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arXiv 1006.4574astro-ph.GA
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双杆Galerkin中快、慢内杆的轨道支撑

Orbital Support of Fast and Slow Inner Bars in Double Barred Galaxies

Witold Maciejewski, Emma E. Small

摘要:

我们分析了如何在一个双棒星系(嵌套酒吧)的内部酒吧的轨道支持取决于这个酒吧的角速度(即模式速度)。本文用不变环方法研究了七种双杆模型中的轨道。图案速度的范围被详尽地覆盖。我们发现,并不是所有的模式速度时,允许内杆旋转的方向与外杆相同。低于某个最小模式速度,轨道对内棒的支持突然消失,而在这个速度的高值时,轨道表明一个越来越圆的棒,看起来更像是核等照度线的扭曲,而不是动力学独立的组件。对于这两个极端之间的值,支持内棒的轨道随着棒的图案速度的降低而进一步向外延伸,它们相应的环变得更加偏心,脉动更多,并且它们的旋转变得越来越不均匀,因为它们在运动中加速和减速。较低的花型速度也导致不太连贯的杆,因为支撑内部杆的环之间的脉动和加速度越来越多地变化。从这里研究的轨道结构的快速和缓慢的内部酒吧的形态预期最近恢复观测分解的双棒星系。我们的研究结果使我们能够将观察到的形态与内部酒吧的动态联系起来。

英文摘要:

We analyze how the orbital support of the inner bar in a double-barred galaxy (nested bars) depends on the angular velocity (i.e. pattern speed) of this bar. We study orbits in seven models of double bars using the method of invariant loops. The range of pattern speed is covered exhaustively. We find that not all pattern speeds are allowed when the inner bar rotates in the same direction as the outer bar. Below a certain minimum pattern speed orbital support for the inner bar abruptly disappears, while at high values of this speed the orbits indicate an increasingly round bar that looks more like a twist in the nuclear isophotes than a dynamically independent component. For values between these two extremes, orbits supporting the inner bar extend further out as the bar's pattern speed decreases, their corresponding loops become more eccentric, pulsate more, and their rotation becomes increasingly non-uniform, as they speed up and slow down in their motion. Lower pattern speeds also lead to a less coherent bar, as the pulsation and acceleration increasingly varies among the loops supporting the inner bar. The morphologies of fast and slow inner bars expected from the orbital structure studied here are recently recovered observationally by decomposition of double barred galaxies. Our findings allow us to link the observed morphology to the dynamics of the inner bar.

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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