We present sofia 2, the fully automated 3D source finding pipeline for the WALLABY extragalactic H i survey with the Australian SKA Pathfinder (ASKAP). sofia 2 is a reimplementation of parts of the original sofia pipeline in the c programming language and makes use of OpenMP for multithreading of the most time-critical algorithms. In addition, we have developed a parallel framework called sofia-X that allows the processing of large data cubes to be split across multiple computing nodes. As a result of these efforts, sofia 2 is substantially faster and comes with a much reduced memory footprint compared to its predecessor, thus allowing the large WALLABY data volumes of hundreds of gigabytes of imaging data per epoch to be processed in real time. The source code has been made publicly available to the entire community under an open-source licence. Performance tests using mock galaxies injected into genuine ASKAP data suggest that in the absence of significant imaging artefacts sofia 2 is capable of achieving near-100 per cent completeness and reliability above an integrated signal-to-noise ratio (SNR) of about 5–6. We also demonstrate that sofia 2 generally recovers the location, integrated flux, and w20 line width of galaxies with high accuracy. Other parameters, including the peak flux density and w50 line width, are more strongly biased due to the influence of the noise on the measurement. In addition, very faint galaxies below an integrated SNR of about 10 may get broken up into multiple components, thus requiring a strategy to identify fragmented sources and ensure that they do not affect the integrity of any scientific analysis based on the sofia 2 output.

中文翻译：

---

sofia 2 – 用于 WALLABY 调查的自动化、并行 H i 源查找管道

我们展示了 sofia 2，这是一个全自动的 3D 源查找管道，用于与澳大利亚 SKA 探路者 (ASKAP) 进行的 WALLABY 河外 H i 调查。sofia 2 是用 c 编程语言重新实现了原始 sofia 管道的一部分，并利用 OpenMP 对时间要求最严格的算法进行多线程处理。此外，我们还开发了一个名为 sofia-X 的并行框架，它允许将大型数据立方体的处理拆分到多个计算节点上。由于这些努力，sofia 2 的速度比其前身快得多，内存占用也大大减少，因此可以实时处理每个时期数百 GB 成像数据的大型 WALLABY 数据量。源代码已在开源许可下向整个社区公开。使用注入真实 ASKAP 数据的模拟星系进行的性能测试表明，在没有显着成像伪影的情况下，sofia 2 能够实现接近 100% 的完整性和可靠性，高于约 5-6 的综合信噪比 (SNR) . 我们还证明了 sofia 2 通常可以高精度地恢复星系的位置、积分通量和 w20 线宽。由于噪声对测量的影响，其他参数，包括峰值通量密度和 w50 线宽，偏差更大。此外，低于约 10 的综合信噪比的非常微弱的星系可能会分解成多个成分，因此需要一种策略来识别碎片来源并确保它们不会影响基于 sofia 2 输出的任何科学分析的完整性。