail, radio galaxies, including the X-shaped radio galaxy PKS 2014-558 and ‘the dancing ghosts’, known collectively as PKS 2130-538. The modern framework behind uSARA utilizes parallelization and automation to solve for thew-effect and efficiently compute the measurement operator, allowing for wide-field reconstruction over the full field-of-view of individual ASKAP beams (up to ∼3.3° each). The precision capability of uSARA produces images with both super-resolution and enhanced sensitivity to diffuse components, surpassing traditional CLEAN algorithms that typically require a compromise between such yields. Our resulting monochromatic uSARA-ASKAP images of the selected data highlight both extended, diffuse emission and compact, filamentary emission at very high resolution (up to 2.2 arcsec), revealing never-before-seen structure. Here we present a validation of our uSARA-ASKAP images by comparing the morphology of reconstructed sources, measurements of diffuse flux, and spectral index maps with those obtained from images made withWSClean.