Andromeda Galaxy Cannibal Feast Revealed by Dark Stream

An international team of scientists, led by an astrophysicist from the University of Sydney, found Leftovers from a massive cannibalistic event far out in the Andromeda galaxy.

Tim Adams, an honors student at the University of Sydney, and Yuan Lee at the University of Auckland discovered the structure of stars. globular cluster (GC), the interior of the Andromeda Galaxy. The structure originated outside the constellation Andromeda and represents the remnants of a giant feeding event, providing evidence that galaxies bloat by consuming smaller systems.

It is unclear whether the structure is a galaxy-like body, as the observed features could be the result of the fragmentation of one large body or seven smaller bodies.

Professor Geraint Lewis, an astrophysicist at the University of Sydney, named it the GC, Durée structure, after the Welsh word for black current. The Duret structure looks like a dark stream illuminated by a star cluster that orbits differently than other star clusters in the Andromeda galaxy. It is unclear whether the structure is a galaxy-like body, as the observed features could be the result of the fragmentation of one large body or seven smaller bodies.

“Over the past few decades, we’ve noticed that galaxies are eating and growing smaller systems,” Lewis said at the University of Sydney. ‘ said Lewis. news release.

It used to be thought that galaxies grew by eating grass over time, eating small amounts of constellations. But the Daley structure suggests another type of more vigorous growth.

“Dwarf galaxy rainfall from the local universe is expected, so there will be grazing between binge feedings,” Lewis said in an email to The Epoch Times.

“But rather than billions of years of steady rain, it’s more like bursts of heavy rain during drizzles,” he said.

Epoch Times photo
An illustration depicting the motion of the Durée structure in the Andromeda galaxy. (Image credit: Professor Geraint Lewis/University of Sydney)

understanding the growth of the universe

According to Lewis, the discovery gives a clearer picture of how the universe was assembled, indicating that at least one of the universe’s larger galaxies was sporadically feeding on a smaller galaxy.

“It has opened new doors in terms of our understanding. But exactly what it tells us, I think we still need to work it out.

“From our observations, we can infer that Andromeda experienced two gluttonies.”

Lewis said they believe the most recent binge happened within the last few billion years. But he noted that the older feeding is estimated to have occurred about 8 billion years ago, although dates are difficult to pinpoint.

Lewis also hypothesizes that the event is a bit more opportunistic, because the researchers don’t recognize any particular pattern in the feeding, falling from a larger-scale mass distribution and making the Andromeda galaxy We hypothesize that it is like a small group of galaxies captured by .

the universe is around 13.7 billion years old and always ExpandingThe timing of the feeding event suggests that it may have occurred when the substances were closer together and more condensed.

“But we want to give a detailed date, because it helps clarify where things fell from,” he said.

According to Lewis, the next question is what was consumed at the feeding event? He said that Andromeda appears to have consumed a collection of things, all of which are slowly being torn apart.

Understanding life in the galaxy

Astrophysicists like Lewis observe the Andromeda Galaxy to better understand our home galaxy, the Milky Way.

Given that the Andromeda and Milky Way galaxies are similar in size, and that they share a spiral structure, the researchers say this discovery shows what the Milky Way did to achieve its large size. It is hypothesized that there is a possibility that

“What we want to know is whether the Milky Way did the same thing or different, both of which have interesting consequences for the bigger picture of how galaxies form,” Lewis said. I was.

He said that lenticular, elliptical, and irregular galaxies all grow in similar ways by eating smaller systems.

Feeding habits and even the shape of galaxies may be shaped by the environment, Lewis said, adding that some elliptical galaxies started out as spirals but changed shape after intense feeding. It is believed that, he added.

He said researchers are now realizing that the Andromeda constellation and the Milky Way galaxy are similar, but not identical.

“Andromeda looks bigger and has more, and it’s been suggested that this is just due to eating habits,” he said.

He added that the team of scientists would like to know if these gluttony events were completely random, or if Andromeda was in the right place at the right time when the food dropped. .

“As with all new discoveries, we end up with more questions than answers!” he said.

Epoch Times photo
Lewis said the new results give a clearer picture of how the universe has changed. Assembled. (Illustration by MENAHEM KAHANA/AFP via Getty Images)

Create 2D and 3D views

Lewis hopes that researchers will devise a more accurate clock that can ascertain the timing of these massive feeding events, which he argues should be included in models of how galaxies evolve. I said yes.

Lewis and his colleagues were able to create a two-dimensional view of history through the analysis of data on the velocities and chemistry of the globular clusters that make up the Durée structure.

“The speed and chemistry of GCs give us their individuality. In images, GCs appear as groups of about a million stars each, and it can be difficult to see if they are related. says Lewis.

Lewis says chemistry could provide information about which bodies may have originated together, based on similarities in their chemical features, and their velocities give details of their trajectories. said it can. He said that knowledge of GC trajectories can be used to infer whether they came from the same direction.

“Like humans, the more information we can get, the more we can learn about how things are interconnected,” he said.

Moreover, to construct a three-dimensional view of history, researchers need to understand distance.

“Astronomical distances are difficult because there are no rulers scattered throughout the universe,” Lewis said.

But Lewis said there are peculiarities in clusters of stars that can be used like standard light bulbs. He said that knowing the true brightness of these stars (which can be calibrated from nearby stars) allows accurate determination of distance.

“But even though these stars are very bright in nature, they are faint in the sky, so we need to harness the power of the Hubble Space Telescope to do these accurately,” he said.

With this information, he hopes, scientists can turn the clock back and achieve a coherent picture of when things settled down.

Lily Kelly


Lily Kelly is an Australia-based reporter for The Epoch Times covering social issues, renewable energy, the environment, health and science.