暗物质晕和重子物质的自旋、速度剪切场及涡量的相关性分析∗

摘要

Using cosmological hydrodynamic simulations, we investigate the align-ments between velocity shear, vorticity, and the spin of dark matter halos, and study the correlation between baryonic and dark matter. We find that (1) mis-alignment between vorticity of baryonic and dark matter would develop on scales<0.2h−1 Mpc;(2) the vorticity of baryonic matter exhibits stronger alignment/anti-alignment with the eigenvectors of velocity shear than that of dark matter; (3) small/massive halos spinning parallel/perpendicular to the host filaments are sensitive to the identification of cosmic web, simulation box size, and resolution. These factors might complicate the connection between the spins of dark matter halos and galaxies, and affect the correlation signal of the alignments of galaxy spin with nearby large-scale structures.%在宇宙学流体力学模拟的基础上，通过对速度剪切场、涡量与暗物质晕自旋方向的相关性，以及重子与暗物质之间关系的研究，发现：(1)在小于0.2h−1 Mpc的尺度上，重子物质涡量与暗物质涡量的差异比较明显；(2)重子物质的涡量与速度剪切张量的相关性比暗物质要强；(3)小质量暗物质晕的自旋方向平行于其所在的纤维结构的方向，而大质量暗物质晕的自旋方向垂直于纤维结构的方向，并且这种相关性的强弱依赖于模拟盒子大小以及模拟精度.这些因素会使暗物质晕自旋与星系自旋之间的关系复杂化，也会对星系自旋方向与大尺度环境的相关性产生影响.