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棒星系中的环和螺旋。一.构件

Rings and spirals in barred galaxies. I Building blocks

E. Athanassoula, M. Romero-Gomez, J. J. Masdemont

备注：
Typos corrected to match the version in press in MNRAS
发表信息：
Mon.Not.Roy.Astron.Soc.394:67-81,2009
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摘要：

在本文中，我们提出的积木，可以解释的形成和性质的螺旋和内外环的棒星系。我们首先简要地总结了我们在其他地方给出的完整理论描述的主要结果，以更物理的方式呈现它们，目的是在不需要扩展动力学系统或轨道结构知识的情况下理解它们。我们以这种方式引入流形的概念，它可以被认为是引导轨道的管道。这些流形的动力学可以控制棒星系中螺旋和内外环的性质。我们发现，酒吧的强度影响如何不稳定的L1和L2拉格朗日点，在5A5A5A歧管内的运动和必要的时间为粒子在一个多方面，使一个完整的转身围绕银河系中心。我们还表明，酒吧的强度，或者，更准确地说，非轴对称强迫和有点超出共转区域，确定所产生的形态。因此，不太强的棒产生R1环或伪环，而较强的棒驱动R2，R1R2和螺旋形态。我们检查的形态作为酒吧的主要参数的函数，并提出描述性的二维图，以利用。我们还推导出如何修改的流形形态和性质，如果L1和L2拉格朗日点变得稳定。最后，我们讨论了耗散如何影响流形性质，并比较了类气体和恒星的情况下的流形。与观测结果的比较，以及有待观测结果检验的明确预测，将在随附的论文中给出。

英文摘要：

In this paper we present building blocks which can explain the formation and properties both of spirals and of inner and outer rings in barred galaxies. We first briefly summarise the main results of the full theoretical description we have given elsewhere, presenting them in a more physical way, aimed to an understanding without the requirement of extended knowledge of dynamical systems or of orbital structure. We introduce in this manner the notion of manifolds, which can be thought of as tubes guiding the orbits. The dynamics of these manifolds can govern the properties of spirals and of inner and outer rings in barred galaxies. We find that the bar strength affects how unstable the L1 and L2 Lagrangian points are, the motion within the 5A5A5Amanifold tubes and the time necessary for particles in a manifold to make a complete turn around the galactic centre. We also show that the strength of the bar, or, to be more precise, of the non-axisymmetric forcing at and somewhat beyond the corotation region, determines the resulting morphology. Thus, less strong bars give rise to R1 rings or pseudorings, while stronger bars drive R2, R1R2 and spiral morphologies. We examine the morphology as a function of the main parameters of the bar and present descriptive two dimensional plots to that avail. We also derive how the manifold morphologies and properties are modified if the L1 and L2 Lagrangian points become stable. Finally, we discuss how dissipation affects the manifold properties and compare the manifolds in gas-like and in stellar cases. Comparison with observations, as well as clear predictions to be tested by observations will be given in an accompanying paper.

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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