Thesis

The non-homogeneous and statistically isotropic Universe: Structure formation tools for Euclid studies

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domains:

  General Relativity | Cosmology | Astrophysics

• Supervisor:

  Antonio da Silva

• Co-Supervisor:

  José Pedro Mimoso

• Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Host Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Abstract:

  The cosmological principle is at the heart of modern cosmology. Combined with the Einstein field equations leads to the popular homogeneous and isotropic LCDM Friedmann-Lemaitre-Robertson-Walker (FLRW) models that have become the present baseline paradigm to analyze and predict large-scale cosmological datasets. The ESA/Euclid satellite mission will be able to further test this baseline paradigm over a wide range of cosmological scales with a variety of probes, and it may put in evidence that a more general class of non-homogeneous Lemaitre-Tolman-Bondi (LTB) models should be considered to accurately describe observations. To achieve its objectives, the Euclid mission will observe billions of galaxies in the visible and infrared sky for weak gravitational lensing and galaxy clustering studies. These data will be used to investigate the nature of dark energy, dark matter and gravity as well as to test the validity of the cosmological principle on a range of distance scales using survey tomographic information. This project addresses the problem of structure formation in the context of non-homogeneous LTB models. It proposes to develop ways to characterize observational signatures of these models and to confront them with future Euclid data. The project includes the development of a set of numerical tools to generate mock simulations of cosmological volumes and projected mass maps that can be used to simulate Euclid observations. The proposed approach should allow to obtain FLRW asymptotic behavior on very large scales and to model and test the transition scale between homogeneity and non-homogeneity for different LTB model hypothesis.