具有中心密度尖点的径向各向异性旋转恒星系统的稳定性
The stability of radially anisotropic rotating stellar systems with a central density cusp
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中文总结 AI 辅助
研究初始球对称且有适度密度尖点的自引力系统中径向速度各向异性与内部旋转的相互作用，通过无碰撞\(N\)体模拟，分析密度等模式及构型指标，发现内部旋转对径向轨道不稳定性有不同影响，还会形成内部棒。
中文摘要 AI 辅助
我们研究了以初始球对称性和适度密度尖点为特征的自引力系统中径向速度各向异性与内部旋转之间的相互作用。我们研究此类构型的稳定性性质，以厘清各向异性、旋转和密度结构对三轴恒星系统形成的影响。我们从具有由奥西波夫和梅里特引入的相空间分布函数的初始平衡态出发，通过林登 - 贝尔守护进程协议施加净全局角动量，进行了一组无碰撞\(N\)体模拟。我们分析了密度和相空间分布模式的增长，以及最终构型的轴比和三轴性指数。我们发现，对于弗里德曼 - 波利亚琴科 - 舒赫曼指数接近一致性值的径向各向异性模型，内部旋转对径向轨道不稳定性的强度有缓解作用，而在接近稳定的模型中，它会略微增强不稳定性的起始。从密度模式增长率的分析中，我们还发现，尽管对于最大旋转初始条件内部棒是不稳定的，但即使在具有中心密度尖点初始轮廓的系统中也会形成内部棒。
英文摘要
We investigate the interplay between radial velocity anisotropy and internal rotation in self-gravitating systems characterised by initial spherical symmetry and a moderate density cusp. We study the stability properties of such configurations to disentangle the impact of anisotropy, rotation, and density structure on the formation of triaxial stellar systems. We perform a set of collisionless $N$-body simulations starting from initial equilibria with a phase space distribution function of the class introduced by Osipkov and Merritt, modified to impose a net global angular momentum with the Lynden-Bell daemon protocol. We analyse the growth of the density and phase space distribution modes, as well as the axial ratios and triaxiality index of the final configurations. We find that internal rotation has a mitigating effect on the strength of the radial orbit instability in radially anisotropic models with Fridman-Polyachenko-Shukhman index close to its value for consistency, while it slightly enhances the onset of the instability in nearly stable models. From the analysis of the growth rate of the density modes, we also find that an inner bar, though unstable for maximally rotating initial conditions, is formed even in systems with initial profiles with a central density cusp.
