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

Jakhongir Ganiev,Salakhutdin Nuritdinov

doi:10.1515/astro-2022-0011

Abstract

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.

Highlights

Gravitational instabilities of disk-like models of self-gravitating systems are of great interest for galactic disks and for accretion ones studied by Lodato (2007), Forgan and Rice (2011a, b), Lodato (2012), Rice (2016), Kratter and Lodato (2016), Paneque-Carreño et al (2021), and Bethune and Latter (2021).Both large-scale and various small-scale formations are observed in disk-like galaxies
There is still no analysis of the problems of their origin and no one has studied in detail small-scale perturbations against the background of nonlinearly non-stationary models of disk-like selfgravitating systems, in particular, for our Galaxy
This raises a number of new questions. Can their global distribution be explained by the corresponding formation theory? It is not clear under what physical conditions these objects can form in disk-like systems, and what are the characteristic times of these phenomena? In addition, it is not clear which objects or structural formations of disk-like subsystems of galaxies are directly related to small-scale disturbances

Summary

Introduction

Gravitational instabilities of disk-like models of self-gravitating systems are of great interest for galactic disks and for accretion ones studied by Lodato (2007), Forgan and Rice (2011a, b), Lodato (2012), Rice (2016), Kratter and Lodato (2016), Paneque-Carreño et al (2021), and Bethune and Latter (2021).Both large-scale and various small-scale formations are observed in disk-like galaxies. There is still no analysis of the problems of their origin and no one has studied in detail small-scale perturbations against the background of nonlinearly non-stationary models of disk-like selfgravitating systems, in particular, for our Galaxy. It is not clear which objects or structural formations of disk-like subsystems of galaxies are directly related to small-scale disturbances.

Results

Conclusion