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Kawaguchi, Kyohei. "Black Hole-Neutron Star Merger -Effect of Black Hole Spin Orientation and Dependence of Kilonova/Macronova-". 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225394.
Pełny tekst źródłaStevenson, Simon. "Insights into binary black hole formation from gravtitational waves". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7667/.
Pełny tekst źródłaShoemaker, Deirdre Marie. "Apparent horizons in binary black hole spacetimes /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
Pełny tekst źródłaVinciguerra, Serena. "Studying neutron-star and black-hole binaries with gravitational-waves". Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8159/.
Pełny tekst źródłaSenturk, Cetin. "Black Hole Collisions At The Speed Of Light". Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611479/index.pdf.
Pełny tekst źródłaTenyotkin, Valery Evans Charles Ross. "New wrinkles on black hole perturbations numerical treatment of acoustic and gravitational waves /". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2316.
Pełny tekst źródłaTitle from electronic title page (viewed Jun. 26, 2009). "...in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics and Astronomy." Discipline: Physics and Astronomy; Department/School: Physics and Astronomy.
PANI, PAOLO. "Applications of perturbation theory in black hole physics". Doctoral thesis, Università degli Studi di Cagliari, 2011. http://hdl.handle.net/11584/266254.
Pełny tekst źródłaSchlue, Volker. "Linear waves on higher dimensional Schwarzschild black holes and Schwarzschild de Sitter spacetimes". Thesis, University of Cambridge, 2012. https://www.repository.cam.ac.uk/handle/1810/243640.
Pełny tekst źródłaMösta, Philipp. "Novel aspects of the dynamics of binary black-hole mergers". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2012/5982/.
Pełny tekst źródłaSchwarze Löcher gehören zu den extremsten und faszinierensten Objekten in unserem Universum. Elektromagnetische Strahlung kann nicht aus ihrem Inneren entkommen, und sie bilden die kompaktesten Objekte, die wir kennen. Wir wissen heute, dass in den Zentren der meisten Galaxien sehr massereiche schwarze Löcher vorhanden sind. Im Fall unserer eigenen Galaxie, der Milchstrasse, ist dieses schwarze Loch ungefähr vier Millionen mal so schwer wie unsere Sonne. Wenn zwei Galaxien miteinander kollidieren, führt dies auch dazu, dass ihre beiden schwarzen Löcher kollidieren und zu einem einzelnen schwarzen Loch verschmelzen. Das Simulieren einer solchen Kollision von zwei schwarzen Löchern, die Vorhersage sowie Analyse der von ihnen abgestrahlten Energie in Form von Gravitations- und elektromagnetischen Wellen, bildet das Thema der vorliegenden Dissertation. Im ersten Teil dieser Arbeit untersuchen wir die Verschmelzung von zwei schwarzen Löchern unter verschiedenen Gesichtspunkten. Wir zeigen, dass Ungleichmässigkeiten in der Geometrie des aus einer Kollision entstehenden schwarzen Loches dazu führen, dass es zuerst beschleunigt und dann abgebremst wird, bis diese Ungleichmässigkeiten in Form von Gravitationswellen abgetrahlt sind. Weiterhin untersuchen wir, wie der genaue Verschmelzungsprozess aus einer geometrischen Sicht abläuft und schlagen neue Methoden zur Analyse der Raumzeitgeometrie in Systemen vor, die schwarze Löcher enthalten. Im zweiten Teil dieser Arbeit beschäftigen wir uns mit den Gravitationswellen und elektromagnetischer Strahlung, die bei einer Kollision von zwei schwarzen Löchern freigesetzt wird. Gravitationswellen sind Wellen, die Raum und Zeit dehnen und komprimieren. Durchläuft uns eine Gravitationswelle, werden wir in einer Richtung minimal gestreckt, während wir in einer anderen Richtung minimal zusammengedrückt werden. Diese Effekte sind allerdings so klein, dass wir sie weder spüren, noch auf einfache Weise messen können. Bei einer Kollision von zwei schwarzen Löchern wird eine grosse Menge Energie in Form von Gravitationswellen und elektromagnetischen Wellen abgestrahlt. Wir zeigen, dass beide Signale in ihrer Struktur sehr ähnlich sind, dass aber die abgestrahlte Energie in Gravitationswellen um ein Vielfaches grösser ist als in elektromagnetischer Strahlung. Wir führen eine neue Methode ein, um die elektromagnetische Strahlung in unseren Simulationen zu messen und zeigen, dass diese dazu führt, dass sich die räumliche Struktur der Strahlung verändert. Abschliessend folgern wir, dass in der Kombination der Signale aus Gravitationswellen und elektromagnetischer Strahlung eine grosse Chance liegt, ein System aus zwei schwarzen Löchern zu detektieren und in einem weiteren Schritt zu analysieren. Im dritten und letzen Teil dieser Dissertation entwickeln wir ein verbessertes Suchverfahren für Gravitationswellen, dass in modernen Laser-Interferometerexperimenten genutzt werden kann. Wir zeigen, wie dieses Verfahren die Chancen für die Detektion eines Gravitationswellensignals deutlich erhöht, und auch, dass im Falle einer erfolgreichen Detektion eines solchen Signals, seine Parameter besser bestimmt werden können. Wir schliessen die Arbeit mit dem Fazit, dass die Kollision von zwei schwarzen Löchern ein hochinteressantes Phenomenon darstellt, das uns neue Möglichkeiten bietet die Gravitation sowie eine Vielzahl anderer fundamentaler Vorgänge in unserem Universum besser zu verstehen.
Uchida, Haruki. "Black Hole Formation, Explosion and Gravitational Wave Emission from Rapidly Rotating Very Massive Stars". Kyoto University, 2019. http://hdl.handle.net/2433/242595.
Pełny tekst źródłaBowyer, E. P. "Experimental investigation of damping structural vibrations using the acoustic black hole effect". Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10983.
Pełny tekst źródłaTagoshi, Hideyuki. "Post-Newtonian expansion of gravitational waves from a particle in slightly eccentric orbit around a rotating black hole". 京都大学 (Kyoto University), 1995. http://hdl.handle.net/2433/160892.
Pełny tekst źródłaKyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第5895号
理博第1602号
新制||理||893(附属図書館)
UT51-95-D214
京都大学大学院理学研究科物理学第二専攻
(主査)教授 佐藤 文隆, 教授 益川 敏英, 教授 九後 太一
学位規則第4条第1項該当
Leng, Julien. "Controlling flexural waves using subwavelength perfect absorbers : application to Acoustic Black Holes". Thesis, Le Mans, 2019. http://www.theses.fr/2019LEMA1027/document.
Pełny tekst źródłaThe vibration control adapted to light structures is a scientific and technological challenge due toincreasingly stringent economic and ecological standards. Meanwhile, recent studies in audible acoustics havefocused on broadband wave absorption at low frequencies by means of subwavelength perfect absorbers. Suchmetamaterials can totally absorb the energy of an incident wave. The generalisation of this method for applicationsin elastodynamics could be of great interest for the vibration control of light structures.This thesis aims at adapting the perfect absorption problem for flexural waves in 1D and 2D systems with localresonators using the critical coupling condition. A study of 1D systems with simple geometries is first proposed. Thisprovides methods to design simple resonators for an effective absorption of flexural waves. The 1D systems thenbecome more complex by studying the critical coupling of 1D Acoustic Black Holes (ABH). The ABH effect is theninterpreted using the concept of critical coupling, and key features for future optimisation procedures of ABHs arepresented. The critical coupling condition is then extended to 2D systems. The perfect absorption by the firstaxisymmetric mode of a circular resonator inserted in a thin plate is analysed. Multiple scattering by an array ofcircular resonators inserted in an infinite or semi-infinite 2D thin plate, called metaplate, is also considered to getclose to practical applications. Through this thesis, analytical models, numerical simulations and experiments areshown to validate the physical behaviour of the systems presented
Harms, Enno [Verfasser], Bernd [Gutachter] Brügmann, Claus [Gutachter] Lämmerzahl i Scott [Gutachter] Hughes. "Gravitational waves from black hole binaries in the point-particle limit / Enno Harms ; Gutachter: Bernd Brügmann, Claus Lämmerzahl, Scott Hughes". Jena : Friedrich-Schiller-Universität Jena, 2016. http://d-nb.info/117761264X/34.
Pełny tekst źródłaPereira, Rheymisson. "Gravitational Waves and the Stability of Binary Systems". Thesis, Uppsala universitet, Teoretisk fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-331700.
Pełny tekst źródłaRitter, Patxi. "Ondes gravitationnelles et calcul de la force propre pour un astre compact en mouvement autour d'un trou noir super-massif". Thesis, Orléans, 2013. http://www.theses.fr/2013ORLE2038/document.
Pełny tekst źródłaThis thesis focuses on modelling the gravitational waves and the relativistic motion associated to Extreme Mass Ratio Inspiral (EMRI) systems. These systems consist of a stellar mass compact object gravitationally captured by a super-massive black hole. In black hole perturbation theory, we further develop a numerical method which computes waveforms generated by a point mass particle orbiting a Schwarzschild black hole. The Regge-Wheeler-Zerilli wave equation is solved in time domain. The gauge invariant solution is related to the polarisation modes, the energy and the angular momentum carried by the gravitational waves. In reaction to the energy and the moment lost, the trajectory is modified all along. In the MiSaTaQuWa formalism, we compute the self-force acting upon a point particle which is initially at rest, and then falling into a Schwarzschild black hole. We show how this quantity is defined in the Regge-Wheeler gauge by using the mode-sum regularisation technique. We take into account the self-force effect on the motion of the particle by using an iterative and osculating orbit method conceived herein. We quantify the orbital deviation with respect to the geodesic motion, but also the perturbed wave forms and the associated radiated energy
Moore, Christopher James. "Gravitational waves : understanding black holes". Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/257043.
Pełny tekst źródłaMacedo, Rodrigo Panosso. "Emissão de ondas gravitacionais por fontes compactas: o regime não-linear". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-31032011-120147/.
Pełny tekst źródłaColliding black holes are one of the most important sources of gravitational waves and the anisotropic emission of the radiation generally causes the recoil of the final hole. This scenario has been known for decades, but it is only thanks to the recent progress in numerical relativity that the final velocity have been accurately computed. The values found can be large enough to play an important role in the growth of supermassive black holes via mergers of galaxies and on the number of galaxies containing them. This is a genuine nonlinear effect of general relativity and this thesis provides a new methodology to study some features on the dynamics of the collision. We propose that the horizon is a canonical screen, which encodes he information of its surroundings. With this assumption, phenomena such as the anti-kick, namely the sudden deceleration before reaching the final velocity, are explained in terms of the dissipation of the horizons deformation. We first study the Robinson-Trautman spacetime. One of the simplest solutions of Einsteins equations, it provides us with a powerful toymodel to investigate both the mass loss of the system and the recoil of the final object. We show that, for the case of reflectionsymmetric initial configurations, the mass of the remnant black-hole and the total energy radiated away are completely determined by the initial data, allowing us to obtain analytical expressions for some numerical results that had appeared in the literature. Moreover, by using the Galerkin spectral method to analyze the non-linear regime of the equations involved, we found that the recoil velocity can be estimated with good accuracy from some symmetry measures of the initial data. Then we introduce the effective urvature as a measure of intrinsic deformations on the horizon. Not only does it account for overall deformation, but also for the differences on the north and south hemispheres. In the Robinson-Trautman spacetime, this quantity correlates in an injective way with the final velocity. To overcome some caveats of this solutions, we apply the same procedure to the results given by numerical simulations of a head-on collision. In the case, the effective curvature is actually correlated with the acceleration of the system. Further improvement and generalizations of this technic is also discussed and proposed for future work.
Dempsey, David. "Wave propagation on black hole spacetimes". Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18023/.
Pełny tekst źródłaEkehult, Joanna, i Anna Karpinska. "Gravitational Waves and Coalescing Black Holes". Thesis, KTH, Skolan för teknikvetenskap (SCI), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210848.
Pełny tekst źródłaJoanna, Ekehult, i Anna Karpinska. "Gravitational Waves and Coalescing Black Holes". Thesis, KTH, Skolan för teknikvetenskap (SCI), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210849.
Pełny tekst źródłaDel, Pozzo Walter. "Black Holes, Galaxy Clusters and Gravitational Waves". Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1321/.
Pełny tekst źródłaJulié, Félix-Louis. "Sur le problème à deux corps et le rayonnement gravitationnel en théories scalaire-tenseur et Einstein-Maxwell-dilaton". Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC131/document.
Pełny tekst źródłaWith the birth of "gravitational wave astronomy" comes the opportunity to test general relativity and its alternatives in a strong field regime that had never been observed so far: that of the coalescence of a compact binary sytem. This thesis studies the problem of motion and gravitational radiation from such systems in modified gravities, by adapting some of the key analytical tools that were first developed in the context of general relativity. First, we show how to widen the "effective-one-body" (EOB) formalism to a large class of modified gravities, including, e.g., scalar-tensor theories. In the latter, the gravitational interaction is described by supplementing general relativity with a (massless) scalar degree of freedom. The corresponding two-body lagrangian being known at post-post-keplerian order, we build an associated EOB hamiltonian, which describes the motion of a test particle orbiting in effective external fields. This enables to simplify and resum the two-body dynamics; and hence, to explore the strong-field regime near merger. We then "tackle", for the first time, the analytical description of "hairy" binary black hole systems, and obtain their (EOB) gravitational waveform counterparts in Einstein-Maxwell-dilaton theories, which generalize scalar-tensor theories by means of a (massless) vector field. To that end, we derive the two-body lagrangian at post-keplerian order as well as the energy flux radiated at infinity at quadrupolar order. As in general relativity, our developments rely on the phenomenological description of the black hole’s trajectories as worldlines of point particles that are, in turn, described by a "skeleton" action generalizing that of general relativity. Finally, we develop a formalism based on Katz’ "superpotentials" to define the mass (as a nœther charge) of a black hole that is endowed with vector and scalar "hair". We then deduce the first law of thermodynamics, which is particularly suitable to describe its readjustments when interacting with a faraway companion. Black hole thermodynamics is lastly shown to be a powerful tool to interpret and discuss the scope of their "skeletonization"
Gültekin, Kayhan. "Growing intermediate-mass black holes with gravitational waves". College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3749.
Pełny tekst źródłaThesis research directed by: Astronomy. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Kim, Yunho. "Quadratic Gravity with Black Holes and Gravitational Waves". Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/26707.
Pełny tekst źródłaKunduri, Hari Krishna. "Black holes in Anti de Sitter spacetime, black rings, and plane waves". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614266.
Pełny tekst źródłaPedron, Nicola. "Gravitational waves from primordial black holes in string inflation". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23236/.
Pełny tekst źródłaPlowman, Joseph Eugene. "Constraining massive black hole population models with gravitational wave observations". Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/plowman/PlowmanJ0510.pdf.
Pełny tekst źródłaImbiriba, Breno Cesar de Oliveira. "Numerical simulation and wave extraction of binary black hole system". College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6670.
Pełny tekst źródłaThesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Stone, Nicholas Chamberlain. "Tidal Disruption of Stars by Supermassive Black Holes". Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10998.
Pełny tekst źródłaAstronomy
FRANZIN, EDGARDO. "Aspects of Black Hole Physics: Scalar Sources, Holography and Gravitational Wave Emission". Doctoral thesis, Università degli Studi di Cagliari, 2017. http://hdl.handle.net/11584/248734.
Pełny tekst źródłaWe investigate several aspects of black hole physics. First, we consider models of gravity minimally coupled to scalar fields. We derive a new class of asymptotically flat black holes sourced by a non-trivial asymptotically massless scalar field; we discuss their relationship with known solutions and standard no-hair theorems and their thermodynamics. We derive exact neutral and charged brane solutions sourced by a scalar field with vanishing potential, which are conformal to the Lifshitz spacetime; we discuss the symmetries and their holographic application for hyperscaling violation; we also give a quite general classification of brane solutions sourced by scalar fields useful for holographic applications. We study an inflationary model inspired by the domain wall/cosmology correspondence in which inflation is driven by a scalar with a two-exponential potential; we derive its phenomenological consequences in the slow-roll approximation and compare its predictions with the Planck 2015 data. Second, we investigate ultra-compact astrophysical objects which can act as black hole mimickers, in particular boson stars and wormholes. We discuss the existence and the stability of boson stars in higher dimensions and boson stars built with multiple scalars. We compute tidal Love numbers for various mimickers and discuss how to distinguish black holes from their possible mimickers with gravitational-wave data. We study the gravitational radiation emitted by a particle falling into an exotic compact object and show that the initial ringdown signal cannot be use distinguish between a black hole and a black hole mimicker.
Muir, Alistair. "Towards improving detection rates of gravitational waves from precessing binary black holes". Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/118182/.
Pełny tekst źródłaKamaretsos, I. "Gravitational-wave radiation from merging binary black holes and Supernovae". Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/46220/.
Pełny tekst źródłaSchmidt, Patricia. "Studying and modelling the complete gravitational-wave signal from precessing black hole binaries". Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/64062/.
Pełny tekst źródłaMANGIAGLI, ALBERTO. "The astrophysics of black hole binaries in the era of gravitational wave astronomy". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/299791.
Pełny tekst źródłaBlack holes (BHs) are variegated and fascinating objects in Nature. Their realm extends from the stellar BHs with mass $sim 10-10^2 msun$ to the supermassive BHs of $10^{9-10} msun$ that reside in the center of galaxies. While the former are the expected outcome of stellar evolution, the latter are the results of multiple dark matter halo mergers in the standard $Lambda$CDM scenario. When two BHs are close enough, they form a binary BHs (BHBs) and emit gravitational waves (GWs) that we can detect with our inteferometers. Similarly to BHs, also BHBs can be divided into different sub-populations, each with its unique features and characteristics: stellar BHBs (SBHBs) form from the co-evolution of binary stars or in dense region, while massive BHBs (MBHBs) are the result of galaxy mergers. The challenges of GW astronomy are still numerous and require different knowledge and expertise to be solved. For this reason, I start this Thesis presenting result for SBHBs in the initial chapters and moving to MBHBs in the end. Each chapter has its own brief introduction and discussion of the main results and conclusions. In Chapter 1 I introduce some basic General Relativity (GR) concepts related to the emission of GWs. I summarise the current status of GW astronomy. I explain how GWs from BHBs can be easily modeled under some reasonable assumptions and report some formulas useful to understand the concepts of the following chapters. In Chapter 2 I study the minimum Post-Newtonian (PN) order necessary to accurately track SBHBs in LISA and perform an unbiased parameter estimation. SBHBs are expected to spend a large number of cycles in band, therefore an accurate waveform is necessary to avoid biases in the binary parameters. I show that the main factor affecting the PN accuracy is the time to coalescence with systems closer to merger requiring higher PN contributions. I apply the previous result to a realistic population of SBHBs in LISA in order to draw more realistic estimates: I find that most of the sources can be modeled with just 2PN corrections while systems merging during LISA time mission require up to 2.5PN and 3PN contributions. The topic of Chapter 3 is a model to describe SBHBs above the pair-instability mass gap, i.e. BHs with mass $> 120 msun$. I build a simple approach and, under the assumption that the binary formation does not change beyond the mass gap, I estimate the detected rate for current detectors, ET and LISA. Finally I also suggest the possibility that the undetected sources form a new source of stochastic background in LISA. In Chapter 4 I move to MBHBs, detectable only from space by LISA. I provide an introduction on MBHBs formation and evolution and the multimessenger possibilities. I also explain how we estimate source information with the so-called Fisher matrix formalism. In Chapter 5 I present a work I contributed where we explore the possibility to detect a Doppler modulated X-ray emission during the inspiral of MBHBs. In the last stage of merger, X-ray emission is expected as the result of gas accretion on each BHs and the orbital motion of the binary might imprint a Doppler modulation on the electromagnetic (EM) emission in phase with the GW signal. The detection of this modulation would allow to pinpoint the exact source location in the relatively large error area provided by LISA. From our analysis, we estimate few modulation detections over LISA time mission. Finally in Chapter 6 I report the results for the parameter estimation of MBHBs on the fly, i.e. as function of time before coalescence. In particular I focus on sky position, luminosity distance, chirp mass and mass ratio and how their errors decrease as the system approaches merger. For the benefit of the community, I release also the complete set of data and analytical fits to describe the time evolution in the aforementioned parameters. Finally I discuss the multimessenger prospects.
Ramos, Buades Antoni. "Gravitacional waves from generic binary black holes: from numerical simulations to observational results". Doctoral thesis, Universitat de les Illes Balears, 2020. http://hdl.handle.net/10803/671467.
Pełny tekst źródła[spa] Esta tesis recoge el trabajo realizado en los últimos cuatro años de investigación enfocados en la producción de simulaciones de relatividad numérica de agujeros negros binarios en configuraciones genéricas, así como en el análisis de las ondas gravitacionales extraídas de dichas simulaciones, sus consecuencias para los modelos de formas de ondas existentes y sus implicaciones para la búsqueda y la estimación de los parámetros de dichos sistemas en la naturaleza. Para empezar, he estudiado la prescripción de parámetros iniciales en las simulaciones de relatividad numérica. Un problema bien conocido en relatividad numérica es la dificultad de obtener simulaciones de agujeros negros en órbitas casi-circulares, debido a imprecisiones en la generación de los datos iniciales que provocan órbitas casi-elípticas con una excentricidad residual. El primer proyecto de esta tesis ha sido el desarrollo de un procedimiento iterativo, sencillo y computacionalmente eficaz para la reducción de la excentricidad en simulaciones de relatividad numérica de agujeros negros binarios, ver Cap. 4. Con este método se han generado formas de onda gravitacionales casi-circulares con una excentricidad negligible, e O �� 10��4 , que han sido usadas por nuestro grupo para generar modelos de formas de onda casi-circulares. La flexibilidad del método anterior permite no solo reducir la excentricidad de las simulaciones numéricas, sino también aumentarla. Este hecho ha permitido la generación de un banco de más de 60 simulaciones de relatividad numérica con excentricidad moderada e 0:5. Este ha sido el segundo proyecto de investigación de la tesis, ver Cap. 5. Con este grupo de simulaciones he generado formas de onda híbridas para el modo dominante (2; 2) entre las ondas obtenidas a partir de la teoría post- Newtoniana y las de relatividad numérica. Además, con colaboradores he estimado las limitaciones de los modelos casi-circulares actuales para estimar los parámetros de estas fuentes. Los resultados obtenidos demuestran que los modelos casi-circulares de formas de onda que incluyen modos subdominantes reducen el sesgo en algunos parámetros como la distancia y el ratio de masa, respecto a los modelos sin modos subdominantes. Por otro lado, durante el doctorado también se han estudiado las limitaciones de dos aproximaciones utilizadas comúnmente para modelos de onda casi-circulares con espines precesantes, ver Cap. 6. Estas dos aproximaciones se han analizado usando únicamente simulaciones de relatividad numérica incluyendo modos subdominantes. Los resultados obtenidos confirman el buen funcionamiento de las aproximaciones para los modos dominantes (2; 2), mientras que para los modos subdominantes se observa una degradación importante debido a diferentes causas dependiendo del modo estudiado, por ejemplo, los modos (2; 1) son muy sensibles a las asimetrías entre modos que las aproximaciones negligen, mientras que los modos (4; 3) y (3; 2) padecen mezcla de modos en la parte del decaimiento de la onda que las aproximaciones no tienen en cuenta. Finalmente, con colaboradores he analizado la sensibilidad de dos algoritmos de búsqueda, utilizados por las colaboraciones LIGO y Virgo durante el segundo período de observación O2, para detectar señales completas de ondas gravitacionales procedentes de binarias de agujeros negros excéntricos, ver Cap. 7. En este trabajo preliminar se ha cuantificado el impacto de la excentricidad sobre dos algoritmos de búsqueda: un código de filtrado adaptado y un código de búsqueda sin modelado. En este estudio se estima por primera vez la sensibilidad de ambos algoritmos inyectando señales excéntricas calculadas a partir de simulaciones de relatividad numérica. Los resultados muestran una mayor degradación de la sensibilidad del algoritmo de filtrado adaptado a medida que aumenta la excentricidad, mientras que el algoritmo sin modelado no se ve casi afectado por el aumento de la excentricidad, y por tanto, se puede identificar este último como una herramienta robusta para la detección robusta de señales excéntricas.
[eng] This thesis gathers all the work done in my last four years of research focused on the production of numerical relativity simulations of generic binary black holes, as well as the analysis of the gravitational waveforms from these simulations and their implications for searches and parameter estimation on those systems. I have started studying the prescription of initial parameters in numerical relativity simulations. A well known problem in numerical relativity is the difficulty to obtain simulations of black holes orbiting in quasi-circular orbits due to inaccuracies of the initial data, which cause elliptical orbits with residual eccentricity. The first project of the thesis has been the development of a simple, iterative and computationally efficient procedure to reduce the eccentricity in binary black hole numerical relativity simulations, see Chap. 4. With this method we have produced quasi-circular waveforms with negligible eccentricity, e O � 10�4 , which have been used in our group to generate quasi-circular waveform models. The flexibility of the previous method permits not only the reduction of the eccentricity, but also increasing it. Using this fact I have produced a data set of more than 60 numerical relativity simulations with moderate eccentricity e 0:5. This has been the second project of the thesis, see Chap. 5. Taking this set of simulations, with collaborators I have generated hybrid waveforms for the dominant (2; 2) mode between post-Newtonian and numerical relativity waveforms. Moreover, we have estimated the limitations of the current quasi-circular waveform models to estimate the parameters from those sources. We have found that the quasi-circular models which include higher order modes reduce the bias in some parameters like the mass ratio and luminosity distance, with respect to those models not including higher order modes. Furthermore, during the Ph.D. I have also studied the limitations of two approximations commonly used by precessing quasi-circular waveform models, see Chap. 6. These two approximations have been analysed using exclusively numerical relativity simulations including higher order modes. The results confirm the good performance of the approximations for the (2; 2) modes, while one observes a clear degradation for higher order modes due to different reasons depending on the considered mode. For instance, the (2; 1) modes are found to be very sensitive to asymmetries which the approximations neglect, while the (4; 3) and (3; 2) modes, have mode-mixing in the ringdown part which is not properly taken into account by the simple approximations. Finally, with collaborators I have analysed the sensitivity of two search pipelines, used by the LIGO and Virgo collaborations during the O2 Science Run, to the full gravitational wave signal of eccentric binary black holes, see Chap. 7. In this preliminary work we have quantified the impact of eccentricity on two search pipelines: a matched-filter and an unmodeled search algorithm. We have for the first time estimated the sensitivity of both algorithms injecting eccentric signals computed from numerical relativity simulations. The results show a larger degradation of the sensitivity of the matched-filter algorithm with increasing eccentricity, while the sensitivity of the unmodeled search algorithm remains barely unaffected to the increase of eccentricity, thus, we consider the latter one a robust tool to detect such eccentric signals.
Teodoro, Matheus do Carmo. "Perturbations of black holes pierced by cosmic strings". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-05062018-104405/.
Pełny tekst źródłaO atual interesse em ondas gravitacionais, justificado pelas detecções diretas feitas pela colaboração LIGO recentemente, está abrindo a excitante possibilidade de responder várias questões a respeito da Relatividade Geral em condições estremas. Uma dessas questões é se buracos negros são – realmente – totalmente discritos apenas por sua massa, carga e momento angular ou se eles podem ter os chamados cabelos de longo alcance adicionais. Nosso projeto se preocupa em responder esta pergunta. Nosso objetivo está em estudar a influência de uma estrutura adicional no horizonte de eventos de um buraco negro através do comportamento da equação linearizada de Einstein quando a solução é perturbada. Mais precisamente, nós estudaremos a solução de Schwarzschild atravessada por uma corda cósmica infinitamente fina, tal corda faz com que o espaço-tempo tenha um hiato angular em seu plano equatorial. Acredita-se que modos quasi-normais dominem a emissão de ondas gravitacionais durante a fase de ringing down de buracos negros excitados que podem, por exemplo, se originar da colisão de objetos ultra compactos, portanto perturbações lineares podem ser consideradas. Com o advento da astronomia através de ondas gravitacionais o estudo proposto será importante para que se possa reconstruir a origem de sinais detectados.
Chua, Alvin J. K. "Topics in gravitational-wave astronomy : theoretical studies, source modelling and statistical methods". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/263652.
Pełny tekst źródłaCole, Robert Harry. "Gravitational waves from extreme-mass-ratio inspirals". Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709066.
Pełny tekst źródłaBlecha, Laura Elizabeth. "The Dynamics and Evolution of Supermassive Black Holes in Merging Galaxies". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10257.
Pełny tekst źródłaAstronomy
Reisswig, Christian. "Binary black hole mergers and novel approaches to gravitational wave extraction in numerical relativity". Hannover Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1004001134/34.
Pełny tekst źródłaRamos, Oscar. "Testing Lorentz invariance by binary black holes". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS199/document.
Pełny tekst źródłaHorava gravity breaks Lorentz symmetry by introducing a preferred spacetime foliation, which is defined by a timelike dynamical scalar field, the khronon. The presence of this preferred foliation makes black hole solutions more complicated than in General Relativity, with the appearance of multiple distinct event horizons: a matter horizon for matter fields; a spin-0 horizon for the scalar excitations of the khronon; a spin-2 horizon for tensorial gravitational waves; and even a universal horizon for instantaneously propagating modes appearing in the ultraviolet. We study how black hole solutions in Horava gravity change when the black hole is allowed to move with low velocity relative to the preferred foliation. These slowly moving solutions are a crucial ingredient to compute black hole sensitivities and predict gravitational wave emission (and particularly dipolar radiation) from the inspiral of binary black hole systems. We find that for generic values of the theory's three dimensionless coupling constants, slowly moving black holes present curvature singularities at the universal horizon. Singularities at the spin-0 horizon also arise unless one waives the requirement of asymptotic flatness at spatial infinity. Nevertheless, we find that in a one-dimensional subset of the parameter space of the theory's coupling constants, slowly moving black holes are regular everywhere, even though they coincide with the general relativistic ones (thus implying in particular the absence of dipolar gravitational radiation). Remarkably, this subset of the parameter space essentially coincides with the one selected by the recent constraints from GW170817 and by solar system tests
Hartwig, Tilman. "Formation and growth of the first supermassive black holes". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066386/document.
Pełny tekst źródłaSupermassive black holes reside in the centres of most massive galaxies and we observe correlations between their mass and properties of the host galaxies. Besides this correlation between a galaxy and its central black hole (BH), we see BHs more massive than one billion solar masses already a few hundred million years after the Big Bang. These supermassive BHs at high redshift are just the tip of the iceberg of the entire BH population, but they challenge our understanding of the formation and growth of the first BHs. Our improved method to calculate H2 self-shielding yields probabilities to form massive seed BHs that are more than one order of magnitude higher, than previously expected. We find that CR7 might be the first candidate to host such a direct collapse BH and we disprove the initially claimed existence of a massive metal-free stellar population in CR7. We calculate the merger rate density of binary BHs from the first stars and their detection rates with aLIGO. Our model demonstrates that upcoming detections of gravitational waves in the next decades will allow to put tighter constraints on the properties of the first stars and therefore on formation scenarios of the first BHs. We develop a 2D analytical model of active galactic nuclei-driven outflows to demonstrate that a more realistic disc profile reduces the amount of gas that is ejected out of the halo, compared to existing 1D models. The outflow prevents gas accretion on to the central BH for only about ∼1Myr, which permits almost continuous gas inflow in the disc plane. With this thesis, I contribute to a better understanding of the formation and growth of the first supermassive BHs
Di, Gennaro Sofia. "Quantum rotating black holes and extra dimensions". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19851/.
Pełny tekst źródłaBuchman, Luisa T. "A hyperbolic tetrad approach to numerical relativity /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5451.
Pełny tekst źródłaTriantafyllou, Nikolaos. "Primordial black holes and their implications for Inflation". Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673259.
Pełny tekst źródłaEl modelo cosmológico estándar, ΛCDM, con una temprana fase de inflación, nos proporciona una descripción precisa de un Universo casi plano y homogéneo a gran escala, que se expande a un ritmo acelerado. A pesar de las evidencias observacionales, nuestro conocimiento del 95% de la energía del Universo, es decir, la materia oscura (DM) y la energía oscura, está limitado por la falta de una detección directa, debido en parte a la poca interacción, aparte de la gravitacional, que tienen con el resto de la materia. La detección de la primera señal de un sistema binario de agujeros negros, revitalizó el interés por un viejo candidato a materia oscura, los agujeros negros primordiales (PBHs). Los PBHs han recibido atención dado que se pueden formar con abundancias importantes durante el Universo temprano y con una amplia gama de posibles masas. Esta tesis se centra en su empleo para explorar el espectro de potencias de las perturbaciones de curvatura a escala pequeña. Primero, se estudia el efecto de las perturbaciones cosmológicas sobre los parámetros orbitales de los sistemas binarios de PBHs. Cuando hay una meseta de amplitud considerable en el espectro de potencia en las escalas de los sistemas binarios, la tasa de fusión se ve afectada, relajando los limites de la abundancia de PBHs. Segundo, se muestra que debido al acoplamiento modal de las perturbaciones, introducido por la presencia de no-Gaussianidad, se alteran la tasa de fusión y el resultante fondo estocástico de las ondas gravitacionales (SBGW) y que esto tambien resulta en la relajación de las restricciones de la abundancia de PBH. Tercero, se considera la posibilidad de que el SBGW proveniente de los sistemas binarios de PBHs super masivos pueda proporcionar una explicación para la señal detectada por NANOGrav. La presencia de no-Gaussianidad es esencial para que estos PBHs masivos eviten las µ-distorsiones de la CMB y se puedan haberse formado en abundancias del orden ∼ 0, 1%. Los PBHs constituyen una sonda única para explorar las condiciones iniciales del Universo y este trabajo pretende aportar un modelaje más robusto de las consecuencias observacionales de una población de PBHs.
Sbierski, Jan. "On the initial value problem in general relativity and wave propagation in black-hole spacetimes". Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/248837.
Pełny tekst źródłaCavalcanti, Rogério Teixeira. "Aspects of black hole physics beyond general relativity : extra dimensions, horizon wave function and applications". reponame:Repositório Institucional da UFABC, 2017.
Znajdź pełny tekst źródłaTese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Física, 2017.
Neste trabalho foram investigadas algumas conseguências da física de buracos negros em teorias cujo domínio está além do domínio da relatividade geral, em especial em teorias efetivos com dimensões extras. A investigação foi em substancialmente conduzida baseando-se em três efeitos gravitacionais, a saber, a radiação Hawking, o regime de deflexão forte de lentes gravitacionais e a formação de buracos negros quânticos. Uma solução de modelo cosmológico imerso em uma brana espessa foi também investigada. Modelos e teorias efetivas fornecem meios para testar os limites de validade de teorias conhecidas e indicam o que deveríamos esperar além desses limites. Baseado nessa ideia foram usados alguns modelos efetivos para estudar efeitos não previstos pela relatividade geral, associados a cada um dos fenômenos mencionados.
This work is devoted to investigate some consequences of black holes physics beyond the domain of general relativity, mainly in effective extra dimensional models. The investigation is carried along three gravitational effects, namely the Hawking radiation, the strong deflection of gravitational lensing and the formation of quantum black holes. A cosmological thick brane solution is also investigated. Effective theories and models provide a prominent approach for testing the limits of known theories and show what would be expected beyond that. Based on such idea we have used effective models for finding deviations of general relativity associated to each of the mentioned phenomena.
Fernández, Núñez Isabel. "Wave propagation in metamaterials mimicking spacetime geometry: black holes and cosmic strings". Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663393.
Pełny tekst źródłaLa investigación en gravitación análoga consiste en el estudio de sistemas físicos donde se pueden reproducir algunos de los fenómenos propios de relatividad general. Esta tesis se centra en la conocida propagación análoga de las ondas electromagnéticas en un espacio-tiempo curvado y en un medio con una permitividad y permeabilidad generalmente anisótropas. Para la realización de este tipo de medios, fue necesaria la aparición de los metamateriales, materiales artificiales diseñados para tener propiedades electromagnéticas fuera de lo común. En este contexto, se estudian modelos análogos a dos objetos estáticos con distinta simetría: uno con simetría esférica y otro con topología cónica. Ambos casos están motivados por soluciones a las ecuaciones de Einstein: el agujero negro de Schwarzschild y la cuerda cósmica, respectivamente. A través de las ecuaciones de óptica de transformación, determinamos los parámetros de los medios análogos a estos espacio-tiempos. Estudiamos la propagación de ondas electromagnéticas en los materiales obtenidos mediante simulaciones numéricas y comparamos los resultados con teorías analíticas, encontrando muy buen acuerdo. Por un lado, los contrastamos con las geodésicas en los espacio-tiempos considerados a través del formalismo Hamiltoniano. Por otro lado, desarrollamos modelos analíticos para describir la difracción de una onda (en principio tanto electromagnética como gravitatoria) debido a la cuerda cósmica. Para ello, usamos teorías asintóticas de difracción en un espacio virtual plano con un déficit de ángulo, ya que es una representación equivalente a la geometría cónica de la cuerda. De este modo, se obtienen expresiones que nos permiten explicar detalladamente los fenómenos ondulatorios de interferencia y difracción que se producen en este espacio-tiempo. Observamos que estos efectos pueden ser comparables a los términos de óptica geométrica: añaden una modulación en la amplificación del campo relacionada con la formación de imágenes dobles propia de la topología de la cuerda. Cabe destacar que estos fenómenos son conceptualmente distintos a los que se podrían esperar en la difracción sobre un objeto sólido como una barra. Utilizando nuestros modelos analíticos, obtenemos el patrón de difracción característico de la cuerda cósmica, que podría ser de interés para su detección.
Reisswig, Christian [Verfasser]. "Binary black hole mergers and novel approaches to gravitational wave extraction in numerical relativity / Christian Reisswig". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1004001134/34.
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