TY - JOUR

T1 - Gravitational instability in a system of particles with mass spectrum

AU - Volkov, E.

AU - Ortega, V. G.

N1 - Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2000/3/21

Y1 - 2000/3/21

N2 - We investigate the conditions under which a self-gravitating system of particles of different masses may be gravitationally unstable if there is a systematic correlation between the random velocity of a particle and its mass. For an isotropic uniform medium without rotation but with mass spectrum and velocity depending on the particle mass, a situation arises where the Jeans length for such a system may be significantly smaller than for the case when some mean values are used instead of mass and velocity spectra. For a differentially rotating medium, representing a spiral galaxy, we obtain the analogue of the Toomre parameter for a heterogeneous (multi-component) system. We demonstrate that the gas system in spirals represented by an ensemble of giant molecular clouds may be considerably less stable in the case of random velocity-mass correlation than for a system with unique velocity dispersion.

AB - We investigate the conditions under which a self-gravitating system of particles of different masses may be gravitationally unstable if there is a systematic correlation between the random velocity of a particle and its mass. For an isotropic uniform medium without rotation but with mass spectrum and velocity depending on the particle mass, a situation arises where the Jeans length for such a system may be significantly smaller than for the case when some mean values are used instead of mass and velocity spectra. For a differentially rotating medium, representing a spiral galaxy, we obtain the analogue of the Toomre parameter for a heterogeneous (multi-component) system. We demonstrate that the gas system in spirals represented by an ensemble of giant molecular clouds may be considerably less stable in the case of random velocity-mass correlation than for a system with unique velocity dispersion.

KW - Galaxies: ISM

KW - Galaxies: spiral

KW - Gravitation

KW - Instabilities

KW - ISM: clouds

UR - http://www.scopus.com/inward/record.url?scp=1542634336&partnerID=8YFLogxK

U2 - 10.1046/j.1365-8711.2000.03223.x

DO - 10.1046/j.1365-8711.2000.03223.x

M3 - Article

AN - SCOPUS:1542634336

VL - 313

SP - 112

EP - 116

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 1

ER -