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Books > Science & Mathematics > Physics > Applied physics & special topics > Astrophysics
This thesis sheds valuable new light on the second-order cosmological perturbation theory, extensively discussing it in the context of cosmic microwave background (CMB) fluctuations. It explores the observational consequences of the second-order vector mode, and addresses magnetic field generation and the weak lensing signatures, which are key phenomena of the vector mode. The author demonstrates that the second-order vector mode, which never appears at the linear-order level, naturally arises from the non-linear coupling of the first-order scalar modes. This leads to the remarkable statement that the vector-order mode clearly contributes to the generation of cosmological magnetic fields. Moreover, the weak lensing observations are shown to be accessible to the vector mode. On the basis of ongoing and forthcoming observations, the thesis concludes that the second-order vector mode is detectable.
The search for life outside the Earth has been one of the biggest quests of mankind. We have reached a level in technology that allows the first steps towards a scientific investigation. The aim of this workshop was to take an interdisciplinary look at the signatures that would be indicative for past or present life on another planet, to compare them to biosignatures on Earth, and to discuss state-of-the-art in-situ instruments that are envisioned to search for these signatures in the exploration of the solar system as well as concepts for the search for habitable planets around other stars.
How planets form is one of the long-standing questions in astrophysics. In particular, formation scenarios of planetesimals which are kilometer-sized bodies and a precursor of planets are still unclear and under debate although some promising mechanisms have been proposed. This book highlight disk instabilities that have the potential to explain the origin of planetesimals. Using linear analyses and numerical simulations, it addresses how a disk evolves through the development of instabilities, and also presents a new instability driven by dust coagulation. As a result, the simulation demonstrates a scenario of planetesimal formation: A successive development of multiple instabilities triggers planetesimal formation in resulting dusty rings.
The symposium Star Clusters in the Era of Large Surveys was held in Lisbon on Sep 9-10 during the JENAM 2010. It served as a platform for discussing what and how recent, on-going and planned large-area ground-based and space-based surveys can contribute to producing a major leap in this research field, which has a strong European history. Scientific topics addressed included: cluster searches, clustered vs. isolated star formation, large-scale star formation, enrichment of the field population, structure, populations and evolution of the Milky Way, cluster dynamics (internal and within the Milky Way), variability of stars in clusters (from time-resolved surveys), analysis techniques for large samples and archiving. This proceedings book provides a snapshot of the ongoing discussion on the role of large surveys in star cluster research, and serves as a reference volume for the state-of-the art in the field.
A host of astrophysical measurements suggest that most of the matter in the Universe is an invisible, nonluminous substance that physicists call "dark matter." Understanding the nature of dark matter is one of the greatest challenges of modern physics and is of paramount importance to our theories of cosmology and particle physics. This text explores one of the leading hypotheses to explain dark matter: that it consists of ultralight bosons forming an oscillating field that feebly interacts with light and matter. Many new experiments have emerged over the last decade to test this hypothesis, involving state-of-the-art microwave cavities, precision nuclear magnetic resonance (NMR) measurements, dark matter "radios," and synchronized global networks of atomic clocks, magnetometers, and interferometers. The editors have gathered leading experts from around the world to present the theories motivating these searches, evidence about dark matter from astrophysics, and the diverse experimental techniques employed in searches for ultralight bosonic dark matter. The text provides a comprehensive and accessible introduction to this blossoming field of research for advanced undergraduates, beginning graduate students, or anyone new to the field, with tutorials and solved problems in every chapter. The multifaceted nature of the research - combining ideas and methods from atomic, molecular, and optical physics, nuclear physics, condensed matter physics, electrical engineering, particle physics, astrophysics, and cosmology - makes this introductory approach attractive for beginning researchers as well as members of the broader scientific community. This is an open access book.
Proceedings of IAU Symposium No. 64, Warsaw, Poland, September 5-8, 1973
Non-accelerator particle physicists, especially those studying neutrino oscillation experiments, will read with profit the in-depth discussions of new results and their interpretations. new guidelines are also set out for new developments in this and related fields. Discussions are presented of neutrino oscillations, neutrino astronomy, high energy cosmic rays, gravitational waves, magnetic monopoles and dark matter. The future large-scale research projects discussed include the experiments on long baseline neutrino beams from CERN to Gran Sasso and Fermilab to the Soudan mine; large underwater and under-ice experiments; the highest energy cosmic rays; gravitational waves; and the search for new particles and new phenomena.
Observations and physical concepts are interwoven to give basic explanations of phenomena and also show the limitations in these explanations and identify some fundamental questions. Compared to conventional plasma physics textbooks this book focuses on the concepts relevant in the large-scale space plasmas. It combines basic concepts with current research and new observations in interplanetary space and in the magnetospheres. Graduate students and young researchers starting to work in this special field of science, will find the numerous references to review articles as well as important original papers helpful to orientate themselves in the literature. Emphasis is on energetic particles and their interaction with the plasma as examples for non-thermal phenomena, shocks and their role in particle acceleration as examples for non-linear phenomena. This second edition has been updated and extended. Improvements include: the use of SI units; addition of recent results from SOHO and Ulysses; improved treatment of the magnetosphere as a dynamic phenomenon; text restructured to provide a closer coupling between basic physical concepts and observed complex phenomena.
1. 1 Schematic Picture of AGN Some galaxies are known to emit radiation with extremely high luminosities from a rather small volume in the ??ray, X-ray and UV continuum. Such active cores are the so-called Active Galactic Nuclei (AGN) and the radiation is commonly believed to be a result of gravitational energy released by matter spiraling around 9 a supermassive central black hole of about 10 M (see Fig. 1). Though the central engine which produces the enormous observed activity cannot be resolved observationally, a standard picture of an AGN has gradually emerged to explain the richness of the radiation spectra: * an accretion disk with radius from about 2 to 100 gravitational radii, R , g feeding the central black hole and emitting mainly in the UV and soft X-rays; * the broad line optically emitting clouds (BLR), which seem to be absent in 3 some sources (e. g. FRI, see hereafter) and extend up to a few 10 R from g the center.
This book presents experiments which will teach physics relevant to astronomy. The astronomer, as instructor, frequently faces this need when his college or university has no astronomy department and any astronomy course is taught in the physics department. The physicist, as instructor, will find this intellectually appealing when faced with teaching an introductory astronomy course. From these experiments, the student will acquire important analytical tools, learn physics appropriate to astronomy, and experience instrument calibration and the direct gathering and analysis of data. Experiments that can be performed in one laboratory session as well as semester-long observation projects are included.
Stellar pulsations provide a complex system in stars. This complexity is studied by analyzing the non-sinusoidal, semi-regular, or irregular light curves. This unique volume summarizes the application of recent theoretical results obtained from stellar pulsation studies. In addition, the latest developments in hydrodynamic simulations are discussed. A historical sketch of the study of beat Cepheids, first known for their variable amplitudes, is given as an introduction to the book. This introduction clearly demonstrates how complicated the study of variable stars can be, and therefore challenges and invites the reader to study the entire book.
Features * Fully updated with the latest results from the spacecraft Hinode, Stereo, Solar Dynamics Observatory (SDO), Interface Region Imaging Spectrograph (IRIS), and Parker Solar Probe * Presents step-by-step explanations for calculating numerical models of the photosphere, convection zone, and radiative interior with exercises and simulation problems to test learning * Describes the structure of polytropic spheres and the acoustic power in the Sun and the process of thermal conduction in different physical conditions
Prior to the 1920s it was generally thought, with a few exceptions, that our galaxy, the Milky Way, was the entire Universe. Based on the work of Henrietta Leavitt with Cepheid variables, astronomer Edwin Hubble was able to determine that the Andromeda Galaxy and others had to lie outside our own. Moreover, based on the work of Vesto Slipher, involving the redshifts of these galaxies, Hubble was able to determine that the Universe was not static, as had been previously thought, but expanding. The number of galaxies has also been expanding, with estimates varying from 100 billion to 2 trillion. While every galaxy in the Universe is interesting just by its very fact of being, the author has selected 60 of those that possess some unusual qualities that make them of some particular interest. These galaxies have complex evolutionary histories, with some having supermassive black holes at their core, others are powerful radio sources, a very few are relatively nearby and even visible to the naked eye, whereas the light from one recent discovery has been travelling for the past 13.4 billion years to show us its infancy, and from a time when the Universe was in its infancy. And in spite of the vastness of the Universe, some galaxies are colliding with others, embraced in a graceful gravitational dance. Indeed, as the Andromeda Galaxy is heading towards us, a similar fate awaits our Milky Way. When looking at a modern image of a galaxy, one is in awe at the shear wondrous nature of such a magnificent creation, with its boundless secrets that it is keeping from us, its endless possibilities for harboring alien civilizations, and we remain left with the ultimate knowledge that we are connected to its glory.
Three eminent scientists, each well known for the clarity of their writing, present for students and researchers what is known about the internal structure, origin and evolution of White Dwarfs, Neutron Stars and Black Holes, all objects at the final stage of stellar evolution. They cover fascinating topics such as pulsation of white dwarfs, millisecond pulsars or the dynamics around black holes. The book is written for graduate students in astrophysics, but is also of interest to professional astronomers and physicists.
This book contains lectures presented in the symposium on "wave Instabili ties in S: pace Plasmas" organized wi thin the progrem of .t.y . XIX URSI General Assembly held in Helsinki, Finland, during tJ: l
This unique , authoritative book introduces and accurately depicts the current state-of-the art in the field of space storms. Professor Koskinen, renowned expert in the field, takes the basic understanding of the system, together with the pyhsics of space plasmas, and produces a treatment of space storms. He combines a solid base describing space physics phenomena with a rigourous theoretical basis. The topics range from the storms in the solar atmosphere through the solar wind, magnetosphere and ionosphere to the production of the storm-related geoelectric field on the ground. The most up-to-date information available ist presented in a clear, analytical and quantitative way. The book is divided into three parts. Part 1 is a phenomenological introduction to space weather from the Sun to the Earth. Part 2 comprehensively presents the fundamental concepts of space plasma physics. It consists of discussions of fundamental concepts of plasma physics, starting from underlying electrodynamics and statistical physics of charged particles and continuing to single particle motion in homogeneous electromagnetic fields, waves in cold plasma approximation, Vlasov theory, magnetohydrodynamics, instabilities in space plasmas, reconnection and dynamo. Part 3 bridges the gap between the fundamental plasma physics and research level physics of space storms. This part discusses radiation and scattering processes, transport and diffiusion, shocks and shock acceleration, storms on the Sun, in the magnetosphere, the coupling to the atmosphere and ground. The book is concluded wtih a brief review of what is known of space stroms on other planets. One tool for building this briege ist extensive cross-referencing between the various chapters. Exercise problems of varying difficulty are embedded within the main body of the text.
This volume gives an overview of knowledge about the light nuclei created in the Hot Early Universe: H, D, 3He, 4He, and 7Li. It combines observational and theoretical results on the early Universe, the distant galaxies, our Milky Way, the local interstellar cloud, and the solar nebula. The implications for cosmology, galactic and stellar evolution, dark matter research etc. are outlined and directions of future research are indicated.
The Symposium 'Meteorite Research' was conceived originally at the second meeting of the UNESCO Working Group on Meteorites, held in Paris October 18-20, 1965, under the chairmanship of Professor J. Orce ' In addition to the Chairman the fol lowing were present: Dr. G. Harbottle, Dr. M. H. Hey, Dr. B. H. Mason, Dr. P. M. Millman, Professor K. I. Sztr6kay. Dr. E. M. Fournier d'Albe represented the UNESCO Secretariat. Recommendation No.4 from the minutes of this meeting reads as follows: "The Working Group, in view ofthe need to strengthen international co-operation in meteorite research, asks that the International Atomic Energy Agency be requested to consider the possibility of organizing, in 1968, an interdisciplinary conference on meteorites, in collaboration with UNESCO and the appropriate international scientific organizations." After approval in principle of this recommendation had been secured from various international agencies and unions, plans for the symposium were consolidated at the third and final meeting of the Working Group, held in Paris October 12-14, 1966, the members in attendance being the same as for the second meeting."
The per iod of an oscillator tells us much about its structure. J. J. Thomson's deduction that a particle with the e/rn of an electron was in the atom is perhaps the most stunning instance. For us, the deduction of the mean density of a star from its oscillation period is another important example. What then can we deduce about an oscillator that is not periodic? If there are several frequencies or if the behavior is chaotic, may we not hope to learn even more delicate vital statistics about its workings? The recent progress in the theory of dynamical systems, particularly in the elucidat ion of the nature of chaos, makes it seem reasonable to ask this now. This is an account of some of the happenings of a workshop at which this question was raised and discussed. ~iTe were inc0rested in seeing ways in which the present understanding of chaos might guide astrophysical modelling and the interpretation of observations. But we did not try to conceal that we were also interested in chaos itself, and that made for a pleasant rapport between the chaoticists and astrophysicists at the meeting. We have several introductory papers on chaos in these proceedings, particularly on the analysis of data from systems that may be suspected of chaotic behavior. The papers of Geisel, Grassberger and Guckenheimer introduce the ways of characterizing chaos and Perdang illustrates how some of these ideas may be put into practice in explicit cases.
In the last few years great improvements in the study of stellar jets and bipolar outflows have been achieved, both observationally and theoretically. High resolution observations at various frequencies (radio, IR, optical and X-ray) of these features in different types of objects have shown a large variety of morphologies at all scales often revealing contrasting symmetries which do not allow straightforward kinematic interpretations valid for all cases. In particular, at present, it seems very difficult to give a statistical definition of what the "standard properties" of jets and bipolar outflows are. On the theoretical side, the identification of physical processes capable of producing the observed rich morphological variety of jets and bipolar outflows and supporting them over long lifetimes is still controversial. Furthermore several models are actively discussed in an attempt of reaching a complete understanding of the phenomenon. The workshop provided an unique opportunity for both observers and theoreticians to gather together and produce an updated and exhaustive picture of the field. In addition the meeting has been enriched by the presentation of some works on jets in external galaxies. This topic was focused on what people working on stellar jets could learn from colleagues working on extragalactic jets and vice versa. Invited papers were prepared with the aim of giving the state of the art about scientific subjects; contributed papers and some selected poster papers presented, on the contrary, very recent results in the various fields.
I. Initial Angular Momentum Distribution.- Angular Momentum Effects in Star Formation.- Evolutionary Properties of Intermediate-Mass Protostar.- Small-Scale Structure and Angular Momentum Transfer in Protostellar Environments.- Ekman Pumping in a Rotating Protostar.- Rotation in Pre-Main Sequence Stars; Properties and Evolution.- Disks Associated with Intermediate Mass Stars.- Differential Rotation of Fully Convective Pre-Main Sequence Stars.- The X-ray Emission from PMS Stars in Taurus-Auriga, and the Relationship with Other Diagnostics of Activity.- Multifrequency Monitoring of RU Lupi; Observational Results and a Model.- Polarimetry and CCD Imaging of Herbig Ae/Be Stars and Star Forming Regions.- II: Angular Momentum Evolution.- Rotational Velocities of Low Mass Stars in Young Clusters.- Rotation of Young Stars in the Orion Nebula Region.- Rotational Velocities of Stars in Open Clusters; the Time-Dependence Revisited.- Main Sequence Angular Momentum Loss in Low-Mass Stars.- The Angular Momentum Evolution of Young and Old Binary Components.- Ages of Spotted Late-Type Stars.- Rotation of Evolved Stars.- Rotational Discontinuity of Evolved Stars; What Interpretation?.- III: Consequence of Rotation.- Magnetic Activity and Rotation.- Lithium, Rotation and Age.- Rotation, Chromospheric Activity, and Lithium Abundances in G and K Dwarfs of the Pleiades.- Lithium Abundance and Rotation in Southern Chromospherically Active Stars.- Lithium Depletion Induced by Rotation in Young Stars.- Rotational Mixing and Lithium in Young Stars.- IV: Internal Rotation and Models.- Internal Solar Rotation.- Stellar Activity Belts as Potential Indicators of Internal Rotation and Angular Momentum Distribution.- Dynamics of Spot Groups and Rotation of the External Convective Layers in the Sun and Magnetically Active Stars.- Theory of Magnetic Braking of Late-Type Stars.- Pre-Main Sequence and Main Sequence Rotational Evolution; Constraints on Models Derived from Observations.- Evolutionary Models of Rotating Stars.- The Internal Rotation of the Sun; Implications on the History of its Angular Momentum.- Angular Momentum Transport, Rotational Instabilities, Magnetic Fields and Mixing.- The Spin-Down of Main Sequence Stars Based on Observed Magnetic Field Strength.- Session V: Observational Perspectives.- Observational Perspectives.- PRISMA: a Space Facility for Studying Rotation and Activity.- The Spectrum-UV Project.- Summary of the Workshop.- Panel Discussion: Initial Angular Momentum.- Panel Discussion: Dynamos and Internal Rotation.- Author Index.- Object Index.
This thesis reports on investigations of a specific collective mode of nuclear vibration, the isoscalar giant monopole resonance (ISGMR), the nuclear "breathing mode", the energy of which is directly related to a fundamental property of nuclei-the nuclear incompressibility. The alpha inelastic scattering experiments reported in this thesis have been critical to answering some fundamental questions about nuclear incompressibility and the symmetry energy, quantities that are crucial to our understanding of a number of phenomena in nuclear physics and astrophysics, including collective excitations in nuclei, radii of neutron stars, and the nature of stellar collapse and supernova explosions. The work described included three sets of experiments and subsequent sophisticated data analysis, both leading to results that have been welcomed by the community and recognised as important contributions to the field.
This book describes the basic physical principles of atomic spectroscopy and the absorption and emission of radiation in astrophysical and laboratory plasmas. It summarizes the basics of electromagnetism and thermodynamics and then describes in detail the theory of atomic spectra for complex atoms, with emphasis on astrophysical applications. Both equilibrium and non-equilibrium phenomena in plasmas are considered. The interaction between radiation and matter is described, together with various types of radiation (e.g., cyclotron, synchrotron, bremsstrahlung, Compton). The basic theory of polarization is explained, as is the theory of radiative transfer for astrophysical applications. Atomic Spectroscopy and Radiative Processes bridges the gap between basic books on atomic spectroscopy and the very specialized publications for the advanced researcher: it will provide under- and postgraduates with a clear in-depth description of theoretical aspects, supported by practical examples of applications.
This textbook is designed to serve as a link between the basic disciplines of physics and the frontier topics within high energy astrophysics, aiming at a level of difficulty congruent with that of other physics topics studied at undergraduate level. Therefore, this preparatory and introductory text serves as a gateway to a more detailed study of many of the most interesting and complex phenomena being investigated by contemporary astrophysics. Among others, these include: the evolution of stars, supernovae, neutron stars, black holes, solar neutrinos, and - importantly - the exciting new field of gravitational wave astronomy. The book is supplemented by a collection of problems with which students can test their understanding of the material presented. |
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