Download or read book Star Clusters and Dark Matter as Probes of the Spacetime Geometry of Massive Black Holes written by Laleh Sadeghian and published by . This book was released on 2013 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis includes two main projects. In the first part, we assess the feasibility of a recently suggested strong-field general relativity test, in which future observations of a hypothetical class of stars orbiting very close to the supermassive black hole at the center of our galaxy, known as Sgr A*, could provide tests of the so-called no-hair theorem of general relativity through the measurement of precessions of their orbital planes. By considering how a distribution of stars and stellar mass black holes in the central cluster would perturb the orbits of those hypothetical stars, we show that for stars within about 0.2 milliparsecs (about 6 light-hours) of the black hole, the relativistic precessions dominate, leaving a potential window for tests of no-hair theorems. Our results are in agreement with N-body simulation results. In the second part, we develop a fully general relativistic phase-space formulation to consider the effects of the Galactic center supermassive black hole Sgr A* on the dark-matter density profile and its applications in the indirect detection of dark matter. We find significant differences from the non-relativistic result of Gondolo and Silk (1999), including a higher density for the spike and a larger degree of central concentration. Having the dark matter profile density in the presence of the massive black hole, we calculate its perturbing effect on the orbital motions of stars in the Galactic center, and find that for the stars of interest, relativistic effects related to the hair on the black hole will dominate the effects of dark matter.
Download or read book New Worlds New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
Download or read book Black Holes in the Era of Gravitational Wave Astronomy written by Manuel Arca Sedda and published by Elsevier. This book was released on 2024-05-14 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Black Holes in the Era of Gravitational-Wave Astronomy provides a multidisciplinary, up-to-date view of the physics of black holes, along with an exhaustive overview of crucial open questions and recent advancements in the astrophysics of black holes in the wake of incredible advancements made in the last decade. It includes discussions on improvements in theoretical modeling and observational perspectives for black holes of all sizes, along with associated challenges. The book's structure and themes will enable an entwined understanding of black hole physics at all scales, thus avoiding the compartmentalized view that is typical of more specialized manuscripts and reviews.This book is a complete reference for scientists interested in a multidirectional approach to the study of black holes. It provides substantial discussions about the interplay of different types of black holes and gives professionals a heterogeneous and comprehensive overview of the astrophysics of black holes of all masses. - Focuses on recent advances and future perspectives surrounding black holes, providing researchers with a clear view of cutting-edge research - Offers readers a multidisciplinary, fresh view on black holes, discussing and reviewing the most recent advancements in theoretical, numerical and observational techniques put in place to detect black holes - Provides a bridge among different black hole areas, fostering new collaborations among professionals working in different, but intrinsically interconnected fields
Download or read book Joint Evolution of Black Holes and Galaxies written by M. Colpi and published by CRC Press. This book was released on 2006-01-27 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Black holes are among the most mysterious objects that the human mind has been capable of imagining. As pure mathematical constructions, they are tools for exploiting the fundamental laws of physics. As astronomical sources, they are part of our cosmic landscape, warping space-time, coupled to the large-scale properties and life cycle of their host
Download or read book Probing the Nature of Dark Matter with the First Stars and Black Holes written by Boyuan Liu (Ph. D. in astronomy) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use semi-analytical models and cosmological hydrodynamic simulations to derive the imprints of dark matter physics on the first generation of stars, black holes and galaxies, which, combined with observational data, place constraints on the properties of dark matter. Inspired by the recent detection of gravitational waves, we further investigate the gravitational waves of the first star remnants as a promising probe for early star/structure formation and dark matter physics. Our results indicate that although the first stars only make up a tiny fraction (~ 10−5) of all stars (ever formed) in the Universe, a much higher fraction (~ 10−3 -0.1) of massive compact object mergers can originate from the first stars, which carry valuable information of the early Universe. Finally, we explore the effects of primordial black holes, which can make up all or part of dark matter, on first star formation, and discuss their implications on using gravitational waves as a direct probe of dark matter
Download or read book In Search of Dark Matter written by Ken Freeman and published by Springer Science & Business Media. This book was released on 2006-03-21 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written for the educated non-scientist and scientist alike, it spans a variety of scientific disciplines, from observational astronomy to particle physics. Concepts that the reader will encounter along the way are at the cutting edge of scientific research. However the themes are explained in such a way that no prior understanding of science beyond a high school education is necessary.
Download or read book Progress in Dark Matter Research written by J. Val Blain and published by Nova Publishers. This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Black Holes A Laboratory for Testing Strong Gravity written by Cosimo Bambi and published by Springer. This book was released on 2017-06-01 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook introduces the current astrophysical observations of black holes, and discusses the leading techniques to study the strong gravity region around these objects with electromagnetic radiation. More importantly, it provides the basic tools for writing an astrophysical code and testing the Kerr paradigm. Astrophysical black holes are an ideal laboratory for testing strong gravity. According to general relativity, the spacetime geometry around these objects should be well described by the Kerr solution. The electromagnetic radiation emitted by the gas in the inner part of the accretion disk can probe the metric of the strong gravity region and test the Kerr black hole hypothesis. With exercises and examples in each chapter, as well as calculations and analytical details in the appendix, the book is especially useful to the beginners or graduate students who are familiar with general relativity while they do not have any background in astronomy or astrophysics.“/p>
Download or read book Black Holes and Relativistic Stars written by Robert M. Wald and published by University of Chicago Press. This book was released on 1998 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive summary of progress made during the past decade on the theory of black holes and relativistic stars, this collection includes discussion of structure and oscillations of relativistic stars, the use of gravitational radiation detectors, observational evidence for black holes, cosmic censorship, numerical work related to black hole collisions, the internal structure of black holes, black hole thermodynamics, information loss and other issues related to the quantum properties of black holes, and recent developments in the theory of black holes in the context of string theory. Volume contributors: Valeria Ferrari, John L. Friedman, James B. Hartle, Stephen W. Hawking, Gary T. Horowitz, Werner Israel, Roger Penrose, Martin J. Rees, Rafael D. Sorkin, Saul A. Teukolsky, Kip S. Thorne, and Robert M. Wald.
Download or read book Clusters of Galaxies Physics and Cosmology written by Andrei M. Bykov and published by Springer. This book was released on 2020-10-31 with total page 535 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of galaxies are large assemblies of galaxies, hot gas and dark matter bound together by gravity. Galaxy clusters are now one of the most important cosmological probes to test the standard cosmological models. Constraints on the Dark Energy equation of state from the cluster number density measurements, deviations from the Gaussian perturbation models, the Sunyaev-Zeldovich effect as well as the dark matter proles are among the issues to be studied with clusters. The baryonic composition of clusters is dominated by hot gas that is in quasi-hydrostatic equilibrium within the dark matter-dominated gravitational potential well of the cluster. The hot gas is visible through spatially extended thermal X-ray emission, and it has been studied extensively both for assessing its physical properties and as a tracer of the large-scale structure of the Universe. Magnetic fields as well as a number of non-thermal plasma processes play a role in clusters of galaxies as we observe from radioastronomical observations. The goal of this volume is to review these processes and to investigate how they are interlinked. Overall, these papers provide a timely and comprehensive review of the multi-wavelength observations and theoretical understanding of clusters of galaxies in the cosmological context. Thus, the volume will be particularly useful to postgraduate students and researchers active in various areas of astrophysics and space science. Originally published in Space Science Reviews in the Topical Collection "Clusters of Galaxies: Physics and Cosmology"
Download or read book Supermassive Black Holes in the Distant Universe written by A.J. Barger and published by Springer Science & Business Media. This book was released on 2013-11-09 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quasars, and the menagerie of other galaxies with "unusual nuclei", now collectively known as Active Galactic Nuclei or AGN, have, in one form or another, sparked the interest of astronomers for over 60 years. The only known mechanism that can explain the staggering amounts of energy emitted by the innermost regions of these systems is gravitational energy release by matter falling towards a supermassive black hole --- a black hole whose mass is millions to billions of times the mass of our Sun. AGN emit radiation at all wavelengths. X-rays originating at a distance of a few times the event horizon of the black hole are the emissions closest to the black hole that we can detect; thus, X-rays directly reveal the presence of active supermassive black holes. Oftentimes, however, the supermassive black holes that lie at the centers of AGN are cocooned in gas and dust that absorb the emitted low energy X-rays and the optical and ultraviolet light, hiding the black hole from view at these wavelengths. Until recently, this low-energy absorption presented a major obstacle in observational efforts to map the accretion history of the universe. In 1999 and 2000, the launches of the Chandra and XMM-Newton X-ray Observatories finally broke the impasse. The impact of these observatories on X-ray astronomy is similar to the impact that the Hubble Space Telescope had on optical astronomy. The astounding new data from these observatories have enabled astronomers to make enormous advances in their understanding of when accretion occurs.
Download or read book Superradiance written by Richard Brito and published by Springer Nature. This book was released on 2020-08-21 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on one mechanism in black hole physics which has proven to be universal, multifaceted and with a rich phenomenology: rotational superradiance. This is an energy extraction process, whereby black holes can deposit their rotational energy in their surroundings, leading to Penrose processes, black-hole bombs, and even Hawking radiation. Black holes are key players in star formation mechanisms and as engines to some of the most violent events in our universe. Their simplicity and compactness make them perfect laboratories, ideally suited to probe new fields or modifications to the theory of gravity. Thus, black holes can also be used to probe some of the most important open problems in physics, including the nature of dark matter or the strong CP problem in particle physics. This monograph is directed to researchers and graduate students and provides a unified view of the subject, covering the theoretical machinery, experimental efforts in the laboratory, and astrophysics searches. It is focused on recent developments and works out a number of novel examples and applications, ranging from fundamental physics to astrophysics. Non-specialists with a scientific background should also find this text a valuable resource for understanding the critical issues of contemporary research in black-hole physics. This second edition stresses the role of ergoregions in superradiance, and completes its catalogue of energy-extraction processes. It presents a unified description of instabilities of spinning black holes in the presence of massive fields. Finally, it covers the first experimental observation of superradiance, and reviews the state-of-the-art in the searches for new light fields in the universe using superradiance as a mechanism.
Download or read book Dense Stellar Systems and Massive Black Holes written by Pau Amaro-Seoane and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravity dictates the structure of the whole Universe and, although it is triumphantly described by the theory of General Relativity, it is the force that we least understand in nature. One of the cardinal predictions of this theory are black holes. Massive, dark objects are found in the majority of galaxies. Our own galactic center very contains such an object with a mass of about four million solar masses. Are these objects supermassive black holes (SMBHs), or do we need alternatives? The answer lies in the event horizon, the characteristic that defines a black hole. The key to probe the horizon is to model the movement of stars around a SMBH, and the interactions between them, and look for deviations from real observations. Nuclear star clusters harboring a massive, dark object with a mass of up to ~ ten million solar masses are good testbeds to probe the event horizon of the potential SMBH with stars. The channel for interactions between stars and the central MBH are the fact that (a) compact stars and stellar-mass black holes can gradually inspiral into the SMBH due to the emission of gravitational radiation, which is known as an "Extreme Mass Ratio Inspiral" (EMRI), and (b) stars can produce gases which will be accreted by the SMBH through normal stellar evolution, or by collisions and disruptions brought about by the strong central tidal field. Such processes can contribute significantly to the mass of the SMBH. These two processes involve different disciplines, which combined will provide us with detailed information about the fabric of space and time. In this habilitation I present nine articles of my recent work directly related with these topics.
Download or read book Trends in Dark Matter Research written by J. Val Blain and published by Nova Publishers. This book was released on 2005 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 Ù) is less than unity. If the universe is closed, Ù is greater than unity. For the case where Ù is exactly equal to one the universe is "flat". This new book details leading-edge research from around the globe.
Download or read book Connecting Quarks with the Cosmos written by National Research Council and published by National Academies Press. This book was released on 2003-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.
Download or read book Gravitational Physics written by National Research Council and published by National Academies Press. This book was released on 1999-11-03 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravitational Physics assesses the achievements of the field over the past decade in both theory and experiment, identifies the most promising opportunities for research in the next decade, and describes the resources necessary to realize those opportunities. A major theme running through the opportunities is the exploration of strong gravitational fields, such as those associated with black holes. The book, part of the ongoing decadal survey Physics in a New Era, examines topics such as gravitational waves and their detection, classical and quantum theory of strong gravitational fields, precision measurements, and astronomical observations relevant to the predictions of Einstein's theory of general relativity.
Download or read book Supermassive Black Hole written by Celestial Angell and published by Dedona Publishing. This book was released on with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: A black hole is a region in space where the gravitational pull is so strong that nothing, not even light, can escape from it. This occurs when a massive amount of matter is compressed into a very small area, creating a powerful gravitational field. Black holes form through various processes that involve the collapse of massive astronomical objects and the merging of smaller black holes. One primary method is the stellar collapse. Stars, during their lifecycle, fuse hydrogen into helium in their cores. When the hydrogen is depleted, they begin fusing heavier elements until iron is produced. For stars more than 20 times the mass of the Sun, the end of this fusion process leads to a supernova explosion. The core of the star collapses rapidly due to gravity, and if the core's mass is sufficiently large (typically more than about three times the mass of the Sun), it will continue collapsing into a singularity, forming a stellar-mass black hole. Another way black holes can form is through accretion and growth. A compact object like a neutron star or a white dwarf can accumulate matter from a companion star or its surroundings. As this matter accumulates, the mass of the compact object increases, and it may eventually reach a critical mass where it collapses into a black hole.
