Supernovae
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. Formação e evolução de galáxias: populações estelares na Via Láctea, galáxias elípticas e propriedades de galáxias em grupos / Galaxy Formation and Evolution: From the Milky Way to Galaxies in Groups
Understanding the way galaxies form and evolve throughout the cosmic time remains one of the greatest challenges of modern cosmology. Several processes are known to play a role in the formation of galaxies, such as feedback from supernovae and active galactic nuclei, chemical and dynamical evolution and environmental effects. This thesis encompasses these pr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/03/2012
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2. Fenomenologia dos decaimentos de neutrinos de supernova / Decay phenomenology of supernova neutrinos
Here we present a study of the phenomenology of neutrinos, which starts with a model beyond the Standard Model, which generates mass and decay to neutrinos. The model was proposed by Gelmini and Roncadelli cite Gelmini: 1981, the model needs a triplet that interacts with the scaling doublet Higgs through different potential climb. The triplet also interacts
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/11/2011
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3. Neutrinos de supernova / Supernova neutrinos
Neutrinos de supernova são ferramentas fundamentais, tanto para se entender o mecanismo de explosão de supernovas e formação de núcleos pesados além do ferro, assim como para determinar propriedades ainda desconhecidas e especulativas na física de oscilação de neutrinos, como a existência de neutrinos estéreis e neutrinos com massa variável, mode
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/07/2010
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4. The cold dark matter model with cosmological constant and the flatness constraint
The Hubble parameter, a function of the cosmological redshift, is derived from the Friedmann-Robertson-Walker equation. The three physical parameters H0, Ω0m and ΩΛ are determined fitting the Hubble parameter to the data from measurements of redshift and luminosity distances of type-Ia supernovae. The best fit is not consistent with the flatness constrain
Brazilian Journal of Physics. Publicado em: 2010-12
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5. Dark Energy and The Accelerating Universe: Conceptual Aspects and Observational Tests / Energia escura e aceleração do Universo: Aspectos conceituais e testes observacionais
In the last decade, the extraordinary progress of the astronomical observations (distances with supernovas, matter and cosmic background radiation (CBR) power spectrum, X-ray surface brightness of galaxy clusters, etc) associated with important theoretical developments turned Cosmology one of the most exciting frontiers of contemporary science. In this thesi
Publicado em: 2010
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6. Quantifying the Matter Inhomogeneities with Supernovae and Gamma-Ray Bursts / Quantificando as inomogeneidades da matéria com Supernovas e Gamma-Ray Bursts
In this dissertation we study how the effects of matter (baryonic and dark) inhomogeneities modify the distances thereby affecting the determination of cosmological parameters. The inhomogeneities are phenomenologically described by the clumpiness parameter alpha and quantified through the equation distance proposed by ZeldovichKantowskiDyer Roeder (ZKDR). F
Publicado em: 2009
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7. Magnetized string cosmological model in cylindrically symmetric inhomogeneous universe with time dependent cosmological-term lambda
Cylindrically symmetric inhomogeneous magnetized string cosmological model is investigated with cosmological term lambda varying with time. To get the deterministic solution, it has been assumed that the expansion (theta) in the model is proportional to the eigen value sigma1 1 of the shear tensor sigmai j. The value of cosmological constant for the model is
Brazilian Journal of Physics. Publicado em: 2008-03
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8. Testes observacionais em modelos cosmológicos com interação vácuo-matéria.
In this work we study the observational viability of a cosmological model with vacuum-matter interaction, where the cosmological term is proportional to the Hubble parameter. Type Ia supernovae tests are performed with four diferent samples, from which we conclude that this model fits well the data, leading to an estimative of the current matter density para
Publicado em: 2008
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9. Acelaração do universo e criação gravitacional de matéria escura fria: novos modelos e testes observacionais
Recent astronomical observations (involving supernovae type Ia, cosmic background radiation anisotropy and galaxy clusters probes) have provided strong evidence that the observed universe is described by an accelerating, flat model whose space-time properties can be represented by the FriedmannRobertsonWalker (FRW) metric. However, the nature of the substanc
Publicado em: 2008
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10. Quark matter (strangelets) from astrophysical sources and its detection by terrestrial experiments. / Matéria de quarks (strangelets) de origem astrofísica e sua detecção por experimentos terrestres
The strange quark matter hypothesis, which states that a plasma composed of quarks up, down and strange in roughly equal amounts is absolutely stable at zero pressure, has been studied for more than twenty years, both theoretically and during searches for its detection in specific experiments. If strange quark matter is indeed stable, then there could be imp
Publicado em: 2008
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11. Neutrinos from supernovae / Neutrinos de supernovas
Com este trabalho buscamos entender o fenômeno de oscilações de neutrinos na matéria. Para isto, estudamos a propagação de neutrinos em Supernovas. O estudo é feito nestes objetos astrofísicos, pois são produzidos neutrinos de todos os sabores quando a estrela progenitor da Supernova é muito massiva. Além de isto, estes corpos celestes atingem den
Publicado em: 2008
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12. Decaimentos de neutrinos induzidos por escalares e aplicações a supernovas / Neutrinos decays via scalars and their applications to supernovas
In this work we study nonradiative decays of Majorona neutrinos, via massless bosons, in vacuum and matter. The considerate couplings between the neutrinos and the bosons were scalar and pseudoscalar. In particular we study the processes n i ® nj + c e n i ® n j + c (where is either scalar or pseudoscalar field). In vacuum, we calculate effective rates in
Publicado em: 2006