标题： 测试各向异性宇宙射线输运和银河磁场结构对全天伽马射线辐射的影响 显示英文标题

标题： Testing the influence of anisotropic CR transport and the Galactic magnetic field structure on the all-sky gamma-ray emission

摘要： 在由大尺度背景和小尺度湍流成分组成的磁场中，高能粒子的空间扩散应预期是各向异性的。 虽然这种各向异性扩散在第一性原理等离子体物理中早已为人所知，并且对于理解太阳系中宇宙射线或超新星遗迹附近的传输是必要的，但近年来它在银河系宇宙射线（GCR）传输建模中的重要性也变得尤为突出，尤其是在它们的驻留时间和局部能量谱的背景下。 此外，银河系宇宙射线的大尺度空间分布受到银河系磁场中各向异性扩散的影响，这将直接影响弥漫伽马射线和中微子辐射的发射。 我们使用公开可用的传输代码 CRPropa 来求解银河系中宇宙射线的各向异性扩散传输。 扩散的各向异性由局部磁场垂直和平行方向的扩散系数比值$\epsilon = D_\perp / D_\parallel$表征，我们测试了从几乎平行传输（$\epsilon = 10^{-3}$）到更各向同性扩散（$\epsilon = 10^{-1}$）的不同值。 从银河系中宇宙射线的三维分布出发，我们利用视线积分框架 HERMES 计算全天伽马射线发射。 最后，我们展示了扩散各向异性对伽马射线通量空间分布及其能谱分布的影响。 结果表明，扩散的各向异性和磁场几何结构对其有显著影响。 显示英文摘要

摘要： The spatial diffusion of energetic particles in a magnetic field composed of a large-scale background and a small-scale turbulent component should be expected to be anisotropic. While such anisotropic diffusion has been known for quite a while in first-principle plasma physics and while it is required for an understanding of the transport of cosmic rays in the heliosphere or close to supernova remnants, only in recent years it has also become of particular interest for the modeling of Galactic cosmic ray (GCR) transport in the Milky Way in the context of their residence time and their (local) energy spectra. Also, the large-scale spatial distribution of GCRs is shaped by an anisotropic diffusion in the Galactic magnetic field, which should directly affect both the diffuse gamma-ray and the neutrino emission. We solve the anisotropic diffusive transport of GCRs in the Milky Way using the publicly available transport code CRPropa. The anisotropy of the diffusion is characterized by the ratio between the diffusion coefficient perpendicular and parallel to the local magnetic field $\epsilon = D_\perp / D_\parallel$, where we test different values reaching from nearly parallel transport ($\epsilon = 10^{-3}$) to more isotropic diffusion ($\epsilon = 10^{-1}$). From the three dimensional distribution of GCRs in the Milky Way we calculate the all-sky gamma-ray emission, using the line-of-sight integration framework HERMES. Finally, we demonstrate the impact of the anisotropy in the diffusion on the spatial distribution of the gamma-ray flux and its spectral energy distribution. It shows strong influences by the anisotropy of the diffusion and the magnetic field geometry.