From Lund University [Lunds universitet] (SE) : “How disorderly young galaxies grow up and mature”

From Lund University [Lunds universitet] (SE)

27 August 2021
Oscar Agertz, associate senior lecturer
Department of Astronomy and Theoretical Physics,
Lund University [Lunds universitet] (SE)
+46 700 45 22 20

Using a supercomputer, the researchers created a high-resolution simulation.

Using a supercomputer [below] simulation, a research team at Lund University in Sweden has succeeded in following the development of a galaxy over a span of 13.8 billion years. The study shows how, due to interstellar frontal collisions, young and chaotic galaxies over time mature into spiral galaxies such as the Milky Way.

Soon after the Big Bang 13.8 billion years ago, the Universe was an unruly place. Galaxies constantly collided. Stars formed at an enormous rate inside gigantic gas clouds. However, after a few billion years of intergalactic chaos, the unruly, embryonic galaxies became more stable and over time matured into well-ordered spiral galaxies. The exact course of these developments has long been a mystery to the world’s astronomers. However, in a new study published in MNRAS VINTERGATAN – I. The origins of chemically, kinematically, and structurally distinct discs in a simulated Milky Way-mass galaxy, researchers have been able to provide some clarity on the matter.

Also in MNRAS VINTERGATAN – II. The history of the Milky Way told by its mergers.

and MNRAS VINTERGATAN III. How to reset the metallicity of the Milky Way.

“Using a supercomputer, we have created a high-resolution simulation that provides a detailed picture of a galaxy’s development since the Big Bang, and how young chaotic galaxies transition into well-ordered spirals” says Oscar Agertz, astronomy researcher at Lund University.

In the study, the astronomers, led by Oscar Agertz and Florent Renaud, use the Milky Way’s stars as a starting point. The stars act as time capsules that divulge secrets about distant epochs and the environment in which they were formed. Their positions, speeds and amounts of various chemical elements can therefore, with the assistance of computer simulations, help us understand how our own galaxy was formed.

“We have discovered that when two large galaxies collide, a new disc can be created around the old one due to the enormous inflows of star-forming gas. Our simulation shows that the old and new discs slowly merged over a period of several billion years. This is something that not only resulted in a stable spiral galaxy, but also in populations of stars that are similar to those in the Milky Way”, says Florent Renaud, astronomy researcher at Lund University.

A compact group of interacting galaxies, similar to the chaos of the early days of the Universe. Credit: (National Aeronautics Space Agency (US)/European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), AND THE HUBBLE SM4 ERO TEAM.

The new findings will help astronomers to interpret current and future mappings of the Milky Way. The study points to a new direction for research in which the main focus will be on the interaction between large galaxy collisions and how spiral galaxies’ discs are formed. The research team in Lund has already started new super computer simulations in cooperation with the research infrastructure PRACE (Partnership for Advanced Computing in Europe).

See the full article here.


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Lund University [Lunds universitet] (SE) is a prestigious university in Sweden and one of northern Europe’s oldest universities. The university is located in the city of Lund in the province of Scania, Sweden. It traces its roots back to 1425, when a Franciscan studium generale was founded in Lund. After Sweden won Scania from Denmark in the 1658 Treaty of Roskilde, the university was officially founded in 1666 on the location of the old studium generale next to Lund Cathedral.

Lund University has nine faculties with additional campuses in the cities of Malmö and Helsingborg, with around 44,000 students in 270 different programmes and 1,400 freestanding courses. The university has 640 partner universities in nearly 70 countries and it belongs to the League of European Research Universities (EU) as well as the global Universitas 21 network. Lund University is consistently ranked among the world’s top 100 universities.

Two major facilities for materials research are in Lund University: MAX IV, a synchrotron radiation laboratory – inaugurated in June 2016, and European Spallation Source (ESS), a new European facility that will provide up to 100 times brighter neutron beams than existing facilities today, to be starting to produce neutrons in 2023.

The university centers on the Lundagård park adjacent to the Lund Cathedral, with various departments spread in different locations in town, but mostly concentrated in a belt stretching north from the park connecting to the university hospital area and continuing out to the northeastern periphery of the town, where one finds the large campus of the Faculty of Engineering.

Research centres

The university is organised into more than 20 institutes and research centres, such as:

Lund University Centre for Sustainability Studies (LUCSUS)
Biomedical Centre
Centre for Biomechanics
Centre for Chemistry and Chemical Engineering – Kemicentrum
Centre for East and South-East Asian Studies
Centre for European Studies
Centre for Geographical Information Systems (GIS Centrum)
Centre for Innovation, Research and Competence in the Learning Economy (CIRCLE)
Center for Middle Eastern Studies at Lund University
Centre for Molecular Protein Science
Centre for Risk Analysis and Management (LUCRAM)
International Institute for Industrial Environmental Economics at Lund University (IIIEE)
Lund Functional Food Science Centre
Lund University Diabetes Centre (LUDC)
MAX lab – Accelerator physics, synchrotron radiation and nuclear physics research
Pufendorf Institute
Raoul Wallenberg Institute of Human Rights and Humanitarian Law
Swedish South Asian Studies Network