Related papers: Present-Day Star Formation: Protostellar Outflows …
Stars are often observed to form in clusters. It is therefore important to understand how such a region of concentrated mass is assembled out of the diffuse medium and its properties eventually prescribe the important physical mechanisms…
Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds ($\sim$10s pc) down to the size scales of dense prestellar cores ($\sim$0.1 pc) that are the birth sites of stars. Several physical…
The formation of massive stellar clusters in turbulent molecular clouds is investigated. We include artificial star formation and energy feedback of newly born stars. The obtained systems are not likely to survive. Case studies to determine…
The isothermal dynamical evolution of a clumpy and turbulent molecular cloud region and its fragmentation into a protostellar cluster is investigated numerically. The effect of different initial density and velocity distributions, generated…
We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up,…
Mergers of gas-rich galaxies lead to gravitationally driven increases in gas pressure that can trigger intense bursts of star and cluster formation. Although star formation itself is clustered, most newborn stellar aggregates are unbound…
The rest frame equivalent width of the [OII]3727 emission line, W(OII), has been measured for cluster and field galaxies in the CNOC redshift survey of rich clusters at 0.2<z<0.55. Emission lines of any strength in cluster galaxies at all…
We review recent work that investigates the formation of stellar clusters, ranging in scale from globular clusters through open clusters to the small scale aggregates of stars observed in T associations. In all cases, recent advances in…
We investigate the formation of star clusters in an unbound GMC, where the supporting kinetic energy is twice as large as the cloud's self-gravity. This cloud manages to form a series of star clusters and disperse, all within roughly 2…
Current empirical evidence on the star-formation processes in the extreme, high-pressure environments induced by galaxy encounters (mostly based on high-resolution Hubble Space Telescope observations) strongly suggests that star CLUSTER…
Most if not all stars form in star clusters. Thus the distribution of star clusters preserves the information on the star formation history of a galaxy. Massive clusters form only during episodes of high star formation activity whereas…
It is well known that the energy input from massive stars dominates the thermal and mechanical heating of typical regions in the interstellar medium of galaxies. These effects are amplified tremendously in the immediate environment of young…
Star clusters are born in a highly compact configuration, typically with radii of less than about 1 pc roughly independently of mass. Since the star-formation efficiency is less than 50 per cent by observation and because the residual gas…
The formation of star clusters involves the growth of smaller, gas-rich subclusters through accretion of gas from the giant molecular cloud within which the subclusters are embedded. The two main accretion mechanisms responsible for this…
Protostellar outflows crisscross the regions of star cluster formation, stirring turbulence and altering the evolution of the forming cluster. We model the stirring of turbulent motions by protostellar outflows, building on an observation…
Stars form with a complex and highly structured distribution. For a smooth star cluster to form from these initial conditions, the star cluster must erase this substructure. We study how substructure is removed using N-body simulations that…
After the stars of a new, embedded star cluster have formed they blow the remaining gas out of the cluster. Especially winds of massive stars and definitely the on-set of the first supernovae can remove the residual gas from a cluster. This…
We review recent high spatial resolution millimeter continuum and spectral line observations of (proto-)cluster regions. These observations reveal that the mass distribution of prestellar cores is consistent with the initial mass function…
Stars mostly form in groups consisting of a few dozen to several ten thousand members. For 30 years, theoretical models provide a basic concept of how such star clusters form and develop: they originate from the gas and dust of collapsing…
Stars are usually formed in clusters in the dense cores of molecular clouds. These embedded clusters show a wide variety of morphologies from hierarchical clusters with substructure to centrally condensed ones. Often they are elongated and…