Dinâmica de espaços-tempos com simetria axial: ondas cilíndricas e colapso não-esférico

• Ano de defesa: 2018
• Autor(a) principal: Celestino, Juliana
• Orientador(a): Oliveira, Henrique Pereira de
• Banca de defesa: Jorás, Sergio Eduardo de Carvalho Eyer , Rodrigues, Eduardo Lima , Aranha, Rafael Fernandes , Skea, James Ewan Faskin
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física
• Departamento: Centro de Tecnologia e Ciências::Instituto de Física Armando Dias Tavares
• País: BR
• Palavras-chave em Português: Relatividade Numérica; Ondas Gravitacionais; Colapso gravitacional
• Palavras-chave em Inglês: Numerical Relativity; Gravitational waves; Gravitational collapse
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA GERAL
• Link de acesso: http://www.bdtd.uerj.br/handle/1/12822

The development of numerical methods and computer technology have provided a great advance in the field of General Relativity since it has made it possible to understand the nonlinear dynamics of various models interesting, for example, Bondi's study of the unambiguous description of gravitational radiation in a totally non-linear context and also the characterization of the critical phenomenon in the gravitational collapse made by Choptuik, opening the door to many inquiries in these areas. This thesis consists, in part, in the numerical investigation of concepts such as the Bondi mass and the news functions adapted to the cylindrical symmetry and , in part, consists in the investigation of the deformations of the critical solution in gravitational collapse of uids. The Bondi mass decays due to the presence of the news functions associated with the polarization modes in which we interpret each polarization as channels through which the mass is extracted. From this perspective, we present the enhancement effect of the polarization for the + mode due to the nonlinear interaction with the mode x. After discussing the behavior of matrices in cylindrical symmetry, we have extended the numerical code to include electromagnetic fields. We also perform extremely nonlinear numerical simulations to study deformations of the critical solution in gravitational collapse of fluids. Adopting a perturbative calculation, Gundlach predicted that these perturbations behave like damped or growing oscillations, with the frequency and damping (or growth) rates depending on the equation of state. We consider a number of different equations of state and degrees of asphericity and find very good agreement with the findings of Gundlach for the polar l= 2. We have found that the degree of asphericity has at most a small effect on the frequency and damping parameter, or on the critical exponents on the power law scales. Our results also confirm, for the first time, Gundlach's prediction that l = 2 modes become instinctive for equations of sufficiently fast state. In this scheme, the spherically symmetric self-similar solution can no longer be retrieved by fine-tuning at the black hole threshold, and one can no longer expect the scale of the power law to be maintained at arbitrarily small scales.