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 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 Spectra and Timing of Compact X ray Binaries written by Pranab Ghosh and published by . This book was released on 2006 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book X ray Timing and Spectral Observations of Galactic Black Hole Candidate XTE J1550 564 During Outburst written by Kaice Theodore Reilly and published by . This book was released on 2002 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 X Ray Timing 2003 written by Philip Kaaret and published by American Institute of Physics. This book was released on 2004-07-22 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cambridge, Massachusetts, 3-5 November 2003
Download or read book X ray Studies of the Central Engine in Active Galactic Nuclei with Suzaku written by Hirofumi Noda and published by Springer. This book was released on 2018-12-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this research was to use the X-ray satellite Suzaku to establish a picture of a central engine that effectively converts the gravitational energy of accreting matter onto the supermassive black hole to a huge amount of radiation in an active galactic nucleus. Although the engine is known to consist of a Comptonizing corona and an accretion disk, its image has remained unclear because primary emissions, coming directly from the engine, cannot be identified in X-ray spectra without models. The book describes a technique of time variability assisted spectral decomposition to model-independently examine X-ray signals, and how this was applied to the Suzaku archive data of active galactic nuclei. As a result, at least three distinct primary X-ray components have been discovered in an X-ray from an active galactic nucleus, presumably indicating a novel picture that the engine is composed of multiple coronae with different physical properties in an accretion flow. Furthermore, the determination of the spectral shapes of the primary X-rays has a significant impact on estimations of black hole spins, because it is essential to quantify reprocessed X-ray spectra. The successful model-independent decomposition of X-ray spectral components with flux variations of active galactic nuclei is likely to be effective in future data analyses from the soon-to-be-launched Japanese X-ray satellite ASTRO-H, which is capable of achieving unprecedented fine spectros copy and broad energy band coverage.
Download or read book Galactic Black Hole Binaries High Energy Radiation written by and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observations of galactic black hole candidates made by the instruments aboard the Compton GRO in the hard X-ray and gamma-ray bands have significantly enhanced our knowledge of the emission properties of these objects. Understanding these observations presents a formidable challenge to theoretical models of the accretion flow onto the compact object and of the physical mechanisms that generate high-energy radiation. Here we summarize the current state of observations and theoretical interpretation of the emission from black hole candidates above 20 keV. The all-sky monitoring capability of BATSE allows, for the first time, nearly continuous studies of the high-energy emission from more than a dozen black hole candidates. These long-term datasets are particularly well-suited to multi- wavelength comparison studies, from the radio upward in frequency (Zhang et al. 1997a, these proceedings). Energy spectral evolution and/or spectral state transitions have been observed from many of the black hole candidates. Moderately deep searches of the galactic plane suggest a deficit of weak gamma-ray transients. Such population studies have implications for the origin of black hole binaries and the nature of accretion events.
Download or read book Black Holes in Binaries and Galactic Nuclei Diagnostics Demography and Formation written by Riccardo Giacconi and published by Springer Science & Business Media. This book was released on 2001-02-26 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observational evidence for the existence of black holes has grown significantly over recent decades. Stellar-mass black holes are detected as X-ray sources in binary systems, while supermassive black holes, with masses more than a million times the mass of the Sun, lurk in the nuclei of galaxies. These proceedings provide a useful and up-to-date overview of the observations of black holes in binaries, in the center of the Milky Way, and in the nuclei of galaxies, presented by leading expert astronomers. Special attention is given to the formation (including the recent evidence from gamma-ray bursts), physical properties, and demographics of black holes.
Download or read book A Population Explosion written by Reba Bandyopadhyay and published by American Institute of Physics. This book was released on 2008-06-04 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technological advances in X-ray astronomy have recently led to the discovery of a large number of previously undetected accreting binaries, increasing by an order of magnitude their known population in the Galaxy. This meeting addressed the current state of observational and theoretical research into the X-ray binary population as a whole, including both well-studied systems and the newly discovered populations, and examined the interaction of X-ray binaries with their environment within our own Galaxy and in external galaxies.
Download or read book The Violent Universe written by Kimberly Weaver and published by JHU Press. This book was released on 2005 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The book includes four-color images of galaxies, quasars, pulsars, and black holes captured by Chandra, an enormous x-ray satellite that orbits Earth from a distance 200 times higher than that of the Hubble Telescope."--BOOK JACKET.
Download or read book Compact Stellar X ray Sources written by Walter Lewin and published by Cambridge University Press. This book was released on 2006-04-06 with total page 667 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray astronomy is the prime available window on astrophysical compact objects: black holes, neutron stars and white dwarfs. In this book, prominent experts provide a comprehensive overview of the observations and astrophysics of these objects. This is a valuable reference for graduate students and active researchers.
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 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 X and Gamma Ray Astronomy written by H. Bradt and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: The IAU Symposium No. 55 on 'X-Ray and Gamma-Ray Astronomy' has occurred, not entirely by coincidence, at an important moment in the development of these new branches of observational astronomy. In X-ray astronomy the data from the first X-ray observatory UHURU have contributed to a new view of the X-ray sky and a new conception of the nature and properties of galactic and extragalactic X-ray sources. In gamma-ray astronomy the exciting and often controversial nature of the results underlines the importance of the forthcoming launch of SAS-B, the first orbiting y-ray observatory. As Bruno Rossi reminds us (p. I), the Symposium occurred almost exactly ten years after the first detection of the X-ray star Sco X-I. During this time we have moved from the detection of a handful of the nearest and brightest sources to the detailed study of the nature of stellar sources in the farthest reaches of our own galaxy and in external galaxies of the local group. The detection of pulsating X-ray sources in bi nary systems permits the measurement of pulsation periods, and orbital parameters with precisions comparable to any yet achieved with traditional observational techniques. The strong indications that most X-ray sources are extremely compact objects give us confidence that X-ray astronomy will playa significant and possibly decisive role in the study of stars near the end point of stellar evolution.
Download or read book X Ray Timing and Spectral Observations of Galactic Black Hole Candidate XTE J1550 564 During Outburst written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soft X-ray transients (SXTs), a sub-class of low-mass X-ray binaries (LMXBs), provide a unique opportunity to test General Relativity and to probe fundamental physics under conditions terrestrially unattainable. SXT outbursts are of great interest because they allow the study of LMXBs under a wide range of accretion rates. The majority of known SXTs contain black holes, therefore SXT outbursts are key to understanding accretion physics around black holes and in active galactic nuclei, which are thought to contain supermassive, M (almost equal to) 106 - 101° M{circle_dot}, where M{circle_dot} is one solar mass, central compact objects. These compact objects are most likely black holes, which exhibit, on a much larger scale, accretion physics similar to that around black holes in SXTs. In this work, the timing and spectral properties of the SXT and microquasar XTE J1550-564 during outburst are studied. Observations made by the Unconventional Stellar Aspect (USA) Experiment on board the Advanced Research and Global Observation Satellite (ARGOS) are emphasized. USA data show a low-frequency quasi-periodic oscillation (LFQPO) with a centroid frequency that tends to increase with increasing USA flux and a fractional rms amplitude which is correlated with the USA hardness ratio (4-16 keV/1-4 keV). Several high-frequency quasi-periodic oscillations (HFQPOs) were detected by the Rossi X-ray Timing Explorer (RXTE), during periods where the LFQPO is seen to be weakening or not detectable at all. The evolution of the USA hardness ratio with time and source flux is examined. The hardness-intensity diagram shows counterclockwise cyclical evolution and possibly indicates the presence of two independent accretion flows: a geometrically thin, optically thick accretion disk and a hot sub-Keplerian flow.
