▪ Abstract Turbulence affects the structure and motions of nearly all temperature and density
regimes in the interstellar gas. This two-part review summarizes the observations, theory …

Stars form within molecular clouds but our understanding of this fundamental process
remains hampered by the complexity of the physics that drives their evolution. We review our …

Context. Even though turbulent motions are found everywhere in astrophysical systems, the
origin of this turbulence is poorly understood. When cosmic structures form, they grow in …

We study the formation of giant dense cloud complexes and of stars within them using SPH
numerical simulations of the collision of gas streams (``inflows'') in the WNM at moderately …

We discuss molecular cloud formation by large-scale supersonic compressions in the diffuse
warm neutral medium (WNM). Initially, a shocked layer forms, and within it, a thin cold layer …

Context. Supersonic turbulence is ubiquitous in the interstellar medium and plays an
important role in contemporary star formation. Aims. We performed high-resolution …

We review the properties of turbulent molecular clouds (MCs), focusing on the physical
processes that influence star formation (SF). MC formation appears to occur during large …

We present the first numerical simulations that self-consistently follow the formation of dense
molecular clouds in colliding flows. Our calculations include a time-dependent model for the …

We compile a holistic scenario for molecular cloud (MC) evolution and control of the star
formation efficiency (SFE) and present a first set of numerical tests of it. A lossy compressible …

We discuss the lifetimes and evolution of clumps and cores formed as turbulent density
fluctuations in nearly isothermal molecular clouds. In order to maintain a broad perspective …