A river of stars flowing outside the galaxy has been discovered

Michelle Starr*

A stunning river of stars flowing through intergalactic space has been discovered in a galaxy cluster about 300 million light-years away from us.

Bridges like this are known as ‘star streams’. This formation, called the ‘Giant Hair Stream’, is 1.7 million light years long and is the longest river we have seen so far. And that’s not all: The pale river is the first of its kind seen outside a galaxy.

The discovery caused great surprise. In a dynamically and gravitationally complex environment such as a galaxy cluster, a weak formation such as a stellar stream is not expected to last very long. But despite everything, there it is.

The new finding could be used to study galaxy clusters and the mysterious dark matter gathering within them in more detail.

Observational astrophysicist Javier Román, who works at the University of Groningen in the Netherlands and the University of La Laguna in Spain, said: “We crossed paths with this giant stream by chance. “We were studying the halos of stars orbiting large galaxies,” he said.

Stellar streams are a common phenomenon in the Milky Way Galaxy. The streams are thought to consist of the fragmented debris of dense globular star clusters that have been torn apart by the Milky Way’s tidal forces. However, it is difficult to define it. The relationships of the stars are not immediately clear, because the distances to the stars are extremely difficult to measure; The star rivers also flow rather weakly.

This faint view of intergalactic space also makes it difficult to detect loose relationships between objects. Space is full of extremely bright objects, and the dimmer an object is, the greater the chance of missing it.

TWO TELESCOPES WERE USED TO SEARCH FOR THE ‘HAIR CLUSTER’

On the other hand, telescope technology and analysis techniques developed in recent years have also revealed things that are weaker than what we could previously detect.

This is also the case with Giant Hair Flow.

Román and his colleagues used the 0.7-meter Jeanne Rich Telescope and the 4.2-meter William Herschel Telescope to search for faint structures in the Coma Cluster, a cluster containing thousands of recorded galaxies. They were trying to study ‘galactic halos’, which consist of dark matter surrounding the scattered, spherical regions of rare stars and the crowded planes of galaxies.

THE RESULTS ARE UNEXPECTED

However, the data they obtained revealed an unexpected phenomenon: This was not a galaxy, but a long and vast belt of stars flowing between galaxies within the cluster. This belt was also distinctly different from the thin bonds that form the cosmic network that binds galaxies together in clusters. It was nothing like the stellar streams in the Milky Way and was on a much more spectacular scale.

Although they are very large and appear calm, galaxy clusters are gravitational complex environments, and the huge celestial bodies within them push and pull on each other in all directions. It is surprising that a stellar stream can persist for long periods of time in an environment like this; However, researchers realized that this environment offers us some clues about the source of the current.

Researchers ran several simulations and found that, although rare, streams like this could be created by a dwarf galaxy inside a galaxy cluster being torn apart by the gravity of larger galaxies. In cosmic terms, the current is not expected to last long; At this time in the history of the universe, we are fortunate to have the technology to see this structure as it continues to be disassembled.

RIVERS MAY ALSO BE HIDING IN OTHER CLUSTERS

However, its presence can be used to examine the environment contained in this cluster. Because galaxy clusters are weighed down with mysterious dark matter, they attract the attention of scientists investigating what this matter is made of.

Giant Hair Flow suggests that similar structures may exist in other clusters. Researchers hope to use larger telescopes to take a closer look at these massive clusters to uncover other secrets we may have missed. And to see the Giant Hair Flow itself in more detail…

“We want to observe each of the stars in and around the stream and gain more information about dark matter,” said astronomer Reynier Peletier from the University of Groningen. The research paper was published in the journal Astronomy and Astrophysics.

*Journalist.

Original article Science Alert taken from the website. (Translated by: Tarkan Tufan)