Browsing Institutt for teoretisk astrofysikk by Issue Date
Now showing items 21-40 of 1297
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(Master thesis / Masteroppgave, 2008)Observations of how matter is distributed on different length scales in the universe are an important test of cosmological models. For example, such observations can give an upper limit for the mass of neutrinos: As the ...
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(Master thesis / Masteroppgave, 2008)In between the Cosmic Microwave Background (CMB) and the instrument there are other sources of radiation, called foregrounds. The foregrounds radiate in the same frequency bands as the background, and cause contamination ...
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(Master thesis / Masteroppgave, 2008)Observations of the Cosmic Microwave Background is impaired by other astrophysical sources that also radiate in the microwave spectrum. These other, non-CMB sources are known as foregrounds. In this thesis, three different ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2008)Conditional sampling methods are generalized by applying a matched-filter on the reference signal. This generalized method is illustrated by data obtained in a magnetized toroidal plasma without rotational transform. By ...
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(Master thesis / Masteroppgave, 2009)I have investigated the total energy of Friedmann-Robertson-Walker universes. This is an interesting issue, because if the energy of the universe turns out not to be conserved, it will be in conflict with our common ...
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(Master thesis / Masteroppgave, 2009)
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(Master thesis / Masteroppgave, 2009)The cosmic microwave background (CMB) radiation at 2.7 K is the leftover radiation from the Big Bang. By studying this radiation we can extract much information about the universe we live in. CMB experiments over the last ...
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(Master thesis / Masteroppgave, 2009)En mulig forklaring på at universet gikk inn i en fase av akselerert ekspansjon for 5-6 milliarder år siden, er at energitettheten i universet inneholder et bidrag fra et dynamisk skalarfelt. Problemet med denne forklaringen ...
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(Master thesis / Masteroppgave, 2010)The solar chromosphere is a region where the thermodynamics are out of equilibrium, and realistic values of temperature and electron densities here are difficult to obtain. Hydrogen, being the most abundant element in solar ...
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(Master thesis / Masteroppgave, 2010)The theory of inflation gives certain predictions for the amount of primordial gravitational waves compared to the amount of density perturbations. These predictions are, in principle, verifiable through observation of the ...
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(Master thesis / Masteroppgave, 2010)Neutrino cosmology is a very interesting field of research, where properties of some of the smallest constituents of the universe are probed by the very largest structures of the universe; large scale structures of the ...
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(Master thesis / Masteroppgave, 2010)The statistical analysis of the Cosmic Microwave Background radiation to make estimates of the Power Spectrum is a comutationally heavy operation, involving large covariance matrices. In this thesis I explore the possibility ...
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(Master thesis / Masteroppgave, 2010)We investigate scalar-field theories with a field-dependent coupling to matter and show the existence of a chameleon mechanism. The thin-shell solutions for a spherical body are found, and used to investigate the consequences ...
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(Master thesis / Masteroppgave, 2010)
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(Doctoral thesis / Doktoravhandling, 2010)
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(Doctoral thesis / Doktoravhandling, 2010)
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(Master thesis / Masteroppgave, 2010)In this thesis the correlation between star formation and dynamical state of a statistical well defined selection of galaxy clusters have been studied. From simulations and theory it is expected strong correlations between ...
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(Master thesis / Masteroppgave, 2011)There have been many reports on anomalies in the CMB from different research groups. In this work statistical tests using the gradients of the CMB temperature, applied to the seven year WMAP data, have been investigated. ...
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(Master thesis / Masteroppgave, 2011)Spicules are relatively small, narrow and elongated structures that stick out above the edge of the solar disk. They are very dynamic and appear as jets that shoot out into the outer solar atmosphere. Up until recently, ...
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(Master thesis / Masteroppgave, 2011)The standard model of cosmology has proven to be a great success. Through measurements of the Cosmic Microwave Background radiation, cosmologists have been able to constrain parameters such as the age and geometry of the ...