Chandra discovers galaxy cluster with intersecting streams

20 Sep. (OTR/PRESS) –

Astronomers using NASA’s Chandra X-ray Observatory have discovered that a galaxy cluster has two streams of superheated gas passing each other.

This result shows that the crossing of the currents can lead to the creation of a new structure.

Researchers have discovered a huge, comet-like tail of hot gas stretching over 1.6 million light-years, trailing behind a galaxy within the galaxy cluster called Zwicky 8338 (Z8338 for short). This tail, which was generated when the galaxy lost some of its gas to the hot gas it passed through, has split into two streams, NASA reports in a statement.

This is the second pair of tails trailing behind a galaxy in this system. Previously, astronomers They discovered a pair of shorter tails from a different galaxy near the latter. This newer, longer set of tails was only seen due to a deeper observation with Chandra that revealed fainter X-rays.

Astronomers now have evidence that these streams trailing behind fast-moving galaxies have passed each other. Z8338 is a chaotic landscape of galaxies, superheated gas, and shock waves (similar to the sonic booms created by supersonic jets). in a relatively small region of spaceThese galaxies are moving because they were part of two galaxy clusters that collided with each other to create Z8338.

The galaxy cluster Z8338 and its tangle of galactic streams are located about 670 million light-years from Earth. In 2023, a paper describing these results appeared in Monthly Notices of the Royal Astronomical Society.

This new composite image shows just such a spectacle. Chandra X-rays (shown in violet) outline the multimillion-degree gas that overwhelms all of the cluster’s galaxies. The Chandra data also show where this gas has been flung out behind the moving galaxies. Meanwhile, an optical image from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile shows the individual galaxies scattered across the same field of view.

The original gas tail discovered in Z8338 is about 800,000 light-years long and appears vertical in this image (see labeled version). Researchers believe that the gas in this tail is being stripped away from a large galaxy as it travels through the galaxy cluster. The head of the tail is a cloud of relatively cold gas about 100,000 light-years away from the galaxy from which it was torn away.This tail is also separated into two parts.

The team proposes that the tail stripping from the large galaxy may have been caused by the passage of the other, longer tail. Under this scenario, the tail was torn off from the galaxy due to the crossing of the currents.

The results provide useful information on the shedding and destruction of colder gas clouds like those seen at the head of the detached tail. This work demonstrates that the cloud can survive at least 30 million years after breaking off, time during which a new generation of stars and planets could form inside it.