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Accretion Power in Astrophysics examines accretion as a source of energy in both binary star systems containing compact objects, and in active galactic nuclei. Assuming a basic knowledge of physics, the authors describe the physical processes at work in accretion discs and other accretion flows. The first three chapters explain why accretion is a source of energy, and then present the gas dynamics and plasma concepts necessary for astrophysical applications. The next three chapters then develop accretion in stellar systems, including accretion onto compact objects. Further chapters give extensive treatment of accretion in active galactic nuclei, and describe thick accretion discs. A new chapter discusses recently discovered accretion flow solutions. The third edition is greatly expanded and thoroughly updated. New material includes a detailed treatment of disc instabilities, irradiated discs, disc warping, and general accretion flows. The treatment is suitable for advanced undergraduates, graduate students and researchers.

Accretion (Astrophysics) --- Astrophysics

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Accretion (Astrophysics) --- Be stars. --- Double stars --- Evolution. --- Evolution --- B emission stars --- B stars --- Astrophysics

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This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes of disk oscillations, studies on binary systems are of importance, as they offer valuable information on wave–wave coupling processes in disk oscillations. Accordingly, some characteristics of oscillations in deformed disks are also presented in this book. The book consists of two parts. Points covered in Part I include, for instance, the basic characteristics of disk oscillations, classification of oscillation modes, and trapping of oscillations. In Part II, the focus is mainly on excitation processes of oscillations, while applications to observations are also discussed.

Physics. --- Planetology. --- Mathematical physics. --- Astronomy. --- Astrophysics. --- Cosmology. --- Astronomy, Astrophysics and Cosmology. --- Theoretical, Mathematical and Computational Physics. --- Mathematical Applications in the Physical Sciences. --- Accretion (Astrophysics) --- Astrophysics --- Planetary sciences --- Planetology --- Physical mathematics --- Physics --- Astronomical physics --- Astronomy --- Cosmic physics --- Mathematics

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Our understanding of the formation of stars and planetary systems has changed greatly since the first edition of this book was published. This new edition has been thoroughly updated, and now includes material on molecular clouds, binaries, star clusters and the stellar initial mass function (IMF), disk evolution and planet formation. This book provides a comprehensive picture of the formation of stars and planetary systems, from their beginnings in cold clouds of molecular gas to their emergence as new suns with planet-forming disks. At each stage gravity induces an inward accretion of mass, and this is a central theme for the book. The author brings together current observations, rigorous treatments of the relevant astrophysics, and 150 illustrations, to clarify the sequence of events in star and planet formation. It is a comprehensive account of the underlying physical processes of accretion for graduate students and researchers.

Stars --- Accretion (Astrophysics) --- Disks (Astrophysics) --- Gravitational collapse. --- Etoiles --- Accrétion (Astrophysique) --- Disques (Astrophysique) --- Effondrement gravitationnel --- Formation. --- Formation --- Birth, Stellar --- Formation, Star --- Formation, Stellar --- Stellar birth --- Stellar formation --- Collapse, Gravitational --- Astrophysical discs --- Astrophysical disks --- Discs (Astrophysics) --- Disk systems (Astrophysics) --- Astrophysics --- Evolution

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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.

Physics. --- Astronomy, Observations and Techniques. --- Physique --- Astronomy & Astrophysics --- Physical Sciences & Mathematics --- Astronomy - General --- X-ray astronomy. --- Accretion (Astrophysics) --- Black holes (Astronomy) --- Astrophysics. --- Astronomical physics --- Frozen stars --- Observations, Astronomical. --- Astronomy --- Observations. --- Cosmic physics --- Physics --- Compact objects (Astronomy) --- Gravitational collapse --- Stars --- Astrophysics --- Space astronomy --- X-rays --- Astronomical observations --- Observations, Astronomical --- Natural philosophy --- Philosophy, Natural --- Physical sciences --- Dynamics --- Astronomy—Observations.