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Previous issue date: 2016-03-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Grandes esfor?os observacionais t?m sido direcionados para investigar a natureza da chamada energia escura. Nesta disserta??o derivamos v?nculos sobre modelos de energia escura utilizando tr?s diferentes observ?veis: medidas da taxa de expans?o H(z) (compiladas por Meng et al. em 2015); m?dulo de dist?ncia de 580 Supernovas do Tipo Ia (cat?logo Union Compilation 2.1, 2011); e as observa??es do pico de oscila??o de b?rions (BAO) e a radia??o c?smica de fundo (CMB) utilizando a chamada raz?o CMB/BAO, que relaciona 6 picos de BAO (um pico determinado atrav?s dos dados do Survey 6dFGS, dois atrav?s do SDSS e tr?s atrav?s do WiggleZ). A an?lise estat?stica utilizada foi o m?todo do ?2 m?nimo (marginalizado ou minimizado sobre h sempre que poss?vel) para vincular os par?metro cosmol?gicos: ?m, ??, ? e ??0. Esses testes foram aplicados em duas parametriza??es do par?metro ? da equa??o de estado da energia escura, p=?? (aqui, p ? a press?o e ? ? a densidade de energia da componente). Numa, ? ? considerado constante e menor que -1/3, conhecido como modelo XCDM; na outra parametriza??o, o par?metro da equa??o de estado varia com o redshift, no qual o chamamos de Modelo GS. Esta ?ltima parametriza??o ? baseada em argumentos que surgem da teoria da infla??o cosmol?gica. Para efeitos de compara??o tamb?m foi feita a an?lise do modelo ?CDM. A compara??o dos modelos cosmol?gicos com as diferentes observa??es leva a diferentes melhores ajustes. Assim, para classificar a viabilidade observacional dos diferentes modelos te?ricos, utilizamos dois crit?rios de informa??o, ou seja, o crit?rio de informa??o bayesiana (BIC) e o crit?rio de informa??o Akaike (AIC). A ferramenta matriz de Fisher foi incorporada aos nossos testes para nos fornecer a incerteza dos par?metros de cada modelo te?rico. Verificamos que a complementariedade dos testes ? necess?ria para n?o termos espa?os param?tricos degenerados. Fazendo o processo de minimiza??o encontramos, dentro da regi?o de 1? (68%), que para o Modelo XCDM os melhores ajustes dos par?metros s?o ?m=0,28?0,012 e ?X=-1,01?0,052. Enquanto que para o Modelo GS os melhores ajustes s?o ?m=0,28?0,011 e ??0=0,00?0,059. E realizando uma marginaliza??o encontramos, dentro da regi?o de 1? (68%), que para o Modelo XCDM os melhores ajustes dos par?metros s?o ?m=0,28?0,012 e ?X=-1,01?0,052. Enquanto que para o Modelo GS os melhores ajustes s?o ?m=0,28?0,011 e ??0=0,00?0,059. / A significant observational effort has been directed to investigate the nature
of the so-called dark energy. In this dissertation we derive constraints
on dark energy models using three different observable: measurements of the
Hubble rate H(z) (compiled by Meng et al. in 2015.); distance modulus of
580 Supernovae Type Ia (Union catalog Compilation 2.1, 2011); and the observations
of baryon acoustic oscilations (BAO) and the cosmic microwave
background (CMB) by using the so-called CMB/BAO of six peaks of BAO
(a peak determined through the Survey 6dFGS data, two through the SDSS
and three through WiggleZ). The statistical analysis used was the method
of the ?2 minimum (marginalized or minimized over h whenever possible)
to link the cosmological parameter: m, ? and ??0. These tests were
applied in two parameterization of the parameter ? of the equation of state
of dark energy, p = ?? (here, p is the pressure and ? is the component of
energy density). In one, ? is considered constant and less than -1/3, known
as XCDM model; in the other the parameter of state equantion varies with
the redshift, where we the call model GS. This last model is based on arguments
that arise from the theory of cosmological inflation. For comparison it was also made the analysis of model CDM. Comparison of cosmological models with different observations lead to different optimal settings. Thus,
to classify the observational viability of different theoretical models we use two criteria information, the Bayesian information criterion (BIC) and the Akaike information criteria (AIC). The Fisher matrix tool was incorporated into our testing to provide us with the uncertainty of the parameters of each
theoretical model. We found that the complementarity of tests is necessary inorder we do not have degenerate parametric spaces. Making the minimization process we found (68%), for the Model XCDM the best fit parameters are m = 0.28 ? 0, 012 and ?X = ?1.01 ? 0, 052. While for Model GS the best settings are m = 0.28 ? 0, 011 and ??0 = 0.00 ? 0, 059. Performing a marginalization we found (68%), for the Model XCDM the best fit parameters are m = 0.28 ? 0, 012 and ?X = ?1.01 ? 0, 052. While for Model GS the best settings are M = 0.28 ? 0, 011 and ??0 = 0.00 ? 0, 059.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21086 |
| Date | 02 March 2016 |
| Creators | Moura, ?caro Kennedy Francelino |
| Contributors | 38110326404, http://lattes.cnpq.br/2463198529477607, Silva J?nior, Raimundo, 72106310463, http://lattes.cnpq.br/2680905746363331, Dantas, Maria Aldinez, 01286739403, http://lattes.cnpq.br/4109484014804133, Pires, Nilza |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM F?SICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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