Related papers: Why are most molecular clouds not gravitationally …
In compact and dense star-forming clouds a global star cluster wind could be suppressed. In this case the stellar feedback is unable to expel the leftover gas from the cluster. Young massive stars remain embedded into a dense residual gas…
On galactic scales, the surface density of star formation appears to be well correlated with the surface density of molecular gas. This has lead many authors to suggest that there exists a causal relationship between the chemical state of…
(Abridged) The formation of molecular clouds (MCs) from the diffuse interstellar gas appears to be a necessary step for star formation, as young stars invariably occur within them. However, the mechanisms controlling the formation of MCs…
Modern extragalactic molecular gas surveys now reach the scales of star-forming giant molecular clouds (GMCs, 20-50 pc). Systematic variations in GMC properties with galaxy environment imply that clouds are not universally self-gravitating…
Stars form from cold molecular interstellar gas. Since this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of…
Large-scale star formation in disk galaxies is hypothesized to be driven by global gravitational instability. The observed gas surface density is commonly used to compute the strength of gravitational instability, but according to this…
We propose a simple theoretical model for star formation in which the local star formation rate in a galaxy is determined by three factors. First, the interplay between the interstellar radiation field and molecular self-shielding…
We present the results from simulations of GMC formation in spiral galaxies. First we discuss cloud formation by cloud-cloud collisions, and gravitational instabilities, arguing that the former is prevalent at lower galactic surface…
Observational evidence from local star-forming regions mandates that star formation occurs shortly after, or even during, molecular cloud formation. Models of the formation of molecular clouds in large-scale converging flows have identified…
Giant molecular clouds (GMCs) are the primary reservoirs of cold, star-forming molecular gas in the Milky Way and similar galaxies, and thus any understanding of star formation must encompass a model for GMC formation, evolution, and…
Stars and star clusters form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest…
We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…
We introduce a model for the large-scale, global 3D structure of molecular clouds. Motivated by the morphological appearance of clouds in surface density maps, we model clouds as cylinders, with the aim of backing out information about the…
Molecular clouds are a fundamental ingredient of galaxies: they are the channels that transform the diffuse gas into stars. The detailed process of how they do it is not completely understood. We review the current knowledge of molecular…
Recent progress in the understanding of star formation is summarized. A consistent picture is emerging where molecular clouds form with turbulent velocity fields and clumpy substructure, imprinted already during their formation. The clouds…
We present numerical simulations of the passage of clumpy gas through a galactic spiral shock and the subsequent formation of giant molecular clouds (GMCs). The spiral shock forms dense clouds while dissipating kinetic energy, producing…
Using the PHANGS-ALMA CO (2-1) survey, we characterize molecular gas properties on ${\sim}$100 pc scales across 102,778 independent sightlines in 70 nearby galaxies. This yields the best synthetic view of molecular gas properties on cloud…
I describe the scenario of molecular cloud (MC) evolution that has emerged over the past decade or so. MCs can start out as cold atomic clouds formed by compressive motions in the warm neutral medium (WNM) of galaxies. Such motions can be…
We analyse extinction maps of nearby Giant Molecular Clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self…
Here we model a star forming factory in which the continuous creation of stars results in a highly concentrated, massive (globular cluster-like) stellar system. We show that under very general conditions a large-scale gravitational…