As a cosmologist, I’m interested in how the Universe works on the largest scales. The current dominant component in our Universe is dark energy, and this is the main focus of my research. Here’s a video of me giving a short introduction to my work!
Dark energy is the name given to the substance that drives the late-time accelerating expansion of the Universe. There are many theories and models that try to describe dark energy in a way that fits with observational data. The standard model of cosmology is called the ΛCDM model, where dark energy is represented by the cosmological constant, Λ, and the other dark component of the Universe is CDM, or Cold Dark Matter.
The cosmological constant is the simplest explanation for dark energy, but the model has a number of flaws that drive theorists to look for alternative explanations for the late-time acceleration. A large competing class of models are called dynamical dark energy models, where, unlike in the cosmological constant model, the dark energy does not have a constant value.
My PhD thesis mainly focused on studying interacting vacuum dark energy models, where dark energy is modelled by a dynamical vacuum energy and dark matter can decay into the vacuum. I used the numerical codes CAMB, CosmoMC and Cobaya to analyse these models and make predictions which I tested against observational data.
Towards the end of my PhD, I also worked on forecasting constraints on the distance duality relation, which tells us how luminosity and angular diameter distances are related. A violation of the relation could be a signature of as-yet-unknown physics, such as photons converting into a “dark” particle like the hypothetical axion. I worked on producing forecasts for distance duality violation using mock datasets of merging neutron stars (also known as standard sirens) and supernovae whose light had been gravitationally lensed.
You can see the talk I recorded for Cosmology from Home 2021 here, where I present the work on constraining violations of distance duality using standard sirens.
During my first postdoc, I am continuing to develop my research in all of these areas. In particular, I am interested in finding new applications for standard siren data in cosmology, especially when considering the effects of modified gravity. I am also working on the development of an enhancement of future weak lensing surveys using Einstein rings, the ring-like images created during strong gravitational lensing.