论文标题
定期宇宙学模拟中功率谱的各向异性
The anisotropy of the power spectrum in periodic cosmological simulations
论文作者
论文摘要
圆环上的经典引力力是各向异性的，总是低于牛顿的$ 1/r^2 $法律。我们证明了仅$ n $ n $ body模拟球形崩溃和标准$λ$ CDM初始条件的效果。周期性边界条件在宇宙结构形成的宇宙学模拟中导致总体负和各向异性偏差。小型周期模拟的功率光谱的较低振幅是缺失的大型模式和同样重要的较小周期力的结果。当最大的轻度非线性尺度与模拟框的线性大小相当时，这种效果是最重要的，而高分辨率流体动力学模拟通常是这种情况。球形塌陷变成类似于八面体的形状。各向异性生长扭曲了大规模$λ$ CDM暗物质结构。我们在模拟体积的八面体组下介绍了方向依赖性的功率谱不变，并表明结果破坏了球形对称性。
The classical gravitational force on a torus is anisotropic and always lower than Newton's $1/r^2$ law. We demonstrate the effects of periodicity in dark matter only $N$-body simulations of spherical collapse and standard $Λ$CDM initial conditions. Periodic boundary conditions cause an overall negative and anisotropic bias in cosmological simulations of cosmic structure formation. The lower amplitude of power spectra of small periodic simulations are a consequence of the missing large scale modes and the equally important smaller periodic forces. The effect is most significant when the largest mildly non-linear scales are comparable to the linear size of the simulation box, as often is the case for high-resolution hydrodynamical simulations. Spherical collapse morphs into a shape similar to an octahedron. The anisotropic growth distorts the large-scale $Λ$CDM dark matter structures. We introduce the direction-dependent power spectrum invariant under the octahedral group of the simulation volume and show that the results break spherical symmetry.
