New Galaxy Formation Simulations Model Cold, Dusty Gas

An international research team has released a new suite of galaxy formation simulations, named COLIBRE. The simulations model the evolution of galaxies from the first billion years after the Big Bang to the present day and incorporate the physics of cold interstellar gas and small dust grains, elements often omitted in prior large-scale models. The study has been published in the journal Monthly Notices of the Royal Astronomical Society.

Simulation Scope and Advancements

The COLIBRE simulations were created by a team led by astronomers from Leiden University. A key advancement is the direct modelling of cold, dusty gas within galaxies. Previous large-scale simulations typically imposed an artificial limit, preventing gas from cooling below approximately 10,000 degrees, despite observational evidence that stars form in colder gas environments.

The new simulations include the influence of small dust grains, which affect how hydrogen molecules form and how gas is shielded from ultraviolet radiation. According to the researchers, advances in computational algorithms and supercomputing power have enabled the use of up to 20 times more resolution elements than in earlier comparable simulations.

"Including cold and dusty gas was a component previous simulations had to ignore." — Professor Joop Schaye, Project Leader, Leiden University.

Purpose and Research Applications

The simulations are designed as a tool for astrophysicists to test theories of galaxy formation and to interpret observational data. A stated goal is to create "virtual observations" to analyze how astronomers process and understand data from real telescopes.

Co-author Dr. Aaron Ludlow of the International Centre for Radio Astronomy Research at the University of Western Australia said the work created new methods for comparing theoretical models with observations.

"Directly modelling dust, which absorbs and scatters light, provides new ways to compare simulation outputs with real astronomical images." — Dr. Aaron Ludlow.

Collaboration and Availability

The COLIBRE project is a collaboration involving researchers from multiple institutions across several countries, including:

• Leiden University (Netherlands)
• The universities of Durham, Portsmouth, Hull, Liverpool, and Nottingham (United Kingdom)
• The University of Vienna (Austria)
• The University of Milano-Bicocca (Italy)
• The University of Western Australia
• The University of Ghent (Belgium)
• The University of Pennsylvania (United States)

Images, videos, and interactive material generated from the COLIBRE simulations are publicly available online.