On the Formation of Galactic Warps and Spiral Arms

• Main Authors: Yi-Jen Lee, 李宜蓁
• Other Authors: Ing-Guey Jiang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/93944066411691423116

碩士 === 國立中央大學 === 天文研究所 === 91 === The warping of galactic discs is a general phenomenon for disc galaxies and it has been an important subject for four decades since its first discovery. Sparke (2002)gives an argument showing that the warps are a gravitational phenomenon. We thus follow this line and focus on the gravity here, and we wish to further explore the parameter spaces for the model proposed by Jiang & Binney (1999). We try different types of cosmic infall with different total mass and also study the effect of disc accretion. Then we study the relation between warps and spiral arms. We find that the mass accretion along the galactic plane is not helpful for the formation of warps but could be a good way to produce halo stars and high velocity clouds. On the other hand, all three types of cosmic infall we introduce could produce warps with different amplitudes and shapes at different time. These results reconfirm that warps is a halo phenomenon and closely related to the tilted non-axisymmetric component of halo. Warps and spiral arms are projections on different two-dimensional plane of the same non-axisymmetric structure in three-dimensional space.