This is the first comprehensive treatment of active galactic nuclei--the cosmic powerhouses at the core of many distant galaxies. The term "active galactic nuclei" refers to quasars, radio galaxies, Seyfert galaxies, blazars, and related objects, all of which are believed to share a similar central engine--a supermassive black hole many times the mass of the Sun. Astrophysicists have studied these phenomena for the past several decades and have begun to develop a consensus about many of their properties and internal mechanisms. Julian Krolik, one of the world's leading authorities on the subject, sums up leading ideas from across the entire range of research, making this book an invaluable resource for astronomers, physicists interested in applications of the theory of gravitation, and graduate students.

Krolik begins by addressing basic questions about active galactic nuclei: What are they? How can they be found? How do they evolve? He assesses the evidence for massive black holes and considers how they generate power by accretion. He discusses X-ray and g-ray emission, radio emission and jets, emission and absorption lines, anisotropic appearance, and the relationship between an active nucleus and its host galaxy. He explores the mysteries of what ignites, fuels, and extinguishes active galactic nuclei, and concludes with a general review of where the field now stands. The book is unique in paying careful attention to relevant physics as well as astronomy, reflecting in part the importance of general relativity to understanding active galactic nuclei. Clear, authoritative, and detailed, this is crucial reading for anyone interested in one of the most dynamic areas of astrophysics today.

I have spent many wonderful nights observing at a variety of places around the world, but many of my fondest memories come from those made at the Custer Observatory in Southold on Long Island, where I grew up. I was only perhaps a dozen years old when I started out, and now more than three decades later I have logged millions of miles on the various telescopes there. Some of the best memories are of observing and discussing astronomical topics with the many really terrific people who make up Custer. It truly holds a special place in my heart. Star clusters were always among my favorite objects to observe and discuss there. This book is the result of the exposure to these objects, many of which I observed for the first time at Custer. The Custer Institute Observatory was founded in the 1920s by local resident Charles W. Elmer of Perkin-Elmer Corp. fame. The original crew met at his house in Cedar Beach a few miles down the road from the institute. In the 1930s the group built an observatory complete with Mr. Elmer's donated 5" Alvan Clark refractor. Later the observatory expanded to include a 6" Clark refractor and other even larger instruments.

ASTRONOMERSa (TM) OBSERVING GUIDES provide up-to-date information for amateur astronomers who want to know all about what it is they are observing. This is the basis of the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments.

Star Clusters and How to Observe Them is a mine of information for all levels of amateur observers, from beginners to experienced observers. It begins with a detailed yet easily assimilated description of star clusters, how they were formed as our Milky Way galaxy evolved, and how they are classified. The latest research has revealed a vast amount of fascinating information about the clusters, along with some spectacular photographs.

Modern commercially-made telescopes enable amateur astronomers to see a surprising amount of detail, and to record a" using CCD cameras, video, webcams or even film a" some remarkably beautiful and detailed images. There is detailed information on using refractors, reflectors, SCTa (TM)s (like Meade and Celestron) and computer-controlled telescopes

The book includes an Observing List cataloguing star clusters to be observed or imaged using a variety of different instruments, all of them available commercially to amateur astronomers.

Written specially for practical amateur astronomers who not only want to observe, but want to know and understand the details of exactly what they are looking at.

Presents an up-to-date detailed description of the objects, their physics and their evolution (part one); and then (part two) to consider how to observe and record them successfully.

Delivers a wealth of information for all levels of amateur observers, from the beginner to the experienced; it is equally fascinating for practical astronomers, and also for those who simply want to find out more about these unusual star systems.

This text presents numerous illustrations of the observed variability of cataclysmic variable stars. It provides a clear explanation and thorough up-to-date overview of this phenomena at a level accessible to the advanced amateur or undergraduate student.

Spacecraft have explored the interplanetary medium between the orbits of Mercury and Pluto, revealing the exotic and beautiful nature of the environment of our planet and sun. This book summarizes the principle results of these historic expeditions. Magnetohydrodynamics provides the framework for interpreting the observations, and the observations have greatly enriched the subject of magnetohydrodynamics. Numerous figures in the book illustrate the essential observations and fundamental concepts. Simple equations summarize basic physical and phenomenological relations observed in the interplanetary medium. Fundamental objects observed in the interplanetary medium include various types of MHD shocks, tangenital and rotational discontinuities, and force-free field configurations. Fundamental processes observed in the interplanetary medium include the interaction among shocks (which can be classified using catastrophic theory), the formation of merged interaction region regions associated with various types of flows, the destruction of flows, the growth of the Kelvin-Helmholtz instability and formation of a heliospheric vortex street, the development of multifractal fluctuations on various scales, and the evolution of multifractal intermittent turbulence. These physical objects and processes are of fundamental interest in themselves. The knowledge about them derived from interplanetary investigations has applications to magnetospheric physics, solar physics, cosmic ray physics and astrophysics. The book contains an extensive set of reference that gives the readers access to the detailed results in the literature.

The world of science has been transformed. Where once astronomers sat at the controls of giant telescopes in remote locations, praying for clear skies, now they have no need to budge from their desks, as data arrives in their inbox. And what they receive is overwhelming; projects now being built provide more data in a few nights than in the whole of humanity's history of observing the Universe. It's not just astronomy either - dealing with this deluge of data is the major challenge for scientists at CERN, and for biologists who use automated cameras to spy on animals in their natural habitats. Artificial intelligence is one part of the solution - but will it spell the end of human involvement in scientific discovery? No, argues Chris Lintott. We humans still have unique capabilities to bring to bear - our curiosity, our capacity for wonder, and, most importantly, our capacity for surprise. It seems that humans and computers working together do better than computers can on their own. But with so much scientific data, you need a lot of scientists - a crowd, in fact. Lintott found such a crowd in the Zooniverse, the web-based project that allows hundreds of thousands of enthusiastic volunteers to contribute to science. In this book, Lintott describes the exciting discoveries that people all over the world have made, from galaxies to pulsars, exoplanets to moons, and from penguin behaviour to old ship's logs. This approach builds on a long history of so-called 'citizen science', given new power by fast internet and distributed data. Discovery is no longer the remit only of scientists in specialist labs or academics in ivory towers. It's something we can all take part in. As Lintott shows, it's a wonderful way to engage with science, yielding new insights daily. You, too, can help explore the Universe in your lunch hour.

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.

Albert Einstein is often viewed as the icon of genius, and his theories are admired for their beauty and correctness. Yet the final judge of any theory is the rigorous test of experiment, not the fame of its inventor or the allure of its mathematics. For decades, general relativity has passed test after test with flying colors, including some remarkable new tests using the recently detected gravitational waves. Still, there are reasons for doubt. Einstein's theory of gravity, as beautiful as it is, seems to be in direct contradiction with another theory he helped create: quantum mechanics. Until recently, this was considered to be a purely academic affair. But as more and more data pour in from the most distant corners of the universe, hinting at bizarre stuff called "dark energy" and "dark matter," some scientists have begun to explore the possibility that Einstein's theory may not provide a complete picture of the cosmos. This book chronicles the latest adventures of scientists as they put Einstein's theory to the test in ever more precise and astonishing ways, and in ever more extreme situations, when gravity is unfathomably intense and rapidly churning. From the explosions of neutron stars and the collisions of black holes to the modern scientific process as a means to seek truth and understanding in the cosmos, this book takes the reader on a journey of learning and discovery that has been 100 years in the making.

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.

Written in an informal and engaging style, this volume traces the discoveries that led to our understanding of the size and structure of the Milky Way, and the conclusive evidence for a massive black hole at its center. Robert H. Sanders, an astronomer who witnessed many of these developments, describes how we parted the veil of interstellar dust to probe the strange phenomena within. We now know that the most luminous objects in the Universe - quasars and radio galaxies - are powered by massive black holes at their hearts. But how did black holes emerge from being a mathematical peculiarity, a theoretical consequence of Einstein's theory of gravity, to become part of the modern paradigm that explains active galactic nuclei and galaxy evolution in normal galaxies such as the Milky Way? This story, aimed at non-specialist readers and students and historians of astronomy, will both inform and entertain.

A leading astronomer takes readers behind the scenes of the thrilling science of stellar archaeology Astronomers study the oldest observable stars in the universe in much the same way archaeologists study ancient artifacts on Earth. Anna Frebel takes readers into the far-flung depths of space and time to provide a gripping firsthand account of the cutting-edge science of stellar archaeology. Weaving the latest findings in astronomy with her own compelling insights as one of the world's leading researchers in the field, she explains how sections of the night sky are "excavated" in the hunt for these extremely rare, 13-billion-year-old relic stars and how this astonishing quest is revealing tantalizing new details about the origins and evolution of the cosmos. Along the way, Frebel recounts her own stories of discovery, offering an insider's perspective on this exciting frontier of science.

Clusters of Galaxies & Extragalactic Radio Sources

Amateur astronomers are always on the lookout for new observing challenges. This exciting book retraces the steps of the greatest visual observer and celestial explorer who ever lived. This is a practical guide to locating and viewing the most impressive of Herschel 's star clusters, nebulae and galaxies, cataloging more than 600 of the brightest objects, and offering detailed descriptions and images of 150 to 200 of the best.

The search for life in the universe, once the stuff of science fiction, is now a robust worldwide research program with a well-defined roadmap probing both scientific and societal issues. This volume examines the humanistic aspects of astrobiology, systematically discussing the approaches, critical issues, and implications of discovering life beyond Earth. What do the concepts of life and intelligence, culture and civilization, technology and communication mean in a cosmic context? What are the theological and philosophical implications if we find life - and if we do not? Steven J. Dick argues that given recent scientific findings, the discovery of life in some form beyond Earth is likely and so we need to study the possible impacts of such a discovery and formulate policies to deal with them. The remarkable and often surprising results are presented here in a form accessible to disciplines across the sciences, social sciences, and humanities.

Studies of stars and stellar populations, and the discovery and characterization of exoplanets, are being revolutionized by new satellite and telescope observations of unprecedented quality and scope. Some of the most significant advances have been in the field of asteroseismology, the study of stars by observation of their oscillations. Asteroseismic Data Analysis gives a comprehensive technical introduction to this discipline. This book not only helps students and researchers learn about asteroseismology; it also serves as an essential instruction manual for those entering the field. The book presents readers with the foundational techniques used in the analysis and interpretation of asteroseismic data on cool stars that show solar-like oscillations. The techniques have been refined, and in some cases developed, to analyze asteroseismic data collected by the NASA Kepler mission. Topics range from the analysis of time-series observations to extract seismic data for stars to the use of those data to determine global and internal properties of the stars. Reading lists and problem sets are provided, and data necessary for the problem sets are available online. The first book to describe in detail the different techniques used to analyze the data on stellar oscillations, Asteroseismic Data Analysis offers an invaluable window into the hearts of stars. * Introduces the asteroseismic study of stars and the theory of stellar oscillations* Describes the analysis of observational (time-domain) data* Examines how seismic parameters are extracted from observations* Explores how stellar properties are determined from seismic data* Looks at the "inverse problem," where frequencies are used to infer internal structures of stars

'A book that will make the night sky your lifelong passion. An invitation to immerse yourself in the nature around you and the universe beyond.' - Professor Brian Cox The Secret World of Stargazing is the ultimate astronomy book to set you on your epic journey around the cosmos - it's a simple guide to the skies and makes stargazing fun, easy and enjoyable for all - absolutely no equipment is required! Adrian West, AKA the internet sensation VirtualAstro, will take you through the seasons, showing you exactly what you can spot in the sky throughout the year, whether you're in your back garden or sitting on an exotic beach somewhere! While you're learning how to spot constellations, meteors and comets, you will be switching off your busy mind, sitting still in nature and paying attention to the small details that make up the big picture of life. You'll finish reading this beautiful book and come away with a sense of grounding, connection, knowledge and a whole new appreciation of the sky above and the world outside your own - it will soothe your soul. 'An excellent, readable, bright guide to the night sky.' - Dara O'Briain 'A superb introduction to astronomy.' - Chris Packham

With the development of nuclear physics the theory of the stellar interior entered a new phase. Many new investigations have been conducted and the results published in a variety of specialized media. This book brings these results together in a single volume and summarizes the present status of the theory of stellar evolution. Originally published in 1958. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

The sum of centuries of speculation on the probable course of evolution in stars is discussed by one of the world's greatest astronomers, with a full report of his own conclusions, How long stars exist, the relation of their luminosity to their mass, the evolution of a star in relation to the main sequence, the significance of rotation, are among the crucial problems considered. While the discussion is replete with technical detail, sufficient background is included to enable the amateur astronomer or anyone with scientific training to follow the argument. Originally published in 1950. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Take a trip to outer space with this weird and wonderful guide to our universe, the perfect gift for both young and old Vargic's beautifully innovative designs will help to explain all of the bizarre and fascinating aspects of the cosmos; from the history of the universe to what makes up our solar system and even how human life fits into the wider picture. Be taken on an unforgettable journey through space with chapters on . . . * Exploring the Cosmos * The Night Sky * Maps of the Inner Solar System * Timeline of the Universe * Cosmologies throughout History * Journey Into Outer Space * Scale of the Universe This is a book that celebrates the scale and spectacle of the universe on every page, and one which you'll treasure forever. _______ '5***** In more than one hundred pages filled with facts and illustrations he takes the reader on a journey through the history of the cosmos' BBC Sky at Night 'Packs in so much of our astronomical knowledge, so many tidbits about the history of astronomy and space exploration that I felt wonderfully enriched by it all. It is visually striking and beautifully illustrated' Dr. Alfredo Carpineti

This book provides a comprehensive overview of the history of ideas about the sun and the stars, from antiquity to modern times. Two theoretical astrophysicists who have been active in the field since the early 1960s tell the story in fluent prose. About half of the book covers most of the theoretical research done from 1940 to the close of the twentieth century, a large body of work that has to date been little explored by historians. The first chapter, which outlines the period from about 3000 B.C. to 1700 A.D., shows that at every stage in history human beings have had a particular understanding of the sun and stars, and that this has continually evolved over the centuries. Next the authors systematically address the immense mass of observations astronomy accumulated from the early seventeenth century to the early twentieth. The remaining four chapters examine the history of the field from the physicists perspective, the emphasis being on theoretical work from the mid-1840s to the late 1990s--from thermodynamics to quantum mechanics, from nuclear physics and magnetohydrodynamics to the remarkable advances through to the late 1960s, and finally, to more recent theoretical work. Intended mainly for students and teachers of astronomy, this book will also be a useful reference for practicing astronomers and scientifically curious general readers.

Black holes are a constant source of fascination to many due to their mysterious nature. In this Very Short Introduction, Katherine Blundell addresses a variety of questions, including what a black hole actually is, how they are characterized and discovered, and what would happen if you came too close to one. She explains how black holes form and grow - by stealing material that belongs to stars, as well as how many there may be in the Universe. She also explores the large black holes found in the centres of galaxies, and how black holes give rise to quasars and other spectacular phenomena in the cosmos. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.

Could Einstein have possibly anticipated directly testing the most captivating prediction of general relativity, that there exist isolated pockets of spacetime shielded completely from our own? Now, almost a century after that theory emerged, one of the world's leading astrophysicists presents a wealth of recent evidence that just such an entity, with a mass of about three million suns, is indeed lurking at the center of our galaxy, the Milky Way--in the form of a supermassive ''black hole''

With this superbly illustrated, elegantly written, nontechnical account of the most enigmatic astronomical object yet observed, Fulvio Melia captures all the excitement of the growing realization that we are on the verge of actually seeing this exotic object within the next few years.

Melia traces our intellectual pilgrimage to the ''brooding behemoth'' at the heart of the Milky Way. He describes the dizzying technological advances that have recently brought us to the point of seeing through all the cosmic dust to a dark spot in a clouded cluster of stars in the constellation Sagittarius. Carefully assembling the compelling circumstantial evidence for its black hole status, he shows that it is primed to reveal itself as a glorious panorama of activity within this decade--through revolutionary images of its ''event horizon'' against the bright backdrop of nearby, radiating gas.

Uniquely, this book brings together a specific and fascinating astronomical subject--black holes--with a top researcher to provide both amateur and armchair astronomers, but also professional scientists seeking a concise overview of the topic, a real sense of the palpable thrill in the scientific community when an important discovery is imminent.

Opinions on the large-scale structure of the early universe range widely from primeval chaos to a well-ordered mass distribution. P.J.E. Peebles argues that the evolution proceeded from a nearly uniform initial state to a progressively more irregular and clumpy universe. The discussion centers on the largest known structures, the clusters of galaxies, the empirical evidence of the nature of the clustering, and the theories of how the clustering evolves in an expanding universe.

In Chapter One the author provides an historical introduction to the subject. Chapter Two contains a survey of methods used to deal with the Newtonian approximation to the theory of the evolution of the mass distribution. Recent progress in the use of statistical measures of the clustering is described in Chapter Three. Chapters Four and Five return to techniques for dealing with cosmic evolution, in the statistical measures of clustering and under general relativity theory. Lastly, in Chapter Six Professor Peebles assesses the progress in attempts to link theory and observation to arrive at a well established physical picture of the nature and evolution of the universe.

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.