In the past few decades there have been an overabundance of models describing inflation, a period where the universe expands exponentially quickly. This led to the rise of the cosmological bootstrap, which aims at constraining cosmological observables in a model independent way. This is achieved by directly imposing physical principles such as unit...
In this thesis I will present work on constraining and testing cosmological models with different probes of the large scale structure of the Universe. I will introduce different large scale structure observables and discuss relevant modelling approaches. In particular, I will motivate the use of complementary probes to examine some of the tensions ...
This thesis explores the potential for probing the properties of the first stars, in particular their mass distribution, using the cosmological 21-cm signal. We begin in Part I by introducing the first stars, 21-cm cosmology, and the link between them (Chapter 1), as well as describing in detail the semi-numerical 21-cm signal simulation code 21cmS...
Jacques de Néa Skètè (†1869) est un auteur inclassable, dont l’œuvre relève de la théologie populaire. Confronté à l’héliocentrisme, traversant une véritable crise gnoséologique, il élabore une cosmologie paradoxale, à la fois morale et métaphysique. Dans celle-ci, son guide n’est ni un Père de l’Église, ni bien sûr un « physiologue », mais André l...
Over the last two decades, the standard cosmological model "Λ cold dark matter" (ΛCDM) has been firmly established by a variety of observations. Nevertheless, the nature of the dominant components of the Universe - namely dark matter and dark energy - and the process of creation of its initial conditions - namely inflation - are not yet known. Furt...
Les halos de matière noire sont des structures fondamentales en cosmologie. La complexité de leur processus de formation est une conséquence directe du caractère fortement non-linéaire de la dynamique gravitationnelle dont ils sont le produit. Ainsi, les propriétés des halos ne dépendent pas seulement des détails de leur environnement immédiat; ell...
Published in Research in Astronomy and Astrophysics
In observational cosmology, a supernova Ia is used as a standard candle in order to extend the Hubble diagram to a higher redshift range. Astrophysicists found that the observed brightness of high redshift supernovae Ia is dimmer than expected. This dimming effect is considered observational evidence for the existence of dark energy in the universe...
Jacques de Néa Skètè († 1869) est un auteur inclassable, dont l’œuvre relève de la théologie populaire. Confronté à l’héliocentrisme, traversant une véritable crise gnoséologique, il élabore une cosmologie paradoxale, à la fois morale et métaphysique. Dans celle-ci, son guide n’est ni un Père de l’Église, ni bien sûr un « physiologue », mais André ...
The great mathematician, physicist, and philosopher, Hermann Weyl, once called mathematics the “science of the infinite.” This is a fitting title: contemporary mathematics—especially Cantorian set theory—provides us with marvelous ways of taming and clarifying the infinite. Nonetheless, I believe that the epistemic significance of mathematical infi...
The Cosmic Microwave Background (CMB) is a window into the physics of the early universe, and polarization-sensitive measurements of the CMB allow us to test cosmological theories such as inflation. Achieving the required sensitivity to perform these measurements requires large arrays of highly sensitive cryogenic detectors. This thesis will discus...
