潮汐力矩作用下的自相似球面坍缩
Self-Similar Spherical Collapse with Tidal Torque
摘要：
N体模拟已经揭示了大量关于暗物质晕的信息，然而他们的结果在很大程度上是经验的。使用分析手段，我们试图揭示模拟结果概括的自相似二次降雨模型，包括潮汐扭矩。在这两篇论文中的第一篇中，我们描述了我们的晕形成模型，并将我们的结果与N体模拟启发的经验质量分布进行了比较。每个光环由四个参数决定。一个参数设定质量尺度，其他三个参数定义质量壳层内的粒子在整个演化过程中如何被扭转。我们选择的扭矩参数的潮汐扭矩理论和N体模拟和解析计算的结构晕在不同的径向制度。我们发现，角动量起着重要的作用，在确定小半径的密度分布。对于宇宙学初始条件，小尺度上的密度分布由粒子角动量的时间变化率以及晕质量决定。然而，在中间尺度上，$ρ\propto r^{-2}$，而$ρ\propto r^{-3}$接近维里半径。
英文摘要：
N-body simulations have revealed a wealth of information about dark matter halos however their results are largely empirical. Using analytic means, we attempt to shed light on simulation results by generalizing the self-similar secondary infall model to include tidal torque. In this first of two papers, we describe our halo formation model and compare our results to empirical mass profiles inspired by N-body simulations. Each halo is determined by four parameters. One parameter sets the mass scale and the other three define how particles within a mass shell are torqued throughout evolution. We choose torque parameters motivated by tidal torque theory and N-body simulations and analytically calculate the structure of the halo in different radial regimes. We find that angular momentum plays an important role in determining the density profile at small radii. For cosmological initial conditions, the density profile on small scales is set by the time rate of change of the angular momentum of particles as well as the halo mass. On intermediate scales, however, $ρ\propto r^{-2}$, while $ρ\propto r^{-3}$ close to the virial radius.
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