论文标题
在初始宇宙密度场中峰的重力崩溃的迅速尖端形成
Prompt cusp formation from the gravitational collapse of peaks in the initial cosmological density field
论文作者
论文摘要
我提出了一个分析模型，用于在充满无碰撞和无压力“灰尘”的宇宙中初始波动的相干量表上球形密度峰的早期爆发后演变。在与峰值的倒塌时间$ T_0 $相比的时间尺度上，其内部区域定位为具有幂律密度剖面的平衡尖端，$ρ\ propto r^{ - 12/7} $。在此尖端中，每个半径的圆形轨道周期$ p $与$ p = t_0（m/m_c）^{2/3} $相关的质量$ m $，其中$ m_c $是初始峰的适当定义的特征质量。产生该尖峰的松弛机制使人们可以深入了解在冷或温暖的暗物质宇宙中首次晕圈形成的高分辨率模拟中，实际上，一个简单的论点表明，相同的幂律指数$γ= -12/7 $应该描述在任何对称性假设的通用峰值中形成的迅速牙齿。需要进一步的工作来研究是否需要其他因素来解释在峰值崩溃的高分辨率数值模拟中发现的$γ\约-1.5 $。
I present an analytic model for the early post-collapse evolution of a spherical density peak on the coherence scale of the initial fluctuations in a universe filled with collisionless and pressure-free "dust". On a time-scale which is short compared to the peak's collapse time $t_0$, its inner regions settle into an equilibrium cusp with a power-law density profile, $ρ\propto r^{-12/7}$. Within this cusp, the circular orbit period $P$ at each radius is related to the enclosed mass $M$ by $P = t_0 (M/M_c)^{2/3}$ where $M_c$ is a suitably defined characteristic mass for the initial peak. The relaxation mechanism which produces this cusp gives insight into those which are active in high-resolution simulations of first halo formation in Cold or Warm Dark Matter universes, and, indeed, a simple argument suggests that the same power-law index $γ=-12/7$ should describe the prompt cusps formed during the collapse of generic peaks, independent of any symmetry assumption. Further work is needed to investigate whether additional factors are required to explain the slightly flatter exponent, $γ\approx -1.5$, found in high-resolution numerical simulations of peak collapse.
