【摘要】 本文分析了在巨分子云聚合形成机制下旋臂扰动的影响 .结果表明 ,在巨分子云聚合形成过程中 ,当不考虑恒星形成引起的巨分子云的碎裂时 ,旋臂的存在使分子云在绕星系中心作自转运动时 ,在旋臂区域分子云的密度大大增加而使较多的大质量分子云由于碰撞而形成 ,特别能促使一些质量更大的巨分子云形成 .但当这些聚合形成的大质量分子云走出旋臂区域进入臂间区域时 ,它们又会自动瓦解 .因此在整个星系盘上 ,与没有旋臂扰动情况相比 ,F(M )∝logM的曲线只是相应地往上有一平移 ,而对形成的中间质量的巨分子云的数量基本没有影响更多还原

【Abstract】 The effect of spiral arm perturbation on the aggregation formation of giant molecular clouds (GMCs) is analyzed in this paper. It is shown that the presence of spiral structure may promote the formation rate of massive GMCs, especially a few very massive GMCs, by collisions in arm region due to the orbit crowding resulting from the rotational motion of clouds, which will increase the cloud density in that region, if the disruption of GMCs caused by star formation is neglected. However, when the more massive GMCs move from an arm into an inter arm region, they could disintegrate spontaneously. Therefore, compared to the case without spiral arm perturbation, the curve F(M)∝ log M, which is a measure of the formation rate of more massive clouds in the whole disk, is just displaced upwards and the amount of GMCs with intermediate mass, i.e., those with mass in the range between 10 5 and 10 6 M ⊙ , will hardly be affected.更多还原