Related papers: Nuclear Star Clusters - Structure and Stellar Popu…
Nuclear stellar cluster (NSCs) are known to exist around massive black holes (MBHs) in galactic nuclei. Two formation scenarios were suggested for their origin: (1) Build-up of NSCs from consecutive infall of stellar cluster and (2)…
Nuclear Star Clusters (NSCs) are often present in spiral galaxies as well as resolved Stellar Nuclei (SNi) in elliptical galaxies centres. Ever growing observational data indicate the existence of correlations between the properties of…
Clusters of galaxies are the most massive objects in the Universe and precise knowledge of their mass structure is important to understand the history of structure formation and constrain still unknown types of dark contents of the…
Many, if not all, galaxies host massive compact objects at their centers. They are present as singularities (super massive black holes) or high density star clusters (nuclear tar clusters). In some cases they coexist, and interact more or…
Globular clusters are gravitationally bound stellar systems containing on the order of 100,000 stars. Due to the high stellar densities in the cores of these clusters, close encounters and even physical collisions between stars are…
I review (1) Physics of Star Formation & Open Questions; (2) Structure & Dynamics of Star-Forming Clouds & Young Clusters; (3) Star Formation Rates: Observations & Theoretical Implications.
Clustering is one of the most complex phenomena known to the structure of atomic nuclei. A comprehensive description of this ubiquitous phenomenon goes beyond standard shell model and cluster model frameworks. We argue that clustering is a…
Star clusters have hierarchical patterns in space and time, suggesting formation processes in the densest regions of a turbulent interstellar medium. Clusters also have hierarchical substructure when they are young, which makes them all…
The relationship of an AGN to its host galaxy is a crucial question in the study of galaxy evolution. We perform stellar population synthesis in the central regions of galaxies of different activity levels. A large number of stellar…
Recent progress in studies of globular clusters has shown that they are not simple stellar populations, being rather made of multiple generations. Evidence stems both from photometry and spectroscopy. A new paradigm is then arising for the…
A catalogue of superclusters of galaxies is used to investigate the influence of the supercluster environment on galaxy populations, considering galaxies brighter than M$_r<$-21+5$\log$ h. Empirical spectral synthesis techniques are applied…
A large fraction of bulgeless disk galaxies contain young compact stellar systems at their centers, in spite of the local gravitational stability of these disks. We evaluate two contrasting hypotheses for the origin of the nuclear star…
Clusters of galaxies are studied from a theoretical point of view, comparing with observational results whenever possible. The problem is approached both analytically as well as by means of high-resoultion numerical simulations. The dark…
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…
Around the turn of the last century, star clusters of all kinds were considered "simple" stellar populations. Over the past decade, this situation has changed dramatically. At the same time, star clusters are among the brightest stellar…
Globular clusters provide a unique probe of galaxy formation and evolution. Here I briefly summarize the known observational properties of globular cluster systems. One re-occurring theme is that the globular cluster systems of spirals and…
Stellar populations, building blocks of galaxies, are direct tracers of the star formation history, the chemical enrichment and the assembly of galaxies in the Universe. They therfore allow us to understand how galaxies formed and evolved.…
Studies have suggested that there is a strong correlation between the masses of nuclear star clusters (NSCs) and their host galaxies, a correlation which said to be an extension of the well-known correlations between supermassive black…
I review the status of massive star formation theories: accretion from collapsing, massive, turbulent cores; competitive accretion; and stellar collisions. I conclude the observational and theoretical evidence favors the first of these…
This short encyclopedia article, reviewing current information on neutron stars, is intended for a broad scientific audience.