Gravitation Astrophysics And Cosmology

The past twenty years have seen a number of breakthroughs in astrophysics and cosmology, some of which have been awarded Nobel prizes. These physics triumphs highlight the fact that while students need a solid grounding in the fundamentals of astrophysics and cosmology, sight of the basics of the fundamental interactions in physics must not be lost. This book presents papers based on lectures given at the 200th Course of the International School of Physics “Enrico Fermi”, on Gravitation and Cosmology, held in Varenna, Italy, from 3 - 12 July 2017. The aim of the school was to expose students to state-of-the-art research in the field of gravitational waves and cosmology, from both a theoretical and experimental point of view. Lectures were organized in such a way as to foster interaction between the two communities, and a wide range of topics was addressed. In the gravitational waves section, topics covered include experimental issues connected with gravitational wave detection and the new field of multi-messenger astronomy, as well as more astrophysical aspects. In the section on cosmology, there are contributions on the early universe, on the cosmic microwave background (CMB) and on redshift surveys. Other areas covered include a review of inflationary scenarios; the non-Gaussian features of primordial density fluctuations; and the physical mechanisms responsible for the spectral distortions of the blackbody spectrum of the CMB. The book provides an overview of important research developments and will be of interest to all students of gravitation and cosmology.

General relativity and quantum mechanics have become the two central pillars of theoretical physics. Moreover, general relativity has important applications in astrophysics and high-energy particle physics. Covering the fundamentals of the subject, Principles of Cosmology and Gravitation describes the universe as revealed by observations and presents a theoretical framework to enable important cosmological formulae to be derived and numerical calculations performed. Avoiding elaborate formal discussions, the book presents a practical approach that focuses on the general theory of relativity. It examines different evolutionary models and the gravitational effects of massive bodies. The book also includes a large number of worked examples and problems, half with solutions.

The two-volume book Gravitational Waves provides a comprehensive and detailed account of the physics of gravitational waves. While Volume 1 is devoted to the theory and experiments, Volume 2 discusses what can be learned from gravitational waves in astrophysics and in cosmology, by systematizing a large body of theoretical developments that have taken place over the last decades. The second volume also includes a detailed discussion of the first direct detections of gravitational waves. In the author's typical style, the theoretical results are generally derived afresh, clarifying or streamlining the existing derivations whenever possible, and providing a coherent and consistent picture of the field. The first volume of Gravitational Waves , which appeared in 2007, has established itself as the standard reference in the field. The scientific community has eagerly awaited this second volume. The recent direct detection of gravitational waves makes the topics in this book particularly timely.

This book describes several basic results and applications of global aspects in gravitation theory and cosmology within the framework of Einstein's theory of gravity. Topics include results on the structure and topology of space-time, exact solutions to Einstein equations and singularities, the status of quantum gravity, and quantum effects near space-time singularities in strong curvature fields. Also covered are the global upper limits in cosmology on elementary particle masses which might constitute the dark matter of the universe. After discussing in detail the fundamental role played by global considerations in gravity and general relativity, the author points out the significant problems that remain: the nature and structure of space-time singularities, the cosmic censorship problem in black hole physics, and the issue of quantum effects in strong gravity fields. The author's treatment of gravitational collapse illustrates how powerfully-strong curvature naked singularities could result from the continual gravitational collapse of matter with several reasonable equations of state--including inflowing radiation, dust, or a perfect fluid. Students and mathematicians, astrophysicists, and physicists will find this theoretically rich book a landmark in relativity theory.

' The ICGAC-12 aimed to serve as a common platform around the Asia-Pacific region for the exchange and communication among all researchers in the fields of gravitation, astrophysics and cosmology. The scope covered in the conference includes dark matter, dark energy, experimental study of gravity, black holes, quantum Yang-Mills gravity, GR extension, variation of constants, fundamental physics space projects, relativistic astrophysics, white dwarfs, neutron stars, and gamma ray bursts. Contents:Classical Gravity and GR ExtensionsClassical and Quantum Cosmology, Dark Matter and Dark EnergyBlack Holes and WormholesStrings, Branes, Higher Spin Fields, Quantum GravityExtra Dimensions and Variation of ConstantsGravitational ExperimentsRelativistic Astrophysics Readership: Students and Professionals in the areas of Gravitation, Astrophysics, and Cosmology. Key Features:New approach to accelerated cosmic expansion based on extremely weak gauge fields associated with conserved baryon numberQuantum gravity based on Yang-Mills type gauge symmetry of space-time and translational gauge symmetryProminent contributors: A Beesham, R Maartence (South Africa); Shapiro, C Romero, D Ditman (Brazil); V Frolov (Canada); V Man''ko (Mexico); A Dolgov (Italy); and well-known scientists from RussiaKeywords:Astrophysics;Cosmology;Dark Matter;Dark Energy;Black Holes;Quantum Yang–Mills Gravity;GR Extension;Variation of Constants;Experimental Study of Gravity'

This book provides a compilation of in-depth articles and reviews on key topics within gravitation, cosmology and related issues. It is a celebratory volume dedicated to Prof. Thanu Padmanabhan ("Paddy"), the renowned relativist and cosmologist from IUCAA, India, on the occasion of his 60th birthday. The authors, many of them leaders of their fields, are all colleagues, collaborators and former students of Paddy, who have worked with him over a research career spanning more than four decades. Paddy is a scientist of diverse interests, who attaches great importance to teaching. With this in mind, the aim of this compilation is to provide an accessible pedagogic introduction to, and overview of, various important topics in cosmology, gravitation and astrophysics. As such it will be an invaluable resource for scientists, graduate students and also advanced undergraduates seeking to broaden their horizons.

With a focus on modified gravity this book presents a review of the recent developments in the fields of gravity and cosmology, presenting the state of the art, high-lighting the open problems, and outlining the directions of future research. General Relativity and the ΛCDM framework are currently the standard lore and constitute the concordance paradigm of cosmology. Nevertheless, long-standing open theoretical issues, as well as possible new observational ones arising from the explosive development of cosmology in the last two decades, offer the motivation and lead a large amount of research to be devoted in constructing various extensions and modifications. In this review all extended theories and scenarios are first examined under the light of theoretical consistency, and are then applied in various geometrical backgrounds, such as the cosmological and the spherical symmetric ones. Their predictions at both the background and perturbation levels, and concerning cosmology at early, intermediate and late times, are then confronted with the huge amount of observational data that astrophysics and cosmology has been able to offer in the last two decades. Theories, scenarios and models that successfully and efficiently pass the above steps are classified as viable and are candidates for the description of Nature, allowing readers to get a clear overview of the state of the art and where the field of modified gravity is likely to go. This work was performed in the framework of the COST European Action “Cosmology and Astrophysics Network for Theoretical Advances and Training Actions” - CANTATA.