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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 62 for “"x-ray binaries"”.
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Spectral Comparisons of Neutron Star Low-Mass X-Ray Binaries with Black Hole X-Ray Binaries
The study of high-resolution X-ray spectra of neutron star low-mass X-ray binaries (LMXBs) allows the investigation of the innermost parts of the accretion disk and immediate surroundings of the compact object. The weak magnetic eld of old neutron stars present in such systems allows the accretion …
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Spectral analysis of X-ray binaries
… projects associated with observations of X-ray binaries. Two of those revolve around spectral characteristics of neutron star low-mass X-ray binaries (NS-LMXBs), with a particular source, XTE J1701-462, playing a central role. First, I construct and study color-color and hardness-intensity …
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Gamma-Ray Observations of X-ray Binaries
<p>The detection of GeV/TeV emission from X-ray binaries (XRBs) has established a new class of high-energy (HE, >0.1 GeV) and very-high-energy (VHE, >100 GeV) gamma-ray emitters. XRBs are formed by a compact object, either a neutron star or a black hole, and by an optical companion star. Some XRBs …
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Formation of Low-Mass X-Ray Binaries
… study of the origin and properties of low-mass X-ray binaries (compact objects with Roche-lobe filling low-mass companions) by means of population syntheses is presented. A semi-analytical synthesis method that offers major advantages in terms of statistical accuracy and computational efficiency …
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Disk-magnetosphere interaction in X-ray binaries
Binary X-ray pulsars are strongly magnetic neutron stars accreting matter from a companion star. The strong magnetic fields of the neutron stars guide the accreting plasma to the magnetic poles, and X-ray pulsations result from the rotation of the beamed emission at the magnetic poles through the …
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Accretion and outflow in black-hole x-ray binaries
Black hole X-ray binaries (BHXBs) are stellar binary systems consisting of a black hole (BH) and a companion star. They are known to produce X-ray emission through the accretion of mass from the companion star onto the black hole via an accretion disc, as well as radio emission originating from …
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X-ray spectroscopy of low-mass X-ray binaries
I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first part of this thesis concentrates on results from the subset of LMXBs with …
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X-ray binaries in the Milky Way and other galaxies
Die vorliegende Arbeit beschäftigt sich im ersten Teil mit der Verteilung und den Eigenschaften der Populationen von Röntgendoppelsternen in der Milchstraße. Im zweiten Teil geht es um den Zusammenhang zwischen der Sternentstehungsrate einer Galaxis mit dem Auftreten Sternsysteme mit einem massiven …
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Exploring the super-orbital periodic behaviour of X-Ray binaries
… are an established feature of several luminous X-ray binaries. The mechanisms that have been proposed to be responsible for such modulations include irradiation-driven warping/tilting and tidally-induced precession of the accretion disc, jet precession and the modulation of the mass-transfer rate …
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Observational and evolutionary studies of neutron star X-ray binaries
… and evolutionary studies of neutron stars in X-ray binary systems. A variety of topics are discussed, which are all related by a single scientific theme, namely, helping to set constraints on the mass-radius relation of neutron stars, and hence on their equations of state (EOS). In Chapter 1 we …
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The Properties of AGN in the context of X-ray Binaries
Black holes are undoubtedly the most fascinating and exciting objects in the Universe, capturing the imagination of scientists and film writers alike. It has been a long standing objective of the scientific community to understand how these objects work and whether the black holes seen in the …
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How circumstellar discs affect mass accretion in Be X-ray binaries
… spectroscopic monitoring of Galactic Be X-ray binaries (BeXBs) is performed using the Liverpool Telescope and the Southern African Large Telescope on northern and southern objects, respectively. Be disc size variations are presented to investigate their influence on mass accretion producing …
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Long-term properties of X-ray binaries in the magellanic clouds
Long-term variability in all types of X-ray binaries is a well established characteristic, but due to observation limitations and lack of long-term monitoring capability these variations have not been studied before in a systematic way. In this thesis, we exploit the ~ 16 yr optical light curves …
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The accretion process in neutron-star low-mass X-ray binaries
… of accreting neutron stars (NSs) in low-mass X-ray binaries involving the X-ray spectral decomposition, the relations between subtypes (mainly atoll and Z sources), and the origins of different X- ray states. Atoll sources are less luminous and have both hard and soft spectral states, while Z …
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X-ray spectroscopy of neutron star low-mass X-ray binaries
… of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. First, I give an overview of important X- ray astrophysics relevant to the work I present in subsequent chapters, as well as …
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Accretion flows and neutron star heating in low-mass X-ray binaries
X-ray binaries are excellent test beds for studies of high-energy accretion flows and the properties of compact objects. Neutron star (NS) low-mass X-ray binaries (LMXBs) vary in brightness by almost 8 orders of magnitude and are hosts to diverse accretion flows, transporting varying amounts of …
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The Connection Between X-Ray Binaries and Star Clusters in the Andromeda Galaxy
The exploration of X-ray binaries (XRBs) and their relationship with star clusters is an important aspect of astrophysics, offering insights into the processes that govern stellar evolution and the dynamical interactions within star clusters. XRBs are fascinating astronomical systems where a star …
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Multiwavelength variability of black hole x-ray binaries in the low/hard state
The behaviour of black hole X-ray binaries can be classified into five spectral states which are defined in terms of the X-ray spectral and timing properties of the source. These states show distinct and observable characteristics and transitions from one state to another often take place. Perhaps …
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Spectral-Timing Observations of Disk-Jet Coupling in Black Hole X-ray Binaries
… and geometry of the hot (hundreds of keV) X-ray emitting plasma called the “corona". X-ray Reverberation Mapping, where X-rays produced close to the BH reverberate off inspiraling gas, allows us to map out scales close to the event horizon -- orders of magnitude better than the resolution of …
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