盘星系外围的多臂螺旋
Multiarm spirals on the periphery of disc galaxies
摘要：
一些盘状星系的螺旋图案在中心有两个臂，在外围有三个或更多的臂。在恒星盘和气体盘的数值模拟中也得到了同样的结果。我们认为，这种模式可能是由于气体的快速冷却，导致形成巨大的分子云。这一过程的时间尺度是5000万年，比普通的长期不稳定性短10倍。巨大的分子云通过摆动放大机制产生多臂螺旋。
英文摘要：
Spiral patterns in some disc galaxies have two arms in the centre, and three or more arms on the periphery. The same result is also obtained in numerical simulations of stellar and gaseous discs. We argue that such patterns may occur due to fast cooling of the gas, resulting in formation of giant molecular clouds. The timescale of this process is 50 Myr, the factor of 10 shorter than of ordinary secular instability. The giant molecular clouds give rise to multiarm spirals through the mechanism of swing amplification.
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。
