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Inhomogeneous cosmological models
Vrba, David ; Svítek, Otakar (advisor) ; Pravda, Vojtěch (referee) ; Žofka, Martin (referee)
In this work we study inhomogeneous cosmological models. After a brief review of applications of inhomogeneous solutions to Einstein equations in cosmology, we give a short description of the most widely used inhomogeneous cosmological models. In the second chapter we study in detail geometrical prop- erties of the Szekeres spacetime and we are concerned with the interpretation of the metric functions in different types of geometries. In the last chapter we model inhomogeneity in Szekeres spacetime. We derive formula for the density contrast and investigate its behaviour. We also derive conditions for the density extremes that are necessary for avoiding the shell crossing singularity in Szekeres spacetime. 1
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Gravitational field of gyratons on various background spacetimes
Kadlecová, Hedvika
Title: Gravitational field of gyratons on various background spacetimes Author: Hedvika Kadlecová Department: Institute of Theoretical Physics Supervisor: doc. Pavel Krtouš, Ph.D. Supervisor's e-mail address: Pavel.Krtous@mff.cuni.cz Abstract: In this work we have found and analyzed several gyraton solutions on various non-trivial backgrounds in the large Kundt class of spacetimes. Namely, the gyraton solutions on direct product spacetimes, gyraton solutions on Melvin universe and its generalization which includes the cosmological constant. These solutions are of algebraic type II. Also we have investigated type III solutions within the Kundt class and we have found the gyratons on de Sitter spacetime. We have generalized the gyraton solutions on direct product spacetimes to higher dimensions. Keywords: Kundt class of spacetimes, gravitational waves, Einstein-Maxwell equations, NP formalism Název práce: Gravitační pole gyratonů na pozadích různých prostoročasů Autor: Hedvika Kadlecová Ústav: Institut teoretické fyziky Školitel: doc. Pavel Krtouš, Ph.D. Školitelova e-mailová adresa: Pavel.Krtous@mff.cuni.cz Abstrakt: V této práci jsme nalezli a analyzovali několik různých gyratonových řešení na různých netriviálních pozadích z široké třídě Kundtových prostoročasů:...
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Space-times of ring sources
Pešta, Milan ; Semerák, Oldřich (advisor) ; Ledvinka, Tomáš (referee)
Marginally outer-trapped surfaces (MOTSs) are found for a family of space-like hypersurfaces described by the Brill-Lindquist initial data. These hypersurfaces contain a singular ring characterized by its radius, mass and charge. Due to the ring character of the singularity, these surfaces are natural candidates for MOTSs with toroidal topology. By adjusting and employing the numerical method of geodesics, we indeed localize MOTSs of both spherical and toroidal topology, and compare the results with those obtained previously by Jaramillo & Lousto.
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Inhomogeneous cosmological models
Vrba, David ; Svítek, Otakar (advisor) ; Pravda, Vojtěch (referee) ; Žofka, Martin (referee)
In this work we study inhomogeneous cosmological models. After a brief review of applications of inhomogeneous solutions to Einstein equations in cosmology, we give a short description of the most widely used inhomogeneous cosmological models. In the second chapter we study in detail geometrical prop- erties of the Szekeres spacetime and we are concerned with the interpretation of the metric functions in different types of geometries. In the last chapter we model inhomogeneity in Szekeres spacetime. We derive formula for the density contrast and investigate its behaviour. We also derive conditions for the density extremes that are necessary for avoiding the shell crossing singularity in Szekeres spacetime. 1
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Gravitational field of gyratons on various background spacetimes
Kadlecová, Hedvika
Title: Gravitational field of gyratons on various background spacetimes Author: Hedvika Kadlecová Department: Institute of Theoretical Physics Supervisor: doc. Pavel Krtouš, Ph.D. Supervisor's e-mail address: Pavel.Krtous@mff.cuni.cz Abstract: In this work we have found and analyzed several gyraton solutions on various non-trivial backgrounds in the large Kundt class of spacetimes. Namely, the gyraton solutions on direct product spacetimes, gyraton solutions on Melvin universe and its generalization which includes the cosmological constant. These solutions are of algebraic type II. Also we have investigated type III solutions within the Kundt class and we have found the gyratons on de Sitter spacetime. We have generalized the gyraton solutions on direct product spacetimes to higher dimensions. Keywords: Kundt class of spacetimes, gravitational waves, Einstein-Maxwell equations, NP formalism Název práce: Gravitační pole gyratonů na pozadích různých prostoročasů Autor: Hedvika Kadlecová Ústav: Institut teoretické fyziky Školitel: doc. Pavel Krtouš, Ph.D. Školitelova e-mailová adresa: Pavel.Krtous@mff.cuni.cz Abstrakt: V této práci jsme nalezli a analyzovali několik různých gyratonových řešení na různých netriviálních pozadích z široké třídě Kundtových prostoročasů:...
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