A Symmetry-induced Expression of Spiral Galaxy Patterns and its Physical Implication

Understanding galaxies, the basic components of the universe, is one of the most challenging tasks we meet. There are two major phenomena of spiral galaxies which are not given acceptable explanation. One is the almost constant rotation curve and the other is the bar pattern. In my previous work, I proposed to use curvilinear coordinate system and a symmetry principle to study galaxy patterns. In the present paper, the spiral galaxy patterns (ordinary and barred) are studied by this method and an analytic expression of galactic bars is obtained. The bar expression is fitted to real galaxy images and the fitting result is satisfactory. I also present a preliminary study on the physical implication of the symmetry. A new stellar dynamics is proposed and a model of galactic rotation curves is developed and fitted to real data. keywords: Methods : Analytical – Galaxies : Structure – Stellar Dynamics