The extragalactic γ-ray sky is dominated by relativistic jets aligned to the observer’s line of sight, i.e., blazars. A few of their misaligned counterparts, e.g., radio galaxies, are also detected with the Fermi-Large Area Telescope (LAT), albeit in a small number (∼50), indicating the crucial role played by the jet viewing angle in detecting γ-ray emission from jets. These γ-ray emitting misaligned active galactic nuclei (AGN) provide us with a unique opportunity to understand the high-energy emission production mechanisms from a different viewpoint than the more common blazars. With this goal in mind, we have systematically studied the radio morphology of γ-ray emitting sources present in the fourth data release of the fourth catalog of Fermi-LAT detected γ-ray sources to identify misaligned AGN. By utilizing the high-resolution and sensitive MHz and GHz frequency observations delivered by the Very Large Array Sky Survey, Low-Frequency Array Two-metre Sky Survey, Faint Images of the Radio Sky at Twenty Centimeters, and Rapid ASKAP Continuum Survey, here we present a catalog of 149 γ-ray detected misaligned AGN, thus approximately tripling the number of known objects of this class. Our sample includes a variety of radio morphologies, e.g., edge-darkened and edge-brightened, hybrids, wide-angle-tailed, bent jets, and giants. Since the γ-ray emission is thought to be highly sensitive to the jet viewing angle, such an enlarged sample of γ-ray detected misaligned radio sources will permit us to explore the origin of high-energy emission in relativistic jets and radio lobes and study AGN unification, in general.

中文翻译：

---

伽马射线源的射电形态学：双瓣射电源


银河系外的γ射线天空由与观察者视线对齐的相对论喷流主导，即 blazars。费米大面积望远镜 （LAT） 也探测到一些未对准的对应物，例如射电星系，尽管数量很少 （∼50），这表明喷流视角在探测喷流发射的γ射线方面发挥着至关重要的作用。这些γ射线发射错位的活跃星系核 （AGN） 为我们提供了一个独特的机会，可以从与更常见的 blazar 不同的角度来理解高能发射的产生机制。考虑到这个目标，我们系统地研究了 γ 射线发射源的射电形态，这些源出现在第四个费米 LAT 探测到的γ射线源的第四次数据发布中，以识别未对准的 AGN。通过利用甚大阵列巡天、低频阵列 2 米巡天、20 厘米射电天空的微弱图像和快速 ASKAP 连续巡天提供的高分辨率和灵敏的 MHz 和 GHz 频率观测，我们在这里提出了 149 个γ射线探测到的未对准 AGN 的目录，从而大约增加了此类已知天体数量的三倍。我们的样本包括各种射电形态，例如边缘变暗和边缘变亮、混合、广角尾、弯曲射流和巨型射流。由于人们认为γ射线发射对喷流视角高度敏感，因此这种放大的γ射线检测到未对准的射电源样本将使我们能够探索相对论性喷流和射流瓣中高能发射的起源，并研究一般的 AGN 统一。