Global ETD Search
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 21 for “"relativistic jets"”.
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A theoretical study of relativistic jets and accretion processes
… The adiabatic energy losses suffered by conical jets are successfully countered to reproduce the canonical flat/inverted synchrotron spectrum associated with compact radio jets.<br/><br/>The iShocks model uses discrete packets of plasma, or shells, to simulate a jet. The shell collisions give …
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Magnetic Field Evolution in Black Hole Accretion Disks and Relativistic Jets
… generally, and in accretion and the launching of relativistic jets in particular. This thesis aims to tackle both topics using three-dimensional magnetohydrodynamics (MHD) and relativistic magnetohydrodynamics (RMHD) simulations. In the first half (Chapters 2 and 3), I focus on the role of …
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Relativistic Jets from Compact Binary Mergers as Electromagnetic Counterparts to Gravitational Wave Sources
… a study of the electromagnetic emission from relativistic jets that accompany the merger of binary neutron stars or black hole-neutron star systems. These counterparts provide a probe for the structure and dynamics of these relativistic outflows. Binary neutron star, or neutron star-black …
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Modeling the high resolution X-ray spectra from the relativistic jets of the X-ray binary SS 433
We test the physical model of the relativistic jets in the galactic X-ray binary SS 433 that was proposed by Marshall et al. 2002 (Paper I) using additional observations from the Chandra High Energy Transmission Grating Spectrometer. These observations sample two new orbital/precessional phase …
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The Discontinuous Galerkin Method applied on the equations of ideal relativistic hydrodynamics
To solve numerically the problems of ideal relativistic hydrodynamics we have developed a high-order accurate and time-explicite code. For the spatial discretisation we use the Discontinuous Galerkin Method (DGM). Numerical we studied the propagation of relativistic jets and the accretion onto …
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Gamma-Ray Observations of X-ray Binaries
… star. Some XRBs are known to possess collimated relativistic jets, and are called microquasars. VERITAS has conducted observations of the high-mass X-ray binary (HMXB) 1A 0535+262 and of the microquasar Cygnus X-3. Many theoretical models predict VHE emission when these sources manifest …
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Radiative signatures of the jet launching region in astronomical objects
Relativistic jets are observed in a wide range of accreting black hole systems, from stellar-mass black holes in X-ray binaries (XRBs), to supermassive black holes in active galactic nuclei (AGN). However, despite decades of observational and theoretical research, the mechanism by which …
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General relativistic magnetohydrodynamic simulations of binary neutron star mergers
… thesis I present results of my fully general relativistic magnetohydrodynamic (GRMHD) binary neutron star merger (BNS) simulations, conducted by using the numerical code "Whisky" under various conditions, such as, different Equation of State (EOS) for neutron matter (APR4, Ideal fluid and H4 …
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Search for microquasar features in cosmic ray spectra with AMS-01
… binaries are sometimes observed to emit compact, relativistic jets of cool plasma; these objects are called "microquasars". It is possible that these jets are responsible for a large flux of galactic cosmic ray protons and nuclei. The energy spectrum from these sources will be very different from …
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Accretion and outflow in black-hole x-ray binaries
… as well as radio emission originating from their jets. My thesis splits into two projects. On one hand, I focus on the connection between the X-ray emitting accretion disc and the radio jets of BHXBs in general, by studying the quasi-simultaneous evolution of the radio fluxes and the X-ray fluxes …
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Understanding the Nature of Blazars High Energy Emission with Time Dependent Multi-zone Modeling
… of the formation and propagation of relativistic jets, and hence the related physics of the black hole - accretion disk - jet system. However, the understanding of these variability demands highly sophisticated theoretical analysis and numerical simulations. Especially, the inclusion …
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Estimating the stellar masses of NLS1 galaxies using multifrequency data
… rates and their ability to host powerful relativistic jets. The stellar masses are derived using the Code Investigating GALaxy Emission (CIGALE) which models galaxy spectral energy distributions through a Bayesian comparison of theoretical and observed data. The NLS1 sample used in this …
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On electromagnetic observables from supermassive black hole accretion flows
Relativistic jets have been observed to originate from the centers of many galaxies. It is likely that the jets are powered by spinning supermassive black holes via a dynamical interaction between magnetic fields close to the hole and the warped spacetime predicted by general relativity. This …
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Laboratory Experiments of High-Energy-Density Shocks in Magnetized Supersonic Plasma Flows
… shocks. Some examples include extrastellar jets from radio galaxies, relativistic jets from quasars and blazars, Herbig-Haro jets from Young Stellar Objects, and shocks in core-collapse supernovae and supernova remnants. In this study, we mimic these extreme astrophysical environments using …
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The development of new methods for high resolution radio astronomy imaging
… (VLBI) polarisation observations of the relativistic jets from Active Galactic Nuclei (AGN) allow the magnetic field environment around the jet to be probed. In particular, multi-wavelength observations of AGN jets allow the creation of Faraday rotation measure maps which can be used to …
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Nuclear and particle interactions to multi-messenger signals: Core-collapse supernovae
… systems may be able to accelerate nuclei in relativistic jets. If these jets are beamed toward us, the gamma ray lines from the decays of unstable nuclei can be boosted to high energies and are detectable from extragalactic distances.
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Spectral-Timing Observations of Disk-Jet Coupling in Black Hole X-ray Binaries
… horizon inspiraling gases reach, and how the relativistic jets are launched. The puzzle piece linking these two challenges together is the nature 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 …
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High cadence optical polarimetry for time domain astronomy on the Liverpool Telescope
… observed radiation from GRBs is released from relativistic jets. Launched from a black hole central engine, the energy within the jets is converted to the observed radi- ation predominantly through a synchrotron process, which can produce highly linearly polarised radiation. Polarimetric …
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The complex interplay between AGN jet feedback and galaxy evolution
… indicate the presence of collimated, relativistic jets as well as powerful, multiphase winds emanating from these active galactic nuclei (AGN). Whilst the clearest observational signatures of AGN jet feedback are found in galaxy clusters, there is growing evidence that these jets are, …
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