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Proceedings of International Meeting held in Trieste, Italy, April 10-13, 1985

The controversial question of whether the majority of the narrow absorption lines observed in QSO spectra represent cosmological intervening systems or ejecta from the QSO themselves is settled. QSO absorption line spectroscopy, initially a mere technique, has matured into an essential extragalactic research tool for understanding the content of the Universe at redshifts between 0 and 4, and beyond. The only previous important meeting devoted to'QSO Absorption Lines'was held in May 1987 at the Space Telescope Science Institute in Baltimore, Maryland, U.S.A. Since that time, nearly a decade ago, research has been ex­ tremely active in this now well-established field of astrophysics. Theoretical stud­ ies and simulations have taken advantage of the constant progress in computer technology, and during these last few years, the observational results have bene­ fited largely from the new facillities offered by the Hubble Space Telescope in the UV wavelength range and the Keck Telescope for high-resolution spectroscopy.

This book contains the proceedings of the sixth Eurographics Workshop on Vir­ tual Environments. The event took place from June 1 to June 2, 2000, in Am­ sterdam. We hope that readers will find these proceedings to be valuable, not only for virtual environment researchers, but also for practitioners developing or using virtual environment applications. We are glad to report that visibility of the workshop continues to expand and that virtual environment researchers and practitioners from allover the world are submitting papers. This year, 40 papers and case studies were submitted of which 20 were accepted. In addition, we are glad to see that the focus of the workshop is also expanding. We accepted 6 research papers on evaluation of virtual environments and there was a broad sampling of other topics. We would like to thank all those involved in organizing the symposium. In particular, thanks go to Mieke Brune who was in charge of the local organization. In addition, we want to thank the international program committee for their excellent, yet laborious, job in reviewing all submitted papers. The quality of the workshop is a reflection of the quality of the submitted papers and the quality of the reviewing process.

Problems associated with a general scarcity of observations of the southern sky have persisted since the present era of galactic research began some sixty years ago. In his 1930 Halley Lecture A. S. Eddington commented on the observational support given to J. H. Oort's theory of galactic rotation by the stellar radial velocities measured by Plaskett o 0 and Pearce:'... out of 250 stars only 4 were between 193 and 343 0 galactic longitude [=£1: 225 < £11 < 15~; a stretch of one-third of the whole circuit was unrepresented by a single star. This is the operation which Kapteyn used to describe as'flying with one wing'. By mathematical dexterity the required constants of rotation have been extracted from the lopsided data; but no mathematical dexterity can avert the possi­ bility that the neglected part of the sky may spring an unpleasant sur­ prise. As a spectator I watch the achievements of our monopterous avia­ tors with keen enthusiasm; but I confess to a feeling of nervousness when my turn comes to depend on this mode of progression.'During the past few years substantial gains have been made in securing fundamental data on the southern sky. Interpretations based on combined southern and northern surveys are producing a balanced descrip­ tion of galactic morphology. These matters were discussed at a Workshop held at the Leiden Observatory, August 4-6, 1982, attended by some 60 astronomers from 9 countries.

The concept of Stellar Populations has played a fundamental role in astronomy in the last few decades. It was introduced by Walter Baade after he was able to resolve the Andromeda Nebula and its companions into stars when he used red-sensitive plates and realised that there were two fundamentally different Herzsprung-Russell diagrams in our and these nearby galaxies (common stars in the solar neighborhood versus globular clusters). This result was published in two papers in 1944 in volume 100 of the Astrophysical Journal. Subsequent research gave the concept a much firmer basis and at the famous Vatican Symposium of 1957 resulted in a general scheme of the concept and a working hypothesis for idea's on the formation and evolution of the Galaxy. This has been a guiding principle of studies of our and other galaxies for decades. Some years ago it seemed to us appropriate to commemorate Baade's seminal work in 1994, when it would have its 50-th anniversary, and to review its present status and also its role in contempory understanding. While we were in Leiden for an administrative committee, we discussed the matter again and over beers on October 29, 1991 we decided the take the initiative for an IAU Symposium on the subject during the 1994 IAU General Assembly in Den Haag, the Netherlands.

The significance of the present IAU symposium,'The Large Scale Structure of the Universe', fortunately requires no elaboration by the editors. The quality of the wide range of observational and theoretical astrophysics contained in this volume speaks for itself. The published version of the proceedings contains all the contributions presented at the symposium with the exception of the introductory lecture by V. A. Ambartsumian. Contributed papers, short contributions and discussions have been included according to the recommendations of the IAU. Many people contributed to the success of the symposium. First of all, thanks are due to the USSR Academy of Sciences and to the Estonian Academy of Sciences for sponsoring this symposium in Tallinn. The efforts of Academician K. Rebane, President of the Estonian Academy of Sciences, are particularly appreciated. The astronomical hosts of the symposium were the members of the W. Struve Astrophysical Observatory of Tartu who made outstanding efforts to lavish participants with Estonian hospitality which was greatly appreciated and enjoyed by them and their guests. The members of the Scientific and Local Organising Committees are listed below and we thank all of them for their contributions which were central to the success of the symposium. In addition are listed members of the Technical Organising Committee who were responsible for all details of the organisation and whose vigilance ensured that all aspects of the symposium ran smoothly and efficiently. Their contributions are all gratefully acknowledged.

The 4th European Regional Meeting in Astronomy, entitled'Stars and Star Systems', was held in Uppsala, Sweden, on August 7 -12, 1978. It was attended by 228 participants from 24 countries. Over 100 papers were presented; this required parallel sessions throughout the Meeting. Financial support was given by the IAU, the Swedish Department of Education, the Swedish Natural Science Research Council, the Swedish Institute and the University of Uppsala. The members of the Scientific and Local Organizing Committees are listed below, and I thank all of them for their contributions to the Meeting. The Meeting was divided into six sections, according to the scien­ tific topics: Galaxies (A) - including galactic structure and star for­ mation; High-Energy Astrophysics (B); Stars (C); Interstellar Processes (D); Astronomical Instrumentation (E) and Education in Astronomy (F). In each section a number of Invited Papers were presented as well as a large number of contributed papers. In addition, each day a General Lecture was given by an Invited Speaker. The present volume contains all the General Lectures and all the Invited Papers presented during the Meeting. In three cases, however, and for various reasons, only brief summaries have been available. Abstracts of the contributed papers may be found in Uppsala Astronomical Observatory, Report No. 12.

Proceedings of IAU Symposium No. 58 held in Canberra, Australia, August 12-15, 1973

This volume consists of invited talks and contributed papers presented at the NATO Advanced Study Institute'The Post Recombination Universe'which was held in Cambridge in the summer of 1987. There have, in recent years, been numerous meetings devoted to problems in observational cosmology. The attention given reflects the exciting rate of de­ velopment of the subject, and a survey of the proceedings from these symposia reveals that a great deal of emphasis has been given to consideration of the very early universe on the one hand, and to large scale structure in the universe at the present epoch on the other. The theme of this meeting was chosen to comple­ ment these efforts by focussing on the state of the universe at quite early times, but at those epochs which are still accessible to direct observations. The meet­ ing provided a broad coverage of the post recombination universe by drawing on experts from a wide variety of fields covering theory, background radiation fields and discrete sources at high redshift. Events in the moderately early universe will have left their mark in a great range of wavebands, from X-rays to the microwave region, and the evolution of the universe can be revealed by studies of the inter­ galactic medium, gravitational lensing and the abundance and clustering of high redshift sources. All of these subjects received much attention at the meeting, and the papers demonstrate the rich interplay between these areas in the rapidly expanding world of observational cosmology.

Recent advances in the instrumentation used to observe star forming regions in both our own Milky Way and in external galaxies have transformed the subject from a phenomenological pursuit into an increasingly unified, physical science. High resolution centimetre, millimetre, infrared, and optical studies of local star forming clouds have allowed us to probe the physics of star formation down to spatial scales approaching those of the solar system. These developments make it possible to better constrain the basic physical processes underlying star formation itself. At the same time, these new instruments have placed extragalactic studies on a footing detailed enough to allow comparison with star forming regions within our own galaxy. This revolution means that we will soon be able to link the physics of local star forming regions to the global star forming properties of galaxies. The entire structure of this NATO Advanced Study Institute was designed to explore this new view of the subject. This Institute on'Galactic and Extragalactic Star Formation'was held from June 21 -July 4, 1987 at the Conference Centre in the village of Whistler, British Columbia, Canada. The informal atmosphere of this lovely mountain resort stim­ ulated many valuable scientific exchanges. The Institute was funded by a major grant from NATO Scientific Affairs. Additional financial and I.I1oral assistance was provided by the Canadian Institute for Theoretical Astrophysics (CITA) and Mc­ Master University.

This book contains the invited and contributed lectures presented at a meeting organised in the context of the XVIII general assembly ofthe IAU, held in Patras, August 19, 1982. Roughly one hundred scientists attended this meeting, the discussions were livel- sometimes heated - and the original time span allocated to the meeting was as a result, comfortably exceeded by about 50%. The aim of this meeting was to determine the role of galactic gamma-ray astronomy within the general concept of galactic astrophysics. The timing, at the end of the COS-B mission, was regarded as opportune, because it gives interested astrophysicists the possibility for interdisciplinary studies using the existing gamma-ray data base (e.g. comparison with infrared, radio, X-ray, etc. astronomies), as well as for theoretical studies. The next generation of gamma-ray detectors will probably not be in operation for another 5 to 10 years, and therefore it is hoped that the proceeding of this meeting can be used (in the intermediate time) as a basis for further studies, as a stimulation for more theoretical work and as an important contribution for defining the aims and operation of future gamma-ray missions. The interrelationship with other branches of astronomy, the astrophysical implications and the study of relevant physical processes using available measurements in the near-Earth environment were important results of the meeting. Many persons contributed to the success of the meeting, in particular all those who either presented a contribution and/or took part in the discussions.

X-ray astronomers discovered the diffuse gas in clusters of galaxies about 20 years ago. It was later realized that the central gas density in some clusters, and in elliptical galaxies, is so high that radiative cooling is a significant energy loss. The cooling time of the gas decreases rapidly towards the centre of the cluster or galaxy and is less than a Hubble time within the innermost few hundred kiloparsecs. This results in a cooling flow in which the gas density rises in order to maintain pressure to support the weight of the overlying gas. The rate at which mass is deposited by the flow is inferred to be several hundreds of solar masses per year in some clusters. The fraction of clusters in which cooling flows are found may exceed 50 per cent. Small flows probably occur in most normal elliptical galaxies that are not in rich clusters. The implications of this simple phenomenon are profound, for we appear to be witnessing the ongoing formation of the central galaxy. In particular, since most of the gas is undetected once it cools below about 3 million K, it appears to form dark matter. There is no reason why it should be detectable with current techniques if each cooling proton only recombines once and the matter condenses into objects of low mass.

The Origin and Evolution of Galaxies is the outstanding problem of modern cosmology. Fortunately. we have a firm cosmological framework on which to base our theories (the hot big bang) and recently there has been substantial progress in providing observations which potentially can constrain these theories. The problem of galaxy formation is. as a consequence. one involving many diverse branches of physics and astrophysics. It has been the aim of the school. and this compendium of lectures and seminars. to bring together these diverse aspects at a level enabling research workers to understand what is going on in other corners of the subject and to see how progress in each area impinges on the others. We are grateful to the contributors to this volume for allowing us considerable editorial license with their articles. We have attempted to provide a representative sample of the talks that were given at the school besides the texts of the invited lecturers. It is regrettable that for reasons of space we have had to leave out a number of other contributions.

The study of the interstellar medium is certainly one of the most recently developed astrophysical topics. Indeed, to understand the physical status of this medium, one should observe it at every wavelength, especially in radio and in the ranges which are only accessible from space such as Infra Red, X and gammas. Thanks to many new observations we now know that interstellar gas is quite inhomogeneous, since it is made from relatively cold and dense phases (interstellar clouds), surrounded by a relatively hot and tenuous medium. The summer school which took place from September 1 to 16 at the Institut d'Etudes Scientifiques of Cargese, and from which this book originates, was devoted to the analysis of this second diffuse, hot and tenuous component. The eleven sets of lectures which were presented at this school constitute the chapters of this book. They review different aspects (observations, determination of the physical properties and evolution) of this diffuse medium. In the first chapter, J. Lequeux (Marseille Observatory) introduces the study of the diffuse interstellar medium which plays a major role in galactic evolution. His contribution provides some historical references on this subject, such as a copious bibliography on the analysis and observations of the interstellar medium.

South Africa - a land of paradigm shifts. A land where we are willing to leave behind the old, to bravely accept the new. What do we need to exit the dark ages in the morphology of galaxies? How prevalent is the cherishing of old concepts? Traditional morphology has been `mask-oriented', focusing on masks of dust and gas which may constitute only 5 percent of the dynamical mass of a galaxy. Some of the world's foremost astronomers flew to South Africa to address morphologically related issues at an International Conference, the proceedings of which are contained in this volume. Examine predicted extinction curves for primordial dust at high redshift. Stars evolve; why not dust? Read about the breakdown of the Hubble sequence at a redshift of one. Explore the morphology of rings; the mysteries of metal-rich globular clusters; vigorous star-formation in the Large Magellanic Cloud; the world of secular evolution, where galaxies change their shapes within one Hubble time. And much more. Examine a new kinematical classification scheme of the unmasked, dust-penetrated near-infrared images of spiral galaxies. This volume contains over 80 refereed contributions (including 18 in-depth keynote review articles), 40 pages of questions and answers, a panel discussion transcribed from tape and 24 colour plates. The volume is unique in that contributions from both high and low redshift experts are represented at a level readily accessible to postdoctoral students entering the exciting world of morphology - whether it be of the local, or more distant, Universe.

The Cologne-Bonn-Zermatt symposium is a well established series of conferences, occurring on a 5-year cycle, on the dense interstellar medium and related topics. The main results constitute valuable proceedings that offer everyone working in this field an authoritative and comprehensive source of reference.

This volume contains a series of lectures delivered at the 2nd course of the International School of Astrophysics at the'Ettore Majorana'Centre for Scientific Culture in Erice (Sicily) from June 22 to July 9, 1974. The course was jointly planned by L. Woltjer and myself and was fully supported by a grant from the NATO Advanced Study Institute Programme. It was organized with the aim of providing students and young researchers with an up to date account of the structure and evolution of galaxies and was attended by 94 participants from 20 countries. The study of galaxies is one of the most important areas of contemporary astrophysics both for its intrinsic interest and because it is a prerequisite to a quantitative understanding of the structure of the universe. Recently, a qualitatively new under­ standing has become available through both observational andtheore­ tical progress. On the observational side, new techniques applied at the large optical telescopes and, in particular, the impressive results obtained wi. th the high resolution radio telescopes have made it possible to obtain a detailed mapping of the structure of galaxies other than our own. At the same time, new theoretical insights and the availability of powerful computers to construct models holds out the hope that a full understanding of the structur. es of galaxies may be within our reach.

The last major conference on infrared astronomy was the IAU Symposium No. 96 in June 1980. Since then, the discipline has continued to mature and to contribute to all branches of astrophysics. One particular area of growth has been in spectroscopic capabilities at all infrared wavelengths. The purpose of the Symposium in Toledo was to review the scientific questions to be addressed via infrared spectroscopy and to provide, in the proceedings, a useful summary of the field. The sensitivity of infrared spectroscopic observations is still generally limited by detector characteristics or by thermal background radiation. However in recent years improvements in detector technology together with developments in spectroscopic instrumentation have made possible both quite detailed spectroscopy of the brighter members of many classes of galactic sources and also begun to open up some infrared spectroscopy of extragalactic sources. The potential of the field in the next decade or two is clear. The lRAS mission has completed one of the pre-requisites, namely an all-sky photometric survey. Major space missions utilising cryogenic infrared telescopes have been approved in Europe (ISO) and seem likely in the USA (SIRTF); plans for space submillimeter telescopes are firming up. On the ground large telescopes optimized for infrared observations are now in operation at high altitude sites and specialized submillimeter facilities are under construction. The particular advantages of planned, very large telescopes for infrared observations are widely accepted.

IAU Symposium 97, Extragalactic Radio Sources, was held at Albuquerque, New Mexico August 3-7, 1981. It was co-sponsored by IAU Commissions 28, 40, 47 and 48 and by URSI Commission J. Financial and organizational support were provided by the National Radio Astronomy Observatory, the University of New Mexico, and the National Science Foundation. A wide variety of interesting objects and phenomena can be covered under the heading'Extragalactic Radio Sources', and a diverse set of topics was in fact discussed at the symposium. Radio galaxies, quasars, Seyfert galaxies and BL Lacertids received the most attention, but normal galaxies, the galactic center, and even SS433 were also discussed. While the unifying theme of the symposium was radio emission, studies at all wavelengths--X-ray, UV, optical, IR, and radio--were included. In general, the emphasis was on individual objects and the physical processes associated with them, but there were also papers on statistical studies and cosmology. The symposium was attended by 209 scientists from 18 countries.

IAU Symposium No. 168, Examining the Big Bang and Diffuse Background Radiations, took place on August 23-26, 1994 at the XXIInd IAU General Assembly in the Hague, Netherlands. The meeting attracted a large number - over 250 - of astronomers, reflecting the strong interest engendered by the great advances in cosmology made in recent years. There is still a multitude of unresolved problems in modern cosmology and the symposium offered a wonderful occasion to examine them objectively, at a place where many leading workers in related fields gathered together. After the introduction by IAU President L. Woltjer and the historical background by Vice Present Virginia Trimble, the volume begins with reviews of the cosmic microwave radiation from COBE (Cosmic Background Explorer). Reviews of recent observations then extend from radio to infrared, visible light, ultraviolet, X-rays and gamma-rays. It is followed by theoretical models for the Big Bang and Inflation, and alternative views to the Big Bang. Following a discourse on Probes and Future Tests, the meeting ended with a Panel Discussion on `Major Unsolved Problems of Cosmology'. Some forty-four contributed papers - both oral and poster reports - are included after the invited talks and panel discussions.

On the 100th anniversary of Marconi's successful experiment on radio broadcasting, 250 astronomers from all over the world met in Bologna (Italy) for five days, to update their knowledge of the physics and statistical properties of powerful extragalactic radio sources. Since their discovery in the fifties enormous progress has been made. The existence of superluminal motions in the cores of radio sources, the presence there of a black hole surrounded by an absorbing dust torus, as inferred mostly from studies at other wavelengths, are now accepted ideas. Nevertheless, in spite of these efforts, there are many questions still unanswered. For instance we do not know which mechanism produces the huge amount of energy supplied to radio sources, how the jets connecting the `engine'to the lobes are formed and collimated, which of the differences observed among the various classes of radio sources are apparent and which are real. These and other related topics are discussed in this book.

One approach to learning about stellar populations is to study them at three different levels of resolution. First in our own Galaxy; secondly from nearby galaxies where stars can still be resolved; and thirdly in remote galaxies in which the stellar population can only be studied in integrated light. This IAU Symposium covered the entire range of galaxies in its study of their stellar populations. Interspersed with theoretical papers, the wealth of observational results provides an important state-of-the-art presentation of the progress that has been made in this field.

The morphological scheme devised by Hubble and followers to classify galaxies has proven over many decades to be quite effective in directing our quest for the fundamental pa­ rameters describing the extragalactic manifold. This statement is however far more true for spirals than for ellipticals. Echoing the concluding remarks in Scott Tremaine's sum­ mary talk at the Princeton meeting on Structure and Dynamics of Elliptical Galaxies,'the Hubble classification of spirals is useful because many properties of spirals (gas con­ tent, spiral arm morphology, bulge prominence, etc.) all correlate with Hubble time. By contrast, almost nothing correlates with the elliptical Hubble sequence El to E7.'During the last few years much effort has been put into the search for a more meaningful classification of ellipticals than Hubble's. Concomitantly, forwarded by some provocative conjectures by R. Michard, the classical question of whether E galaxies form a physically homogeneous family has been brushed up once more. Results of these and other parallel studies look rather promising and point to suture part of the dichotomy between ellipticals and disk galaxies which had become popular in the early eighties, owing to dynamical arguments. At the same time it appears more and more clear that, besides the usual genetic varieties of galaxies, products of environmental evolution must also be contemplated in building our modern picture of the'reign of galaxies'. The above considerations prompted us to solicit Prof.

It is sometimes said that astronomy is the crossroads of physics. In the same spirit, it can forcefully be argued that galaxies are the crossroads of astronomy. Internal pro ces ses within galaxies involve all of the fundamental components of astrophysics: stellar evolution, star formation, low-density astrophysics, dynamics, hydrodynamics, and high-energy astrophysics. Indeed, one can hardly name an observational datum in any wavelength range on any kind of celestial object that does not provide a useful clue to galaxy formation and evolution. Although internal processes in galaxies until recently occupied most of our attention, we now know that it is also vital to relate galaxies to their environment. How galaxies congregate in larger structures and are in turn influenced by them are crucial questions for galactic evolution. On a grander level we have also come to regard galaxies as the basic building blocks of the universe, the basic units whereby the large­ scale structure of the universe is apprehended and quantified. On a grander level still, we also believe strongly that galaxies are the direct descendents of early density irregularities in the Big Bang. Galaxy properties are now viewed as providing a crucial constraint on the physics of the Big Bang and a vital link between the macroscopic and microscopic structure of the universe.

This workshop was intended as an update and an extension of the workshop 011 the'Spectral Evolution of Galaxies'that was held in Erice two years ago. It concentrates 011 Ilew developments concerning galaxies seen at large look back times. This seemed also a good opportunity to look ahead to the next generation of ground- and space­ based instrumentation, and to consider various future strategies for collecting information concerning the edge of the observable universe. The main idea was to bring together people with specialities in modelling galaxy components (such as stars, clusters, gas, and dust) as well as whole stellar systems (stellar populations, star formation rates, chemical enrichment), and people specialized in making direct measurements of galaxies and clusters at large look back times. The confrontation of expectations and observations was planned to be the central theme of the conference, which explains the title'Towards Understanding Galaxies at Large Redshift'. The first part of the workshop focussed on the physical processes that operate in galaxies, and that would likely have some observable manifestation at large redshifts. In the second part the most recent observational work was reported, and we were pleased to have the participation of most of the groups active in this field. The last part was directed towards new approaches to be made possible by the next generation of instrumentation, although in general all the contributions were indeed in this spirit of setting more ambitious goals.

Along with the traditional optical window, many new windows have been opened on galaxies in the last two decades, made possible by new developments in groundbased detectors and by space missions that allow detection of photons that are otherwise absorbed by the Earth's atmosphere. Galaxies can now be observed in the radio, submillimeter, IR, optical, UV, X- and gamma-ray bands, each window allowing us to learn more about galactic components and properties. These developments have also imposed the view that a deeper understanding of even normal galaxies requires a panchromatic approach, making use of all of the data gathered from the different windows to synthesize a comprehensive physical image of these complex astronomical systems. Windows on Galaxies presents a comprehensive view of galaxies through all the available windows, bringing together both theoretical and experimental approaches in the form of a series of reviews reporting the most recent developments complemented by contributed talks and discussions. TEXT NO. 2 The sixth workshop of the Advanced School of Astronomy examined galaxies through all available wavelength windows. Over the last twenty years, new wavelength windows have been opened in astronomy which have created many new possibilities for the observation of the properties of galaxies. The outcome of the meeting clearly stated that the approach towards the studying of galaxies should be panchromatic. Each window, from radio to gamma-rays, shows different components, and a synthesis of this knowledge presents astronomers with a comprehensive physical image of these astronomical systems: star formation, evolution of galaxies, molecular contents, gas flows, interstellar matter and properties of galaxies in the several wavelength fields are discussed in this volume.

The date: September 30, 1880 The place: A private observatory in Hastings-on-Hudson Profession of the observer: A medical doctor The instrument: An l1-inch Clark refractor. The significance of that night marked one of the truly great turning points in the development of astronomical techniques: Dr Henry Draper, a wealthy New York medical doctor, had secured the first photograph of a nebula: a 51-minute exposure on a dry gelatinobromide plate showing the wispy nebulosity of the Orion Nebula. By March 1882, Draper had secured an exposure of 137 minutes, showing far richer detail of both bright and dark features. The rest is histapy. The photographic era heralded in a universe where hints of the presence of cosmic dust were strongly alluded to: from star-forming regions such as Messier 17, to the Horsehead Nebula in Orion, to the striking dark finger in the Cone Nebula, to the magnificent dark bands in the plane of our Milky Way.'Historically, astromomers from the very beginning have been afraid of dust.

Thirty years after the pioneering enterprise of Neugebauer and collabo­ rators, the astronomical sky is surveyed anew in the near infrared range with a gain in sensitivity greater than 4 orders of magnitude. Data have started to come through the'pipelines'routinely and at the turn of the century, the astronomical community will be provided with immense databases that will eventually contain accurate positions and 3- colour (or even 4-colour after merging DENIS and 2MASS data) photometry for hundreds million of stars and millions of galaxies. This fantastic harvest of data will eventually result of the huge effort that has been deployed on both sides of the Antlantic to promote 2 major projects, 2MASS and DENIS. rd The basic aim of this 3 Euroconference (and last in the series), was to put in close contact the scientific teams of 2MASS and DENIS in order to present and discuss the first significant results of the two surveys and to start promoting possible future plans

Proceedings of IAU Symposium No. 100, held in Besançon, France, August 9-13, 1982

From 12 April to 14 April 1988, 120 of Gerard and Antoinette de Vaucouleurs's friends and colleagues gathered at the Institut d'Astrophysique in Paris to cel­ ebrate Gerard's 70th birthday and his remarkable career in Astronomy. The gathering also honored the memory of Antoinette (who died 29 August 1987 after a long illness) and her own no less remarkable career. This volume collects the 24 invited review papers and the 60 contributed poster papers presented at the meeting. Gerard de Vaucouleurs Gerard de Vaucouleurs was born on 25 April 1918 in Paris, where he spent his boyhood. He became an active amateur astronomer in the early 1930's, making extensive observations of Mars, Jupiter, and variable stars (including the bright supernova of 1937 in IC 4182). He also began life-long interests in astronomical photography and galaxy cataloguing during this period. In 1939, he met the director of the Paris transport system and an equally avid amateur astronomer, Julien Peridier. De Vaucouleurs worked at Peridier's private observatory at Le Houga in southwestern France on and off throughout the next decade. His undergraduate work was in mathematics, astronomy, and experimental physics; this, combined with his interest in observational astronomy, formed his life-long empirical approach to science. After spending 18 months in the French army early in 1939 - 41, Gerard returned to the Peridier observatory and then, in 1943, to his studies at the Sorbonne, where he met Antoinette.

Various kinds of masks obscure our view of our galaxy, the Milky Way, as well as of other galaxies. Masks of interstellar dust affect our measurements within galaxies, on scales ranging from individual supernovae to the galaxies themselves. The “mass mask” (our inability to image mass rather than light) gives astronomers a very incomplete picture of the size and structure of galaxies themselves, because we cannot image the dark matter which provides most of the galactic mass. Another mass is the “dynamical mask”: as galaxies form, much dynamical information is lost in the birthing process. A new thrust in research is to retrieve such information by means of chemical tagging. About 50 astronomers flew into Namibia in April 2010, to celebrate the 70th birthday of Professor K.C. Freeman, Fellow of the Royal Society. At age 70, Freeman, a father of dark matter in galaxies, continues to be one of planet's most highly cited astronomers. The current volume affords readers a unique perspective on galaxies by probing the thoughts of some of the greatest astronomers of our age. Contributions focus on galaxies from within our Local Group to those in our high redshift Universe. Approximately 40 in-depth review and contributed papers are contained in the volume, each written by an expert in the field. Two unusual features of the current volume include the “Star Country” of the San people of southern Africa as well as the introduction into astronomy of “The Treachery of Images” by the Belgian surrealist artist René Magritte. “Everything we see hides another thing, we always want to see what is hidden by what we see”, said Magritte. These words resonate the theme of the current volume “Galaxies and their Masks”, which is written at a level to be appreciated by both specialist and doctoral student alike.

This book presents an up-to-date collection of reviews and contributed articles in the field of ultraviolet astronomy. Its content has been mainly motivated by the recent access to the rest frame UV light of distant red galaxies, gained through large optical facilities. This driveway has derived in a renewed interest on the stars that presumably dominate or have important effects on the integrated UV properties of evolved systems of the nearby and faraway Universe. The topics included in this volume extend from the fresh spectroscopic analyses of high redshift early-type galaxies observed with the 8-10m class telescopes to the fundamental outcomes from various satellites, from the long-lived International Ultraviolet Explorer to current facilities, such as the Galaxy Evolution Explorer. This is one of the few volumes published in recent years devoted to UV astronomical research and the only one dedicated to the properties of evolved stellar populations at these wavelengths. This contemporary panorama will be an invaluable resource in the preparation of the next planned space missions, such as the World Space Observatory and the Ultraviolet Imaging Telescope.

For every galaxy in the field or in clusters, there are about three galaxies in groups. The Milky Way itself resides in a group, and groups can be found at high redshift. The current generation of 10-m class telescopes and space facilities allows the observation of the members of nearby groups with exquisite detail, and their properties can be correlated with the global properties of their host group. Groups in the local Universe offer us the chance to study galaxies in environments characterized by strong interactions. In the cosmological context, groups trace large-scale structures better than clusters, and the evolution of groups and clusters appears to be related. All these aspects of research on groups of galaxies are summarized in this book written by scientists working in various fields.

The school introduces the experimental and theoretical particle physics background underlying several aspects of cosmology: matter anti-matter asymmetry, dark matter, the acceleration of the expansion, the 3K Cosmological Background Radiation, the geometry of the universe. The theoretical lectures offer reviews by experts on topics which include the limits of the standard model, a description of the neutrino mass, supersymmetry, leptogenesis/baryogenesis, scalar fields, and extra-dimensions. The status experimental observations in particle physics and astrophysics (CP violation, neutrino oscillations, dark matter, 3K radiation) is also covered.

Our knowledge of the environment of the nucleus of our galaxy has been greatly enhanced, by more extensive and sensitive observations at radio and infrared wavelengths, the advent of high resolution x-ray imaging and spectroscopy, and considerable theoretical activity to understand the nucleus and its components, and their activity. The Galactic Center Workshop 2002 was organized to review recent research on the galactic center, including the latest state-of-the-art observations and important theoretical developments. The workshop covered phenomena on scales ranging from the central several hundred parsecs to the central parsec and within. Each topic was approached from both multi-wavelength observational and theoretical perspectives.

This volume presents a multi-disciplinary approach to the physical mechanisms which structure the shape, evolution and fate of the Galaxy. It contains 4 panel sessions (the recording transcripts of the galactic'tertulias'), an introductory historical overview on the Galaxy research, 17 reviews, and the proceedings of more than 50 oral and poster contributions. This book is not a new edition of a previous volume but it is in some way related to the book'The Formation of the Milky Way'(1995; Cambridge University Press), which contains the proceedings of the first IAA-IAC-University of Pisa mee.

This book constitutes the proceedings of a very topical workshop aimed at understanding the shapes of the baryonic and dark matter components of galaxies. Several groups presented their recent results from observations and numerical N-body simulations.

This volume comprises lectures delivered at the First Equatorial School of Relativistic Astrophysics. It covers various topics related to observational and theoretical problems of galaxies, quasars and cosmology. The aim is to analyze current problems.

Galaxies represent the most readily visible fabric of the cosmos. Their morphological types, luminosities and environmental surroundings contain valuable clues as to their origin and evolution. Locally, a strong correlation is seen between galaxy morphology and environmental location; this may have been molded at surprisingly modest redshifts. Spectroscopic and photometric studies of deep fields also suggest remarkably recent changes in the galaxy population. The associated growth of structure during the same interval can be tracked via X-ray studies of distant clusters of galaxies.Very recently, impressive observational facilities have been completed, each of which has extended the astronomers'dataset to look-back times where such evolutionary effects can be studied.This volume discusses surveys which share a common theme — the need for a large number of ground-based spectra. It focuses on the various approaches via a single theme concerned with the evolution of galaxies and their distribution. In the near future, impressive new observational facilities will be able to generate large statistical spectroscopic surveys, and the aim of this volume is to assess the scientific impact that ongoing and future spectroscopic surveys can make. Emphasis is placed on the role of non-optical and satellite facilities and the co-ordination of international efforts.

Giant Molecular Clouds in the Galaxy: Third Gregynog Astrophysics Workshop covers the proceedings of the 1977 Third Gregynog Astrophysics Workshop on Giant Molecular Clouds (GMC), held at the University of Wales. This book is organized into 11 parts encompassing 33 chapters. After a brief introduction to the significant features of GMC, this book goes on examining radio, millimeter, and galactic center observations of GMC, along with their infrared properties and kinematics. Other parts deal with the water sources in GMC; time variation in interstellar water masers; and the relation of HII regions to molecular clouds. The remaining parts discuss the evolution of interstellar molecular clouds and the role of magnetic fields in the collapse of protostellar gas clouds. These parts also cover the chemistry of interstellar molecules containing nitrogen and the search for other planetary systems. This book will prove useful to cloud scientists, physicists, astronomers, and researchers.

Contents:The Great Astronomer Guo Shoujing and Gou Shoujing Summer School on Astrophysics (Wang Shouguan)Star Formation (C F McKee, notes by Lin Jian-Yu)The Age of Globular Clusters (P Giannone)Stellar Disks in Early-Type Galaxies (P Goldreich, notes by Huang Siqin)The Luminosity Function of Galaxies (Q Chincarini)The Structure of Dark Matter in Galaxies (J Kormendy, notes by Gao Yu)Cosmic Strings and Fractals in the Distribution of Galaxies (Fang Li Zhi)and other papers Readership: Graduate students and researchers in astrophysics. Key Features:A distinctive focus on credit risk related topics that are relevant for academics, policymakers and practitioners, linking rigorous theoretical and empirical research with clear practical implicationsAn annual update on global credit market dynamics and financial regulationsTouches on current topics such as the measurement of systemic risk, the role of reserve requirements in monetary policy, and changes in credit portfolio management