This is a review of the basic elements directly connected to the evolution of galaxies. Owing to advances in observational astronomy and astrophysics, data has become available about remote galaxies, which are consequently in the first stages of their evolution. It is therefore essential to link these data to the observation of very old populations in our own Galaxy, which are the remnants of the populations which existed in the first stages of galactic evolution. In this meeting, the relationship between these two different points of view is emphasized in the texts presented by well-known specialists as well as by young researchers active in the field. The difficulties of the problem and the remaining uncertainties are discussed.

Interstellar and solar system solids are different stages of the same materials. In this book, the sources and evolution of circumstellar dust, interstellar dust, comets, meteorites and interplanetary dust are carefully discussed in the context of their interrelations. One of the major questions raised is: how do characteristically 1/10 micron interstellar dust particles evolve to rocky materials 1000 times larger or more? The closest we appear to be getting in relating interstellar dust to particles in the solar system is the evidence for submicron organic coated particles in interplanetary dust particles collected in the upper atmosphere, which allow direct laboratory investigation on Earth. What we know about comets, however, either results from remote observation or space measurements in situ. Comet volatiles compare very well with interstellar ices. These astrophysical problems bring to bear a very wide range of theoretical, observational and laboratory expertise in such fields as astronomy, physics and chemistry and, with the evidence of complex prebiotic organics in meteorites.

A conference on "Observational Evidence for Black Holes in the Universe" was held in Calcutta during January 10-17, 1998. This was the first time that experts had gathered to debate and discuss topics such as: Should black holes exist?; If so, how to detect them?; And Have we found them? This book is the essence of this gathering. Black holes are enigmatic objects since it is impossible to locate them through direct observations. State-of-the-art theoretical works and numerical simulations have given us enough clues of what to look for. Observations, from both ground and space-based missions, have been able to find these tell-tale signatures. This book is a compendium of our present knowledge about these theories and observations at the end of the 20th century. Combined, they give an idea of whether black holes, galactic as well as extragalactic, have been detected or not.

This volume collects the contributions to the 10th European Workshop on White Dwarfs held in Blanes, Spain, in June 1996. The Workshop gathered together a number of specialists working in this area of research and provided an updated description of the current work of the field as well as its connections with other topics. This text provides a snapshot of current understanding of the origin, structure and evolution of white dwarf stars from both the theoretical and the observational points of view. It also takes into account the properties of white dwarfs as members of binary systems, stellar clusters and galactic populations.

This Symposium on fundamental stellar properties was held to honour Emeritus Professor Robert Hanbury Brown on the occasion of his 80th birthday. The speakers described current advances in interferometry, astrometry, spectroscopy and in theoretical models of stellar atmospheres and interiors. The emphasis was on the critical assessment of the quality, accuracy, and prospects for improvement of the observational data and theoretical models, on the outstanding problems in stellar astrophysics, and on the feasibility of achieving the observational and theoretical advances required for their solution. These proceedings should be of interest to researchers and graduate students in all fields of astrophysics.

Interstellar carbon monoxide (CO) was first detected in 1970 by R. W. Wilson, K. B. Jefferts, and A. A. Penzias through observations of its lowest rotational transition at 2.6 mm wavelength. This discovery opened the door to a profound new understanding of several diverse yet related fields, including the phases of the interstellar medium, the initial and final phases of stellar evolution, the chemistry of dense and diffuse interstellar matter and of the solar system, the structure of the Milky Way galaxy, and the content and structure of other galaxies. These are among the most fundamental research areas in astrophysics, and spectroscopic information about CO and other molecules serves as a primary tool of investigation. Continuing developments in instrumentation will further increase the power and utility of millimeter and submillimeter-wavelength molecular line spectroscopy. The 25th anniversary of the detection of CO was an opportunity for researchers from all branches of millimeter-wave astronomy to gather and review progress and future directions. These Proceedings discuss the state of the field and consider important unanswered questions.

In addition to being fascinating astrophysical laboratories in their own right, Herbig-Haro flows have in recent years emerged as key phenomena in our attempts to understand the complex and violent processes that govern the birth of low mass stars. This work provides an overview of the major advances which the study of Herbig-Haro jets has enjoyed since 1995. On the observational side, Hubble Space Telescope images have revealed the intricate details of the shock structures in these supersonic flows, millimetre interferometry and infrared imaging can now probe the detailed structure of the molecular component of deeply embedded jets, and sub-millimetre and radio continuum maps now enable us to study the near environment of the optically invisible driving sources of jets. On the theoretical side, detailed numerical and analytical magnetohydrodynamic models have reached a level of sophistication that allows realistic comparison with observations and insights into the jet formation mechanisms. Similarly detailed observational and theoretical studies of the disks and winds of T Tauri stars are now gradually being linked to the Herbig-Haro flows, providing a first glimpse of how stars can be born by both accreting and ejecting infalling material.

These proceedings present observational and theoretical results on cataclysmic variables (CVs). Main topics include: interrelations among CVs; theory and evolution of classical, recurrent, symbiotic novae; dwarf novae, nova-like and accretion-induced phenomena; the role of magnetic fields in CV evolution; CVs as possible precursors of SNI-a; and links between CVs and super-soft X-ray sources. The work should be useful for astronomers interested in cataclysmic variables.

The papers in this study cover a range of scenarios, from disk and envelope around young stellar objects and protostars through to more aged stars and highly-evolved objects which exhibit considerable mass loss features. Significant advances and developments in observing facilities, instrumentation, computing power and techniques are described, together with a variety of theories, suggestions, observations and models. The formation, composition, effects and evolution of the material surrounding a stellar environment are also included.

Foreword; J. Davies, D. Burstein. Introductory Remarks; M. Disney. Interstellar grain evolution and temperatures in spiral galaxies; J. Mayo Greenberg, A. Li. Radiative transfer models; G. Bruzual A. Radiative transfer in dusty galaxies; A.N. Witt. Opacity Diagnostics in spiral galaxies; N.D. Kylafis. Modeling dusty galaxies; G. Magris C., G. Bruzual A. Inclination-dependence of spiral galaxy physical properties: history and tests; D. Burstein, et al. Why a distance selection effect invalidates the Burstein, Haynes and Faber opacity test; J.I. Davies, et al. Statistical tests for opacity; E.A. Valentijn. Statistical measures of internal absorption in spiral galaxies; B. Cunow. The distribution of galactic inclinations; H. Jones, et al. Optical thickness of Sb-Scd galaxies from the Tully--Fisher relation; L. Gouguenhei, et al. Extinction in Sc galaxies at I band and in the 21cm line; R. Giovanelli. Extinction in the galaxy and in galactic discs; G. de Vaucouleurs. Properties of dust in backlit galaxies; W. Keel, R.E. White. The optical depth through NGC 3314A; P. James, P. Puxley. Dust extinction in highly inclined spirals; J. Knapen, et al. An optical search for dusty disks; M. Naslund, S. Joersater. Photometric asymmetry and dust opacity of spiral galaxies; Y.I. Byun. The scale-length test for dust in face-on spirals; J.E. Beckman, et al. Color gradients in spiral galaxies; S. Courteau, J. Holtzman. Constraints on the opacity of spiral disks from near-infrared observations; H.W. Rix. Arcsecond resolution of cold dust in spiral galaxies using optical and NIR imaging -- dust masses increase by nine hundred percent; D.L. Block, et al. Unveiling stars and dust in spiral galaxies;R.F. Pelletier, et al. Azimuthal distribution of dust in NGC 2997; P. Grosbol, et al. Internal extinction in spiral galaxies at optical and near infrared wavelengths; A. Boselli, G. Gavazzi. The opacity of spiral galaxy disks; N. Devereux. The far infrared/stellar energy balance; R. Evans. Opacity from luminosity functions; M. Trewhella, et al. Estimating disk opacities using infrared images; W. van Driel. DIRBE observations of galactic extinction; R.G. Arendt, et al. Kinematics of edge-on galaxies and the opacity of spiral disks; A. Bosma. Spectroscopic studies of the disk and halo of M82; C.D. McKeith, et al. Disk origin and evolution; J. Silk. The luminosity and opacity of galaxies; B. Wang. Dust obscuration in starburst galaxies; D. Calzetti. Polarimetry of dusty edge-on galaxies; R.D. Wolstencroft, S.M. Scarrott. HII regions and extinction in the spiral galaxy M83; S. Ryder, et al. A search for dust in galactic halos; D. Zaritsky. Concluding thoughts and reflections: dust in galaxies; H.A. Thronson Jr.

This text comprises selected lectures presented in the 9th course of the International School of Cosmic-Ray Astrophysics held at the Ettore Majorana Centre in Erice, Sicily, May 7-18, 1994. Devoted to problems and prospects in high-energy astrophysics and cosmology, the major areas explored are: gamma- ray, X-ray, and neutrino astronomies; cosmic rays; pulsars and supernova remnants; and cosmology, as well as cosmogony. Among the principal developments in gamma-ray astrophysics are those generated by the Compton Gamma Ray Observatory. Cosmic neutrinos at MeV energies, i.e. those from the Sun and from Supernova 1987a are discussed, as well as neutrino masses in astrophysics. The source composition of cosmic rays and extensive air shower experiments receive special attention. The early universe according to COBE data, and as viewed by theorists of cosmology, is reviewed.

In this symposium on Wolf-Rayet stars, binary aspects received ample attention, notably because of the recognition that many observations of spectral and photometric variability at all accessible wavelengths are related to colliding winds or other forms of wind interaction. The basic structure of the conference and its proceedings is: basic parameters and general properties of WR stars; state of the art model atmospheres for WR stars, anisotropic mass loss and disk formation of WR stars, properties of WR binaries; influence of stellar winds on mass transfer in hot massive binary evolution; dust formation near WR stars and other circumstellar phenomena; and hydrodynamics and high-energy physics of colliding winds in WR+O binaries and of WR winds interacting with compact objects. Within this framework 20 invited reviews, 38 invited oral contributions, and 76 poster papers were presented at the Symposium, entertaining 111 astronomers from 24 countries. These proceedings provide up-to-date information on all aspects of Wolf-Rayet atmospheres, binaries, and colliding winds.

These proceedings of a workshop held at Isle-aux-Coudres, Quebec, Canada in August 1993, provide an assessment of a fundamental subject in modern stellar astrophysics. Hot, luminous stars play a crucial role in the rapid recycling of matter in dense regions of the Universe. The most luminous objects generate the strongest outflows of material, which in turn have a profound impact on both the interstellar medium and the underlying stars themselves. However, recent observational and theoretical advances have shown that these outflows are highly unstable and inhomogeneous. These characteristics constitute a fundamental property of the outflows that can no longer be disregarded. This text provides an assessment of this important phenomenon from both an observational and a theoretical perspective. It includes up-to- date discussions of the observational diagnostics of time-dependent stellar-wind structure, the theoretical understanding of the origin of such structures, and its consequences for the process of mass loss via stellar winds.

Physics of Neutron Stars

The presentations of this NATO Advanced Study Institute centre around X-ray clusters of galaxies and their role in understanding the structure and evolution of the universe. Reminiscences of the beginning of the extra-solar X-ray astronomy some 30 years ago, of subsequent X-ray satellites which, among other discoveries, found galaxy clusters to be an important new class of intrinsically bright X-ray sources, and highlights from the most recent All Sky Survey by ROSAT serve as an introduction. The topics range from X-ray clusters and cluster environments to cluster masses and dynamics, cooling flows and chemical abundances, cluster lensing and the Sunyaev-Sel'dovich effect, cluster formation and evolution to large-scale structure in the universe and cosmological parameters. The reviews, introducing the various topics, generally conclude with presentations of current and future work and are frequently followed by shorter research notes pertaining to ongoing projects. More than 200 figures illustrate the discussions, more than 20 tables and many quotations in the text provide numerical data for almost 100 clusters of galaxies and give new estimates for the cosmological parameters. Together with a sample of equations, this text should constitute a useful collection of empirical and theoretical quantities and relations in extragalactic X-ray astronomy and cosmology.

In this Symposium, researchers specializing in pulsation, rotation, magnetic fields and stellar winds are brought together for the first time in order to broaden our understanding of O and B stars. Thanks to advances in digital spectroscopy, new types of pulsating B stars have been discovered. The pulsations can be understood in terms of the recent revision of metal opacities, but the effects of rapid rotation and magnetic fields need further study. Observations in the UV and X-ray regions demonstrate that many B and Be stars show other activity, besides pulsation which is not yet understood. The reason for the enhanced mass loss in B stars is a question which dominates the Symposium and which remains unanswered, although it is surely to be found in activity at or near the photosphere coupled with rotation. It is shown that the geometry of the circumstellar envelopes around Be stars is indeed a flattened disk as they can now be optically resolved. The variability of radiatively-driven winds from O and B stars are likely related to the rotation of the star. This underlines the central theme of the book: that the various phenomena seen in these stars cannot be studied in isolation.

Cosmical Aerodynamics - Why was it so Difficult?.- Shaping Planetary Nebulae.- Investigating the Kinematics of the Faint Giant Haloes of Planetary Nebulae.- Shock Modelling of Planetary Nebulae.- Imaging Polarimetry of Proto-Planetary Nebulae.- IRAS 17423-1755: a BQ[ ] Star with a Variable Velocity Outflow.- Spectroscopic Constraints on Outflows from BN-type Objects.- First Wavelet Analysis of Emission Line Variations in Wolf-Rayet Stars-Turbulence in Hot-Star Outflows.- Complex Structure Associated with the Wolf-Rayet Star WR147.- The Importance of Continuum Radiation for the Stellar Wind Hydrodynamics of Hot Stars.- Herbig Ae/Be Stars.- 3-D Radiative Line Transfer for Be Star Envelopes.- Radiatively Driven Winds Using Lagrangian Hydrodynamics.- Parametric Determination of the Inclination of Keplerian Circumstellar Discs from Spectropolarimetric Profiles of Scattered Lines.- Observational Evidence for Global Oscillations in Be Star Disks.- Coupled Stellar Jet/Molecular Outflow Models.- Modelling Jet-Driven Molecular Outflows.- Jets.- A Simulation of a Jet with the Hiccups.- Interactions Between Molecular Outflows and Optical Jets.- Proper Motion Measurements in the HH 46/47 Outflow.- The Serpens Radio Jet: Evidence of Precession or Nutation.- Fragmentation and Heating of Streamers in Orion.- Highly Supersonic Molecular Flows in Wind-Clump Boundary Layers.- High Density Tracers in Outflow Regions: NH3 vs. CS.- Modelling the Constancy of X.- Gas-Grain Interaction in the Low Mass Star-Forming Region B335.- The Structure and Dynamics of M17SW.- The Hydrodynamics of Bipolar Explosions.- Shock-Heated Gas in the Outbursts of Classical Novae.- The Crab Nebula Revisited.- Pulsar Magnetospheres: Classical and Quasi-Classical Descriptions.- The Global Structure of the Insterstellar Medium.- A Power Spectrum Description of Galactic Neutral Hydrogen.- A Statistical Description of Astrophysical Turbulence.- Rosat Wide Field Camera Data and the Temperature of the Interstellar Medium.- Hierarchial Galactic Dynamo and Seed Magnetic Field Problem.- Cosmic Ray Diffusion at Energies of 1 MeV to 105 GeV.- Alfvenic Waves and Alignment of Large Grains.- An Interstellar Thermostat: Gas Temperature Regulated by Grain Charge.- Recent Optical Observations of Circumstellar and Interstellar Phenomena.- Internal Motions of HII Regions and Giant HII Regions.- High-Speed Flows in the Vicinity of the Trapezium Stars.- The Orion Nebula: Structure, Dynamics, and Population.- An Evolutionary Model for the Wolf Rayet Nebula NGC 2539.- Supersonic Turbulence in Giant Extragalactic HII Regions.- The Dynamics of the Ring Nebula Surrounding the LBV Candidate He 3-519.- Turbulent Mixing in Wind-Blown HII Regions.- Shock Wave Structure in the Cygnus Loop.- Catastrophic Cooling Diagnostics.- Star Formation in Shocked Layers.- Binary and Multiple Star Formation.- Galactic Fountains.- The Solution Topology of Galactic Winds.- Galactic Scale Gas Flows in Colliding Galaxies: 3-Dimensional, N-Body/Hydrodynamics Experiments.- Gas Flow in a Two Component Galactic Disk.- How Faithful Are N-Body Simulations of Disc Galaxies? - Artificial Suppression of Gaseous Dynamical Instabilities.- Long-Lived Spiral Structure in N-Body Simulations: Work in Progress.- The Use of Gravitational Microlensing to Scan the Structure of BAL QSOs.- Anomalous Component Motion in the MAS Double Radio Source 0646+600.- Effects of Dense Medium Surrounding Galactic-Sized Radio Sources.- 8.4 Ghz Vla Observations of the CfA Seyfert Sample.- Relativistic Jet Simulations.- Active Galactic Nuclei Flow Velocities and the Highest Energy Cosmic Rays.- Hidden Broad Line Regions and Anisotropy in AGN.- The Starburst Galaxy NGC1808: Another M82?.- List of Forthcoming Papers.- The 'KLUWER' LaTeX Style File.

The nonlinear theory of oscillating systems has introduced new aspects to the study of variable stars. Beyond the comparison of linear periods and the estimate of stability, the appearance and disappearance of possible models can be studied in detail. While nonlinearity in stellar pulsations is not a very complicated concept, it generally requires extensive and sometimes sophisticated numerical studies. The development of appropriate computational tools has allowed us to apply the nonlinear theory to real phenomena in variable stars. The International Astronomical Union Colloquium No. 134 presents a review of the new frontiers of variable star studies, one which should encourage further development of this field.

Planetary nebulae are a keystone for the understanding of the evolution of stars, for deep insights into the physical processes prevailing in highly excited dilute nebulae, and for the chemical evolution in galaxies. These objects, displaying an intriguing morphology, have a "short" lifetime of a few tens of thousands of years, and have become one of the best studied classes of celestial sources. However, despite large and successful efforts from both the observational and theoretical side, planetary nebulae still keep some of their secrets (like the widely unknown distances) and will undoubtedly also be objects of thorough investigations in the years to come.

This book presents a complete overview of what we know, and would like to know, about the evolution and structure of massive stars. The spectra of early-type stars are produced by elaborate model atmospheres enveloping the internal structure. The book should be of value to researchers into the evolution, structure and atmospheres of massive stars. The book is also appropriate for astrophysics courses at university level, where it can be used to get acquainted with the most recent observational data, modelling of the internal and atmospheric structure, and the refined development of single and binary evolution scenarios of massive stars.

The recent meeting of the world's white dwarf specialists was held in Leicester, in July 1992, reporting on the wealth of astronomical data that has been made available from a new generation of space-based observatories and recent theoretical advances which are essential for interpretation of the results. Astronomers now have access to previously unavailable spectral ranges and dramatically improved sensitivity in those wavebands already explored. Results from the ROSAT all-sky survey, Hubble Space Telescope, Hopkins Ultraviolet Telescope and the Colorado Rocket-borne Spectrometer shed new light on the composition of white dwarfs and their evolution. Considerable progress has been made in understanding the internal structure of white dwarfs with asteroseismological techniques which are outlined in several papers. New observational results, which utilize this theoretical work are also presented. This text is suitable for graduate students and postdoctoral researchers interested in isolated white dwarfs or binary systems containing a white dwarf component.

This book contains the proceedings of the first large IAU Symposium dedicated to the bulges of spiral galaxies. Detailed attention is paid to the bulge of the Milky Way, one of the major building blocks of this system. Topics include the definition of the bulge in our Galaxy and its relation to the so-called spheroid. Discussions are presented regarding the stars contained in this bulge, their astrophysical properties, their motions and the metallicity variations which appear to be present. The possible existence of a bar in the bulge and its origin and future are also examined. The same topics are discussed in less detail for the bulges of other galaxies.

In July 1992, over 300 astronomers attended the Third Tetons Summer School on the subject of "The Environment and Evolution of Galaxies". This book presents 28 papers based on invited review talks and a panel discussion on "The Nature of High Redshift Objects". The major themes include: the interstellar and intergalactic medium, galaxy formation and evolution, cooling flows, quasars and radiation backgrounds, and interactions between galaxies/AGNs and their environment. Recent advances with the ROSAT, COBE and Hubble Space Telescope are discussed, together with current theoretical developments. The tutorial nature of the papers should make this book a useful supplement for professional astonomers, graduate students, and senior undergraduates. As with previous Tetons conferences, this book provides both the current state of observational and theoretical research and material complementary to courses in extragalactic and interstellar astrophysics.

More than two centuries have elapsed since the story of interacting binary stars began with the rediscovery of the variability of Algol by John Goodricke and the interpretation he proposed for explaining the regular periodic brightness variations which he found. Over this long span of time our knowledge about these systems has been growing, and we have now reached a fairly good understanding of the structure and behaviour of this interesting group of objects. This book contains a timely summary of our present knowledge of interacting binary stars. The chapters have been written by distinguished scientists who have done relevant research in the field of interacting binary stars.

The motivation for the workshop on which this book is based was the discovery in recent years of a large number of binary and millisecond radio pulsars, in the galactic disk as well as in globular star clusters, the oldest stellar systems in our galaxy. These discoveries have revolutionized our thinking on many aspects concerning the interior structure and evolution of neutron stars, and have revived the interest in the study of neutron star physics in general. In this book some three dozen of the world's experts in the field of radio pulsars, X-ray binaries, stellar evolution, neutron star interiors and stellar dynamics review the latest observational discoveries as well as the current theoretical thinking on the formation and physics of binary X-ray sources and of the binary and milli-second pulsars. These include discoveries such as that of the elevent millisecond pulsars in the globular cluster 47 Tucanae, the relativistic effects in the new double neturon star system PSR 1534+12 and spectacular results from Germany's ROSAT X-Ray Observatory.