标题： 3C 403：一个中微子发射的射电星系候选者 显示英文标题

标题： 3C 403: a candidate neutrino-emitting radio galaxy

摘要： 3C 403是一个著名的FRII射电星系，其喷流可延伸到千秒差距尺度。在本文中，我们将其确认为ANTARES合作组织15年中微子数据集中检查的150多个源中第二重要的源，可能使其成为第一个具有中微子辐射的射电星系。在先前将耀变体与中微子事件相关联的基础上，我们旨在研究喷流特性及其在中微子产生中的可能作用。我们收集了多尺度射电观测数据，以评估从千秒差距到天文单位尺度的喷流特性。此外，还检查了其活动星系核的高能特性。通过分析不同尺度上的喷流方向，我们验证了内部喷流或扩展喷流似乎都不接近视线方向。相反，喷流似乎位于天球平面上。此外，我们对最近提出的中微子和硬X射线通量之间的标度关系进行了测试，该关系已针对耀变体和赛弗特星系确定，并与3C 304的测量通量进行了对比。我们发现该源位于耀变体和赛弗特星系之间，尽管目前中微子通量的上限不允许我们对相关性做出明确结论。在这方面，3C 403是之前中微子关联案例之间的中间情况，为未来模型提供了一个有用的测试案例。 显示英文摘要

摘要： 3C 403 is a well known FRII radio galaxy, whose jets extend up to the kpc scale. In this letter, we present its identification as the second most significant source among the more than 150 inspected using the 15-year neutrino dataset of the ANTARES Collaboration, possibly making it the first radio galaxy with neutrino emission. Following the previous association of blazars with netrinos events, we aimed at studying the jet properties and its possible role in neutrino production. We collected multi-scale radio observations to assess the properties of the jet from the kpc to pc scale. Moreover, the high-energy properties of its AGN were inspected. Through the analysis of the jet orientation on the different scales, we verified that neither the inner nor the extended jet seems to have a viewing angle close to the line of sight. Instead, the jet seems to lie on the plane of the sky. In addition, we tested the recently proposed scaling relation between neutrino and hard X-rays fluxes, identified for blazars and Seyfert galaxies, against the measured fluxes for 3C 304. We found that the source lies in the region between blazars and Seyferts, altough the current upper limit on neutrino flux does not allow us to be conclusive on the correlation. In these regards, 3C 403 is an intermediate case between the previous cases of neutrino associations, providing a useful test case for future models.