We compare the results of high-resolution simulations of individual dark matter subhalos evolving in external tidal fields with and without baryonic bulge and disk components, where the average dark matter particle mass is three orders of magnitude smaller than cosmological zoom-in simulations of galaxy formation. The Via Lactea II simulation is used to setup our initial conditions and provides a basis for our simulations of subhalos in a dark matter-only tidal field, while an observationally motivated model for the Milky Way is used for the tidal field that is comprised of a dark matter halo, a stellar disk, and a stellar bulge. Our simulations indicate that including stellar components in the tidal field results in the number of subhalos in Milky Way-like galaxies being only $65\%$ of what is predicted by $\Lambda$ Cold Dark Matter ($\Lambda$CDM). For subhalos with small pericentres $(r_p \lesssim 25$ kpc), the subhalo abundance is reduced further to $40\%$, with the surviving subhalos being less dense and having a tangentially-anisotropic orbital distribution. Conversely, subhalos with larger pericentres are minimally affected by the inclusion of a stellar component in the tidal field, with the total number of outer subhalos $\approx 75\%$ of the $\Lambda$CDM prediction. The densities of outer subhalos are comparable to predictions from $\Lambda$CDM, with the subhalos having an isotropic distribution of orbits. These ratios are higher than those found in previous studies that include the effects baryonic matter, which are affected by spurious disruption caused by low resolution.

中文翻译：

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类银河系潮汐场暗物质亚晕破坏的高分辨率模拟

我们比较了在有和没有重子凸起和盘状成分的外部潮汐场中演化的单个暗物质亚晕的高分辨率模拟结果，其中暗物质粒子的平均质量比星系形成的宇宙放大模拟小三个数量级. Via Lactea II 模拟用于设置我们的初始条件，并为我们在仅暗物质的潮汐场中模拟亚晕提供基础，而银河系的观测动机模型用于潮汐场，该潮汐场由暗物质晕、恒星盘和恒星隆起。我们的模拟表明，在潮汐场中包含恒星成分会导致类银河系中亚晕的数量仅为 $\Lambda$ 冷暗物质 ($\Lambda$CDM) 预测的 $65\%$。对于具有小周边中心 $(r_p \lesssim 25$ kpc) 的亚晕，亚晕丰度进一步降低到 $40\%$，幸存的亚晕密度较小，并且具有切向各向异性的轨道分布。相反，具有较大中心周的次晕受潮汐场中包含恒星成分的影响最小，外次晕的总数约为 $\Lambda$CDM 预测的 75%$。外亚晕的密度与 $\Lambda$CDM 的预测相当，亚晕具有各向同性的轨道分布。