From The Realm Of The Nebulae To Populations Of Galaxies

In order to outline possible future directions in galaxy research, this book wants to be a short stopover, a moment of self-reflection of the past century of achievements in this area. Since the pioneering years of galaxy research in the early 20th century, the research on galaxies has seen a relentless advance directly connected to the parallel exponential growth of new technologies. Through a series of interviews with distinguished astronomers the editors provide a snapshot of the achievements obtained in understanding galaxies. While many initial questions about their nature have been addressed, many are still open and require new efforts to achieve a solution. The discussions may reveal paradigms worthwhile revisiting. With the help of some of those scientists who have contributed to it, the editors sketch the history of this scientific journey and ask them for inspirations for future directions of galaxy research.

Nebulae, star clusters, and galaxies are outside our solar system. They belong to the 'deep sky' and lead the observer to great distances and at the same time the view goes far into the past. The light of the most distant galaxies took billions of years to reach us. No less fascinating is our home galaxy, the Milky Way, offering many bright nebulae and star clusters. The book covers three important topics related to deep-sky objects: history, astrophysics, and observation. When beginners observe an object visually, not knowing anything about it, they will only perceive a faint spot of light - nothing really exciting. So, to get the right 'cosmic' feeling, the view should be enriched with stories about the object's discovery, distance, physical nature, or evolution. Supplied with this kind of information, deep-sky observing becomes a fascinating activity - braving the cold and darkness. Over time, advanced fields such as observation techniques or astrophotography come into play. The book informs the reader about all these topics and offers a comprehensive collection of interesting targets.

**This is the chapter slice "Nebulae" from the full lesson plan "Galaxies & The Universe"** Get the big picture about Galaxies and our Universe. From the smallest particles of matter to the biggest star system, our universe is made up of all things that exist in space. Our resource takes you through the Milky Way Galaxy, Black Holes and Gravity, then on to Nebulae, Sources of Light and the Speed of Light, and finally to Quasars, the most distant objects in the universe. Written using simplified language and vocabulary, our resource presents science concepts in a way that makes them accessible to students and easier to understand. Comprised of reading passages, student activities for before and after reading, hands-on activities, and color mini posters, our resource can be used effectively for test prep, whole-class, small group and independent work. All of our content is aligned to your State Standards and are written to Bloom's Taxonomy and STEM initiatives.

Evolution of Stars and Stellar Populations is a comprehensive presentation of the theory of stellar evolution and its application to the study of stellar populations in galaxies. Taking a unique approach to the subject, this self-contained text introduces first the theory of stellar evolution in a clear and accessible manner, with particular emphasis placed on explaining the evolution with time of observable stellar properties, such as luminosities and surface chemical abundances. This is followed by a detailed presentation and discussion of a broad range of related techniques, that are widely applied by researchers in the field to investigate the formation and evolution of galaxies. This book will be invaluable for undergraduates and graduate students in astronomy and astrophysics, and will also be of interest to researchers working in the field of Galactic, extragalactic astronomy and cosmology. comprehensive presentation of stellar evolution theory introduces the concept of stellar population and describes "stellar population synthesis" methods to study ages and star formation histories of star clusters and galaxies presents stellar evolution as a tool for investigating the evolution of galaxies and of the universe in general

Galaxies have a history. This has become clear from recent sky surveys which have shown that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. New observational windows at ultraviolet, infrared and millimetric wavelengths (provided by ROSAT, IRAM, IUE, IRAS, ISO) have revealed that galaxies contain a wealth of components: very hot gas, atomic hydrogen, molecules, dust, dark matter ... A significant advance is expected due to new instruments (VLT, FIRST, XMM) which will allow one to explore the most distant Universe. Three Euroconferences have been planned to punctuate this new epoch in galactic research, bringing together specialists in various fields of Astronomy. The first one, held in Granada (Spain) in May 2000, addressed the observational clues. The second one took place in October 2001 in St Denis de la Réunion (France) and reviewed the basic building blocks and small-scale processes in galaxy evolution. The third one will take place in July 2002 in Kiel (Germany) and will be devoted to the overall modelling of galaxy evolution. This book contains the proceedings of the second conference. It is suitable for researchers and PhD students in Astrophysics.

A key component of astronomy is the study of how galaxies change over time. Once thought to be static "island universes" today, we know that galaxies are dynamic systems reacting to changes in their internal and external environments in myriad ways. From simple observables like their shapes and colors to the complex interplay of their intricate stellar populations, evolving galaxies contain a wealth of information about their past. Yet, these observables alone are not enough to allow us to determine how these galaxies came to be or what they will become. For that, we need to combine theoretical models assembled from fundamental laboratory physics and apply them to galaxies through the use of state- of-the-art computer simulations. This careful combination of observation and computation has allowed our understanding of galaxy evolution to transition from the simple realm of the nebulae into a substantial field of astronomy. In this thesis, we explore three perspectives of galaxy evolution at different levels of detail- through both observations and computer simulations. We begin with a simple observation: the stars in our galaxy appear to be moving in strange ways. If our Galaxy were living an uneventful life, we would expect all of the stars to be moving in nearly circular orbits with small, but appreciable, vertical motions- much like the horse on a carousel. However, recent surveys of nearby stars have found substantial deviations from such a perfect life. With the stars moving vertically in ways that indicate the galaxy has been rung like a bell. Some observers have posited that interactions with very nearby galaxies like the Sagittarius dwarf may be responsible for these unusual stellar motions. In Chapter 2, we use a simulated version of the Milky Way that is undergoing an interaction with a small companion galaxy to explore how such an interaction can affect the motions of stars near the Sun and what effect this may have on the nearly century-old ii problem known as the Oort Limit. Our own galaxy is but one example of an entire population disk-like galaxies with blue colors due to the presence of newly-formed stars. Opposite this population of "blue cloud" galaxies is the "red sequence" which is made up of spheroidal galaxies with red colors due to having nearly no ongoing star formation. In Chapter 3, we take a detailed look at an exceptionally rare, but quite important subpopulation of galaxies that are thought to be transitioning between the blue cloud and the red sequence through the so-called "green valley." Much like transitional fossils in biology, these galaxies have properties intermediate between both the disk-like galaxies of the blue cloud and the massive spheroids of the red sequence. Although few in number, the presence in the universe provides us with a critical view of the fleeting transitions these galaxies are undergoing to help us unlock the mysteries of how massive galaxies in the universe form. Our understanding of galaxy evolution at every scale relies heavily on computer simulations. In Chapter 4, we approach the subject through the lens of a software developer writing a modern N-body solver used to simulate the gravitational dynamics of galaxies. In particular, we explore how utilizing accelerator hardware like graphics processing units (GPUs) can increase both the precision and size of problems that can be solved in galaxy evolution both for today and tomorrow.

A look up at the night sky reveals a treasury of wonders. Even to the naked eye, the Moon, stars, planets, the Milky Way and even a few star clusters and nebulae illuminate the heavens. For millennia, humans struggled to make sense of what's out there in the Universe, from all we can see to that which lies beyond the limits of even our most powerful telescopes. Beyond the Galaxy traces our journey from an ancient, Earth-centered Universe all the way to our modern, 21st century understanding of the cosmos. Touching on not only what we know but also how we know it, Ethan Siegel takes us to the very frontiers of modern astrophysics and cosmology, from the birth of our Universe to its ultimate fate, and everything in between.

Our Place in the Universe tells the story of our world, formation of the first galaxies and stars formed from great clouds containing the primordial elements made in the first few minutes; birth of stars, their lives and deaths in fiery supernova explosions; formation of the solar system, its planets and many moons; life on Earth, its needs and vicissitudes on land and in the seas; finally exoplanets, planets that surround distant stars. Interspersed in the text are short pieces on some of those who revealed these wonders to us.It is written in a very authoritative and readable form and contains more than 100 color prints of the marvelous galaxies, and nebula that have been taken from space-based and land-based telescopes carried by NASA missions, the European Space Agency, the European Southern Laboratory in Chile and many other sources.

The Local Group is a small cluster of galaxies that includes the Milky Way. At least half of all galaxies in the Universe are thought to belong to similar groups. This authoritative volume provides a comprehensive synthesis of what is known about the Local Group. It begins with a summary of each member galaxy, as well as those galaxies previously regarded as possible members. The book examines the mass, stability and evolution of the Local Group as a whole and includes many important previously unpublished results and conclusions. With clarity, Professor van den Bergh provides a masterful summary of all that is known about the galaxies of the Local Group and their evolution, and expertly places this knowledge in the wider context of on-going studies of galaxy formation and evolution, the cosmic distance scale, and the conditions in the early Universe.