Faculty of Science

Maggie Lieu

Maggie Lieu

Maggie Lieu

Research Fellow, School of Physics and Astronomy 

Not only is it rewarding to see what the students get out of the course, but also it reinforces my own understanding of these techniques which were never something I was taught but instead self-taught throughout my career. 


1. Describe your research topic in ten words or less?

Learning about our Universe from clusters of galaxies.

2. Now describe it in everyday terms?

Most galaxies orbit each other, like the planets in our solar system orbit the Sun. In our solar system the gravity of our Star keeps things in orbit, but in Clusters of Galaxies, stars contribute little. Clusters also contain gas, but the majority of a cluster is dark matter - an illusive substance that doesn’t emit or reflect light to be observed directly. We measure it’s presence from the gravitational influence it has on its surroundings. Clusters are the largest structures in our Universe. Understanding their contents in turn provides us with a better understanding of the contents of our Universe.

3. What inspired you to pursue this research area?

Cosmology is the study of the Universe. During my undergraduate, I took a class in Cosmology, and I learned that the entire Universe could be captured into just a handful of numbers. That our entire existence relies on these numbers coincidently taking the values that they take. I knew from this moment that I wanted to learn more about this, I chose to look at clusters of galaxies and their gravitational signatures because visually, these are beautiful astronomical objects to work with and the field wasn't very large so there was more opportunity for me to make an impact.

4. What are some of your day-to-day research activities?

Every day starts off with a browse of the arxiv. This is a pre-print journal website that allows me to keep up to date with the latest research developments, and typically I will read at least one paper from here. Much of my work is then analysing astronomical or simulated data, so developing code to do this. Frequently, I will be sharing ideas, results and problems in meetings with collaborators. When not coding, I will be writing the research up for publication or writing proposal research. 

5. What do you enjoy most about your research?

I enjoy the mental challenge of obtaining a successful research outcome. We are obtaining new data all the time that allows us to push our knowledge on the Universe, be it through higher resolution imaging or more data allowing us to obtain less noisy and tighter constraints on measurements we are interested in. But there is also a treasure trove of data in astronomical archives that are unexplored but can only be exploited now with the development of new algorithms and hardware.

6. How have you approached any challenges you’ve faced in your research?

I find that the best way to face a problem in my research is firstly step back from it, usually this allows you to take a new perspective on the problem when you come back to it. Secondly, is to talk about it. Talking about your research is so important not just for networking and publicising your research, but also if you are stuck on a problem, its likely that someone else has encountered a similar problem and can help you with it.

7. What questions have emerged as a result of your recent work?

Galaxy clusters have a property known as cooling time, it's a measure of the rate of gas cooling at the centre of a cluster. Clusters that have recently undergone a collision with another cluster are expected to have a low cooling time. Unfortunately, cooling time is not something we can directly measure in real observations, but we can obtain it from simulations. The question I'm currently interested in is whether we can naturally recover some variable that mimics the cooling time based on just an observation using unsupervised machine learning methods.

8. What kind of impact do you hope your research will have?

Clusters of galaxies are but one probe of cosmology, but they are the most complex to work with due to all the astrophysics that govern them. I hope that my research will enable us to better understand the astrophysics and systematics in these systems so that they can provide a robust and competitive measure of cosmology.

9. How do you link your research with your teaching?

Currently I teach Machine learning in science II which is about deep learning methods applied in science. My own research uses these techniques so I feel really fortunate to be given the opportunity to teach this course. Not only is it rewarding to see what the students get out of the course, but also it reinforces my own understanding of these techniques which were never something I was taught but instead self-taught throughout my career.

10. What one piece of advice would you give your younger, less experienced research self?

Imposter syndrome is a belief that you are not as good as people think you are. That you are only here by chance and that you will be found out at any moment. You are not the only one to feel like this, everyone does. I still feel it sometimes, but 2 post-docs later and I'm still here. My advice would be to believe in yourself.


Faculty of Science

The University of Nottingham
University Park
Nottingham, NG7 2RD