Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 56 for “"Cosmic Microwave Background (CMB)"”.
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Perturbações das equações de Einstein-Boltzmann e suas aplicações à radiação cósmica de fundo
… the basics of the new and growing topic of cosmic microwave background (CMB) physics. We present the fundamental concepts, principles and results related with this problem. Since the relevant equations are essentially the Einstein-Boltzmann perturbed equations, a great part of this work is …
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Dark energy and CMB anisotropy
… to the WMAP and earlier COBE observations, the Cosmic Microwave Background (CMB) anisotropy power on large angular scales appears to be significantly lower than predicted by the standard model of cosmology. We propose a scalar field model of the dark energy as a mechanism for suppressing low l …
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Solving the system of atomic rate equations during recombination
… at z ~ 800 - 1800 induces distortions to the Cosmic Microwave Background (CMB) spectrum. We present a careful calculation and analysis of all of the main transitions occurring during this period in order to find the electron density throughout recombination and its dependence on each process. …
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Spectator fields and their imprints on the Cosmic Microwave Background
… the spectator, may leave its impact on the Cosmic Microwave Background (CMB) radiation and be consequently constrained. We first introduce the observables of the CMB, namely the power spectrum Pζ , spectral index ns and its running dns/d ln k, the non-Gaussianities fNL, gNL and τNL, and the …
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Hi-line mapping of large-scale structures in the zone of avoidance
… the dynamics in the nearby Universe and the Cosmic Microwave Background (CMB) dipole. While this survey is supposed to cover the whole sky, it excludes the inner ZoA because of difficulties in detecting galaxies due to the heavy obscuration caused by dust and stellar crowding. The lack of …
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The Weak Lensing Hat-Trick: Constraining Cosmology with Galaxy, CMB, and Kinematic Lensing
… of millions of galaxies and high-resolution microwave sky maps, but also create challenges in terms of exquisite systematics control. In this thesis, I will present how weak lensing, combined with other probes, can play a crucial role in mitigating systematics and understandingdark energy and …
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Results from the QUIET Q-Band Observing Season
… is designed to measure the polarization of the Cosmic Microwave Background (CMB) in the Q and W frequency bands (43 and 95 GHz respectively) using coherent polarimeters. From 2008 October to 2010 December, data from more than 10,000 observing hours were collected, first with the Q-band receiver …
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Cosmic acceleration and the coincidence problem
… including Type Ia Supernovae (SNIa), the Cosmic Microwave Background (CMB), Large Scale Structure (LSS), and Weak Lensing (WL). This confirmation however, lacks a fundamental physics explanation. The hypothetical form of energy termed 'dark energy' (DE) assumed to account for that …
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Relativistic corrections to weak lensing convergence
… universe. Many cosmological observations of the Cosmic Microwave Background (CMB), Baryon Acoustic Oscillation (BAO) and weak lensing have been carried out to try to understand the nature of this repulsive dark force. With the advent of advanced experiments like the Square Kilometer Array we …
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Bayesian modeling of microwave foregrounds
… to new limits. Since the discovery of the cosmic microwave background (CMB) radiation in 1965 by Penzias and Wilson, precise measurements of various cosmological parameters have provided a glimpse into the dynamics of the early Universe and the fate that awaits it in the very distant …
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Inhomogeneities in the early universe from the configuration space perspective
… these solutions to analyze the anisotropy of the cosmic microwave background (CMB) radiation. In particular, we observe that wavefront singularities in Green's functions cause temperature anti-correlation for two regions that just established an acoustic contact. The experimental signature of this …
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Exploring The Universe With The Atacama Cosmology Telescope: Polarization-Sensitive Measurements Of The Cosmic Microwave Background
… the past twenty-five years, observations of the Cosmic Microwave Background (CMB) temperature fluctuations have served as an important tool for answering some of the most fundamental questions of modern cosmology: how did the universe begin, what is it made of, and how did it evolve? More …
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Design and Analysis of the Optical Beam Combiner and Corrugated Feed Horns for the QUBIC Instrument
… B-modes in the polarisation pattern of the Cosmic Microwave Background (CMB). These primordial B-modes are extremely faint and unprecedented levels of sensitivity will be required to detect them. The QUBIC (Q & U Bolometric Interferometer for Cosmology) instrument, first proposed in 2008 and …
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Quasi-Optical Design and Analysis of a Bolometric Interferometer for Cosmic Microwave Background Radiation Experiments
… a group met to propose the idea of observing the Cosmic Microwave Background (CMB) in order to determine its polarisation properties, i.e. E- and B-modes. B-modes, a smoking gun for inflation theory, are a long sought after observation for cosmologists. From this the QUBIC collaboration was born. …
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Design and Analysis of Telescope Receiver Systems for Future Far-Infrared Missions
… of this thesis is the design and analysis of the Cosmic ORigins Explorer (CORE) telescope, a proposed mission for the ESA M5 mission call. Its focus was the study of the Cosmic Microwave Background (CMB), particularly its polarisation. An ambitious space mission, it would endeavour to detect …
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Analysis and Measurement of Horn Antennas for CMB Experiments
… and sub-millimetre wave horn antennas for Cosmic Microwave Background (CMB) experiments is presented. This computational work particularly concerns the analysis of the multimode channels of the High Frequency Instrument (HFI) of the European Space Agency (ESA) Planck satellite using mode …
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Rayleigh scattering of the Cosmic Microwave Background: Towards a first detection with the next generation of surveys.
The cosmic microwave background (CMB) has been a treasure trove for cosmology. CMB experiments such as Planck have put stringent constraints on the now standard model for Cosmology: ΛCDM. Over the next decade, current and planned CMB experiments are expected to exhaust nearly all primary CMB …
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High-Resolution CMB Bispectrum Estimator
The Cosmic Microwave Background (CMB) is one of the most valuable probes of the universe we have today. Anisotropies present in the ancient light contain rich statistical information about the perturbations in the early universe and their subsequent evolution until now. The CMB bispectrum, the …
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Primordial Nucleosynthesis in the New Age of Cosmology: Determining Uncertainties, Examining Concordance, and Probing New Physics
… probe of the universal baryon density. Recent cosmic microwave background (CMB) anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a …
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Primordial Nucleosynthesis In The New Age Of Cosmology: Determining Uncertainties, Examining Concordance, And Probing New Physics
… probe of the universal baryon density. Recent cosmic microwave background (CMB) anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a …
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