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Formation of Disks of Galaxies and Polar-ring Galaxies

星系盘和极环星系的形成

基本信息

批准号：
07640353
负责人：
WAKAMATSU Ken-ichi
金额：
$ 0.58万
依托单位：
GIFU University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640353/
关键词：
Galaxies Polar ring Disk 銀河形成銀河衝突円盤銀河

项目摘要

Galaxies have been classified into two basic categories, elliptical Galaxies and disk galaxies. The latter type of galaxies are supported by rotational motion of constituent stars, while the former type by their random motion. The disk Galaxies consist of a cental bulge and a rotational thin disk. However, no clear understanding is given for their formation mechanisms and which system was firstly formed from proto galaxy clouds.Polar ring galaxies are identified as peculiar galaxies with a rotating disk with rotation axis prthogonal to that of the main disk, where the second disk are believed to be form from infalling gas from colliding partner galaxies. These peculiar galaxies may be a nice targets to study formation process of disks during formation process of disk galaxies in the early universe.We have tried to observe several polar ring galaxies at Okayama Astrophysical Observatory. Due to poor wheather condition, no scientific results have been obtained. However, we obtained nice spectra of a bright Sa (r! ) galaxy NGC 7742, which has a bright prominent nuclear ring. By using HST archival data on this galaxy, we found the disk of the galaxy shows only a few percent deviation from circular symmetry on its surface photometry. Nuclear ring could be formed due to Lindblad resonance of the disk with a small amound of oval asymmmetry.

星系被分为两类，椭圆星系和盘状星系。后一种类型的星系是由组成恒星的自转运动支撑的，而前一种类型的星系是由它们的随机运动支撑的。盘状星系由中心凸起和旋转的薄盘组成。然而，对于它们的形成机制以及哪个系统最早是由原星系云形成的，目前还没有明确的认识。极环星系被认为是特殊的星系，其旋转盘的旋转轴与主盘的旋转轴垂直，其中第二个盘被认为是由碰撞的伙伴星系注入的气体形成的。这些奇特的星系可能是研究早期宇宙盘状星系形成过程中盘状星系形成过程的一个很好的目标。我们在冈山天体物理观测站对几个极环星系进行了观测。由于地质条件较差，目前还没有得到科学的结果。然而，我们得到了明亮的Sa(r！)星系NGC7742，它有一个明亮突出的核环。通过使用这个星系的HST档案数据，我们发现银河系的圆盘在其表面光度学上只显示出几个百分点的偏离圆对称性。由于圆盘的Lindblad共振，可以形成核环，其中有少量的椭圆形不对称。