Scientists find the longest stellar stream

Scientists found a stellar stream in the Coma Cluster of galaxies, the length of which is 10 times the diameter of the Milky Way. It hangs in the intergalactic space between several large star systems.

Intergalactic stellar stream. Source: William Herschel Telescope/Román et al

Stellar stream in the Coma Berenices cluster

Scientists discovered a stellar stream hanging in intergalactic space like a giant ribbon. It was discovered almost by accident when they were studying the giant Coma Cluster of galaxies. Stellar streams, that is, bands that consist of stars but lie far away in intergalactic space, have been known for a long time, but only near the Milky Way.

It is believed that these structures are constantly formed when a large galaxy tears a smaller one to pieces. They should be a common phenomenon in space, but they have not been seen at great distances so far.

The first observations that made it possible to discover the stream were made using a relatively small 70-centimeter telescope by astronomer Michael Rich in California (USA). Next, the researchers focused the 4.2-meter William Herschel telescope (La Palma, Spain) on this area. After processing the image, they saw an extremely weak stream, the length of which was 10 times the length of the Milky Way.

Amazing intergalactic structure

The Coma Cluster got its name from the constellation Coma Berenices, where it is located. According to the latest data, it includes up to 11 thousand galaxies, and the distance to it is 300 million light-years. Among systems of this size, it is the most studied.

The cluster was discovered in 1933 by Swiss astronomer Fritz Zwicky. He drew attention to the huge number of galaxies concentrated in this area and came to the conclusion that they formed a single system. Later, analyzing their movement, he first suggested the existence of dark matter.

Actually, scientists discovered a new stellar stream quite by accident. They were studying halos, i.e., the scattered spherical components of galaxies, in search of answers regarding dark matter when they saw this extremely dim structure. It is very vulnerable to gravitational forces. Therefore, the fact that it is hanging in the middle of the cluster is very surprising to them.

According to

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