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| Author(s): |
Claiton Pimentel de Oliveira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2014-06-16 |
| Examining board members: |
Alberto Vazquez Saa;
Javier Fernando Ramos Caro;
Vilson Tonin Zanchin;
Arlene Cristina Aguilar;
Samuel Rocha de Oliveira
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| Advisor: | Alberto Vazquez Saa; Orlando Luis Goulart Peres |
| Abstract | |
Matter, accumulating around a compact object (e.g., a black hole), appears naturally in the form of a thick disk (torus) in rotation. The material of the disk can be considered as a fluid, and its hydrodynamic equilibrium structures can be obtained from the basic equations of hydrodynamics. In this work I present an extensive review of the basic theory of thick accretion disks, in the framework of the classical and relativistic theories, including an analysis of the so called marginally stable circular orbit. I formulate the problem including the torus self gravitational interaction, in which case the equilibrium structures problem becomes a free boundary problem, making it difficult getting the solutions. I revise the methods and numerical techniques used to attack this problem and I develop a numeric code, named BLATOS, that generates autogravitating tori solutions around black holes. Further, I develop a methodology for applying the nodal spectral element method to unbounded domains. The development of this new type of element, the so called infinite element, generates a natural extension to unbounded elements with asymptotic curved edges. I apply the resulting numerical solutions in the study of runaway instability, showing how the identification of the instability can be done from these solutions. The rotation law and the torus/black hole mass ratio can be changed from the numerical code in order to conduct a study of the solution space (AU) | |