Criteria for gravitational instability and quasi-isolated gravitational collapse in turbulent medium
Abstract
We study the evolution of structures in turbulent, self-gravitating media, and present an analytical criterion M_crit ≈ ɛ _cascade^{2/3} η ^{-2/3} G^{-1} l^{5/3} (where Mcrit is the critical mass, l is the scale, ɛ _cascade≈ η σ _v^3 /l is the turbulence energy dissipation rate of the ambient medium, G is the gravitational constant, σv is the velocity dispersion and η ≈ 0.2 is an efficiency parameter) for an object to undergo quasi-isolated gravitational collapse. The criterion also defines the critical scale (l_crit ≈ ɛ _cascade^{1/2} η ^{-1/2} G^{-3/4} ρ ^{-3/4}) for turbulent gravitational instability to develop. The analytical formalism explains the size dependence of the masses of the progenitors of star clusters (M_cluster ∼ R_cluster^{1.67}) in our Galaxy.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2017
- DOI:
- 10.1093/mnras/stw2707
- arXiv:
- arXiv:1610.06577
- Bibcode:
- 2017MNRAS.465..667L
- Keywords:
-
- gravitation;
- instabilities;
- turbulence;
- methods: analytical;
- ISM: kinematics and dynamics;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted by MNRAS