Download or read book Uncovering Black Holes Via X Ray Spectroscopy written by Jirí Svoboda and published by LAP Lambert Academic Publishing. This book was released on 2011-03 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray observations of active galactic nuclei and black-hole binaries offer a unique laboratory for testing general relativity in the strong-gravity regime, for studying accretion physics around black holes, and for constraining properties of accreting black holes. This book represents the author's Doctoral Thesis. It contains a brief introduction to the black-hole physics and X-ray astronomy as well as the original scientific results. A special attention is focused on black hole spin measurements employing the relativistic iron line profiles in the X-ray domain.
Download or read book Fast Spectral Variability in the X ray Emission of Accreting Black Holes written by Chris Skipper and published by Springer. This book was released on 2014-09-04 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis brings together the various techniques of X-ray spectral analysis in order to examine the properties of black holes that vary in mass by several orders of magnitude. In all these systems it is widely accepted that the X-ray emission is produced by Compton up-scattering of lower energy seed photons in a hot corona or accretion flow, and here these processes are examined through a study of the X-ray spectral variability of each source. A new technique is introduced, in which models are fitted to over 2 million X-ray spectra on time-scales as short as 16 ms, and subsequently it is shown that the nature of the correlation between intensity and spectral index is strongly dependent upon the spectral state of the black hole. Finally, the results of an extensive survey of nearby galactic nuclei using the Chandra X-ray telescope are presented in the form of images and spectra, and these results are used along with data from the literature to search for Compton-thick nuclei.
Download or read book From X ray Binaries to Quasars Black Holes on All Mass Scales written by Thomas J. Maccarone and published by Springer Science & Business Media. This book was released on 2007-01-28 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume brings together contributions from many of the world's leading authorities on black hole accretion. The papers within represent part of a new movement to make use of the relative advantages of studying stellar mass and supermassive black holes, and to bring together the knowledge gained from the two approaches. The topics discussed include black hole observational and theoretical work-variability, spectroscopy, disk-jet connections, and multi-wavelength campaigns on black holes.
Download or read book The X ray Background written by Xavier Barcons and published by Cambridge University Press. This book was released on 1992-07-31 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the current observational knowledge and understanding of the cosmic X-ray background.
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 High resolution X ray Spectroscopy of the Black hole Cygnus X 1 with the Chandra X ray Observatory written by Manfred Hanke and published by . This book was released on 2007 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measuring the Angular Momentum of Supermassive Black Holes written by Laura Brenneman and published by Springer Science & Business Media. This book was released on 2013-06-26 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measuring the spin distribution of supermassive black holes is of critical importance for understanding how these black holes and their host galaxies form and evolve over time, yet this type of study is only in its infancy. This brief describes how astronomers measure spin in supermassive black holes using X-ray spectroscopy. It also reviews the constraints that have been placed on the spin distribution in local, bright active galaxies over the past six years, and the cosmological implications of these constraints. Finally, it summarizes the open questions that remain in this exciting new field of research and points toward future discoveries soon to be made by the next generation of space-based observatories.
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 X ray Spectroscopic and Timing Studies of Galactic Black Hole Binaries written by Jon Matthew Miller and published by . This book was released on 2002 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: In rare cases, optical observations of Galactic binary star systems which are bright in the X-ray portion of the electromagnetic spectrum dynamically constrain the mass of one component to be well above theoretical limits for a neutron star. These systems - and systems with similar X-ray properties - are classified as black hole binaries. In this thesis, I report on observations of black hole binaries made with satellite observatories in the X-ray band. The region closest to the black hole is revealed in X-rays due to the viscous heating of matter that is accreted from the companion star. X-ray observations of these systems may therefore reveal General Relativistic effects. A fundamental and testable prediction of General Relativity is that matter may orbit more closely around black holes with significant angular momentum. I have investigated the possibility of black hole "spin" and the geometry of accretion flows in these systems using X-ray continuum spectroscopy, fast variability studies, and the shape of iron fluorescent emission lines in this band. I present evidence for black hole spin in XTE J1550-564, XTE J1650-500, and XTE J1748-248. Spin is not required by high-resolution spectral analysis of the archetypical Galactic black hole - Cygnus X-1 but a thermal accretion disk plus hot corona geometry is confirmed. Studies of XTE J1118+480 and GRS 1758-258 at low X-ray luminosity reveal that models for radiatively-inefficient accretion do not satisfactorily describe the geometry in these systems.
Download or read book Relativistic Astrophysics written by Marek Demiański and published by Elsevier. This book was released on 2013-10-22 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity stability; and the properties of pulsar, rotating and neutron stars. The discussion then shifts to the association between gravitational collapse and black holes, as well as the astrophysical investigations of neutron stars and black holes. The final chapters examine the principles of gravitational waves and advances in understanding the field of cosmology. This book will be of great value to astrophysicists and related scientists.
Download or read book Ultraluminous X ray Sources and Intermediate mass Black Holes written by David Cseh and published by . This book was released on 2012 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: More than ten years ago, the discovery of ultraluminous X-ray sources (ULXs) has opened up an entirely new field in astrophysics. Many ideas were developed to explain the nature of these sources, like their emission mechanism, mass, and origin, without any strong conclusions. Their discovery boosted the fields of X-ray binaries, accretion physics, stellar evolution, cosmology, black hole formation and growth, due to the concept of intermediate-mass black holes (IMBHs). Since their discovery is related to the domain of X-ray astrophysics, there have been very few 1 studies made in other wavelengths. This thesis focuses on the multiwavelength nature of ultraluminous X-ray sources and intermediate-mass black holes from various aspects, which help to overcome some difficulties we face today. First, I investigated the accretion signatures of a putative intermediate-mass black hole in a particular globular cluster. To this purpose, 1 I characterized the nature of the innermost X-ray sources in the cluster. Then I calculated an upper limit on the mass of the black hole by studying | possible accretion efficiencies and rates based on the dedicated X-ray and radio observations. The accreting properties of the source was described with standard spherical accretion and in the context of inefficient accretion. Secondly, I attempted to dynamically measure the mass of the black hole in a particular ULX via optical spectroscopy. I discovered that a certain emission line has a broad component that markedly shifts in wavelength. I investigated the possibility whether this line originates in the accretion disk, and thus might trace the orbital motion of the binary System. I also characterized the parameters of the binary system, such as the mass function, possible orbital separation, the size of the line emitting region, and an upper limit on the mass of the black hole. Then I studied the environment of a number of ULXs that are associated with large- scale optical and radio nebulae. 1 use these nebulae as a calorimeters to infer the total intrinsic power of these ULXs, characterize the feedback on the environment, and com- pare to Galactic sources. I I also investigated the power mechanism of inflating a bubble by jets. Then I discuss the current status of radio observations on ULXs, including ongoing radio surveys. Finally, I studied HLX-1, which is likely the first bona fide IMBH. This involves radio observations and analysis of the radio data that led to a discovery of radio flares from this source during an X-ray state transition. From the strength of the flares, I provided additional constraints on the mass of the black hole and its accretion rate.
Download or read book The Accretion and Obscured Growth of Supermassive Black Holes written by Peter Boorman and published by Springer Nature. This book was released on 2020-12-02 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the application of state-of-the-art high-energy X-ray studies to the astronomical quest for understanding obscured active galactic nuclei (AGN). These AGN are supermassive black holes growing by accretion of matter located in the nuclei of galaxies. The material that feeds these black holes also obscures them from view, rendering them challenging to study. It is possible to study them by effectively 'X-raying' galactic nuclei to peer through these obscuring veils. Beginning with the proof-of-concept application of novel X-ray Monte Carlo codes to the Nuclear Spectroscopic Telescope ARray (NuSTAR) spectrum of a known heavily obscured AGN, the thesis establishes the relevant parameters that characterise the AGN spectrum and central black hole growth rate. Next the largest sample of known heavily obscured AGN is compiled, finding the strength of a prominent iron spectral feature to weaken with AGN power. This is puzzling, and suggests that there may be more hidden AGN than previously thought. Finally by combining an all-sky infrared selection with NuSTAR follow-up, new heavily obscured AGN are identified. Obscuration emits infrared radiation, meaning that the infrared-selected AGN catalogue should be representative of the underlying AGN population. The absence of such representative catalogues has continually plagued cosmological studies, and the resultant obscured AGN fraction will be strongly constraining for AGN models.
Download or read book Black Holes written by Jean-Pierre Luminet and published by Cambridge University Press. This book was released on 1992-08-28 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Black holes are undoubtedly one of the most fascinating discoveries of modern astronomy, and their description one of the most daring intellectual feats of modern times. They have already become legendary, forming the basis of many myths, fantasies and science fiction movies. Are they really the monsters which devour light and stars; bottomless celestial pits into which all matter is sucked and crushed? Are they an observable reality, or are they just hypothetical objects from the theory of relativity? In answering such questions the author takes us on a fabulous journey through space and time. Dr Jean-Pierre Luminet is an astronomer at Meudon Observatory in France, a specialist on the subject of black holes, and has also acquired a reputation for being a gifted writer and communicator. In this book he makes the subject of black holes accessible to any interested reader, who will need no mathematical background.
Download or read book Astrophysical Black Holes written by Francesco Haardt and published by Springer. This book was released on 2015-11-03 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.
Download or read book Hard X ray Emission from Galactic Black Hole Candidates written by Patrick Lee Nolan and published by . This book was released on 1982 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Galactic Supermassive Black Hole written by Fulvio Melia and published by Princeton University Press. This book was released on 2020-12-08 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, one of the world's leading astrophysicists provides the first comprehensive and logically structured overview of the many ideas and discoveries pertaining to the supermassive black hole at the galactic center known as Sagittarius A*. By far the closest galactic nucleus in the universe, Sagittarius A* alone can provide us with a realistic expectation of learning about the physics of strong gravitational fields, and the impact of such fields on the behavior of matter and radiation under severe physical conditions. Its proximity may even provide the opportunity to directly test one of general relativity's most enigmatic predictions--the existence of closed pockets of space-time hidden behind an event horizon. The plethora of research on Sagittarius A* since its discovery in 1974 has long seemed an interwoven pattern of loose threads. No one has successfully synthesized this growing body of work into a manageable, coherent book both for professional researchers and for students taking courses focusing on black holes and galactic nuclei--until now. With Fulvio Melia's The Galactic Supermassive Black Hole, readers finally have at their disposal a one-volume crucible of essential ideas, logically streamlined but with thorough references for those wishing to explore the various topics in greater depth.
Download or read book Three Steps to the Universe written by David Garfinkle and published by University of Chicago Press. This book was released on 2009-05-15 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: If scientists can’t touch the Sun, how do they know what it’s made of? And if we can’t see black holes, how can we be confident they exist? Gravitational physicist David Garfinkle and his brother, science fiction writer Richard Garfinkle, tackle these questions and more in Three Steps to the Universe, a tour through some of the most complex phenomena in the cosmos and an accessible exploration of how scientists acquire knowledge about the universe through observation, indirect detection, and theory. The authors begin by inviting readers to step away from the Earth and reconsider our Sun. What we can directly observe of this star is limited to its surface, but with the advent of telescopes and spectroscopy, scientists know more than ever about its physical characteristics, origins, and projected lifetime. From the Sun, the authors journey further out into space to explore black holes. The Garfinkle brothers explain that our understanding of these astronomical oddities began in theory, and growing mathematical and physical evidence has unexpectedly supported it. From black holes, the authors lead us further into the unknown, to the dark matter and energy that pervade our universe, where science teeters on the edge of theory and discovery. Returning from the depths of space, the final section of the book brings the reader back down to Earth for a final look at the practice of science, ending with a practical guide to discerning real science from pseudoscience among the cacophony of print and online scientific sources. Three Steps to the Universe will reward anyone interested in learning more about the universe around us and shows how scientists uncover its mysteries.
