Thesis

Cosmological tests of gravity theory beyond General Relativity

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domains:

  General Relativity | Astrophysics | Cosmology

• Supervisor:

  Noemi Frusciante

• Co-Supervisor:

  Francisco Lobo

• Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Host Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Abstract:

  An outstanding problem faced by modern cosmology concerns cosmic acceleration, i.e. the phase of accelerated expansion recently entered by the Universe, for which we still lack a satisfactory theoretical explanation. Within the context of General Relativity, an accelerated expansion can be achieved adding an extra ingredient in the energy budget of the Universe, commonly referred to as dark energy. A different approach is to modify the law of gravity describing the Universe at large scales. A plethora of modified gravity models addressing the phenomenon of cosmic acceleration have been proposed and analyzed. The astronomical community has embarked on an intense observational effort to help exploring the real nature of the cosmic acceleration. Up and coming missions will deliver highly accurate data, offering an unprecedented insight into gravity on cosmological scales. This observational effort is not yet balanced by an equally focused effort at theoretical modeling. The ability to constrain various properties of cosmological models using observational data, such as the anisotropies of the cosmic microwave background, the large scale structure of the galaxy distribution, the expansion and acceleration rate of the universe and other such quantities, has become an essential part of modern cosmology. The goal of the PhD project will be to unveil the real nature of the theory of gravity. To achieve this, the student will apply theoretical modeling and numerical methods to the best data available and perform forecasts for future next generation surveys. Development of this project is required for several reasons 1) new theoretical models need to be built; 2) new numerical patches need to be developed which serve to test models against cosmological observations. The analysis tools developed by the student are expected to be used in the upcoming ESA Euclid mission in which the host institution has a leading role. In order to ensure a successful PhD, this project contains theoretical and numerical elements that are flexible such that they can fit with the student’s skills and expertise.