GMC Collisions As Triggers of Star Formation. IV. The Role of Ambipolar Diffusion

Abstract

We investigate the role of ambipolar diffusion (AD) in collisions between magnetized giant molecular clouds (GMCs), which may be an important mechanism for triggering star cluster formation. Three dimensional simulations of GMC collisions are performed using a version of the Enzo magnetohydrodynamics code that has been extended to include AD. The resistivities are calculated using the 31-species chemical model of Wu et al. (2015). We find that in the weak-field, $10\mu \mathrm{G}$ case, AD has only a modest effect on the dynamical evolution during the collision. However, for the stronger-field, $30\mu \mathrm{G}$ case involving near-critical clouds, AD results in formation of dense cores in regions where collapse is otherwise inhibited. The overall efficiency of formation of cores with $n_{\mathrm{H}}\ge 10^6{\mathrm{cm}}^{-3}$ in these simulations is increases from about 0.2% to 2% once AD is included, comparable to observed values in star-forming GMCs. The gas around these cores typically has relatively slow infall at speeds that are a modest fraction of the free-fall speed.

15 pages, 15 figures, Accepted to ApJ

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Cited by in corpus (5)

• GMC Collisions as Triggers of Star Formation. V. Observational Signatures
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) : Molecular clouds toward W33 ; possible evidence for a cloud-cloud collision triggering O star formation
• GMC Collisions as Triggers of Star Formation. VI. Collision-Induced Turbulence
• Non-ideal MHD simulations of subcritical prestellar cores with non-equilibrium chemistry
• GMC Collisions As Triggers of Star Formation. VIII. The Core Mass Function