Title: The Effects of Varying Cosmological Parameters on Halo Substructure Show Chinese title

Title: 宇宙学参数变化对晕结构的影响

Abstract: We investigate how different cosmological parameters, such as those delivered by the WMAP and Planck missions, affect the nature and evolution of dark matter halo substructure. We use a series of flat $\Lambda$ cold dark matter ($\Lambda$CDM) cosmological $N$-body simulations of structure formation, each with a different power spectrum but the same initial white noise field. Our fiducial simulation is based on parameters from the WMAP 7th year cosmology. We then systematically vary the spectral index, $n_s$, matter density, $\Omega_M$, and normalization of the power spectrum, $\sigma_8$, for 7 unique simulations. Across these, we study variations in the subhalo mass function, mass fraction, maximum circular velocity function, spatial distribution, concentration, formation times, accretion times, and peak mass. We eliminate dependence of subhalo properties on host halo mass and average over many hosts to reduce variance. While the "same" subhalos from identical initial overdensity peaks in higher $\sigma_8, n_s$, and $\Omega_m$ simulations accrete earlier and end up less massive and closer to the halo center at $z=0$, the process of continuous subhalo accretion and destruction leads to a steady state distribution of these properties across all subhalos in a given host. This steady state mechanism eliminates cosmological dependence on all properties listed above except subhalo concentration and $V_{max}$, which remain greater for higher $\sigma_8, n_s$ and $\Omega_m$ simulations, and subhalo formation time, which remains earlier. We also find that the numerical technique for computing scale radius and the halo finder used can significantly affect the concentration-mass relationship computed for a simulation. Show Chinese abstract

Abstract: 我们研究不同的宇宙学参数，例如来自WMAP和Planck任务的参数，如何影响暗物质晕子结构的性质和演化。 我们使用一系列平坦的$\Lambda$冷暗物质（$\Lambda$CDM）宇宙学$N$体模拟来研究结构形成，每个模拟具有不同的功率谱但相同的初始白噪声场。 我们的基准模拟基于WMAP第七年宇宙学参数。 然后，我们对光谱指数$n_s$、物质密度$\Omega_M$和功率谱归一化$\sigma_8$进行系统变化，进行7次独特的模拟。 在这些模拟中，我们研究子晕质量函数、质量分数、最大圆周速度函数、空间分布、浓度、形成时间、吸积时间和峰值质量的变化。 我们消除子晕属性对主机晕质量的依赖，并对多个主机进行平均以减少方差。 虽然在更高 $\sigma_8, n_s$ 和 $\Omega_m$ 模拟中来自相同初始密度峰值的“相同”子晕更早吸积，并在 $z=0$ 时质量更小且更接近晕中心，但连续的子晕吸积和破坏过程导致了这些特性在给定宿主中所有子晕中的稳定分布。 这种稳定机制消除了上述所有特性的宇宙学依赖性，除了子晕浓度和 $V_{max}$，它们在更高 $\sigma_8, n_s$ 和 $\Omega_m$ 模拟中仍然更大，以及子晕形成时间，它仍然更早。 我们还发现，计算尺度半径的数值技术和使用的晕探测器可以显著影响模拟中计算出的浓度-质量关系。