Until recently, black holes were often considered as exotic objects of dubious existence. In the last decade, observations have provided overwhelming evidence in favour of the presence of supermassive black holes at the centre of galaxies, including the Milky Way; of stellar-mass black holes in binary stellar systems; and, possibly, of intermediate-mass black holes in ultraluminous X-ray sources in nearby galaxies. Black holes are now widely accepted as real physical entities, playing an important role in modern astrophysics. IAU S238 brought together observers and theoreticians working in...

Presents an interdisciplinary discussion of stellar and solar astronomy, focussing on the recent findings in stellar magnetism and sunspots.

The Proceedings of IAU S248 reflect the state-of-the-art in the field of astrometry, summarizing the scientific achievements at the tenth anniversary of the Hipparcos and Tycho Catalogue release. It shows the latest achievements in ground-based astrometry and details the progress of second-generation astrometric satellites. Currently, the highest accuracies at a micro-arc-second level are reached by interferometric techniques, especially at radio wavelengths. Establishing and maintaining the celestial reference frame at this level, within a relativistic framework, has been identified as one...

Cosmic masers, naturally occurring amplifiers of microwave emission from atoms and molecules in the Milky Way and other galaxies, provide important tools to investigate astrophysical environments. The first, Hydroxyl (OH) masers were discovered in 1965 and since that time several thousand sources of maser emission, from a variety of cosmic molecules have been discovered and studied. Because this natural emission occurs at discrete frequencies, which depend upon specific atomic or molecular transitions, masers are also useful for studying the structure and dynamics of our own galaxy. Masers in...

White dwarfs are the most numerous members of the stellar graveyard. More than ninety percent of all stars will end their lives as white dwarfs. Research on these objects is fascinating in its own right, requiring developments in atomic data and the study of properties of matter under extreme conditions. However, these studies also have enormous impact on other areas of astrophysics, including: cosmology, the composition of extrasolar planets and fundamental physics. The proceedings of IAU Symposium 357 bring together experts from different branches of science working on white dwarfs, but...

IAU Symposium 356 summarises the most recent results in the field of active galaxies and active galactic nuclei (AGN). These are some of the most luminous sources in the Universe, also the most distant ones that we can observe, so they are very important for understanding the early Universe and its evolution through cosmic time. This volume gives an overview of the current status in the field of active galaxies including: AGN multiwavelength observations; different AGN types and their properties; AGN variability; active supermassive black holes and properties of galaxies in which they reside;...

Laboratory astrophysics is the Rosetta Stone that enables astronomers to understand and interpret the distant cosmos. It provides the tools to interpret and guide astronomical observations and delivers the numbers needed to quantitatively model the processes taking place in space, providing a bridge between observers and modelers. IAU Symposium 350 was organized by the International Astronomical Union's Laboratory Astrophysics Commission (B5), and was the first topical symposium on laboratory astrophysics sponsored by the IAU. Active researchers in observational astronomy, space missions,...