论文标题
银河棒中屈曲不稳定的起源：寻找替罪羊
The Origin of Buckling Instability in Galactic Bars: Searching for the Scapegoat
论文作者
论文摘要
出色的酒吧的屈曲过程充满了未解决的问题。我们使用高分辨率的N体模拟分析了恒星棒中屈曲不稳定性的起源。先前的研究促进了非共振的消防不稳定，以使垂直屈曲负责。我们已经根据棒上恒星轨道的共振激发分析了屈曲过程，该轨道将能量泵入垂直振荡。我们发现（1）屈曲与中央质量浓度的突然增加有关，并触发沿条沿杆和旋转轴的速度。投影在主轴之一上的速度场形成循环细胞并增加涡度，而涡度不稳定性不稳定。 （2）当通过拉普拉斯平面的异地密度轮廓或曲率测量时，弯曲振幅为非线性，这对恒星运动具有重大影响； （3）在线性描述中，平面和垂直2：1共振仅在屈曲中出现并迅速达到重叠阶段，从而支持能量传递； （4）使用非线性轨道分析，我们分析沿杆和旋转轴的恒星振荡，并发现恒星与屈曲同时越过垂直的2：1共振。重叠的平面和垂直2：1的共振将超过25％的棒颗粒捕获的“吸烟枪”指向恒星轨道的弯曲与谐振作用之间的紧密关系 - 这些颗粒提供了必要的成分，可确保在生长的垂直不对称的垂直不对称中可确保凝聚力响应。我们得出的结论是，共振激发在触发屈曲不稳定方面很重要，因此应重新评估消防不稳定的贡献。最后，我们讨论了屈曲的一些观察意义。
The buckling process in stellar bars is full of unsolved issues. We analyze the origin of the buckling instability in stellar bars using high-resolution N-body simulations. Previous studies have promoted the nonresonant firehose instability to be responsible for the vertical buckling. We have analyzed the buckling process in terms of the resonant excitation of stellar orbits in the bar, which pumps energy into vertical oscillations. We find that (1) the buckling is associated with an abrupt increase in the central mass concentration and triggers velocities along the bar and along its rotation axis. The velocity field projected on one of the main axes forms circulation cells and increases vorticity, which are absent in firehose instability; (2) The bending amplitude is nonlinear when measured by isodensity contours or curvature of the Laplace plane, which has a substantial effect on the stellar motions; (3) In the linear description, the planar and vertical 2:1 resonances appear only with the buckling and quickly reach the overlapping phase, thus supporting the energy transfer; (4) Using nonlinear orbit analysis, we analyze the stellar oscillations along the bar and along the rotation axis and find that stars cross the vertical 2:1 resonance simultaneously with the buckling. The overlapping planar and vertical 2:1 resonances trapping more than 25% of the bar particles provide the 'smoking gun' pointing to a close relationship between the bending of stellar orbits and the resonant action -- these particles provide the necessary ingredient assuring the cohesive response in the growing vertical asymmetry. We conclude that resonant excitation is important in triggering the buckling instability, and the contribution from the firehose instability should be reevaluated. Finally, we discuss some observational implications of buckling.
