Some of the universe are built differently.
There are spirals with arms that are elegant. There are tiny blobs. There are rings with hollow centers, dim collections of stars, and other weird things.
It's not clear how galaxies get the way they do. New research gave some answers.
A team of Australian scientists used a neural network to uncover how well- structured spiral galaxies change into fuzzy, featureless lenticular and elliptical galaxies.
The research sheds light on an odd phenomenon called the morphology-density relation, which shows that elliptical and lenticular galaxies are more likely to be hanging out by themselves.
The astronomer at the University of Western Australia says there are a few different things going on when there are a lot of galaxies.
The spiral arms of the galaxies are so fragile that they can lose their gas at higher densities. They lose gas and fall into a lenticular shape. Two or more spiral galaxies crashing together to form one large elliptical galaxy is one of the causes.
The work was done using a simulation called Evolution and Assembly of GaLaxies and their Environments.
Scientists believe that EAGLE accurately reflects the evolution of the Universe. They use it as a laboratory in which they can observe changes in real-time.
The researchers let the program loose on the simulation after training it. The time it would take to classify them in the simulation was greatly reduced by the number of galaxies identified. EAGLE accurately recreates the relationship seen in the real universe.
The evolutionary paths that lead to the dominance of certain galaxy types can be observed by scientists. In high-density environments, the shapes of spiral galaxies can be changed by the interaction of two or more galaxies.
There are occasionally fuzzier galaxies in lower density regions of space. The simulation showed that when a black hole is merged, there are some things that happen. Since spiral arms can re-form in low density environments, this alone isn't enough.
Black holes are a key part of these cases. The active galactic nucleus formed when they merged gives feedback. Powerful winds and radiation from the extreme space around an actively feeding black hole blast through the galaxy stripped away the intergalactic gas around that would otherwise replenish the galactic gas and hampered its ability to re-form spiral arms.
The mechanisms are all consistent with previous theories about how the universe changes over time.
Over the years, there have been many suggestions. This is the first work that puts all of the pieces together.
The research has been published in a journal.
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