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Author : Tommaso Giannantonio
Release : 2008
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Kind : eBook
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Book Synopsis Constraining Cosmological Models with Cosmic Microwave Background Fluctuations from the Late Universe by : Tommaso Giannantonio
Download or read book Constraining Cosmological Models with Cosmic Microwave Background Fluctuations from the Late Universe written by Tommaso Giannantonio. This book was released on 2008. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Gabrielle Simard
Release : 2018
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Book Synopsis Constraining Cosmological Parameters with Gravitational Lensing of the Cosmic Microwave Background by : Gabrielle Simard
Download or read book Constraining Cosmological Parameters with Gravitational Lensing of the Cosmic Microwave Background written by Gabrielle Simard. This book was released on 2018. Available in PDF, EPUB and Kindle. Book excerpt: "The cosmic microwave background (CMB) anisotropies are a direct probe of early Universe physics. They also carry information about the late Universe through different secondary effects, including gravitational lensing. Propagating away from the last scattering surface, the primary CMB photons are deflected by the intervening large-scale structure, creating slight distortions in the CMB radiation temperature and polarization patterns that can be detected statistically. In this thesis, we present constraints on the parameters describing our Universe on cosmological scales obtained with the use of CMB gravitational lensing measurements. We begin with a description of the current cosmological model and follow with a review of gravitational lensing effects on the CMB observables.We then present bounds on cosmological parameters set by the lensing power spectrum estimated from a combined SPT+Planck CMB temperature map on the SPT-SZ 2500 square-degrees patch of sky.Adding lensing information to primary CMB data helps tightening constraints on cosmological parameters affecting late-time growth, such as the matter fluctuation amplitude today, the spatial curvature and the sum of neutrino masses.Measurements of the CMB polarization sourced in the early Universe are hindered by the additional polarization created by the gravitational lensing deflections; this contaminating lensing signal can be estimated and removed. We discuss projected constraints on the scale-dependence of the primordial CMB polarization signal assuming that the lensing induced contamination can be subtracted through different scenarios." --
Author : Silvia Galli
Release : 2011
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Book Synopsis Constraining the Thermal History of the Universe with the Cosmic Microwave Background by : Silvia Galli
Download or read book Constraining the Thermal History of the Universe with the Cosmic Microwave Background written by Silvia Galli. This book was released on 2011. Available in PDF, EPUB and Kindle. Book excerpt: The excellent agreement between the Standard Model of Cosmology and the recent measurements of the Cosmic Microwave Background (CMB) permits to constrain a wide range of physical processes. In particular, in this thesis we exploit the remarkable agreement between the theoretical description of the recombination process, occurring at z~1000, and the CMB data to severely constrain phenomena that affect the evolution of the thermal history of the universe. This contributes answering some important issues still unsolved in the standard model of cosmology. We first address the problem of the nature of dark matter. An extra energy injection due to dark matter annihilation during the epoch of recombination would affect the shape of the CMB power spectra. This allows to constrain dark matter properties using the CMB. The second question regards the validity of conventional physics to describe the Universe. New fundamental theories might predict the space-time variation of fundamental 'constants'. In this thesis we test the constancy of the gravitational constant and of the fine structure constant using the CMB. The third question concerns the characteristics (and in particular, the evolution) of dark energy. The information that can be extracted from the CMB is limited, making necessary the use of complementary probes that can break degeneracies between parameters. This is the case for the evolution of the dark energy equation of state with time, that the CMB can only weakly constrain. We thus show how the observation of clusters of galaxies combined with CMB can be a powerful tool to constrain dark energy.
Author : Amedeo Balbi
Release : 2008-10-16
Genre : Science
Kind : eBook
Book Rating : 283/5 ( reviews)
Book Synopsis The Music of the Big Bang by : Amedeo Balbi
Download or read book The Music of the Big Bang written by Amedeo Balbi. This book was released on 2008-10-16. Available in PDF, EPUB and Kindle. Book excerpt: Ever since its infancy, humankind has been seeking answers to some very basic and profound questions. Did the Universe begin? If it did, how old is it, and where did it come from? What is its shape? What is it made of? Fascinating myths and brilliant in- itions attempting to solve such enigmas can be found all through the history of human thought. Every culture has its own legends, itsownworldcreationtales,itsphilosophicalspeculations,itsre- gious beliefs. Modern science, however, cannot content itself with fanciful explanations, no matter how suggestive they are. No- days, our theories about the Universe, built upon rational ded- tion, have to survive the hard test of experiment and observation. Cosmology, the science which studies the origin and evo- tion of the Universe, had to overcome enormous dif?culties before it could achieve the same level of dignity as other physical dis- plines. At ?rst, it had no serious physical model and mathematical tools that could be used to address the complexity of the problems it had to face. Then, it suffered from a chronic lack of experim- tal data, which made it almost impossible to test the theoretical speculations. Given this situation, answering rigorously the many questions on the nature of the Universe seemed nothing more than a delusion. Today, however, things have changed. We live in the golden age of cosmology: an exciting moment, when, for the ?rst time, we are able to scienti?cally understand our Universe.
Author : Norma G. Sànchez
Release : 2012-12-06
Genre : Science
Kind : eBook
Book Rating : 585/5 ( reviews)
Book Synopsis The Early Universe and the Cosmic Microwave Background: Theory and Observations by : Norma G. Sànchez
Download or read book The Early Universe and the Cosmic Microwave Background: Theory and Observations written by Norma G. Sànchez. This book was released on 2012-12-06. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the Daniel Chalonge School on Astrofundamental Physics is to contribute to a theory of the universe (and particularly of the early universe) up to the marks, and at the scientific height of, the unprecedented accuracy, existent and expected, in the observational data. The impressive development of modern cosmology during the last decades is to a large extent due to its unification with elementary particle physics and quantum field theory. The cross-section between these fields has been increasing setting up Astrofundamental Physics. The early universe is an exceptional (theoretical and experimental) laboratory in this new discipline. This NATO Advanced Study Institute provided an up dated understanding, from a fundamental physics and deep point of view, of the progress and key issues in the early universe and the cosmic microwave background: theory and observations. The genuine interplay with large scale structure formation and dark matter problem were discussed. The central focus was placed on the cosmic microwave background. Emphasis was given to the precise inter-relation between fundamental physics and cosmology in these problems, both at the theoretical and experimental/observational levels, within a deep and well defined programme which provided in addition, a careful interdisciplinarity. Special sessions were devoted to high energy cosmic rays, neutrinos in astrophysics, and high energy astrophysics. Deep understanding, clarification, synthesis, careful interdisciplinarity within a fundamental physics framework, were the main goals of the course.
