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Books > Science & Mathematics > Astronomy, space & time > General
In this book, renowned scientists describe the various techniques used to detect and characterize extrasolar planets, or exoplanets, with a view to unveiling the "tricks of the trade" of planet detection to a wider community. The radial velocity method, transit method, microlensing method, and direct imaging method are all clearly explained, drawing attention to their advantages and limitations and highlighting the complementary roles that they can play in improving the characterization of exoplanets' physical and orbital properties. By probing the planetary frequency at different distances and in different conditions, these techniques are helping astrophysicists to reconstruct the scenarios of planetary formation and to give robust scientific answers to questions regarding the frequency of potentially habitable worlds. Twenty years have passed since the discovery of a Jupiter-mass companion to a main sequence star other than the Sun, heralding the birth of extrasolar planetary research; this book fully conveys the exciting progress that has been achieved during the intervening period.
In 1988, in an article on the analysis of the measurements of the variations in the radial velocities of a number of stars, Campbell, Walker, and Yang reported an - teresting phenomenon;the radial velocity variations of Cephei seemed to suggest the existence of a Jupiter-like planet around this star. This was a very exciting and, at the same time, very surprising discovery. It was exciting because if true, it would have marked the detection of the ?rst planet outside of our solar system. It was surprising because the planet-hosting star is the primary of a binary system with a separation less than 19 AU, a distance comparable to the planetary distances in our solar system. The moderatelyclose orbit of the stellar companionof Cephei raised questions about the reality of its planet. The skepticism over the interpretation of the results (which was primarily based on the idea that binary star systems with small sepa- tions would not be favorable places for planet formation) became so strong that in a subsequent paper in 1992, Walker and his colleagues suggested that the planet in the Cephei binary might not be real, and the variations in the radial velocity of this star might have been due to its chromospheric activities.
"Quantum Gravitation" approaches the subject from the point of view of Feynman path integrals, which provide a manifestly covariant approach in which fundamental quantum aspects of the theory such as radiative corrections and the renormalization group can be systematically and consistently addressed. It is shown that the path integral method is suitable for both perturbative as well as non-perturbative studies, and is already known to offer a framework for the theoretical investigation of non-Abelian gauge theories, the basis for three of the four known fundamental forces in nature. The book thus provides a coherent outline of the present status of the theory gravity based on Feynman s formulation, with an emphasis on quantitative results. Topics are organized in such a way that the correspondence to similar methods and results in modern gauge theories becomes apparent. Covariant perturbation theory are developed using the full machinery of Feynman rules, gauge fixing, background methods and ghosts. The renormalization group for gravity and the existence of non-trivial ultraviolet fixed points are investigated, stressing a close correspondence with well understood statistical field theory models. The final chapter addresses contemporary issues in quantum cosmology such as scale dependent gravitational constants and quantum effects in the early universe."
This outstanding thesis by Dominic Bowman provides a thorough investigation of long-standing questions as to whether amplitude modulation is astrophysical, whether it offers insights into pulsating stars, and whether simple beating of modes with stable amplitudes is unrecognised because of a lack of frequency resolution. In this thesis, the author studied a uniform sample of 983 delta Scuti stars-the most common type of main-sequence heat engine pulsator-that were observed nearly continuously for 4 years at stunning photometric precision of only a few parts per million by the Kepler space mission. With no mission planned to supersede the Kepler 4-year data set, this thesis will stand as the definitive study of these questions for many years. With revolutionary photometric data from the planet-hunting Kepler space mission, asteroseismic studies have been carried out on many hundreds of main-sequence solar-type stars and about 10,000 red giants. It is easy to understand why those stochastically driven stars have highly variable amplitudes. Over much of the rest of the Hertzsprung-Russell (HR) diagram, stellar pulsations are driven by heat mechanisms, which are much more regular than the stochastic driving in solar-like pulsators. Yet for decades, amplitude and frequency modulation of pulsation modes have been observed in almost all types of heat-driven pulsating stars. The author shows that the amplitude and frequency modulation are astrophysical, and he has investigated their implications and prospects to provide new insights into the delta Scuti stars and the many other types of heat-engine pulsators across the HR diagram.
This volume aims to make Stephen of Pisa and Antioch's work on the celestial sciences accessible to a wider readership, providing not just the text but a translation and introduction as well. The edition is based on the only known manuscript of the Liber Mamonis, MS Cambrai, Mediatheque d'Agglomeration, A 930. It is split into two parts: the first provides an extensive introduction to Stephen and his work, while the second features the edition and translation. A comprehensive glossary and collection of photographs of plates are also included.
This groundbreaking volume provides an up-to-date, accessible guide to Sanskrit astronomical tables and their analysis. It begins with an overview of Indian mathematical astronomy and its literature, including table texts, in the context of history of pre-modern astronomy. It then discusses the primary mathematical astronomy content of table texts and the attempted taxonomy of this genre before diving into the broad outlines of their representation in the Sanskrit scientific manuscript corpus. Finally, the authors survey the major categories of individual tables compiled in these texts, complete with brief analyses of some of the methods for constructing and using them, and then chronicle the evolution of the table-text genre and the impacts of its changing role on the discipline of Sanskrit jyotisa. There are also three appendices: one inventories all the identified individual works in the genre currently known to the authors; one provides reference information about the details of all the notational, calendric, astronomical, and other classification systems invoked in the study; and one serves as a glossary of the relevant Sanskrit terms.
This volume shows how collective magnetic excitations determine most of the magnetic properties of itinerant electron magnets. Previous theories were mainly restricted to the Curie-Weiss law temperature dependence of magnetic susceptibilities. Based on the spin amplitude conservation idea including the zero-point fluctuation amplitude, this book shows that the entire temperature and magnetic field dependence of magnetization curves, even in the ground state, is determined by the effect of spin fluctuations. It also shows that the theoretical consequences are largely in agreement with many experimental observations. The readers will therefore gain a new comprehensive perspective of their unified understanding of itinerant electron magnetism.
This volume contains the proceedings of possibly the last conference ever on integral-field spectroscopy. The contributors, noted authorities in the field, focus on the scientific questions that can be answered with integral-field spectroscopy, ranging from solar system studies all the way to high redshift surveys. Overall readers get a state-of-the-science review of astronomical 3D spectroscopy.
The Square Kilometre Array (SKA) Project is a global project to design and c- struct a revolutionary new radio telescope with of order 1 million square meters of collecting area in the wavelength range from3mto1cm.It will have two - ders of magnitude greater sensitivity than current telescopes and an unprecedented large instantaneous ?eld-of-view. These capabilities will ensure the SKA will play a leading role in solving the major astrophysical and cosmological questions of the day (see the science case at www.skatelescope.org/pages/page astronom.htm). The SKA will complement major ground- and space-based astronomical facilities under construction or planned in other parts of the electromagnetic spectrum (e.g. ALMA, JWST, ELT, XEUS,...). The current schedule for the SKA foresees a decision on the SKA site in 2006, a decisiononthedesignconceptin2009,constructionofthe?rstphase(international path?nder)from2010to2013,andconstructionofthefullarrayfrom2014to2020. The cost is estimated to be about 1000 M . TheSKAProjectcurrentlyinvolves45institutesin17countries,manyofwhich are involved in nationally- or regionally-funded state-of-the-art technical devel- ments being pursued ahead of the 2009 selection of design concept. This Special Issue of Experimental Astronomy provides a snapshot of SKA engineering act- ity around the world, and is based on presentations made at the SKA meeting in Penticton,BC,CanadainJuly2004.Topicscoveredincludeantennaconcepts,so- ware, signal transport and processing, radio frequency interference mitigation, and reports on related technologies in other radio telescopes now under construction. Further information on the project can be found at www.skatelescope.org.
This book reviews the phenomenology displayed by relativistic jets as well as the most recent theoretical efforts to understand the physical mechanisms at their origin. Relativistic jets have been observed and studied in Active Galactic Nuclei (AGN) for about half a century and are believed to be fueled by accretion onto a supermassive black hole at the center of the host galaxy. Since the first discovery of relativistic jets associated with so-called "micro-quasars" much more recently, it has seemed clear that much of the physics governing the relativistic outflows in stellar X-ray binaries harboring black holes and in AGN must be common, but acting on very different spatial and temporal scales. With new observational and theoretical results piling up every day, this book attempts to synthesize a consistent, unified physical picture of the formation and disruption of jets in accreting black-hole systems. The chapters in this book offer overviews accessible not only to specialists but also to graduate students and astrophysicists working in other areas. Covered topics comprise Relativistic jets in stellar systems Launching of AGN jets Parsec-scale AGN jets Kiloparsec-scale AGN jets Black hole magnetospheres Theory of relativistic jets The structure and dynamics of the inner accretion disk The origin of the jet magnetic field X-ray observations, phenomenology, and connection with theory
Recent Issues and Advances in Astronomy explores the most important developments in astronomy over the last decade, including the results of recent investigations on extrasolar planetary systems, black holes, and the existence of water in space. Besides exploring the societal implications of recent developments, the book also addresses the philosophical questions raised by recent advances, such as whether or not we are alone in the universe. Other chapters offer biographies of prominent astronomers, discussions of important current investigations, summaries of astronomical funding and career statistics, and a glossary of terms. The book also provides an annotated listing of relevant organizations and bibliographies of print and nonprint information resources. The book is illustrated and extensively cross-referenced, and includes a detailed subject index. A special chapter comprises narratives written by four trained astronomers, each of whom describes the particular career path he or she has chosen, both inside and outside the field of astronomy itself.
At the beginning of the 20th century, Kristian Birkeland (1867-1917), a Norwegian scientist of insatiable curiosity, addressed questions that had vexed European scientists for centuries. Why do the northern lights appear overhead when the earth's magnetic field is disturbed? How are magnetic storms connected to disturbances on the sun? To answer these questions Birkeland interpreted his advance laboratory simulations and daring campaigns in the Arctic wilderness in the light of Maxwell's newly discovered laws of electricity and magnetism. Birkeland's ideas were dismissed for decades, only to be vindicated when satellites could fly above the earth's atmosphere.
In the past few years, general astronomical interest has concentrated on s- eral objects and phenomena where white dwarf stars play a key role. T Type Ia supernovae have been used as evidence to show that, in fact, Einstein did not make his greatest blunder when heallowedfor the possibility of a c- mological constant. Improvements in our knowledge of the Hubble parameter have revived interest in the use of white dwarf stars as a different typeofc- mochronometer to measuretheage of the Galaxy andthus set constraints on the age of the Universe. In roughly the same time period, there have been considerable advances in our understanding of white dwarf stars, both as i- lated stars in the ?eld and as members ofinteracting binary systems. Much of thisadvance has come from theavailabilityof spacecraftobservations from missions like HST T T, IU UE, ROSAT T, EXOSAT T, Chandra, ORFEUS, EUVE, HUT T T, and FUSE. The discovery of thousandsof new white dwarfs from a number oflarge surveys and thepotential of theSloan Digital SkySurvey have added impetus to the ?eld. Studies ofinteracting binaries such as classical novae, supersoft X-ray bi- ries, symbiotic variables, dwarf novae and nova-like objects have revealed the diff ferences between thethermal evolution of singleand close binary systems aswell as heightenedinterest in these systems as progenitors of the cosmol- ically important Type I supernovae. A more speculative question is whether classical novae can beunderstood well enough that theymight provide another kind of standard candle.
This volume documents recent developments that have advanced our understanding of the heating and cooling mechanisms in galaxies and galaxy clusters. Chapters detail results from multi-wavelength observations and advances in numerical hydrodynamical simulations. An additional section covers new research findings on feedback and self-regulatory mechanisms during cosmic structure formation in general and in galaxy formation in particular.
This second volume of Frontiers articles contains a broad array of
fascinating topics. The first four
The present volume gathers together the talks presented at the second colloquim on the Future Professional Communication in Astronomy (FPCA II), held at Harvard University (Cambridge, MA) on 13-14 April 2010. This meeting provided a forum for editors, publishers, scientists, librarians and officers of learned societies to discuss the future of the field. The program included talks from leading researchers and practitioners and drew a crowd of approximately 50 attendees from 10 countries. These proceedings contain contributions from invited and contributed talks from leaders in the field, touching on a number of topics. Among them: - The role of disciplinary repositories such as ADS and arXiv in astronomy and the physical sciences; - Current status and future of Open Access Publishing models and their impact on astronomy and astrophysics publishing; - Emerging trends in scientific article publishing: semantic annotations, multimedia content, links to data products hosted by astrophysics archives; - Novel approaches to the evaluation of facilities and projects based on bibliometric indicators; - Impact of Government mandates, Privacy laws, and Intellectual Property Rights on the evolving digital publishing environment in astronomy; - Communicating astronomy to the public: the experience of the International Year of Astronomy 2009.
These astute essays describe the way ordinary people value human relationships and reason through the commonplace contradictions of their local way of life in a global age, rather than measure the actions of their subjects as evidence of either universal rationality or shared cultural beliefs. Each contributor conveys the ways in which people challenge the ascribed moral standards of custom, religious belief, bureaucratic policies through passionate words such as anecdotes, joke, rumors, and gossip. By evaluating moral reasoning at a local level, contributors work to answer the question, what is a good life?
This exhaustive work sheds new light on unsolved questions in gamma-ray astrophysics. It presents not only a complete introduction to the non-thermal Universe, but also a description of the Imaging Atmospheric Cherenkov technique and the MAGIC telescopes. The Fermi-LAT satellite and the HAWC Observatory are also described, as results from both are included. The physics section of the book is divided into microquasars and pulsar wind nebulae (PWNe), and includes extended overviews of both. In turn, the book discusses constraints on particle acceleration and gamma-ray production in microquasar jets, based on the analyses of MAGIC data on Cygnus X-1, Cygnus X-3 and V404 Cygni. Moreover, it presents the discovery of high-energy gamma-ray emissions from Cygnus X-1, using Fermi-LAT data. The book includes the first joint work between MAGIC, Fermi-LAT and HAWC, and discusses the hypothetical PWN nature of the targets in depth. It reports on a PWN population study that discusses, for the first time, the importance of the surrounding medium for gamma-ray production, and in closing presents technical work on the first Large-Size-Telescope (LST; CTA Collaboration), along with a complete description of the camera.
Comets are small bodies, but of great cosmic relevance. Given its pristine nature, they may preserve valuable and unique information on thechemical and physical processes that took place in theearly solar system, and that may be occurring in the formation of other planetary systems. They might have even played a very important role in the origin of life on Earth. Beyond that, since ancient times comets have inspired awe, superstition, and also curiosity anddebate. Their sudden apparitions challenged the long-held view of the immutability of the heavens, which triggered a long debate on whether comets had a heavenly or terrestrial nature. Therefore, comets have a prominent role in the history of scienti?cthought, that goes back to the most ancient civilizations. The last apparition of comet Halley in 1986 was a landmark since it arouse a great expectation in the scienti?c community and in the public at large. For the ?rst time, a ?otilla of spacecrafts visited a comet. Agreat number of popular and technical books were written on Halley, and comets in general, around the mid-eighties. The interest in comets never subsided after Halley's passage which is re?ected in the large volume of printed material on these bodies. I have taken the challenge to write a new book on comets that summarizes most of the recent advances on thesubject, including my own workdeveloped during the last 25 years.
An "intriguing and accessible" (Publishers Weekly) interpretation of the life of Galileo Galilei, one of history's greatest and most fascinating scientists, that sheds new light on his discoveries and how he was challenged by science deniers. "We really need this story now, because we're living through the next chapter of science denial" (Bill McKibben). Galileo's story may be more relevant today than ever before. At present, we face enormous crises-such as minimizing the dangers of climate change-because the science behind these threats is erroneously questioned or ignored. Galileo encountered this problem 400 years ago. His discoveries, based on careful observations and ingenious experiments, contradicted conventional wisdom and the teachings of the church at the time. Consequently, in a blatant assault on freedom of thought, his books were forbidden by church authorities. Astrophysicist and bestselling author Mario Livio draws on his own scientific expertise and uses his "gifts as a great storyteller" (The Washington Post) to provide a "refreshing perspective" (Booklist) into how Galileo reached his bold new conclusions about the cosmos and the laws of nature. A freethinker who followed the evidence wherever it led him, Galileo was one of the most significant figures behind the scientific revolution. He believed that every educated person should know science as well as literature, and insisted on reaching the widest audience possible, publishing his books in Italian rather than Latin. Galileo was put on trial with his life in the balance for refusing to renounce his scientific convictions. He remains a hero and inspiration to scientists and all of those who respect science-which, as Livio reminds us in this "admirably clear and concise" (The Times, London) book, remains threatened everyday. |
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