GMC collisions as triggers of star formation – VIII. The core mass function
Journal article, 2023

Compression in giant molecular cloud (GMC) collisions is a promising mechanism to trigger the formation of massive star clusters and OB associations. We simulate colliding and non-colliding magnetized GMCs and examine the properties of pre-stellar cores, selected from projected mass surface density maps, including after synthetic ALMA observations. We then examine core properties, including mass, size, density, velocity, velocity dispersion, temperature, and magnetic field strength. After 4 Myr, ∼1000 cores have formed in the GMC collision, and the high-mass end of the core mass function (CMF) can be fit by a power-law dN/dlogM ∝ M-α with α ≃ 0.7, i.e. relatively top heavy compared to a Salpeter mass function. Depending on how cores are identified, a break in the power law can appear around a few ×10 M☉. The non-colliding GMCs form fewer cores with a CMF with α ≃ 0.8–1.2, i.e. closer to the Salpeter index. We compare the properties of these CMFs to those of several observed samples of cores. Considering other properties, cores formed from colliding clouds are typically warmer, have more disturbed internal kinematics, and are more likely to be gravitational unbound, than cores formed from non-colliding GMCs. The dynamical state of the protocluster of cores formed in the GMC–GMC collision is intrinsically subvirial but can appear to be supervirial if the total mass measurement is affected by observations that miss mass on large scales or at low densities.

(magnetohydrodynamics) MHD

methods: numerical

ISM: clouds

stars: formation

Author

Chia-Jung Hsu

Chalmers, Physics, E-commons

Jonathan Tan

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

University of Virginia

Duncan Christie

University of Virginia

Max Planck Society

Yu Cheng

National Astronomical Observatory of Japan

University of Virginia

Theo J. O’Neill

Harvard-Smithsonian Center for Astrophysics

University of Virginia

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 522 1 700-720

Subject Categories

Subatomic Physics

Astronomy, Astrophysics and Cosmology

DOI

10.1093/mnras/stad777

More information

Latest update

6/20/2023