对弥散背景、费米泡以及半人马座A的多信使研究

随着近年高能中微子以及引力波的发现，多信使天文学正在进入一个全新的时代。通过宇宙线、中微子、电磁辐射以及引力波信号的联结互补，人们可以更为全面地观察分析极端的天体现象，粒子加速机制以及复杂的宇宙环境。在本青年项目中，申请人将利用高能中微子，伽马射线以及宇宙线的观测，首先对弥散辐射背景进行分析与探索，即利用相互关联的信号，描绘银河系内宇宙线的空间和能量分布，推算出河内中微子源对弥散背景的贡献，并对中微子的河外源模型进行限定。其次对费米泡这一大尺度结构进行形态和能谱分析，理解其物理起源和加速机制。最后我们对河外宇宙线来源最为可能的候选者半人马座A进行深度探索，在充分考虑磁场效应后，利用结合多波段电磁信号推导出的强子模型，计算出中微子和伽马射线的流强，并分析出其中心以及外围结构。总之，本项目通过对这三个天体目标的研究，将增强人们对银河系结构和宇宙线以及磁场分布，中微子起源和天体物理机制的认知。

With the recent discovery of high-energy cosmic neutrinos and gravitational waves, we are entering the new era of multi-messenger astronomy. Through the correlated and complementary information of cosmic rays, neutrinos, electromagnetic radiation and gravitational waves, we could study and exam the extreme astrophysical phenomena, particle acceleration mechanism and complicated cosmic environment. In this project, we will explore the high-energy diffuse background, according to the latest data of cosmic rays, neutrinos and gamma rays. We will unveil our galaxy in detail with the independent and correlated data, depict the spatial and energy distribution of galactic cosmic rays, calculate the contribution from the galactic sources to the background, and constrain the extragalactic source models . Secondly, we will work on the large scale structure in Milky Way, Fermi bubbles, to study the morphology and energy spectrum and understand their origin and mechanism. Last, we will explore Centaurus A, which is one of the most possible candidates of the origin of ultra-high-energy cosmic rays, with the full employment of extragalactic and galactic magnetic fields. With the multi-wavelength and cosmic ray signals, we will calculate the neutrino and gamma ray fluxes, with the consideration of two-zone scenarios, with a focus on hadronic emission. Overall, the diffuse background will play an important role in revealing the structure and history of Milky Way, the production and propagation of cosmic rays, the distribution of galactic magnetic fields and determining the extragalactic origin of the detected high-energy neutrinos by IceCube. The multi-messenger study will have a great advantage of developing and understanding our knowledge of astronomy and physics.