What is (not) driving Star Formation in Molecular Clouds?

Fabian Heitsch

October 02, 2012

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Abstract: Galactic star formation occurs at a surprisingly low rate. Yet, recent large-scale surveys of dark clouds in the Galaxy show that one rarely finds molecular clouds without young stellar objects. Thus, star formation must occur rapidly upon molecular cloud formation. This rapid onset of star formation poses stringent constraints on the physical properties and boundary conditions of the parental molecular cloud, which in turn requires a closer study of the cloud formation process. I will discuss a set of numerical experiments on cloud formation, demonstrating that there is no need (and no way) for turbulent support, but that the observed turbulence in molecular clouds is largely a consequence of global gravitationally driven motions and of the cloud formation process itself.