发表机构
Indian Institute of Science Education and Research; National Centre for Radio Astrophysics - Tata Institute of Fundamental Research（印度科学教育研究所; 塔塔基础研究院国家射电天文中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文报道了巨型S形射电星系J023721.13$-$010528.5，通过多频观测发现其具有四次喷流活动，提出四重双射电星系新类型，并指出此类源是研究多纪元喷流活动的理想目标。
AI 中文摘要
我们利用升级后的巨米波射电望远镜在 band-3（250--500 MHz）和 band-4（550--950 MHz）波段，以及 MeerKAT（1280 MHz）和 VLA（3 GHz）巡天图像，对 J023721.13$-$010528.5 进行了高灵敏度、高分辨率的射电观测。该射电源由一个红移 $z=0.372$ 的亮星系团星系所承载，是一个巨型射电星系，其最外层热斑之间的投影线性尺度为 1.2 Mpc，是已知最大的 $S$ 形射电源之一。其射电形态揭示了四对横跨射电核心的成分，这些成分也是沿射电瓣测量的射电流量密度和等分能量密度剖面中的局部极大值。空间分辨的多频光谱分析显示，从内到外成分的辐射年龄逐渐变老，跨度约为 4--21 Myr。内部三对成分相对于射电核心的高度对称性使得它们不可能是射电喷流中随机分布的结。因此，我们将 J023721.13$-$010528.5 作为一类具有四次喷流活动 episodes 的新型射电星系——四重双射电星系的原型。我们认为，巨型 $S$ 形射电源可能是识别和研究多纪元射电喷流活动最有前景的目标之一，因为它们的大线性尺度和喷流轴演化可以将连续 episodes 的热斑在空间上分离，使其更容易被探测和分析。
英文摘要
We present high-sensitivity, high-resolution radio observations of J023721.13$-$010528.5 using the upgraded Giant Metrewave Radio Telescope in band-3 (250--500\,MHz) and band-4 (550--950\,MHz), along with MeerKAT (1280\,MHz) and VLA (3\,GHz) survey images. The radio source, hosted by a bright cluster galaxy at redshift $z=0.372$, is a giant radio galaxy with a projected linear size between the outermost hotspots of 1.2~Mpc and is one of the largest $S$-shaped radio sources known. Its radio morphology revealed four pairs of components straddling the radio core, which were also local maxima in profiles of radio flux densities and equipartition energy density measured along the radio lobes. Spatially resolved multi-frequency spectral analysis showed progressively older emission from the inner to the outer components, spanning approximately 4--21 Myr. The high degree of symmetry of the inner three component-pairs with respect to the radio core makes it improbable that these are randomly located knots in the radio jet. Therefore, we present J023721.13$-$010528.5 as the prototype of a new class of radio galaxies with four episodes of jet activity --- a quadruple-double radio galaxy. We suggest that giant $S$-shaped radio sources may be among the most promising targets for identifying and studying multi-epoch radio jet activity, since their large linear sizes and jet-axis evolution can spatially separate hotspots from successive episodes, making them easier to detect and analyse.
Comments14 pages, 11 figures, Accepted for publication in The Astrophysical Juornal
