At close inspection every galaxy appears to have its own individuality.A galaxy can be warped, lop-sided, doubly-nucleated, boxy or disky, ... in its own specific, peculiar way. Hence, for a complete description, galaxy taxonomy may ask for finer and finer classification schemes. However, for some applications it may be more fruitful to let details aside and focus on some global properties of galaxies. One is then seeking to measure just a few quantities for each galaxy, a minimum set of globalobservables that yet captures some essential aspect of these objects. One very successful example of this approach is offered by the scaling rela tions of galaxies, the subject of the international workshop held at ESO head quarters in Garching on November 19-21, 1996. Discovered in the late 1970's, the Tully-Fisher relation for the spirals and the Faber-Jackson relation, or its more recent version the Fundamental Plane, for ellipticals have now become flourishing fields of astronomical research in their own right, as well as being widely used tools for a broad range of astronomical investigations. The work shop was designed to address three key issues on galaxy scaling relations, i.e., their Origins, Evolution, and Applications in astronomy. The Origins of galaxy scaling relations still escape our full understanding.

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.

Galaxies, along with their underlying dark matter halos, constitute the building blocks of structure in the Universe. Of all fundamental forces, gravity is the dominant one that drives the evolution of structures from small density seeds at early times to the galaxies we see today. The interactions among myriads of stars, or dark matter particles, in a gravitating structure produce a system with fascinating connotations to thermodynamics, with some analogies and some fundamental differences. Ignacio Ferreras presents a concise introduction to extragalactic astrophysics, with emphasis on stellar dynamics, and the growth of density fluctuations in an expanding Universe. Additional chapters are devoted to smaller systems (stellar clusters) and larger ones (galaxy clusters). Fundamentals of Galaxy Dynamics, Formation and Evolution is written for advanced undergraduates and beginning postgraduate students, providing a useful tool to get up to speed in a starting research career. Some of the derivations for the most important results are presented in detail to enable students appreciate the beauty of maths as a tool to understand the workings of galaxies. Each chapter includes a set of problems to help the student advance with the material.

A review of the current observational knowledge and understanding of the cosmic X-ray background.

This book consists of invited reviews on Galactic Bulges written by experts in the field. A central point of the book is that, while in the standard picture of galaxy formation a significant amount of the baryonic mass is expected to reside in classical bulges, the question what is the fraction of galaxies with no classical bulges in the local Universe has remained open. The most spectacular example of a galaxy with no significant classical bulge is the Milky Way. The reviews of this book attempt to clarify the role of the various types of bulges during the mass build-up of galaxies, based on morphology, kinematics and stellar populations and connecting their properties at low and high redshifts. The observed properties are compared with the predictions of the theoretical models, accounting for the many physical processes leading to the central mass concentration and their destruction in galaxies. This book serves as an entry point for PhD students and non-specialists and as a reference work for researchers in the field.

Chaisson addresses some of the most basic issues we can contemplate: the origin of matter and the origin of life, and the ways matter, life, and radiation interact and change with time. He designs for us an expansive yet intricate model depicting the origin and evolution of all material structures.

Based on a Simons Symposium held in 2018, the proceedings in this volume focus on the theoretical, numerical, and observational quest for dark matter in the universe. Present ground-based and satellite searches have so far severely constrained the long-proposed theoretical models for dark matter. Nevertheless, there is continuously growing astrophysical and cosmological evidence for its existence. To address present and future developments in the field, novel ideas, theories, and approaches are called for. The symposium gathered together a new generation of experts pursuing innovative, more complex theories of dark matter than previously considered.This is being done hand in hand with experts in numerical astrophysical simulations and observational techniques—all paramount for deciphering the nature of dark matter. The proceedings volume provides coverage of the most advanced stage of understanding dark matter in various new frameworks. The collection will be useful for graduate students, postdocs, and investigators interested in cutting-edge research on one of the biggest mysteries of our universe.