IAU Symposium Abstract S186-044P

Nonlinear analysis of the density wave.

N. Terasawa
The Institute of Physical and Chemical Research < terasawa@riken.go.jp >

The density wave equations for the complex of stars and gas in disk galaxies are analyzed nonlinearly as a model for the spiral pattern of spiral galaxies. The origin of the spiral patterns of disk galaxies is still in a great debate and various approaches have been made so far. I analyze the nonlinear equation for the slef-gravitating system of the complex of stars and gas in the disk of spiral galaxies. The stability of the spiral pattern and the natures the solution is discussed in detail comparing with the results of a linear analysis and numerical treatments.