Related papers: Observations and Theory of Dynamical Triggers for …
Triggered star formation in bright rims and shells is reviewed. Shells are commonly observed in the Milky Way and other galaxies, but most diffuse shells seen in HI or the infrared do not have obvious triggered star formation. Dense…
Young massive stars or clusters are often observed at the peripheries of HII regions. What triggers star formation at such locations? Among the scenarios that have been proposed, the `collect and collapse' process is particularly attractive…
Star formation can be triggered by compression from wind or supernova driven shock waves that sweep over molecular clouds. Because these shocks will likely contain processed elements, triggered star formation has been proposed as an…
Star formation is a fundamental process for galactic evolution. One issue over the last several decades has been determining whether star formation is induced by external triggers or is self-regulated in a closed system. The role of an…
Processes that promote the formation of dense cold clouds in the interstellar media of galaxies are reviewed. Those that involve background stellar mass include two-fluid instabilities, spiral density wave shocking, and bar accretion. Young…
The gravitational instability of expanding shells triggering the formation of clouds and stars is analyzed. Disks with different scale-heights, ambient and shell velocity dispersions, mid-plane densities, rotation rates and shear rates are…
Star formation is triggered in essentially three ways: (1) the pressures from existing stars collect and squeeze nearby dense gas into gravitationally unstable configurations, (2) random compression from supersonic turbulence makes new…
Criteria for gravitational collapse of expanding shells in rotating, shearing galaxy disks were determined using three-dimensional numerical simulations in the thin shell approximation. The simulations were run over a grid of 7 independent…
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…
Star formation by gravitational instabilities, sequential triggering, and turbulence triggering are briefly reviewed in order to compare the various mechanisms that are observed in main galaxy disks with those in the inner kiloparsec…
Galaxy interactions/mergers, gravitational instabilities and density waves, such as bars, are frequently invoked to trigger starbursts. These mechanisms have been explored through numerical simulations, with the help of various star…
In order to understand the star formation process under the influence of HII regions, we have carried out extensive investigations to well selected star-forming regions which all have been profoundly affected by existing massive O type…
Stars are formed by gravitational collapse, spontaneously or, in some cases under the constructive influence of nearby massive stars, out of molecular cloud cores. Here we present an observational diagnosis of such triggered formation…
The empirical laws of star formation suggest that galactic-scale gravity is involved, but they do not identify the actual triggering mechanisms for clusters in the final stages. Many other triggering processes satisfy the empirical laws…
Understanding star formation is problematic as it originates in the large scale dynamics of a galaxy but occurs on the small scale of an individual star forming event. This paper presents the first numerical simulations to resolve the star…
The most extreme starbursts occur in galaxy mergers, and it is now acknowledged that dynamical triggering has a primary importance in star formation. This triggering is due partly to the enhanced velocity dispersion provided by…
(ABBREVIATED) Understanding the formation of stars in galaxies is central to much of modern astrophysics. In this review the relation between interstellar turbulence and star formation is discussed. Supersonic turbulence can provide support…
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 invoke star formation triggered by cloud-cloud collisions to explain global star formation rates of disk galaxies and circumnuclear starbursts. Previous theories based on the growth rate of gravitational perturbations ignore the…
This lecture reviews the fundamental physical processes involved in star formation in galaxy interactions and mergers. Interactions and mergers often drive intense starbursts, but the link between interstellar gas physics, large scale…