My DPhil Thesis

TL;DR

A copy of my thesis can be found here. I worked on it at the University of Oxford from October 2021 to January 2026 (end of Michaelmas 2025). Some chapters contain unpublished material which (if understood to be preliminary) may be of interest to some of you. The thesis is 226 pages, contains 7 chapters, 82 figures, and 9 tables

First Paper

When I first started my degree the project that my advisor had in mind was doing dynamical modelling for a set of OASIS galaxies. OASIS was the second integral field spectrograph of Roland Bacon after TIGER (right before SAURON). Some high spatial resolution observations had been made for a number of galaxies but detailed dynamical models, including black hole masses, had never been published for them. The kinematics had already been measured so I performed JAM models for each of the galaxies. This mostly went smoothly but there were a number of galaxies that required a reanalysis of their kinematics, MGE, etc.

As a young student without much previous astrophysics experience, it felt much more feasible to first do a study of a single object, working through all of the details to understand the different codes and analysis approach, and then, with that knowledge, work on the wider set of all galaxies. The galaxy we chose was M87. At some point I had also happened upon high resolution MUSE observations that were publicly available but hadn’t been analysed. This formed the basis of my first paper and chapter 2 of my thesis.

Looking back now, this was probably the best first project I could have asked for. The reason for this is that with M87, essentially everything goes wrong with the data and the dynamical modelling. The photometry is great, but you have to subtract the AGN. The IFS data looks great, but there is lots of gas and skylines to contend with. As a result, I was able to develop a deep appreciation of the issues of working with IFS data which are easy to glance over when everything goes according to plan.

Garching bei München

Part of the funding for DPhil students is an inclusion of funds for a so-called long term attachment (LTA). This is essentially a study abroad academic exchange. I mentioned this to my advisor but he had never heard of it. The deadline to apply for this is quite soon after starting the degree so I doubted I’d manage to go for it. However, soon after mentioning it to my advisor, he mentioned he had just spoken to an old collaborator of his who was interested in working with more students. This is how I ended up in Munich at the Max Planck Institute for Astrophysics (MPA) for 6 months.

The work here ultimately became chapters 3 and 4 of my thesis. The key question was how well galaxy kinematics can be recovered in the presence of realistic systematic uncertainties. This project evolved significantly over the time I was there and I probably had a nearly complete draft of a paper 2 or 3 times before scrapping it and changing most of it.

Welcome to Beijing

Before going to MPA I had mentioned to my advisor that I was planning on visiting China and wondered if there were any natural opportunities for me there to make more of the trip. In fact, a long time collaborator of his was interested in dynamics and machine learning, a topic which almost perfectly matched the official title of my thesis (though at this point I hadn’t done any machine learning yet). I ended up visiting Tsinghua University for the year of 2024.

This proved to be a very productive time for me. I had some interesting results that I was able to present at a few conferences and in some talks across China. This ultimately became chapter 6 of the thesis and was published here.

Wrapping Up

I returned to Oxford at the start of 2025. The goal now was to finish up some key parts of my thesis and submit. There were, broadly speaking, two main things to finish. The first was a project on dynamical modelling, and the second was the introduction

The dynamical modelling took a significant amount of time as it required modifying an existing axisymmetric Schwarzschild code. This work was done in collaboration with some of the students I had met at Tsinghua University.

The introduction was, for a long time, the bane of my existence. Many introductions in papers are boring, serving only as a place to stuff citations from papers you should have read but haven’t. I struggled with writing this for several weeks before deciding I needed a new approach. I wanted to take a somewhat broader historical overview to better understand the develop of my subfield of integral field spectroscopy and dynamical modelling. I ended up finding Marcia Bartusiak’s book ‘The Day We Found the Universe.’ This dramatically turned things around for me. I quickly realised just how interesting the history of astronomy was and appreciated how many of the difficulties I had encountered understanding the astronomical literature was basically the result of a lack of good story telling. I was then able to (somewhat quickly) finish the introduction by doing a nice bit of story telling about the overall history of spectroscopy leading up to integral field spectroscopy and some of the key results discovered there.

The Defense

I had my thesis defense on February 12 2026. My examiners were Niranjan Thatte and Eugene Vasiliev. I had only briefly met Eugene once before and had never met Niranjan so I wasn’t entirely sure how things would go. The typical thesis defense in our department lasts for three hours. Mine lasted nearly five hours. I’m happy to say this was primarily due to the genuine interest of both examiners in the work I had done and interesting ideas they had for future work.

The final thesis, incorporating the excellent suggestions from my examiners, is available on this website here.