NASA’s Chandra discovers galaxy cluster crossing river

Credits: X-ray: NASA/CXC/Xiamen University/C. Ge; Optics: DESI Collaboration; Image Processing: NASA/CXC/SAO/N. Wolk
Astronomers using NASA’s Chandra X-ray observatory have discovered two intersecting streams of superhot gas in a cluster of galaxies, a finding that suggests the intersection of gas streams could lead to the formation of new structures.
Researchers have discovered a huge, comet-like tail of hot gas stretching more than 1.6 million light years behind a galaxy in a galaxy cluster called Zwicky 8338 (or Z8338 for short). The tail was created when the hot gases passing by the galaxy at high speed stripped some of the gas away, splitting it into two streams.
This is the second pair of tails to follow a galaxy in this system. Previously, astronomers had found a shorter pair of tails from another galaxy closer to this latest one. This new, longer pair of tails was only discovered through more detailed observations by Chandra, which revealed fainter X-rays.


Researchers have discovered a second set of tails trailing behind a galaxy in this cluster. Previously, astronomers had found two sets of shorter tails from another galaxy closer to this newest galaxy. The new, longer tails were only discovered when more detailed Chandra observations revealed weaker X-rays that were visible in the optical data. These tails extend for more than a million light-years and will help determine the evolution of the cluster. Credits: X-ray: NASA/CXC/Xiamen University/C. Ge; Optical: DESI Collaboration; Imaging: NASA/CXC/SAO/N. Wolk
Astronomers now have evidence that these streams, flowing behind fast-moving galaxies, have crossed each other. Z8338 is a chaotic mess of galaxies, superheated gas, and shock waves (similar to the sonic booms produced by supersonic jet planes) in a relatively small region of space. The galaxies are moving because they were part of two clusters of galaxies that collided with each other to form Z8338.
The Z8338 galaxy cluster and its flowing collection of galaxies are located about 670 million light-years from Earth. A 2023 paper describing these results was published in the Monthly Notices of the Royal Astronomical Society.
This new composite image shows the scene. X-rays from Chandra (shown in purple) outline millions of degrees of gas that is more massive than all the galaxies in the cluster. The Chandra data also show where this gas was ejected behind the moving galaxy. Meanwhile, optical images from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile show individual galaxies scattered across the same field.
The original gas tail discovered in Z8338 is about 800,000 light-years long and appears vertical in this image (see labeled version). Researchers think that the gas in this tail was ripped off from the larger galaxy as it passed through a galaxy cluster. The tip of the tail is a cloud of relatively cool gas about 100,000 light-years away from the galaxy that ripped it off. This tail also splits into two parts.
The team proposes that the tail may have separated from the larger galaxy due to the passage of another long tail: In this scenario, the tail separated from the galaxy due to crossing streams.
The results provide useful information about the break-off and destruction of cold gas clouds such as those seen at the tip of the broken-off tail. The study shows that the clouds can persist for at least 30 million years after break-off, during which time a new generation of stars and planets could form within them.
Source: NASA’s Chandra discovers galaxy clusters crossing streams (September 19, 2024) Retrieved September 19, 2024 from https://phys.org/news/2024-09-nasa-chandra-galaxy-cluster-streams.html
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