As the most abundant element in the Universe, hydrogen is an ubiquitous tracer of structures at various scales and plays a fundamental role in galaxy formation. Accretion of hydrogen from the intergalactic medium (IGM) feeds galaxies with the raw material necessary for the formation of stars. Continua a leggere The Role of Hydrogen in the Evolution of Galaxies
With the upcoming astrometric satellite Gaia and the complementary large scale ground based surveys, such as LAMOST, Galactic Astronomy is set to enter a new era. We will have access to high quality data for several hundred thousands of stars. Both to obtain as well as interpret such large amounts of data sets new challenges for the Galactic astronomers. The meeting in Lijiang was conceived out of a need to prepare the community for the challenges ahead and, in particular, to foster stronger relations between observers and modellers. Ultimately we wish to create a detailed map of our Galaxy and to understand why it looks like it does. That can only be achieved through constant intercourse between modellers and observers. The SOC hopes that the program at this meeting will help facilitate this process.
The formation and evolution of galaxies is a key topic in contemporary astrophysics. This topic can be studied in essentially two ways: through the study of large numbers of galaxies at different times of the evolution of the universe, or through the detailed study of the Milky Way and its close neighbours. The latter is often referred to as near-field cosmology, and can provide surprisingly strong constraints on models of galaxy formation and evolution. However, the study of the Milky Way as a galaxy is not an easy task. In particular the detailed knowledge of the distribution of the stellar content, both in space and in velocity space, is severely lacking. This means that it is difficult to fully constrain evolution and formation models of the different components of the Milky Way. In 1944 Walter Baade introduced the concept of Stellar Populations. The concept was has remained a highly useful tool to quickly identify and classify different generations of stars in galaxies. However, the last decades have seen a move away from this fairly static, even if complex, concept to a more dynamic and flexible way of characterizing the stellar components in the Galaxy by means of the individual star’s age, metallicity, orbit etc. This shift in how we study major stellar populations in our own and nearby galaxies has benefited from advances both in theory as well as in observations. In particular the advent of wide field CCDs and dedicated survey telescopes as well as advances in computer technology that now allows for truly detailed models of various aspects of the evolution of the Milky Way have moved the study of our Galaxy into the first part of a new era. The advent of Gaia will take us truly into the era of precision studies of the Milky Way. In the meantime several very large surveys have contributed and will continue to contribute to our deepening understanding of the Milky Way as a galaxy. Gaia is scheduled to launch 2013 and will provide parallaxes and proper motions for a billion objects and radial velocities for 150 million stars, enabling the exploration of the Milky Way to take an unprecedented quantum leap forward. We will be working in a completely new regime – that of precision Galactic astronomy. These changes put serious and new demands on our analysis of the data and modeling of the Galaxy. Around the world there are currently a number of on-going or planned major surveys that, although they have their own stand-alone science cases and goals, will complement Gaia in fundamental ways. One of the most ambitious of these projects is the innovative LAMOST telescope, equipped with some 4000 fibres and a 20 square degree field of view. LAMOST is the largest Chinese telescope and one of the National Major Scientific Projects undertaken by the Chinese Academy of Sciences. This and other projects, such as the Gaia-ESO Survey, SEGUE-2, HERMES/GALAH, and APOGEE, will provide vital complementary data to Gaia. Of great importance, they will supplement the high quality proper motions from Gaia with radial velocities of equal quality for stars fainter than Gaia’s limits, enabling a fully detailed 6D phase space map of the Milky Way to be constructed. Theorists and observers alike find these forthcoming projects exciting. This meeting offers a very timely opportunity to bring observers and theoreticians together to discuss in depth the possibilities to overhaul and update our traditional view of the Milky Way and its sub-components. Thus we have a very substantial section on the Milky Way galaxy as seen through observations, a dedicated session on the most recent advances in stellar abundance analysis, extensive coverage and update on on-going surveys, and the conference ends with a major session on modeling of galaxies with special emphasis on reviewing the state of the art of the various modeling approaches and their application to the Milky Way. The aim is to deepen the discussion and interplay between modelers and observers to take advantage of the challenges and possibilities that these new data sets offer. By bringing together theorists, observers, and survey scientists interested in our Galactic system, we will maximise the impact of the Symposium, which is sure to encourage and excite, leading to new insights and a community better prepared to take scientific advantage of Gaia, LAMOST and all the large (by then) on-going or upcoming surveys.