棒星系中的规则和混沌轨道I。应用SALI/GALI方法探索它们在几种模型中的分布
Regular and chaotic orbits in barred galaxies - I. Applying the SALI/GALI method to explore their distribution in several models
摘要：
在星系模型中，轨道的混沌和规则行为的区别是一个重要的问题，可以帮助我们理解星系动力学演化。在本文中，我们处理这个问题，通过应用技术的较小（和广义）ALingment指数，SALI（和GALI），广泛的样本轨道通过数值积分的运动方程在一个棒星系的潜力。我们估计第一部分的混沌和定期轨道的两个自由度（DOF）的情况下（其中星系只在（x，y）-空间），并表明它是一个非单调的功能的能量。对于该模型的三自由度扩展（在z方向上），我们通过探索不同的初始条件集和改变模型参数（如杆的质量，尺寸和图案速度）给出了类似的估计。我们发现，经常运动是更丰富的小径向距离从星系的中心，那里的相对非轴对称强迫是相对较弱的，并在小距离从赤道平面，在稳定的周期性轨道周围的陷阱是很重要的。我们还发现，在一个现实的范围内的值的酒吧模式的速度的变化，并没有太多的影响相空间的定期和混乱的运动的分数。使用不同的初始条件，我们表明，混沌运动是占主导地位的星系模型，其酒吧组件是更大规模的，而模型与胖或厚酒吧一般更经常的行为。最后，我们发现，轨道的比例是混乱的强烈相关的酒吧的强度。
英文摘要：
The distinction between chaotic and regular behavior of orbits in galactic models is an important issue and can help our understanding of galactic dynamical evolution. In this paper, we deal with this issue by applying the techniques of the Smaller (and Generalized) ALingment Indices, SALI (and GALI), to extensive samples of orbits obtained by integrating numerically the equations of motion in a barred galaxy potential. We estimate first the fraction of chaotic and regular orbits for the two-degree-of-freedom (DOF) case (where the galaxy extends only in the (x,y)-space) and show that it is a non-monotonic function of the energy. For the three DOF extension of this model (in the z-direction), we give similar estimates, both by exploring different sets of initial conditions and by varying the model parameters, like the mass, size and pattern speed of the bar. We find that regular motion is more abundant at small radial distances from the center of the galaxy, where the relative non-axisymmetric forcing is relatively weak, and at small distances from the equatorial plane, where trapping around the stable periodic orbits is important. We also find that the variation of the bar pattern speed, within a realistic range of values, does not affect much the phase space's fraction of regular and chaotic motions. Using different sets of initial conditions, we show that chaotic motion is dominant in galaxy models whose bar component is more massive, while models with a fatter or thicker bar present generally more regular behavior. Finally, we find that the fraction of orbits that are chaotic correlates strongly with the bar strength.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
