How disorderly young galaxies grow up and mature

Date:
August 27, 2021
Source:
Lund University
Summary:
Using a supercomputer simulation, a research team 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.



FULL STORY ========================================================================== Using a supercomputer 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 Monthly Notices of
the Royal Astronomical Society, researchers have been able to provide
some clarity on the matter.

"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.

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).

"With the current study and our new computer simulations we will generate
a lot of information which means we can better understand the Milky
Way's fascinating life since the beginning of the Universe," concludes
Oscar Agertz.

========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Oscar Agertz, Florent Renaud, Sofia Feltzing, Justin I Read,
Nils Ryde,
Eric P Andersson, Martin P Rey, Thomas Bensby, Diane K Feuillet.

VINTERGATAN - I. The origins of chemically, kinematically,
and structurally distinct discs in a simulated Milky Way-mass
galaxy. Monthly Notices of the Royal Astronomical Society, 2021;
503 (4): 5826 DOI: 10.1093/mnras/stab322 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210827121447.htm

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