Related papers: Star Formation in the Extreme Galactic Center Envi…
Most stars are born in rich young stellar clusters (YSCs) embedded in giant molecular clouds. The most massive stars live out their short lives there, profoundly influencing their natal environments by ionizing HII regions, inflating…
We characterize star-forming gas in six molecular clouds (Sgr B1-off, Sgr B2, Sgr C, the 20 km s$^{-1}$ and 50 km s$^{-1}$ molecular clouds, and the Brick) in the Galactic central molecular zone (CMZ), and compare their star-forming…
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 present a theoretical framework in which bound stellar clusters arise naturally at the high-density end of the hierarchy of the interstellar medium (ISM). Due to short free-fall times, these high-density regions achieve high local star…
Massive stars are very rare, but their extreme luminosities make them both the only type of young star we can observe in distant galaxies and the dominant energy sources in the universe today. They form rarely because efficient radiative…
Observations show that galaxies and their interstellar media are pervaded by strong magnetic fields with energies in the diffuse component being at least comparable to the thermal and even as large or larger than the turbulent energy. Such…
We show that massive stars and stellar clusters are formed simultaneously, the global evolution of the forming cluster is what allows the central stars to become massive. We predict that massive star forming clumps, such as those observed…
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…
The regulation of galactic-scale star formation rates (SFRs) is a basic problem for theories of galaxy formation and evolution: which processes are responsible for making observed star formation rates so inefficient compared to maximal…
Galaxy star formation rates (SFRs) are sensitive to the local environment; for example, the high-density regions at the cores of dense clusters are known to suppress star formation. It has been suggested that galaxy transformation occurs…
Observations indicate that massive stars form in regions of very high surface density, ~1 g cm^-2. Clusters containing massive stars and globular clusters have a comparable column density. The total pressure in clouds of such a column…
Star formation is inefficient. Recent advances in numerical simulations and theoretical models of molecular clouds show that the combined effects of interstellar turbulence, magnetic fields and stellar feedback can explain the low…
The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the…
In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In…
Molecular clouds in the central molecular zone (CMZ) have been observed to feature turbulent line widths that are significantly higher, and scale with cloud size more steeply, than in the rest of the Milky Way. In the same Galactic region,…
Star formation in strongly self-gravitating cloud cores should be similar at all redshifts, forming single or multiple stars with a range of masses determined by local magneto-hydrodynamics and gravity. The formation processes for these…
The strongest starbursts are observed towards galaxy nuclei, or circumnuclear regions. However in interacting galaxies, star formation is also triggered in overlap regions far from nuclei, in spiral arms and sometimes in tidal tails. What…
Evidence for triggered star formation is difficult to establish because energy feedback from massive stars tend to erase the interstellar conditions that led to the star formation. Young stellar objects (YSOs) mark sites of {\it current}…
Star formation occurs on physical scales corresponding to individual star forming regions, typically of order ~100 parsecs in size, but current observational facilities cannot resolve these scales within field galaxies beyond the local…
The formation of supermassive stars is believed to be an essential intermediate step for the formation of the massive black hole seeds that become the supermassive black holes powering the quasars observed in the early Universe. Numerical…