Effets de lentille gravitationnelle sur le rayonnement de fond cosmique

Abstract : This report will study some phenomenological aspects of the evolution of the large scale structures of the Universe, in the framework of Inflation. General Relativity predicts that the path of light beams is modified by the gravitational potential wells; this phenomenon is called gravitational lensing. We will provide a very accurate description of this effect on the cosmic microwave background radiation, its temperature and its polarization. To do so, after a few reminders on the properties of the underlying cosmological model, we will expose the calculation needed to compute the cosmic microwave background anisotropies and polarization as well as the evolution of the large scale structures. We will also give in great details the general framework of the gravitational lensing effect. With this results, we will be able to study two regimes of the lensing effect on the background radiation: one strong, where we will use a cosmic string as a lens, and one weak, generated by the large scale structures of the Universe. In this last case, we will show how the cosmic microwave background carries information regarding the history of large scale structures up to its emission epoch. We will present and evaluate a promising technique allowing to extract this information and which consists in comparing the microwave background with background galaxies surveys. We will study what this kind of quantities can teach us regarding the properties of the Universe we are living in. Finally, we will spend some time on a class of exotic cosmological models called quintessence, where the cosmological constant has been replaced by a new fluid. We will focus on the large scale structures properties in these models and on the phenomenological consequences one can expect on the gravitational lensing effect.
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Astrophysics. Université Paris Sud - Paris XI, 2001. French


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Submitted on : Thursday, March 28, 2002 - 9:49:04 AM
Last modification on : Thursday, March 28, 2002 - 9:49:04 AM

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Karim Benabed. Effets de lentille gravitationnelle sur le rayonnement de fond cosmique. Astrophysics. Université Paris Sud - Paris XI, 2001. French. <tel-00001288>

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