The effect of dark matter on the Jeans instability with the q-nonextensive velocity distribution

Weiheng Yang,Hui Chen,Sanqiu Liu

doi:10.1063/5.0011567

Abstract

Based on the framework of nonextensive statistics and its related kinetic theory, the Jeans instability in a self-gravitational system composed of dark and bright matters is restudied. The results show that the nonextensivity, the presence of dark matter, has significant effects on the dynamics of Jeans modes. With the increase in the q parameter and the ratio of dispersion velocities, as well as the decreased ratio of densities of dark to bright matters, both critical wave-numbers and growth rates of the instabilities are increased. In addition, as expected, when q → 1, the corresponding results for Maxwellian velocity distribution are recovered. The present results may shed new light on the comprehension of the intrinsic physical mechanism responsible for the collapse of interstellar gas clouds.

Highlights

Jeans instability is a very meaningful topic in the field of selfgravitational matter system,1,2 plasma,3–5 and complex fluid community,6,7 owing to its important role in the explanation of the formation and evolution of gravitational structures
Scitation.org/journal/adv dispersion velocities ratio σ∗(≡ σd/σb), and mass densities ratio ρ∗(≡ ρd0/ρb0) have significant modifications on the dynamics of Jeans modes. (a) In comparison with the Maxwellian case, the matter systems under q-nonextensive statistics is more conducive to the collapse
As a test of the viability of this generalized context, it is proved that the classical Maxwellian case can be restored when q → 1. (b) The increased dispersion velocities ratio σ∗ tends to boost the growth rate of Jeans instability for the interstellar gas clouds

Summary

INTRODUCTION

Jeans instability is a very meaningful topic in the field of selfgravitational matter system, plasma, and complex fluid community, owing to its important role in the explanation of the formation and evolution of gravitational structures. Kremer et al. gave the quantitative analysis of Jeans instabilities of systems composed of dark and baryonic matters within the plasma kinetic theory, and found that the collapse criteria are dependent on the presence of dark matter. Silva et al. fitted dark matter with anisotropic q-Gaussian 3D velocity distributions in Λ CDM haloes Those works show that the q-nonextensive statistics may be more suitable for dark matter systems. Keeping these in mind, in the present work, we give the first quantitative description of the extent the nonextensive effects, the presence of dark matter, modify the dynamics of Jeans modes.

DISPERSION EQUATION

NUMERICAL ANALYSIS

CONCLUSION