Related papers: Multiple stellar generations in massive star formi…
Some of the most massive globular clusters of our Milky Way, such as for example omega-Centauri, show a mixture of stellar populations spanning a few Gyr in age and 1.5 dex in metallicities. In contrast, standard formation scenarios predict…
Wide gravitationally bound pairs of stars can be formed from adjacent prestellar cores that happen to move slowly enough relative to each other. These binaries are remnants of the primordial clustering. It is shown that the expected…
The origin of the chemical anomalies in star clusters is still an open question, although much effort has been employed both from a theoretical and observational point of view. The exploration of whether such multiple stellar populations…
It has now been known for over a decade that low-mass stars located in star-forming regions are very frequently members of binary and multiple systems, even more so than main sequence stars in the solar neighborhood. This high multiplicity…
We present an analysis of the spatial distribution of various stellar populations within the Large and Small Magellanic Clouds. We use optically selected stellar samples with mean ages between ~9 and ~1000 Myr, and existing stellar cluster…
Most stars - especially young stars - are observed to be in multiple systems. Dynamical evolution is unable to pair stars efficiently, which leads to the conclusion that star-forming cores must usually fragment into \geq 2 stars. However,…
We test the hypothesis that globular clusters form in supergiant molecular clouds within high-redshift galaxies. Numerical simulations demonstrate that such large, dense, and cold gas clouds assemble naturally in current hierarchical models…
Over the past ten years, there has been a revolution in our understanding of massive young stellar clusters in the Galaxy. Initially, there were no known examples having masses $>10^4$, yet we now know that there are at least a half dozen…
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…
The ability of HST to resolve objects ten times smaller than possible from the ground has rejuvenated the study of young star clusters. A recurrent morphological theme found in nearby resolved sytems is the observation of young (typically 1…
The mere existence of multiple stellar generations in Milky Way globular clusters indicates that each generation was unable to stop star formation, that instead persisted unimpeded for several million years. This evidence argues for an…
We report on the identification of 54 embedded clusters around 217 massive protostellar candidates of which 34 clusters are new detections. The embedded clusters are identified as stellar surface density enhancements in the 2 $\mu$m All Sky…
I present the latest results from our group about the multiple stellar populations in the old Milky Way globular clusters (GCs) and in the young systems both in the Magellanic Clouds and in the Milky Way. For the ancient GCs in our Galaxy I…
Nuclear star clusters are among the densest stellar systems known and are common in both early- and late-type galaxies. They exhibit scaling relations with their host galaxy which may be related to those of supermassive black holes. These…
The formation of massive stellar clusters is intricately linked to star formation on local and global scales. All actively star forming galaxies are forming clusters, and the local initial conditions likely determine whether bound massive…
The solar system was most likely born in a star cluster containing at least 1000 stars. It is highly probable that this cluster environment influenced various properties of the solar system like its chemical composition, size and the…
Recent studies have shown that an extended main-sequence turn-off is a common feature among intermediate-age clusters (1--3 Gyr) in the Magellanic Clouds. Multiple-generation star formation and stellar rotation or interacting binaries have…
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…
Most stars form in highly clustered environments within molecular clouds, but eventually disperse into the distributed stellar field population. Exactly how the stellar distribution evolves from the embedded stage into gas-free associations…
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…