The nature of dark matter is still one of the most pressing open question of contemporary cosmology and physics. While making up to 80% of the matter in the Universe, it has only been indirectly observed by its properties (collisionless and cold). On small scales, the properties of dark matter can be constrained by observations of the high-redshift Universe, and in particular of the Lyman-alpha forest as well as the abundance of the first galaxies. Studying this connection using a novel simulation technique is the main focus of my thesis.
I am currently developing a finite volume hydrodynamics solver and we are combining it with an existing simulation software that uses novel phase-space tessellation techniques to model the dynamics of dark matter. This will enable us to study more accurately the combined evolution of baryons and dark matter in the high-redshift Universe than previously possible. Using these newly developed tools, in the final part of the thesis, we will investigate the accuracy of current constraints on the properties of the dark matter particles from Lyman-alpha forest observations and other small scale baryonic probes.
I’m interested in the formation of the large scale structure in our Universe using numerical simulations on cosmological scales.
After an early inflationary phase, our Universe is in a highly homogeneous state with tiny density perturbations. These density perturbations gravitationally collapse and form the structures that we can observe in our Universe today: from the temperature fluctuations measured in the Cosmic Microwave Background (CMB), to the filamentary structure of the cosmic web, individual galaxies and galaxy clusters, down to stars and planets.
Gravitational collapse is a non-linear process and requires numerical simulations to be accurately modelled. My work is mainly been in the context of large scale structure formation using numerical N-body simulations. In particular, I’m exploiting the Lagrangian mapping from coordinates in the initial condition to the late time positions and velocities to
Galaxies in our Universe are not randomly distributed, but rather follow the filamentary structure of the cosmic web. Filaments intersect in nodes which host hundreds to thousands of galaxies that are gravitationally bound to each other forming so called galaxy clusters.
These clusters of galaxies occupy a special position in the Universe’s hierarchy : they are the most massive and the largest objects that have had time to undergo gravitational collapse.
They constitute powerful cosmological probes, and from their properties we can learn a lot about the physical processes governing the evolution of our Universe.
In this context, I am particularly interested in the evolution of galaxy clusters and understanding how are they are shaped by different physical processes such as turbulence, magnetic fields and relativistic cosmic rays.
For this purpose, I am performing multi-physics hydrodynamical simulations of galaxy clusters in a cosmological environment using the RAMSES code.