ARI PhD student Anna Durrant helps simulate formation of the Universe

The most realistic picture yet of how galaxies formed and then evolved from the beginning of time has been revealed in a suite of new, state-of-the-art computer simulations.

The simulations, published in Monthly Notices of the Royal Astronomical Society, include LJMU PhD student Anna Durrant, one of the few women in the front line of computational astrophysics.

Unlike earlier simulations, the COLIBRE 'virtual universes' model the cold gas and cosmic dust inside galaxies – the raw materials from which stars form and which strongly affect how galaxies appear to our telescopes. By including these previously missing ingredients and using far more computing power than ever before, the simulations successfully reproduce real galaxies, both in the present-day universe and in the early universe as seen by the James Webb Space Telescope (JWST).

Anna, from London, is thrilled at playing a role in a flagship international project in only the third year of her studies.  “I landed on physics at around age 13 purely because I enjoyed it so much,” says the 26-year-old. “The idea of spending my lifetime studying physics sounded brilliant. At around 15, I decided I wouldn’t be satisfied researching anything on Earth now that I knew that it was such a small part of a vast universe!” 

Mathematic modelling

With a career in Astrophysics beckoning, Anna's ability in mathematics took her to the theoretical side in her Master's degree, which exposed her to “the exciting and complicated” physics of galaxy formation, and ultimately to a PhD with Professor Robert Crain at LJMU, one of Clarivate's 'most highly-cited researchers'.

Now, the two are pushing the boundaries of human knowledge in the COLIBRE Project, an international study, which breaks new ground. Unlike earlier simulations, COLIBRE includes the physical and chemical processes to model cooler gases, which are essential in areas of star formation.

The team also simulate small dust grains, which can greatly influence galactic gas. These solid particles can help hydrogen molecules to form, which dominate the cold gas content of galaxies. The dust also shields gas from harsh ultraviolet radiation and strongly affects how galaxies appear in telescopes. By modelling dust directly, COLIBRE opens new ways to compare simulations with real data.

Added Anna: “This is my first major project. Having the opportunity to run and analyse my own simulations as well as to contribute to the release of the flagship simulations have both been invaluable for my development as a researcher.”

“I get asked all the time by my friends if thinking about galaxy formation on a daily basis means I am in a constant existential crisis, and I never really know what to say because I am constantly reminded of how enormous our universe is as well as how long its history is compared to our lifetimes.”