Research
Relativistic cosmology with an eye on observables
My work is in theoretical and numerical cosmology. Over the years I've looked at a few different ways relativity shapes what we actually observe: light propagation, weak lensing, peculiar velocities. This page gathers the main threads, past and present.
PhD thesis: EXCALIBUR
This project picks up where a master's internship left off, right before my PhD started. You can read that internship report here.
These days I'm building EXCALIBUR (Exact Calculation of Light Bending Using Relativity), which is the main thing I work on. It propagates light rays through cosmological grids using a first-order perturbed FLRW metric, with the goal of reconstructing the sky the way an observer would actually see it in a simulation.
The goal is to quantify how much relativistic effects bias the cosmological quantities we measure. Surveys are getting precise enough now that the usual approximations might not hold up.
- Ray tracing in perturbed FLRW spacetime
- Numerical lightcone construction
- Lensing and relativistic systematics
Selected research experiences
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Weak gravitational flexion in cosmological simulations
Using the Horizon-AGN simulation, I measured second-order "flexion" terms in the weak-lensing regime, to see whether these subtler distortions could sharpen our constraints on halo shapes and masses. Read the internship report.
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Fisher forecasts for peculiar-velocity surveys
At CPPM in Marseille, I ported a C++ forecasting code by Cullan Howlett to Python, mainly to make it easier to tinker with and share. It reproduced the original results, and hopefully makes life easier for whoever uses it next.
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Light propagation in inhomogeneous spacetimes
Even earlier, I worked on light propagation in Lemaitre-Tolman-Bondi spacetimes and perturbed FLRW geodesics. That project is what got me hooked on building relativistic tools for cases where our usual homogeneous intuition stops working.