Ultra-High-Energy Cosmic Rays and other Messengers from Radio Galaxies

超高能宇宙射线（uhecr）的起源仍然是现代天体粒子物理学的一大谜题。迄今为止，仅使用这些带电原子核来识别uhecr的来源一直受到星系和星系外磁场（EGMF）偏转的阻碍。然而，像光子和中微子这样的不带电的信使绕过了这个问题，并提供了额外的信息。已经证明，射电星系（RGs）——特别是它们的相对论性等离子体流出，即所谓的喷流——提供了成为主要来源之一的巨大潜力。然而，到目前为止，并没有对所有UHECR数据的完整解释。提议的项目旨在解释RGs对观测到的uhecr的贡献，包括伴随的二次光子和中微子，以约束必要的源属性。在这个过程中，首先将建立一个基本的射流动力学模型，其中包括这些源内uhecr的相互作用。宿主和申请人已经对这些过程进行了调查，因此第一个关键目标是将这些努力结合起来，产生一个全面的、多信使的RGs模型。其次，开放获取工具CRPropa将用于从这些源向地球传播uhecr和伴随的二次源。在此过程中，将考虑不同的、最新的EGMF模型对UHECR传播的影响。在这里，将得出这些源在距离和源年龄方面的贡献的第一个限制，这标志着拟议项目的第二个关键目标。最后，采用综合拟合算法确定RGs射流的必要性质，从而解释uhecr的观测通量、化学成分和到达方向。因此，从射电观测中已知的源性质以及从高能中微子和扩散伽马射线测量中得到的约束都被考虑在内。总的来说，拟议的项目是申请人先前工作的直接延续，其中最新模型将扩展到RGs的完整多信使模型，随后对数据进行探索。在这个过程中，东道主在多信使天文学方面的综合专业知识将大有裨益。

The origin of Ultra-High-Energy Cosmic Rays (UHECRs) is still one of the great enigmas of modern astroparticle physics. The identification of the sources of UHECRs using only these charged nuclei has been prevented up to now by their deflection in Galactic and extragalactic magnetic fields (EGMF). However, uncharged messengers like photons and neutrinos circumvent this problem and provide additional information.It has already been shown, that radio galaxies (RGs) - in particular their relativistic plasma outflows, the so-called jets - provide great potential of being one of the main sources. However, there is no complete explanation of all UHECR data so far. The proposed project intends to explain the contribution of RGs to the observed UHECRs including the accompanying secondary photons and neutrinos to constrain the necessary source properties. In this process, first a basic model of their jet dynamics will be developed that includes the interactions of the UHECRs within these sources. Those processes have already been investigated by both the host and the applicant, so that the first key objective is to combine these efforts yielding a comprehensive, multi-messenger model of RGs.Secondly, the open-access tool CRPropa will be used to propagate the UHECRs and theaccompanying secondaries from these sources to Earth. In this process, the impact of different, recent EGMF models on the UHECR propagation will be taken into account. Here, first constraints on the contribution of these sources with respect to their distance and source age will be derived, which marks the second key objective of the proposed project.Finally, a comprehensive fitting algorithm will be applied to determine the necessary properties of the jets of RGs, so that the observed flux, chemical composition and arrival directions of the UHECRs can be explained. Hereby, both the source properties known from radio observations and the constraints from high-energy neutrino and diffusive gamma-ray measurements are taken into account.In total the proposed project is a straight continuation of the previous work of the applicant, in which the latest model will be extended to a complete multi-messenger model of RGs that is subsequently probed on data. In this process, the comprehensive expertise of the host in multi-messenger astronomy will be of great benefit.