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arXiv 1608.08991astro-ph.GAnlin.CD
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模拟盘星系的共振和轨道混沌。应用于Milky Way螺旋模型

Modelling resonances and orbital chaos in disk galaxies. Application to a Milky Way spiral model

Tatiana A. Michtchenko, Ronaldo S. S. Vieira, Douglas A. Barros, Jacques R. D. Lépine

摘要:

内容:旋臂结构扰动下恒星轨道运动的共振在旋涡星系盘的演化中起着重要作用。周转近似允许在赤道平面上确定相应的共振半径(对于近圆形轨道),但一般不适用。目标:我们扩大研究的共振轨道通过分析恒星运动扰动的螺旋臂与高斯形的配置文件,没有任何限制的恒星轨道配置,我们扩大的概念Lindblad(周转)共振的轨道与大的径向偏移。方法:我们定义了一个初始条件的代表平面,它覆盖了系统的整个相空间。代表性的平面上的动力学地图构造数值,以表征相空间结构,并确定谐振的精确位置。该研究是补充建设的动力学功率谱,它提供了识别的基本振荡模式的恒星运动。结果如下:我们的方法允许在整个相空间中的共振链的精确描述,给出了一个更广泛的观点相比,经典的周转方法,即使是在逆行运动的对象的动态系统。太阳邻域的分析表明,根据当前太阳相对于旋臂的方位角相位,具有太阳运动学参数的恒星可能在稳定的共旋共振内或在混沌区中演化。结论:我们的方法有助于量化共振轨道的域和整个银河系相空间结构的混沌程度。它可以作为一个起点,应用这些技术的调查团在银河系中的恒星分布,如运动学运动的群体。

英文摘要:

Context: Resonances in the stellar orbital motion under perturbations from spiral arms structure play an important role in the evolution of the disks of spiral galaxies. The epicyclic approximation allows the determination of the corresponding resonant radii on the equatorial plane (for nearly circular orbits), but is not suitable in general. Aims: We expand the study of resonant orbits by analysing stellar motions perturbed by spiral arms with Gaussian-shaped profiles without any restriction on the stellar orbital configurations, and we expand the concept of Lindblad (epicyclic) resonances for orbits with large radial excursions. Methods: We define a representative plane of initial conditions, which covers the whole phase space of the system. Dynamical maps on representative planes are constructed numerically, in order to characterize the phase-space structure and identify the precise location of resonances. The study is complemented by the construction of dynamical power spectra, which provide the identification of fundamental oscillatory patterns in the stellar motion. Results: Our approach allows a precise description of the resonance chains in the whole phase space, giving a broader view of the dynamics of the system when compared to the classical epicyclic approach, even for objects in retrograde motion. The analysis of the solar neighbourhood shows that, depending on the current azimuthal phase of the Sun with respect to the spiral arms, a star with solar kinematic parameters may evolve either inside the stable co-rotation resonance or in a chaotic zone. Conclusions: Our approach contributes to quantifying the domains of resonant orbits and the degree of chaos in the whole Galactic phase-space structure. It may serve as a starting point to apply these techniques to the investigation of clumps in the distribution of stars in the Galaxy, such as kinematic moving groups.

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。

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