Data from : Radio source extraction with PROFOUND

In the current era of radio astronomy, continuum surveys observe a multitude of objects with complex morphologies and sizes, and are not limited to observing point sources. Typical radio source extraction software generates catalogues by using Gaussian components to form a model of the emission. This may not be well suited to complicated jet structures and extended emission, particularly in the era of interferometers with a high density of short baselines, which are sensitive to extended emission. In this paper, we investigate how the optically motivated source detection package PROFOUND (Robotham et al. 2018) may be used to model radio emission of both complicated and point-like radio sources. We use a combination of observations and simulations to investigate how PROFOUND compares to other source extractor packages used for radio surveys. We find that PROFOUND can accurately recover both the flux densities of simulated Gaussian sources as well as extended radio galaxies. PROFOUND can create models that trace the complicated nature of these extended galaxies, which we show is not necessarily the case with other source extraction software. Our work suggests that our knowledge of the emission from extended radio objects may be both over or under-estimated using traditional software. We suggest that PROFOUND offers a useful alternative to the fitting of Gaussian components for generating catalogues from current and future radio surveys. Furthermore, PROFOUND's multiwavelength capabilities will be useful in investigating radio sources in combination with multiwavelength data.

在当前射电天文学时代，连续谱巡天 (continuum surveys) 观测着大量形态与尺度各异的天体，且观测对象并不局限于点源 (point sources)。主流射电源提取软件 (radio source extraction software) 通常通过高斯分量 (Gaussian components) 构建辐射模型以生成源表 (catalogues)，但这类方法难以适配复杂喷流结构 (jet structures) 与延展辐射 (extended emission)；尤其在当前短基线 (short baselines) 密度较高的干涉仪 (interferometers) 时代，这类干涉仪对延展辐射具有较高灵敏度。本文中，我们探究了基于光学波段的源探测软件包 (optically motivated source detection package) PROFOUND (PROFOUND)（Robotham等，2018）在建模复杂射电源与类点射电源辐射方面的应用。我们结合观测与模拟数据，对比了PROFOUND与其他用于射电巡天 (radio surveys) 的源提取软件的性能表现。研究结果表明，PROFOUND可准确恢复模拟高斯源的流量密度 (flux densities)，同时也能精准还原延展射电星系 (extended radio galaxies) 的辐射。PROFOUND能够构建出贴合这类延展星系复杂形态的模型，而我们的分析显示，其他主流源提取软件未必能做到这一点。本研究表明，使用传统软件对延展射电天体辐射的认知可能存在高估或低估的情况；而PROFOUND为当前及未来射电巡天生成源表提供了一种优于高斯分量拟合的可行方案。此外，PROFOUND的多波段处理能力 (multiwavelength capabilities)，在结合多波段数据开展射电源研究时将具备显著应用价值。