论文标题
冷暗物质Subhalos的渐近潮汐残留物
The asymptotic tidal remnants of cold dark matter subhalos
论文作者
论文摘要
我们使用N体模拟研究大量宿主的重力潜力中cuspy冷暗物质（CDM）光晕的演变。潮汐质量损失重塑了CDM光晕，留下了绑定的残留物，其特征密度是由宿主在其各自轨道的围绕中心的平均密度设定的。对于几乎圆形轨道，在〜5个轨道后，最终绑定的残留状态的演变基本上是完整的，而到达相同的残留物需要约25和〜40个轨道，对于偏心轨道，偏心轨道分别为1：5和1:20 Perincentre topercentre topercentre topercentre比率。潮汐残留物的密度曲线是通过质量损失的比例完全指定的，并且在重度质量损失的情况下接近了指数截断的navarro-frenk-white剖面。解决潮汐残留物需要出色的数值分辨率；解决不良的Subhalos的特征密度较低，并且更容易被破坏。当最终残留物以少于3000个粒子的范围解析时，即使是出色的空间和时间分辨率的模拟也会失败。我们得出了一个简单的经验模型，描述了适用于多种轨道偏心率和近美距离的质量的演变和潮汐残留物的密度曲线的演变。应用于银河系，我们的结果表明，$ 10^8 $ - $ 10^{10} $太阳质量晕圈在1:10轨道上以周围距离〜10距离〜10 kpc降至10 kpc，应该被剥离至其原始质量的0.1-1％。这意味着基于直接宇宙学模拟的这种光环的生存和结构（超品种卫星的可能宿主）的估计可能会进行大量修订。
We use N-body simulations to study the evolution of cuspy cold dark matter (CDM) halos in the gravitational potential of a massive host. Tidal mass losses reshape CDM halos, leaving behind bound remnants whose characteristic densities are set by the mean density of the host at the pericentre of their respective orbit. The evolution to the final bound remnant state is essentially complete after ~5 orbits for nearly circular orbits, while reaching the same remnant requires ~25 and ~40 orbits for eccentric orbits with 1:5 and 1:20 pericentre-to-apocentre ratios, respectively. The density profile of tidal remnants is fully specified by the fraction of mass lost, and approaches an exponentially-truncated Navarro-Frenk-White profile in the case of heavy mass loss. Resolving tidal remnants requires excellent numerical resolution; poorly resolved subhalos have systematically lower characteristic densities and are more easily disrupted. Even simulations with excellent spatial and time resolution fail when the final remnant is resolved with fewer than 3000 particles. We derive a simple empirical model that describes the evolution of the mass and the density profile of the tidal remnant applicable to a wide range of orbital eccentricities and pericentric distances. Applied to the Milky Way, our results suggest that $10^8$ - $10^{10}$ solar mass halos accreted ~10 Gyrs ago on 1:10 orbits with pericentric distance ~10 kpc should have been stripped to 0.1 - 1 per cent of their original mass. This implies that estimates of the survival and structure of such halos (the possible hosts of ultra-faint Milky Way satellites) based on direct cosmological simulations may be subject to substantial revision.
