Related papers: Caught in the Act?
Observationally, constraining the baryonic cycle within massive galaxies has proven to be quite difficult. In particular, the role of black hole feedback in regulating star formation, a key process in our theoretical understanding of galaxy…
Active galaxies contain a supermassive black hole at their center, which grows by accreting matter from the surrounding galaxy. The accretion process in the central ~10 parsecs has not been directly resolved in previous observations, due to…
Supermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that…
A new view on our Galaxy has recently emerged, with large consequences on its formation scenarios. Not only new dwarf satellites have been detected, still orbiting and tidally disrupting, but also a multitude of stellar streams or tidal…
Supermassive black holes are found at the centre of massive galaxies. During the growth of these black holes they light up to become visible as active galactic nuclei (AGN) and release extraordinary amounts of energy across the…
Since a black hole does not emit light from its interior, nor does it have a surface on which light from nearby sources can be reflected, observational study of black hole physics requires observing the gravitational impact of the black…
The long-standing issues of determination of the mass distribution and nature of the center of our Galaxy could be probed by a lensing experiment capable of testing the spatial and velocity distributions of stars nearby and beyond it. We…
Giant elliptical galaxies, believed to be built from the merger of lesser galaxies, are known to house a massive black hole at their center rather than a compact star cluster. If low- and intermediate-mass galaxies do indeed partake in the…
Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In…
The formation and evolution of galaxies is one of the great outstanding problems of astrophysics. Within the broad context of hierachical structure formation, we have only a crude picture of how galaxies like our own came into existence. A…
Massive stars have a profound influence on the Universe, but their formation remains poorly understood. We review the current status of observational and theoretical research in this field, describing the various stages of an evolutionary…
The supermassive black hole candidate at the Galactic Center is surrounded by a parsec-scale star cluster, which contains a number of early type stars. The presence of such stars has been called a "paradox of youth" as star formation in the…
The chemical abundances in the atmosphere of a star provide unique information about the gas from which that star formed, and, modulo processes that are not important for the vast majority of stars, such as mass transfer in close binary…
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…
The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCSs), to mark the…
Our knowledge on the central components of disk galaxies has grown substantially in the past few decades, particularly so in the last. This frantic activity and the complexity of the subject promote confusion in the community. In these…
Evidence is summarized that suggests that when a protogalaxy collapses, a fraction $f$ of its gas fails to heat to the virial temperature, where $f$ is large for haloes less massive than the value $M^*$ associated with $L^*$ galaxies. Stars…
We outline a scenario of galaxy formation in which the gas in galaxy-forming regions was preheated to high entropy by vigorous energy feedback associated with the formation of stars in old ellipticals and bulges and with AGN activity. Such…
It has always been believed that feedback from active galactic nuclei (AGN) has an important impact on star formation in massive galaxies. Black hole spin is an important physical parameter of AGN. We use a large sample of massive…
The origin of super-massive black holes in the early universe remains poorly understood.Gravitational collapse of a massive primordial gas cloud is a promising initial process,but theoretical studies have difficulty growing the black hole…