Small-scale sectorial perturbation modes against the background of a pulsating model of disk-like self-gravitating systems

Abstract In this work, we consider small-scale sectorial perturbation modes in a disk-like model of a radially nonstationary spiral galaxy in order to study the gravitational instabilities of these modes. Calculations of horizontal sectorial small-scale perturbation modes, such as ( m ; N ) = ( 10 ; 10 ) \left(m;\hspace{0.33em}N)=\left(10;\hspace{0.33em}10) , (11; 11), (12; 12), (13; 13), (14; 14), and (15; 15), against the background of a nonlinearly nonequilibrium anisotropic model of the self-gravitating disk have been carried out. For each of these perturbation modes, critical diagrams are plotted between the virial parameter and the degree of rotation. The growth rates of instability are calculated and compared for different values of the rotation parameter. The results of calculations and comparisons of instability regions show that with an increase in the degree of small scale, the instability region narrows as the wave numbers increase.