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arXiv 1502.02740astro-ph.GA
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阻势气体流动

Gas flow in barred potentials

Mattia C. Sormani, James Binney, John Magorrian

摘要:

我们使用笛卡尔网格来模拟气体在禁止银河势中的流动,并研究了气体中声速变化和网格分辨率的影响。对于所有的声速和分辨率,流线在大小半径上都紧密地遵循闭合轨道。在中间半径处,激波出现,流线在两族闭合轨道之间移动。激波出现的点和流线在轨道族之间的移动在很大程度上取决于声速和分辨率。对于这两个参数的足够大的值,转移发生在由宾尼等人在二十多年前假设的尖点轨道。对于足够高的分辨率,激波下游的流动变得不稳定。如果这种不稳定性是物理的,就像看起来的那样,它为观测到的CO分布的不对称性提供了一个有希望的解释。

英文摘要:

We use a Cartesian grid to simulate the flow of gas in a barred Galactic potential and investigate the effects of varying the sound speed in the gas and the resolution of the grid. For all sound speeds and resolutions, streamlines closely follow closed orbits at large and small radii. At intermediate radii shocks arise and the streamlines shift between two families of closed orbits. The point at which the shocks appear and the streamlines shift between orbit families depends strongly on sound speed and resolution. For sufficiently large values of these two parameters, the transfer happens at the cusped orbit as hypothesised by Binney et al. over two decades ago. For sufficiently high resolutions the flow downstream of the shocks becomes unsteady. If this unsteadiness is physical, as appears to be the case, it provides a promising explanation for the asymmetry in the observed distribution of CO.

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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