Download or read book X ray Studies of Ultraluminous X ray Sources written by Wasutep Luangtip and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical X ray Studies of Ultraluminous X ray Sources written by Jeanette Claire Gladstone and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultraluminous X-ray Sources (ULXs) are point like X-ray sources situated external to the nucleus of their host galaxy, with inferred X-ray luminosities in excess of 10 {39} erg s {?1} . Although?rst observed? 30 years ago, these sources are yet to be fully understood. Some have suggested that these fascinating objects may contain intermediate mass black holes, whilst others have proposed they are stellar mass black holes residing in a new extreme accretion state. This thesis works towards the conclusion of this debate, by developing our understanding of these systems and their environments. This work begins with a photometric survey of the optical counterparts of ULXs. The main aim of this survey is to?nd plausible candidates to gain radial velocity measurements and therefore mass functions of these systems. However, the collation of this sample also provides the opportunity to classify the stellar objects held within these systems. From this work, we?nd seven good candidates for optical spectroscopic follow-up. Our results also show that many of our sample are consistent with OB type stars, while some contain later type bright giants/supergiants. Possibly our best chance to gain precise measurements of M_{BH}, and settling the debate over the nature of these systems, is by using radial velocity curves of their optical counterparts to calculate a mass function of ULXs. We are currently undertaking a programme to pursue mass function measurements for these systems. To date, we have received the pilot spectra of three optical counterparts. We discuss the progress of this programme to date and perform analysis on both the absorption/emission features and the continuum of these spectra. Initial analysis reveals the presence of the He ii 4686 A line in two of our pilot spectra. This line may be associated with the accretion disc of these systems, and could therefore be used in our pursuit of the mass function. We also?nd the presence of both low and high ionization lines, with some evidence for shock ionisation, and electron temperature of 7,000? 10,000 K. This Balmer decrement also indicates that the extinction can be highly variable across ULX?eld. This combination may suggest a?patchy? environment with separate shock and photoionisation emission regions. While the continuum emission of one of our sample can be explained by either the spectra of an OB star or of a standard accretion disc, the steep slopes of two of our sample indicates non-stellar origins that could represent the optical spectrum of a super-Eddington accretion disc. Finally, this work highlights the need for further observations of these sources in order to unlock their nature. We present results of X-ray spectral variability studies of the ULX population contained within NGC 4485 & 4490. We collate Chandra and XMM-Newton observations of the interacting galaxy pair, to analyse the emission from the six ULXs previously identified, and one additional source observed in the a recent exposure. This provides us with an opportunity to study variability on both short and longer time scales. The spectral variability is generally characterised by a hardening of the source spectra as their luminosities increase. The sources show a variety of long-term light curves; however, short-term (intra-observational) temporal variability is conspicuous by its absence. This survey also reveals the detection of a possible change in accretion state that could be used to gain crude mass estimates of the compact objects. Finally, we explore further the variability of these systems with the aid of two new proprietary observations. Finally, analysis of some of the best quality X-ray spectral data publicly available on these sources has provided the opportunity to explore the nature of these systems. We apply phenomenological models to characterise the spectra of these objects and more physically motivated models in order to explore the physical processes underlying these characteristics. Results show that the spectra of these sources are fundamentally different to that of Galactic X-ray binaries, whilst the application of physical models indicates a more extreme version of the highest known luminosity state, the very high state. We therefore speculate that in observing ULXs we are observing stellar mass black holes residing in a new?ultraluminous? state.

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 Spectral Analysis of Ultraluminous X ray Sources Using the Chandra Xray Observatory written by Akram Chandrajit Singha, A Senorita Devi and published by Sankalp Publication. This book was released on with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive introduction to the data analysis of ultraluminous X-ray sources. This book will provide the readers with a familiar environment in data analysis methods and the different software used in high energy astrophysical data analysis.

Download or read book Astrophysics of Black Holes written by Cosimo Bambi and published by Springer. This book was released on 2016-07-28 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the state of the art of the basic theoretical and observational topics related to black hole astrophysics. It covers all the main topics in this wide field, from the theory of accretion disks and formation mechanisms of jet and outflows, to their observed electromagnetic spectrum, and attempts to measure the spin of these objects. Black holes are one of the most fascinating predictions of general relativity and are currently a very hot topic in both physics and astrophysics. In the last five years there have been significant advances in our understanding of these systems, and in the next five years it should become possible to use them to test fundamental physics, in particular to predict the general relativity in the strong field regime. The book is both a reference work for researchers and a textbook for graduate students.

Download or read book Ultra luminous X ray Sources written by Jifeng Liu and published by . This book was released on 2005 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating the Nature of Ultraluminous X ray written by Paola Mucciarelli and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Astrophysics Of Gas Nebulae and Active Galactic Nuclei written by Donald E. Osterbrock and published by University Science Books. This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly revised and expanded throughout, the new edition is a graduate-level text and reference book on gaseous nebulae, nova and supernova remnants. Much of the new data and new images are from the Hubble Space Telescope with two wholly new chapters being added along with other new features. The previous edition which was tried and tested for thirty years has now been succeeded by a revised, updated, larger edition, which will be valuable to anyone seriously interested in astrophysics.

Download or read book Exploring the X ray Universe written by Frederick D. Seward and published by Cambridge University Press. This book was released on 2010-08-26 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capturing the excitement and accomplishments of X-ray astronomy, this second edition now includes a broader range of astronomical phenomena and dramatic new results from the most powerful X-ray telescopes. Covering all areas of astronomical research, ranging from the smallest to the largest objects, from neutron stars to clusters of galaxies, this textbook is ideal for undergraduate students. Each chapter starts with the basic aspects of the topic, explores the history of discoveries, and examines in detail modern observations and their significance. This new edition has been updated with results from the most recent space-based instruments, including ROSAT, BeppoSAX, ASCA, Chandra, and XMM. New chapters cover X-ray emission processes, the interstellar medium, the Solar System, and gamma-ray bursts. The text is supported by over 300 figures, with tables listing the properties of the sources, and more specialized technical points separated in boxes.

Download or read book A Study of X ray Luminosity Functions of Ultraluminous X ray Sources and the Properties of Their Host Galaxies written by 林隼成 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultraluminous X ray Sources written by Andrew Sutton and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evolutionary Processes in Binary and Multiple Stars written by Peter Eggleton and published by Cambridge University Press. This book was released on 2006-07-20 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Binary systems of stars are as common as single stars. Stars evolve primarily by nuclear reactions in their interiors, but a star with a binary companion can also have its evolution influenced by the companion. Multiple star systems can exist stably for millions of years, but can ultimately become unstable as one star grows in radius until it engulfs another. This volume, first published in 2006, discusses the statistics of binary stars; the evolution of single stars; and several of the most important kinds of interaction between two (and even three or more) stars. Some of the interactions discussed are Roche-lobe overflow, tidal friction, gravitational radiation, magnetic activity driven by rapid rotation, stellar winds, magnetic braking and the influence of a distant third body on a close binary orbit. A series of mathematical appendices gives a concise but full account of the mathematics of these processes.

Download or read book Introduction to Black Hole Astrophysics written by Gustavo E. Romero and published by Springer. This book was released on 2013-09-14 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the lecture notes of a one-semester course on black hole astrophysics given by the author and is aimed at advanced undergraduate and graduate students with an interest in astrophysics. The material included goes beyond that found in classic textbooks and presents details on astrophysical manifestations of black holes. In particular, jet physics and detailed accounts of objects like microquasars, active galactic nuclei, gamma-ray bursts, and ultra-luminous X-ray sources are covered, as well as advanced topics like black holes in alternative theories of gravity. The author avoids unnecessary technicalities and to some degree the book is self-contained. The reader will find some basic general relativity tools in Chapter 1. The appendices provide some additional mathematical details that will be useful for further study, and a guide to the bibliography on the subject.

Download or read book Accretion driven Stellar X ray Sources written by Walter H. G. Lewin and published by . This book was released on 1983 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accretion Power in Astrophysics written by Juhan Frank and published by Cambridge University Press. This book was released on 2002-01-17 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book X Ray Optics written by Yuri Shvyd'ko and published by Springer. This book was released on 2013-11-11 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of x rays has moved in the forefront of science and technology in the second half of the 20th century. This progress has been greatly stimulated by the advent of synchrotron x-ray sources in the 1960s. The undulator-based synchrotron radiation sources which have appeared in the last decade of the 20th century gave a new impetus to such development. The brilliance of the x-ray sources has increased by 12 orders of magnitude in 40 years and this trend does not show any signs of stagnation. The future x-ray sources of the 21th century based on free-electron lasers driven by linear accelerators will provide sub-picosecond radiation pulses with by many orders of magnitude higher brilliance and full transverse coherence. The x-ray sources of the newest generation offer a possibility to realize more than ever before the great potential of x-ray optics and, as a consequence, to elaborate new sophisticated instrumentation with unprecedented resolution and eventually to move in new directions of research in x-ray technology, materials science, fundamental physics, life sciences, etc.

Download or read book High Energy Astrophysics Volume 2 Stars the Galaxy and the Interstellar Medium written by M. S. Longair and published by Cambridge University Press. This book was released on 1992 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: What role does viscosity play in accretion discs? How do you calculate the 'glitch function' of a pulsar? And can strong shocks account for the energy spectrum of electrons in our Galaxy? These are just some of the exciting questions that Professor Longair uses to develop the physics needed by the astronomer and high energy astrophysicist. The highly acclaimed first edition of High Energy Astrophysics instantly established itself as a classic in the teaching of contemporary astronomy. Reflecting the immense interest and developments in the subject, Professor Longair has developed the second edition into three texts; in this second volume he provides a comprehensive discussion of the high energy astrophysics of stars, the Galaxy and the interstellar medium. He develops an understanding for the essential physics with an elegance and infectious enthusiasm for which his teaching is internationally renowned, illustrating the issues throughout with results from forefront research. This book takes the student with a knowledge of physics and mathematics at the undergraduate level - but not necessarily with training in astronomy - to the point where current astronomical research can be understood.