摘要
本文对后发团中心２．６３°×２．６３°范围内１３８个盘星系（９４个Ｓ０星系，４４个Ｓ和Ｉｒ星系）的自转轴方向的分布作了分析，结果表明，后发团中盘星系自转轴方向的分布是非均匀的．相对于假设的均匀分布，有较多的Ｓ０星系的自转轴平行于团平面，并且Ｓ０星系的自转轴在团平面上的投影倾向于沿着偏离团中心方向约４５°的方向；对于Ｓ和Ｉｒｒ星系，自转轴倾向于平行或垂直于团平面，自转轴在团平面上的投影则倾向于平行团中心方向．本文证实了后发团中盘星系自转轴方向分布的非均匀性及其与星系形态类型的相关，而且可能与星系光度也有关．样本越深，自转轴指向的分布似乎越不均匀．本文结果说明后发团存在一个优势平面（可能的团平面），在各种星系团及星系形成理论中，有支持“薄饼”（ｐａｎｃａｋｅ）模型的迹象．
The rotation axes of 138 disk galaxies (94 S0, 44 S and Irr) within an area of 2.63°×2.63° in the Coma cluster have been statistically studied, and an anisotropic distribution is revealed.Relative to the expected isotropic distribution, there are more S0 galaxies having their rotation axes parallel to the cluster plane,and the projection on the cluster plane of the rotation axes of S0 galaxies tend to be along directions deviating from the direction of the cluster center by an angle of about 45°; as to the S and Irr galaxies, their rotation axes tend to be either parallel or perpendicular to the cluster plane, the projection of their rotation axes on the cluster plane tend to be parallel to the direction of the cluster center. In this paper, a morphological dependence of the distribution of the rotation axes of the disk galaxies in the Coma cluster is confirmed; and there is some evidence that the distribution of the rotation axes of the disk galaxies in the Coma cluster may be related to the luminosities of the galaxies. The deeper the sample is , the more likely to be anisotropic the distribution of the rotation axes becomes. Our results imply the presence of a preference plane in the Coma cluster (potential cluster plane), and there is evidence to support the “pancake” scenario among various theories for the formation of galaxies and clusters of galaxies.
基金
中国科学院天文口资助
关键词
星系团
后发团
盘星系
自转轴方向
cluster of galaxies—Coma cluster—disk galaxies—rotation axes
