Instabilities of Bending Modes of Perturbations against the Background of a Nonlinear Nonstationary Self-Gravitating Disk
Abstract
The problem of gravitational instabilities in nonlinearly nonequilibrium composite models of disk galaxies with respect to asymmetric bending modes of vertical perturbations has been investigated. Nonstationary analogs of dispersion equations for asymmetric bending modes have been derived within the framework of these models. Critical diagrams based on the results of numerical solutions of the obtained equations show the dependence of the initial virial ratio on the superposition parameter for various cases of disk rotation. A comparative analysis of the increments of gravitational instabilities of asymmetric bending perturbation modes on the background of composite models has also been carried out. The mechanisms and criteria of the origin of asymmetric bends of the disk of galaxies at an early stage of their evolution are found.