Spiral galaxies like ours can turn into fuzzy balls, and now we know how to do it

(ORDO NEWS) — Not all galaxies are the same.

There are spectacular sparkling spirals with graceful sleeves, gracefully curving into space. There are small fuzzy spots. There are strange rings with hollow centers or vague, dim clusters of stars that don’t look like galaxies at all.

How galaxies become what they are remains a mystery. But a new study has provided some answers.

Using a neural network, a group of Australian scientists have discovered how well-structured spiral galaxies turn into fuzzy, featureless lenticular and elliptical galaxies that don’t have arm structures.

In particular, the study sheds light on a previously unexplained bizarre phenomenon known as the morphology-density relationship: lone galaxies hanging by themselves like the Milky Way are more likely to be spirals, while galaxies in clusters tend to be lenticular or elliptical.

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How the neural network classified the galaxies in the simulation

“We found that when we collect a large number of galaxies, several different things happen,” says astronomer Joel Pfeffer from the University of Western Australia. International Center for Radio Astronomy Research (ICRAR).

“Spiral arms of galaxies are very fragile, and as density increases in galaxy clusters, spiral galaxies begin to lose their gas. This loss of gas causes them to “shed” their spiral arms into a lenticular shape.

Another reason is the merger of galaxies, in which two or more spiral galaxies collide with each other, subsequently forming one large elliptical galaxy.

The work used a project called the Evolution and Assembly of Galaxies and Their Environments (EAGLE), a sophisticated simulation designed to further understand the formation and evolution of galaxies.

Since EAGLE matches observations exactly, scientists are confident that it accurately reflects the actual evolution of t He is the Universe. They use it as a laboratory where they can observe changes that take too long in real time to be seen in action.

The researchers trained an algorithm to recognize galaxies based on their shape and let it run freely on the simulation.

The algorithm identified 20,000 galaxies per minute, greatly reducing the time it would take to classify them in a simulation.

They found that EAGLE accurately recreated the relationship between morphology and density observed in the real universe.

Scientists could then observe evolutionary paths leading to the dominance of certain types of galaxies in different environments.

In high density environments, gravitational interactions and collisions between galaxies change the shape of spiral galaxies, creating more lenticular and elliptical galaxies.

The neural network also identified random, blurrier galaxies in lower density regions. space too. Simulations have shown that this happens when galaxies with supermassive black holes at their respective centers merge.

This alone is not enough to change the shape of a galaxy, as the spiral arms can reform in low-density environments.

In these cases, supermassive black holes play an important role. key role. When they merge, they form an active galactic nucleus, providing the so-called feedback.

Powerful winds and radiation from extreme space around the actively feeding black hole sweep through the galaxy, carrying around intergalactic gas that would otherwise replenish the galactic gas and limiting its ability to reshape the spiral arms.

The researchers say all of these mechanisms are consistent with previous theories about how galaxies change over time, unifying them into a larger picture of galactic interaction and evolution.

“There were a lot of offers over time,” Pfeffer says. “But this is the first work that really puts all the pieces of the puzzle together.”

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