The Role of Gas In Maintaining Quasi-Steady Spiral Structure In Stellar Disks
The Role of Gas In Maintaining Quasi-Steady Spiral Structure In Stellar Disks
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气体在维持恒星盘准稳态螺旋结构中的作用
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发表时间：
2008
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通讯作者：
S. Chakrabarti
中科院分区：
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作者：
S. Chakrabarti
我们研究的螺旋结构的动力学演化在孤立星系的恒星盘使用高分辨率平滑粒子流体动力学（SP H）模拟治疗气体，恒星和暗物质的演化自洽。本文着重研究了恒星盘中的自激螺旋结构问题，并探讨了冷耗散气体组分与恒星组分之间的动力学耦合。我们发现，从气体到恒星的角动量传输corotati内导致一个大致时间稳定的螺旋结构的恒星盘。为了明确这一点，我们将这些结果与不包括能够辐射冷却和耗散能量的冷气体或组件的其他相同模拟进行了对比，并发现螺旋结构在初始时在不包括气体的模拟中更快地消失。我们还利用标准的星星形成公式将气体转化为恒星，发现我们的结果对于典型的气体消耗时间尺度是成立的，与Kennicutt-Schmidt关系雅阁。因此，我们把恒星盘中长寿命的大致时间稳定的螺旋结构归因于气体和恒星之间的动力学耦合以及自引力气体盘由于无碰撞成分和耗散成分之间的方位角相移而对恒星施加的扭矩。
We study the dynamical evolution of spiral structure in the s tellar disks of isolated galaxies using high resolution Smoothed Particle Hydrodynamics (SP H) simulations that treat the evolution of gas, stars, and dark matter self-consistently. We focus this study on the question of self-excited spiral structure in the stellar disk and inves tigate the dynamical coupling between the cold, dissipative gaseous component and the stellar com ponent. We find that angular momentum transport from the gas to the stars inside of corotati on leads to a roughly time-steady spiral structure in the stellar disk. To make this point clea r, we contrast these results with otherwise identical simulations that do not include a cold gase ou component that is able to cool radiatively and dissipate energy, and find that spiral struc ture, when it is incipient, dies out more rapidly in simulations that do not include gas. We also e mploy a standard star formation prescription to convert gas into stars and find that our resul ts hold for typical gas consumption time scales that are in accord with the Kennicutt-Schmidt re lation. We therefore attribute the long-lived roughly time steady spiral structure in the stel lar disk to the dynamical coupling between the gas and the stars and the resultant torques that t he self-gravitating gaseous disk is able to exert on the stars due to an azimuthal phase shift be tween the collisionless and dissipative components.