Two-Arm Spiral Structure of Molecular Gas in the Flocculent Galaxy NGC 5055
Two-Arm Spiral Structure of Molecular Gas in the Flocculent Galaxy NGC 5055
复制标题
絮状星系NGC 5055中分子气体的双臂螺旋结构
DOI：
10.1093/pasj/49.3.275
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发表时间：
1997
影响因子：
2.3
通讯作者：
K. Nishiyama
中科院分区：
文献类型：
--
作者：
N. Kuno;T. Tosaki;N. Nakai;K. Nishiyama
本文介绍了用Nobeyama 45米望远镜对絮状螺旋星系NGC 5055进行CO观测的结果。在星系中发现了一个长而对称的双臂螺旋结构。由于分子臂与在IF '波段看到的老恒星的分子臂重合，它们是由恒星密度波引起的。分子旋臂可以用螺距角为19°的对数螺旋拟合，这与M51中测量的结果相当。臂间比为2-3（R-SO ^-160”），并随银河系中心半径的增加而增加。由于明亮的H11区也沿着分子气体分布，大质量星星的形成发生在臂中。这些结果表明，NGC 5055的絮状螺旋结构不能仅仅用随机的星星形成来解释。
We present the results of CO observations of the flocculent spiral NGC 5055 with the Nobeyama 45-m telescope. A long and symmetric two-arm spiral structure was found in the galaxy. Since the molecular arms are coincident with those of old stars seen in the if'-band, they are caused by a stellar density wave. The molecular spiral arms can be fitted with a logarithmic spiral with a pitch angle of 19°, which is comparable to that measured in M51. The arm-to-inter arm ratio is 2-3 (R — SO^-160") and increases with the galactocentric radius. Since bright Hll regions also distribute along the molecular gas, massive star formation occurs in the arms. These results indicate that the flocculent spiral structure of NGC 5055 can not be explained solely by stochastic star formation.