Summary:

What does an accurate model of the universe consist of? First, it must rely on the correct fundamental laws of physics, as we know them today. Second, because we only observe the universe from a specific vantage point at a specific time in its history, we need to make some assumptions about the symmetries and large-scale
properties of the universe to be able to extrapolate from our observations to what distant regions of the universe might look like. Finally, once the theatre has been set by the fundamental laws and the cosmological hypotheses, we need to describe all the observations we make in models that are detailed enough to not introduce theoretical biases in our interpretation and analysis of observations. This accurate modelling of small but subtle effects is also essential to help uncover new phenomena by pointing to observables challenging minute aspects of the model.
Over the years, I have been involved in investigating all three of these pillars of cosmology with a constant focus on trying to test their limits and robustness. In this defence, I will specifically focus on:
1. tests of the cosmological principle;
2. light propagation in a lumpy universe;
3. line-of-sight effects in strong gravitational lensing.

For more information please contact Larena J.