GMC Collisions as Triggers of Star Formation. VI. Collision-Induced Turbulence

TL;DR

This study uses magnetohydrodynamic simulations to show that collisions between giant molecular clouds significantly enhance turbulence, affecting dense gas structures and potentially influencing star formation processes.

Contribution

It demonstrates how GMC collisions induce turbulence and alter dense gas properties, providing new insights into star formation triggers.

Findings

GMC collisions increase effective Mach number and velocity dispersions.

Dense clumps from collisions sustain near-virial equilibrium longer.

Collisions inject turbulent momentum into high-density gas at high rates.

Abstract

We investigate collisions between giant molecular clouds (GMCs) as potential generators of their internal turbulence. Using magnetohydrodynamic (MHD) simulations of self-gravitating, magnetized, turbulent, GMCs, we compare kinematic and dynamic properties of dense gas structures formed when such clouds collide compared to those that form in non-colliding clouds as self-gravity overwhelms decaying turbulence. We explore the nature of turbulence in these structures via distribution functions of density, velocity dispersions, virial parameters, and momentum injection. We find that the dense clumps formed from GMC collisions have higher effective Mach number, greater overall velocity dispersions, sustain near-virial equilibrium states for longer times, and are the conduit for injection of turbulent momentum into high density gas at high rates.