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

The enormous advances in observational techniques over the last two decades has produced a wealth of data and unexpected discoveries which have helped to reshape astrophysics as a field with well-formulated theories and sophisticated numerical calculations. In nuclear particle physics, plasma physics, as well as in general relativity, the Universe has become a laboratory for cutting-edge research. The courses collected in the book are intended to provide students with this insight, giving a general background on each topic such as cosmic rays, nuclear and neutrino astrophysics, solar physics and strong fields, as well as a presentation of the current research and open problems. The book is aimed at graduate students in physics and astrophysics, as well as researchers, bridging a gap between the specialized reviews and the comprehensive books.

Many of the ISO observers who assembled for this workshop at Ringberg c- tle met for the third time in the Bavarian Alps. At two previous meetings in 1989 and 1990 surveys were only a minor topic. At that time we were excited by the discoveries of the IRAS survey mission and wanted to follow it up with pointed observations using an observatory telescope equipped with versatile instruments. With the rapid development of detector arrays and stimulated by ISO’s Observing Time Allocation Committee, however, surveys eventually became an issue for the upcoming mission. In a review paper on “Infrared S- veys - the Golden Age of Exploration” given at an IAU meeting in 1996, Chas Beichman already mentioned that there are ISO surveys. They were at the bottom of his hit list, while the winners were future space missions (Planck, SIRTF, etc. ) and ground-based surveys in preparation (Sloan, 2MASS, DE- NIS, etc. ). He organized his table according to the relative explorable volume, calculated from the solid angle covered on the sky and the maximum distance derived from the detection sensitivity. Clearly, with this ?gure of merit, ISO, as a pointed observatory, is rated low. Applying the classical de?nition of a survey, i. e. to search in as large a volume as possible for new or rare objects and/or study large numbers of objects of various classes in order to obtain statistical properties, ISO was indeed limited.

The idea of a joint ESO / Australia meeting on the large number of exciting new facilities that are, or will soon be, available tihne southern hemisphere arose quite naturally. In the optical and the near-infrared, the Very Large Telescope (VLT) will soon be operational. In the radio, the Australia Telescope Com pact Array is going to be upgraded to higher frequencies (20 and 100 GHz), together with an improvement in very long baseline interferometry (VLBI) facil ities. Other major facilities, such as the Large Millimetre Array and the lkT are being planned. Moreover, new deep surveys are underway in the southern hemi sphere: the southern Hubble Deep Field, the ESO Imaging Survey (BIS), pan oramic deep surveys with the UK Schmidt telescope, and the Anglo-Australian Telescope (AAT) 2dF galaxy/QSO redshift survey in the optical; and the Parkes multibeam HI survey and Molonglo Observatory Synthesis Telescope (MOST) Wide Field continuum survey at radio wavelengths. With all these new facilities, important progress will be made regarding important issues such as the large scale structure of the universe, the very early universe and the associated first epoch of galaxy formation. The generation of large databases, and the oppor tunity for sensitive follow-up observations in complementary wavebands, mean that coordinated radio, infrared and optical projects in the southern hemisphere are likely to become increasingly attractive and important.

With the bulk of asteroids floating in space between the orbits of Mars and Jupiter, astronomers puzzle over where these rocks came from. Are they the remnants of a planet? Excess not used in the formation of the Solar System? Nothing more than random bits of debris? The location of the belt makes for a quasi-barrier separating the inner from the outer planets. Perhaps asteroids were meant to discourage human space exploration. NASA has sent missions to explore the asteroid belt and the rocks themselves, and those missions have yielded some interesting observations on the composition of the asteroids but no definitive answer as to their origin. Earth-based tools such as telescopes and satellites also contribute to asteroid research but cannot plumb the depths behind these varied chunks of flotsam. Presented in this book is a list of carefully chosen abstracts and citations of relevant literature about asteroids and the research into them. Prior to this listing, though, comes an overview of the nature of the asteroids and what we know now about them and what we hope to discover in the future. lifeless but mysterious rocks inhabiting the solar system. To conclude, easy access is provided through author, title, and subject indexes.

Since the Sun is the main source of space weather effects, the first part of the book is devoted to a general introduction to the physics of the Sun. A better understanding of the phenomena underlying solar activity is also important for prediction of solar outbursts and thus for establishing alert systems for space missions and telecommunication systems. The book contains the following topics: possible influence of the Sun on the Earth's climate; the effects of radiation on humans in space and the expected radiation dose from various solar events; disturbances of the Earth's ionosphere and the implications of radio communication at different wavelength ranges; possible hazardous asteroids and meteoroids and their detection; and space debris and special shielding of spacecraft. In the cited literature more detailed information about the topics may be found. This book provides an introduction and overview of modern solar-terrestrial physics for students as well as for researchers in the field of astrophysics, solar physics, geophysics, and climate research.

Publisher description

Proceedings of the Joint Discussion-17 at the 23rd IAU General Assembly, organised by the Commission 41, held in Kyoto, Japan, August 25-26, 1997

The multielement systems have been widely used in many fields of astron omy and radio science in the last decades. This is caused by the increasing demands on the resolution and sensitivity of such systems over the wide range of the electromagnetic wavelengths, from gamma up to radio. The ground-based optical and radio interferometers, gamma-ray and X-ray or bital telescopes, antenna arrays of radio telescopes and also some other radio devices belong to scientific instruments using multielement systems. There fore, the current problems of the optimal construction of such systems, or precisely, those of searching for the best arrangement of the elements in them, were formulated. A rather large number of scientific papers, including those of the authors, is devoted to these problems, and we believe that the time has come to integrate the basic results of the papers into the mono graph. The offered book consists of three parts. The first part is concerned with the optimal synthesis of optical and radio interferometers of various types and purposes; the synthesis of non-equidistant antenna arrays is con sidered in the second part; and the methods for the construction of coded masks for X-ray and gamma-ray orbital telescopes are expounded in the third one. Since in the text combinatorial constructions which are little known to astronomers are used, the necessary information is given in the appendices. Various tables containing the parameters of the systems consid ered are also represented.