Pulsars are stars, a significant part of whose observed energy output is not continuous but is emitted as distinct flashes or pulses of electromagnetic radiation. Many pulsars also emit some radiation weakly and constantly, forming a background for the more intensive pulses. Three distinct classes of pulsars are presently known to astronomers, according to the source of energy that powers the radiation: Rotation-powered pulsars, where the loss of rotational energy of the star powers the radiation X-ray pulsars, where the gravitational potential energy of accreted matter is the energy source, and Magnetars, where the decay of an extremely strong magnetic field powers the radiation. Although all three classes of objects are neutron stars, their observable behaviour and the underlying physics are quite different. There are, however, connections. For example, X-ray pulsars are probably old rotation-powered pulsars that have already lost most of their energy, and have only become visible again after their binary companions expanded and began transferring matter on to the neutron star. The process of accretion can in turn transfer enough angular momentum to the neutron star to "recycle" it as a rotation-powered millisecond pulsar.

It is generally believed that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the cosmic microwave background enough to form the large-scale structures that we see in the universe today. For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. Dark matter has important consequences for the evolution of the Universe and the structure within it. According to general relativity, the Universe must conform to one of three possible types: open, flat, or closed. The total amount of mass and energy in the universe determines which of the three possibilities applies to the Universe. In the case of an open Universe, the total mass and energy density (denoted by the Greek letter Omega) is less than unity. If the Universe is closed, Omega is greater than unity. For the case where Omega is exactly equal to one the Universe is "flat". This book details leading-edge research from around the globe.

The contentious history of the idea of the black hole-the most fascinating and bizarre celestial object in the heavens For more than half a century, physicists and astronomers engaged in heated dispute over the possibility of black holes in the universe. The weirdly alien notion of a space-time abyss from which nothing escapes-not even light-seemed to confound all logic. This engrossing book tells the story of the fierce black hole debates and the contributions of Einstein and Hawking and other leading thinkers who completely altered our view of the universe. Renowned science writer Marcia Bartusiak shows how the black hole helped revive Einstein's greatest achievement, the general theory of relativity, after decades during which it had been pushed into the shadows. Not until astronomers discovered such surprising new phenomena as neutron stars and black holes did the once-sedate universe transform into an Einsteinian cosmos, filled with sources of titanic energy that can be understood only in the light of relativity. This book celebrates the hundredth anniversary of general relativity, uncovers how the black hole really got its name, and recounts the scientists' frustrating, exhilarating, and at times humorous battles over the acceptance of one of history's most dazzling ideas.

Clusters of Galaxies & Extragalactic Radio Sources

'It is strongly biased towards the author's speciality of galaxy morphology, and particularly to bars and rings. To be fair, these are often given fairly short shrift in other textbooks, so this is a useful source of detail on such topics from an expert. In addition, references to original technical papers are given throughout which makes the book a handy introduction to the literature (which students may well find useful).'The Observatory MagazineThe main goal of the book is to introduce the reader to the world of spiral galaxies, how spirals were discovered, what they represent from a physical point of view, and what people have learned about the universe and the nature of galaxies in general from the study of spirals. Topics include early discoveries of nebulae, the island universe concept, the structure of spirals as seen both visually with telescopes and in images obtained with different filters, the role of spirals in the discovery of interstellar dust and dark matter, the different kinds of spiral galaxies and the importance of bars and rings, how different non-spiral galaxy types such as elliptical galaxies and S0 galaxies connect to spirals, and how spirals have contributed to our understanding of star formation and evolution, galaxy formation and evolution, the cosmological distance scale, and the universal expansion. The Milky Way as a spiral galaxy is also discussed.The book is profusely illustrated and not only a discourse on the spirals, but is also a personal reminiscence based on the author's studies of spiral galaxies over the past 45 years.

Stars are mostly found in binary and multiple systems, with at least 50% of all solar-like stars having companions; this fraction approaches 100% for the most massive stars. A large proportion of these systems interact and alter the structure and evolution of their components, leading to exotic objects such as Algol variables, blue stragglers and other chemically peculiar stars, but also to phenomena such as non-spherical planetary nebulae, supernovae and gamma-ray bursts. While it is understood that binaries play a critical role in the Initial Mass Function, the interactions among binary systems significantly affect the dynamical evolution of stellar clusters and galaxies. This interdisciplinary volume presents results from state-of-the-art models and observations aimed at studying the impact of binaries on stellar evolution in resolved and unresolved populations. Serving as a bridge between observational and theoretical astronomy, it is a comprehensive review for researchers and advanced students of astrophysics.

What force do the Big Bang, the expansion of the Universe, dark matter and dark energy, black holes, and gravitational waves all have in common? This book uncovers gravity as a key to understanding these fascinating phenomena that have so captivated public interest in recent years. Readers will discover the latest findings on how this familiar force in our everyday lives powers the most colossal changes in the Universe. Written by the widely recognized French public scientist and leading astrophysicist Pierre Binetruy, the book also explains the recent experimental confirmation of the existence of gravitational waves.

This book provides an accessible introduction to the fascinating and topical subject of black holes. It bridges the gap between popular non-mathematical expositions and advanced research texts, using simple undergraduate level calculations and the most basic knowledge of relativity to explain current research. This means the theory can be understood by a wide audience of physicists, including those who are not necessarily interested in learning higher-level mathematical techniques.The third edition links more of the current research trends to fundamental aspects of the physics of black holes. Additionally: This new edition introduces a chapter dedicated to a selection of recent results. Existing chapters have been updated and new explanatory material has been added to aid in the understanding of the physics.This book is recommended reading for advanced undergraduate students and first-year postgraduates who will find it a useful stepping-stone to the advanced literature.

Our understanding of the formation of stars and planetary systems has changed greatly since the first edition of this book was published. This new edition has been thoroughly updated, and now includes material on molecular clouds, binaries, star clusters and the stellar initial mass function (IMF), disk evolution and planet formation. This book provides a comprehensive picture of the formation of stars and planetary systems, from their beginnings in cold clouds of molecular gas to their emergence as new suns with planet-forming disks. At each stage gravity induces an inward accretion of mass, and this is a central theme for the book. The author brings together current observations, rigorous treatments of the relevant astrophysics, and 150 illustrations, to clarify the sequence of events in star and planet formation. It is a comprehensive account of the underlying physical processes of accretion for graduate students and researchers.

IAU Symposium 356 summarises the most recent results in the field of active galaxies and active galactic nuclei (AGN). These are some of the most luminous sources in the Universe, also the most distant ones that we can observe, so they are very important for understanding the early Universe and its evolution through cosmic time. This volume gives an overview of the current status in the field of active galaxies including: AGN multiwavelength observations; different AGN types and their properties; AGN variability; active supermassive black holes and properties of galaxies in which they reside; triggering, feedback and shutting off AGN activity; relativistic jets and environments of active galaxies; and AGN evolution. IAU S356 was the third IAU symposium organised in Africa in the past 100 years since the IAU was established, and the first one organised in Ethiopia, highlighting current developments in astronomical research in Africa.

Galaxies are known as the building blocks of the universe, but arriving at this understanding has been a thousand-year odyssey. This journey is told through the lens of the evolving use of images as investigative tools. Initial chapters explore how early insights developed in line with new methods of scientific imaging, particularly photography. The volume then explores the impact of optical, radio and x-ray imaging techniques. The final part of the story discusses the importance of atlases of galaxies; how astronomers organised images in ways that educated, promoted ideas and pushed for new knowledge. Images that created confusion as well as advanced knowledge are included to demonstrate the challenges faced by astronomers and the long road to understanding galaxies. By examining developments in imaging, this text places the study of galaxies in its broader historical context, contributing to both astronomy and the history of science.

**** The perfect Christmas gift for astrology lovers **** Nobody's future is written in the stars, but we can use the stars to help write our future. For thousands of years people have looked to the night sky for the answers to life's problems. Today's practice is a far cry from newspaper horoscopes and fortune-telling, but instead uses the ancient wisdom of astrology to help us better understand our choices and ourselves. It's not about prescriptive descriptions of personality and fate, but about putting the individual at the centre of decision making. In The Signs, Carolyne Faulkner describes with warmth and humour the qualities associated with each star sign - the good and the bad - and explains how you can use your birth chart (a map of the night sky at the time you were born) to make smarter choices, avoid triggers to stress and forge stronger relationships. This is a clear and simple guide to using the stars to take control of every aspect of your life.

This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies.

"The First Galaxies in the Universe" starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more. Provides a comprehensive introduction to this exciting frontier in astrophysics Begins from first principles Covers advanced topics such as the first stars and 21-cm cosmology Prepares students for research using the next generation of large telescopes Discusses many open questions to be explored in the coming decade

In the past two decades, astronomers have discovered an abundance of young stars within ~100 parsecs of the Sun. Thanks to their proximity, these stars provide unique opportunities to investigate early stellar evolution, and they offer readily accessible targets for direct imaging and other measurements of dusty circumstellar disks, newly-formed brown dwarfs and, especially, young exoplanets. This volume highlights major advances in our understanding of the early evolution of stars and planetary systems flowing from investigations of nearby young stars. It features contributions that approach such studies from a wide variety of directions: the identification, ages, and origins of local young moving groups; early stellar evolution from theoretical and observational perspectives; and aspects of nascent or recently formed exoplanet systems. This up-to-date reference on local groups of young stars and their ability to aid the widening search for exoplanets addresses advanced students and researchers in the field.

In less than a century, the accepted picture of the universe transformed from a stagnant place, composed entirely of our own Milky Way galaxy, to a realm inhabited by billions of individual galaxies, hurtling away from one another. We must thank, in part, Edwin P. Hubble, one of the greatest observational astronomers of the 20th century. In 1936, Hubble described his principal observations and conclusions in "The Realm of the Nebulae," which quickly became a classic work. Two new introductory pieces, by Robert P. Kirshner and Sean M. Carroll, explain advances since Hubble's time and his work's foundational importance.
"Meaningful, historically accurate, and thoroughly delightful reading."--Gail O. Clark, "Astronomy"

Galaxies are the basic unit of cosmology. The study of galaxy formation is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning. The physics of galaxy formation is complicated because it deals with the dynamics of stars, thermodynamics of gas and energy production of stars. A black hole is a massive object whose gravitational field is so intense that it prevents any form of matter or radiation to escape. It is hypothesised that the most massive galaxies in the universe -- "elliptical galaxies" -- grow simultaneously with the supermassive black holes at their centres, giving us much stronger evidence that black holes control galaxy formation. This book reviews new evidence in the field.

It is generally believed that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the cosmic microwave background enough to form the large-scale structures that we see in the universe today. For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. Dark matter has important consequences for the evolution of the universe and the structure within it. According to general relativity, the universe must conform to one of three possible types: open, flat, or closed. The total amount of mass and energy in the universe determines which of the three possibilities applies to the universe. In the case of an open universe, the total mass and energy density (denoted by the Greek letter U) is less than unity. If the universe is closed, U is greater than unity. For the case where U is exactly equal to one the universe is "flat". This new book details leading-edge research from around the globe.

Designed with the beginner in mind and useful to anyone interested in astronomy. Star Maps for Beginners is the classic guide to viewing and understanding the heavens. Its superb maps -- drawn in the shape of two crossed ellipses -- provide the reader with a unique perspective on the sky and have been widely acknowledged as the easiest system yet devised for locating any constellation at any time of the year.

Now revised for the 1990s, with updated planet charts and a new section on spotting meteor showers. Star Maps for Beginners includes:

12 complete maps -- one for each month -- showing the positions of the constellations viewed from every direction
a synoptic table that shows how to choose the proper map for use at any time special tables that give approximate positions of the planets for the years 1992 through 1997
the most up-to-date overview of the solar system available today the latest facts about each of the planets -- orbit, size, atmosphere, internal structure, climate, and terrain
a full chapter on the history and development of the constellations, and the ancient legends and mythological lore surrounding them
a special section on meteors -- how they originate and when and where to spot them.

Initially published in 1942 and now celebrating its 50th anniversary, Star Maps for Beginners has sold more than 450,000 copies.

Donald D. Clayton's Principles of Stellar Evolution and Nucleosynthesis remains the standard work on the subject, a popular textbook for students in astronomy and astrophysics and a rich sourcebook for researchers. The basic principles of physics as they apply to the origin and evolution of stars and physical processes of the stellar interior are thoroughly and systematically set out. Clayton's new preface, which includes commentary and selected references to the recent literature, reviews the most important research carried out since the book's original publication in 1968.

Dwarf galaxies are important tools for understanding structure formation and galaxy evolution across cosmic time. These low-mass systems allow us to gain a detailed understanding of stellar, chemical, and dynamical properties in the nearby universe; they also provide a unique window into the complex physics of the early universe. The Proceedings of IAU Symposium 344 present our current understanding of dwarf galaxies, with sections dedicated to: Local Group dwarf galaxies; the interstellar medium and star formation in dwarfs; metallicity, massive stars, and chemical evolution; the dwarf galaxy-environment connection; low-mass galaxies at high redshift; and dwarfs as cosmological probes. Broad overviews from leaders in the field, detailed presentation of cutting-edge results, and short summaries of a wide range of work are included for each of these topics, suitable for both experts and newcomers to the field.